Why some plants are annuals while some are perennials?

The term “Life cycle” counts every event starting from single celled embryo till the organism reach its maturity and finally integrated into Mother Earth. The long journey is parted into various stages. Reproduction is a complex process by which all living beings on earth perpetuate their species. 

Life cycle of flowering plants has different phases like seed germination, then seedling, plantlet and a mature plant. This covers the vegetative phase where all input is invested in building plant body. A transition of vegetative phase into reproductive phase is experienced by a surge in floral hormones. Pollination in flowers result in fruits having seeds that are dispersed by various agents. The dispersed seeds germinate and develop into a new mature plant. 

Reproduction in plant kingdom is a scheduled process. Reproductive event is scheduled such that plantlets gain maximum chances of survival. This is with respect to competitors for sunlight, water, soil and low predator pressure from grazing animals. 

Flowering plants are classified as annuals, perennials, biennials. This classification applies to herbaceous plants while woody trees lie in separate category. Annuals complete their life cycle in single season leaving seeds as dormant kernels. The entire plant body including leaves, roots and stems wither away. The seeds start next generation on advent of favorable environmental conditions. Annuals concentrate their entire energy in building the plant body, reproduction and amplifying their number. This behavior where an organism reproduces for single time throughout its life cycle is called monocarpic or semelparous. Biennials take two years to complete their life cycle. During the first year they grow having leaves in a rosette and during second year of their life cycle, energy is invested for stem elongation, blooming and bearing fruits. After flowering they die off. In contrast, perennials are long living plants and tend to blossom during short period in a particular season. This behavior where an organism reproduces multiple times during its lifetime is called polycarpic behavior. Life cycle of perennials lasts from three to five years. Perennials are best garden fences since the plant body survives over a long period and minimizes the replanting issues to gardeners. 

Reproductive transit

Transition of vegetative phase to flowering is critical in angiosperms. Timeline for this transition changes with genus and is operated by a developmental switch. In annuals this developmental switch operates for a single time throughout their life cycle. 

In plants, growth is not uniform and is concentrated in areas of meristem. On advent of flowering phase, apical meristems differentiate into floral tissues. The floral organs vary among different plant species. Few plants bear single flowers while few bear inflorescence. 

In annuals like cereal crops, flowers are borne on inflorescence that develop to panicle bearing grains. The plant body starts to deteriorate as the panicle starts developing and sooner plant body senesces off. 

Differentiation of apical meristem into inflorescence is suspected to switch alternative pathways promoting burning off the aerial plant parts. The possible reason for this programmed senescence could have been “big fatal” reproduction. Fecundity in monocarpic plants is at the maternal cost of investment. Most of the energy is invested in producing masses of offsprings. However, energy per individual offspring is always low and ignorable because of the high numbers borne on inflorescence. 

This raised doubts on diversion of energy depots from apical growth towards building the floral set up. Metabolic pathways activated during flowering were well studied in the model plant Arabidopsis thaliana. It was observed that vegetative tissues were supplied the least energy and major part of energy resources are diverted as material supply for grain fill in panicles. Lipid mobilization, protein and nucleic acid hydrolysis were reported in somatic tissues of Arabidopsis thaliana post flowering. Fruit development might have been triggering a block in vascular supply so that somatic tissues are deprived of nutrients and result in senescence of aerial parts. 

All the major cereals are annual crops. It is common that we notice farmers cutting heaps of grain filled panicles right from stem length and land is well ploughed for new season. If rice had been a perennial plant it would have decreased the ploughing, tilling, sowing cost for farmers but that never happens.

Transition of meristem is not the same in perennials as seen in annuals. Perennials maintain vegetative growth even after flowering. Flowering is not limited to single time. Either only selective meristems transform to floral organs or few meristems gain the ability to revert back as vegetative tissues after flowering. Enough knowledge about meristem allocation and reversion abilities is not known so far. Studies aiming meristem fate and underlying molecular mechanisms can be helpful in understanding reproductive strategies in evolutionary mechanisms of angiosperms. 

Meristem transition studies in two close relatives of Brassicaceae

Arabidopsis thaliana and Arabidopsis alpina are members of Brassicaceae family with varied habits of flowering, one being monocarpic and other polycarpic respectively. Stems of A. thaliana wither away soon after its first flowering while A. alpina is a perennial. It was found that A. alpina retains some shoot apical meristems (SAM) from floral differentiation. Because A. alpina requires vernalization, researchers have even attempted to increase the time of vernalization so that all the SAM can undergo floral transition and turn to inflorescence. 

An interesting observation was that few meristems refrained themselves and remained vegetative. It is well known that tissues retaining vegetative nature is not solely linked to cell division or growth. Tissues remain vegetative only if they maintain the vascular regularity. Perennials maintains connectivity with vascular bundles so the secondary growth is not hampered throughout their life time. 

Choosing parity as a strategy to avoid climate extremes

Few researchers believe the existence of monocarpic and polycarpic states in nature as an adaptive strategy to avoid harsh environments. 

Annual plants could have evolved from perennial plants as an adaptive strategy under unexpected climatic conditions. Extreme arid climate and frequent disturbances in localized ecology are believed to impose pressure on perennials to start annual behavior. 

From plants perspective it is better to produce maximum possible offspring before the arrival of harsh season. Investing energy on next generation is better choice than investing the same on defense mechanisms. This could also be a possible reason for species variation in parities from different locations on earth. 

Within the same species some variants are annual while some are perennials along different latitudes and longitudes of globe. For example, Snapdragon can survive as perennial in warmer regions while it is strict annual plant in polar regions in order to avoid harsh winter. 

As a supportive factor for this strategy, biologists state that monocarpic behavior might have evolved in species having least chances of survival after reproduction. When the adult survival chances drop down, it’s worthy to invest maximum energy for the next generation so the species continuity is maintained. 

This behavior is also noted in animals where the terminology differs saying it as semelparous and iteroparous. Few invertebrates, spiders, some species of marsupials are semelparous and die after reproduction. While iteroparous behavior defines a continued life time even after reproduction. However, iteroparous or perennial behavior (in case of plants) does not ensure a long life time. 

For example, bamboo grows to its maximum size for years and flowers gregariously producing masses of fruits and finally aerial parts of plant deteriorate. Bamboo do not complete its life cycle in a year hence it is not an annual. Either it is not surviving after its first reproduction. So, being a perennial does not ensure the plant to produce multiple generations of offsprings in repeated cycles of reproduction. However, in the present case, bamboo plants mass blossom at same time giving dozens of fruits that are left even after being eaten by rodents and birds. Though the adult stalks and culms deteriorate there exists a guarantee for the new stalks to sprout out. 

Although bamboo cannot be confused as semelparous, it does not ensure for being iteroparous too. It can be understood as prolonged semelparity or iteroparity on short term. 

Nature holds a number of similar examples in cases of Agave, Yucca where plant body is perennial however flowering follows a monocarpic phenomenon. This cannot be confused as a continuance of life cycle from semelparity towards iteroparity. Studies so far have not been focused over this arena. 

Plants are well known for showing phenotypic plasticity and semelparous species being iteroparous is common within species basing on the environmental conditions. Phenotypic plasticity is phenomenon of single genotype showing different phenotypes basing on the conditions prevailing. 

Being monocarpic or polycarpic is dependent on the environment and surroundings also. Most trees of tropical rain forests complete multiple cycles of reproduction and live for hundreds of years. 

If they had been annuals and produce masses of seeds in reproductive cycles it would have been difficult for the seeds to survive in conditions of high competition for sunlight under the thick canopy. 

In case the parent plant is annual and perishes off after its first reproductive cycle and seeds would not germinate because of competition. This may result in the particular species loss from the entire ecosystem. 

Nature’s reasons are always admirable, making rain forest trees as perennials is a part of nature drama for the survival and continuance of species. 

Understanding theories of Nature has ever been fascinating. It gains lot of attention in knowing mechanisms underlying the clearly visible facts. Every species draws its own importance in its own perspective. Organisms aim for their primal survival and for the continuance of species. Studies on reproductive strategies and the mechanisms behind it help in understanding the evolutionary lines drawn over ages.

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Ketogenic Diet for Weight Loss (Low Carb Diet) | Good or Bad

Changing lifestyle and food habits exposed people to chronic diseases like diabetes, hypertension and heart complications. Most of them are related to obesity complaints which has grown up being a major health issue on globe. There are many measures that have been adopted to fight obesity. Following a strict diet regimen, sticking to perfect exercise schedules, depending on weight loss commercial products have all stocked up in the lane of weight loss process. Ketodiet is one such effective diet proven for providing efficient results in obese individuals. 

What is Ketodiet? 

Ketodiet primarily consists of very low carbohydrate diet, medium protein and a rich fat diet. The concept is to provide healthy fats for body and make it less dependable on body’s sugar depots. 

Concept behind Ketofoods 

Basically, humans digest the polysaccharides (long chain sugars) into monosaccharides (mostly glucose) with the help of digestive enzymes. There are certain metabolisms that can convert the simple sugars (glucose) into pyruvate which is later converted to ATP, the prime fuel molecules of human body. 

This entire process is reset in people feeding on ketodiet. Ketodiet plan ensures that body utilizes stored fats. This is attained by maintaining a very low availability of carbohydrates. 

The purpose of keto diet is not to provide fat and calorie to the body, but to make body switch over to fat metabolism by burning consumed fat and stored fat simultaneously. 

Physiology in consuming ketogenic diet 

Consuming ketogenic diet pushes the body equilibrium towards a low carbohydrate diet. Hence it is similar to physiological state of fasting where the low glucose availability is accompanied with high fats. 

During fasting, low glucose availability prevails in body. The human body adapts two mechanisms. One is gluconeogenesis where body synthesizes its own glucose from lactic acid or glycerol. When these depots are also used up, ketosis takes into action. Low blood sugar is already prevailing in the body and thus there is low insulin secretion. All these physiological situations trigger the metabolic pathways that breakdown stored fats. Finally, ketone bodies replace glucose as central molecule and the situation is termed as Nutritional Ketosis. Butahydroxybutyrate, acetone and acetoacetate are the three most common organic molecules that are referred all together as ketone bodies. A small proportion of ketone bodies does not pose any threat since the blood pH is not disturbed. 

So, during ketogenic diet, when the body is supplied with high fat diet having a low carbohydrate proportion, body’s stored carbohydrate reserves become insufficient to provide enough glucose molecules for energy needs. Then the body reaches a stage of utilizing the available fats for providing ketone bodies which are new energy currency. 

Ketogenic diet however has shown few adverse effects on a short time base. Dizziness, nausea, fatigue, headache, vomiting, insomnia, constipation. Few people suffer from excessive fatigue during workouts and exercise. All together it is called as “keto flu”. 

Maintaining the hydration balance of body and providing enough electrolytes can help subjects to overcome these issues. However, the side effects get resolved in a maximum period of few weeks. 

From being an apprehension to special diet 

Ketosis gained a level of apprehension because it is the main mechanism behind acid ketosis where the number of ketone bodies produced is quite large having a direct impact on blood pH. 

Its use in treating epilepsy by Russel Wilder and recent advances in nutritional research have changed the opinions regarding ketosis. 

After the glucose deposits deplete in human body, the energy demands of brain are met by ketone bodies. Ketone bodies are the sole molecules that can cross the blood brain barrier and reach brain cells avoiding them to starve. 

This logic has been used by Russel Wilder in treating epilepsy. Epilepsy is characterized by sudden electrical disturbances in brain which lead to uncontrollable behavioural changes. In epilepsy patients, glucose is an immediate energy providing source for seizures. So, cutting of glucose availability makes brain dependant on ketone bodies and seizures are supplied with less energy and hence reduced. 

Ketogenic diet occupied crown in therapeutic diets until antiepileptic agents have been discovered and replaced it. Currently it became a weight loss diet and gained good response in very short run.

The Diet 

There is no specific or standard ketogenic diet with proper ratio of macronutrients. The diet typically decreases the total carbohydrate uptake to less than 50 grams a day. Generally, popular ketogenic diet has aspect ratios of 70-80% fat from total daily calories, 5-10% carbohydrate, and 10-20% protein. The protein content in the ketodiet is kept moderate because eating too much protein prevent ketosis. 

Ketogenic diet pushes the body to another edge of utilizing fats as fuels and must ensure a least carbohydrate range in the diet. 

There is fixed nutrient chart for people following ketodiet. A minimum range of 3-6 grams of *net carbohydrates in 100 grams of food is better. It is even accurate if subjects can follow least carbohydrate of 3 grams in 100 grams of food. 

Green leafy vegetables are one best source of low carbohydrate and reserve of essential micronutrients. They are rich in fibre making the stomach full and simultaneously have a low carbohydrate and calorie levels.

Vegan Ketofoods 

Kale, mustard greens, spinach, broccoli, sprouts, lettuce and arugula are popular greens recommended for ketodiet. Vegetables like tomatoes, cucumbers, egg plant, zucchini, radishes, asparagus, turnips, fennel, kohlrabi, green beans, snow peas better choices if ketodiet is followed. 

The best keto flour brands

Meat and sea foods 

Lobsters, crabs, chicken, big fatty sea fishes, lamb, beef are all good options for meat based ketodiet. 

Apart from the above, dairy items are also recommended Ketofoods. Milk based products like ghee, full cream, cream cheese, cottage cheese, yoghurt, parmesan, mozzarella cheese, cheddar cheese, whole milk are all rich fats dietary products having enough quantity of proteins too. 

Oils are an entirely different category in ketogenic diet since they are richest source of fats and some are having special vitamins too. Coconut oil, avocado oil, olive oil, cocoa butter, sesame oil, walnut oil, hazelnut oil is used in ketogenic platter preparation. 

Taking enough care while choosing oil for particular preparation is needed to ensure the essential nutrients are not lost. This is because different oils have different evaporating (smoke) points and cooking beyond that particular temperature can make the nutrients to degrade. For example, avocado oil has a relatively high smoke point so it can be used to ketogenic platter based on grilling, roasting, frying and even as dressing and dipping’s. While sesame oil has a medium smoke point, so beyond cooking it can destroy the nutrients and also the degraded constituents can cause inflammation in subjects as they are already on special diet with a diverted metabolism. 

Coconut oil is rich in saturated fats and medium chain fatty acids. It is extracted from coconut palms and has high smoke point. 

Extra virgin olive oil is rich in flavour having high amount of monounsaturated fatty acids and antioxidants. It has a very low smoke point and so can be used in dressings and marinades. 

Avocado oil is rich in monounsaturated fatty acids and antioxidants like olive oil having an extra dose of proteins, vitamin A and E. It ensures a better absorption of nutrients and maintains cholesterol levels. Hazelnut oil is a pack of rich flavour and essential fatty acids while walnut oil is blende of monounsaturated fatty acids with omega 3 fatty acids. It is a power pack of manganese, zinc, potassium and niacin. 

Medium chain triglyceride diet (MCT)

A dominance in ratio of fats to carbs and proteins make the ketogenic diet less palatable. In 1970’s Medium Chain Triglyceride (MCT) diet has been introduced which is comparatively palatable than the classic ketogenic diet. 

MCT diet contains medium chain fatty acids along with proteins and carbohydrates. Medium chain fatty acids produce ketone bodies more easily in comparison to the long chain fatty acids. this tendency to produce ketone bodies easily makes room for carbohydrates and proteins making the diet more palatable than the classic ketogenic diet. 

A supportive point in favour of MCT diet is that medium chain fatty acids do not require carnitine shuttle. So, people with impaired carnitine levels can rely on MCT diet under clinical supervision. 

It is planned and supplemented such that 30% energy needs are supplied with MCT oil and rest 30% from long chain fatty acids. The balance of energy needs is supplied by carbohydrate and proteins. Though some side effects may pop up differently in different subjects the supply of diet may be variable during short run and can be inculcated on advent of normal conditions. 

The MCT diet is more flexible than the classical ketogenic diet since it expands the diet chart by adding lot many items into the proteins and carbohydrates columns. This makes a variety of items into platter making its comparatively delicious. Specially in case of children where they turn resistant to the classic diet, inculcating MCT can make the diet relatively attractive with a room for fried bread, potatoes and mushrooms. MCT oils can be used in salad dressing and be given directly to children fed on tube in gastrostomy. 

Liquid food is a quite satisfactory point in MCT which can be least availed in case of classic ketogenic diet. MCT shakes can be made out of milk, MCT oil, and protein powders which make the children find interest in adapting to the diet chart. 

If the subject is acclimating to the ketogenic diet chart either MCT or the classical one, a close monitoring of the ketone levels in urine blood are to be monitored. An eye watch on blood sugar levels, fluid intake and body weight is a mandatory point to be kept in mind while in the starting stage.

Best MCT Supplements         MCT Edible Oil

Be cautious before you choose 

Since ketogenic diet shifts the body metabolism to another physiological edge, being cautious before adopting the diet pattern is a minimum essential. 

Ketone body generation is entirely confined to liver. The enzymes associated with fat metabolism are main switches in ketosis. Hence patients with liver disorders, pancreatic failures are restricted to depend on ketogenic diet. 

Pancreatitis is an inflammation of pancreas where its function and enzyme production are impaired. Pancreatic enzymes like pancreatic lipase, cholesterol esterase is chiefly associated with lipid digestion in small intestine. And hence pancreatitis patients are restricted from taking ketogenic diet. 

Carnitine is an amino acid derivative compound which has a very important role in fat metabolism. Carnitine is the basic molecule synthesized from two amino acids lysine and methionine and involved in long chain fatty acid translocation into mitochondria. It carries fatty acids across inner mitochondrial membrane and returns back for the next cycle. The entire process is called as carnitine shuttle. 

Carnitine shuttle is an essential step in fat metabolism because it facilitates the fatty acids with an exposure to inner mitochondrial membrane. The enzyme action causes an oxidation reaction in with a step wise removal of two carbons at a time and finally forming acetyl CoA molecules. The acetyl CoA either enters Krebs cycle to produce ATP or are converted to ketone bodies. 

So, deficiency in fat metabolism enzymes like carnitine palmitoyl transferase, carnitine translocase, primary carnitine deficiency can have a direct impact on ketone body synthesis. So, if patients continue to take ketodiet, there occurs a situation of low energy levels. 

Long term usage of anticonvulsant drugs like sodium valproate can deplete the carnitine stores of body. So, patients who had a long-term treatment based on anticonvulsants are advised not to follow ketodiet. The logic is that already the body is fed with long chain fatty acids and a prevailing low carnitine levels can have a direct impact on fat metabolism and adequate ketone bodies are not formed. Finally, the body suffers from low energy supplies which can pose severe threat to vital organs. 

In some subjects, acetone in body becomes isopropanol by the reduction action of alcohol dehydrogenase of liver. Isopropanol gives false positive results in alcohol breath tests. 

In healthy subjects too ketogenic diet can only be introduced on a slow and gradual base with a periodical observation on kidney functioning. Healthy subjects were reported with dehydration, hypoglycaemia and electrolyte imbalance when fed a ketogenic diet. Staying hydrated while on ketogenic diet have shown effective results for weight loss cases. 

Other approaches for weight loss like reduced calorie intake and low-fat diet have been reported with long term effects. Though the long-term effects of Ketogenic diet are not known due to limited literature. However ketogenic diet has shown efficient results in rodent studies. Any short-term symptoms like ketoflu have sustained for only a short time period. 

Withdrawing the diet plan 

In case of individuals who are fed with ketogenic diet for treatment of medical ailments like epilepsy, sudden abruption in ketodiet immediately is not recommendable. There should be a gradual increase in carbohydrate content along with simultaneous decreasing MCT oil by 10% for three months. If the individual abruptly stops ketogenic diet and shifts to normal diet there can be sudden seizures. For this reason, as the way ketodiet has been inculcated in a step wise manner, withdrawing the diet in a step wise manner is also essential for balancing the health and is strictly recommended under the surveillance of doctor and a dietician.

FAQs

Keto word is primarily taken from word ketosis, a metabolic mechanism in our body to use fat or digest fat and fatty acids. Ketodiet primarily consists of very low carbohydrate diet, medium protein and a rich fat diet. The concept is to provide healthy fats for body and make it less dependable on body’s sugar depots. For diabetic people low carbohydrate diet is recommended, having good amount of protein and low fat. Whereas in ketodiet, the fat consumption is focused by reducing the carbohydrates in diet.

The ketogenic diet has been shown to produce beneficial metabolic changes in the short-term. Along with weight loss, health parameters associated with carrying excess weight have improved, such as insulin resistance, high blood pressure, and elevated cholesterol and triglycerides. There is also growing interest in the use of low-carbohydrate diets, including the ketogenic diet, for type 2 diabetes. Several theories exist as to why the ketogenic diet promotes weight loss, though they have not been consistently shown in research. However, if all the things implemented perfectly it may have beneficial effects on health. /To check your keto plan kindly consult your healthcare professional, do not take the diet with yourself, healthcare professional consult is recommended before you go for keto diet/

Yes, below is the list of organic foods you can eat to maintain your ketodiet. (For consumption values consult your healthcare professional.)

Bell Peppers	Zucchini	Avocado	Cucumber
Onion	Cabbage	Spinach	Nuts and Seeds
Olive oil	Coconut oil	Soya/Almond milk	Tofu
Paneer	Ghee	Cauliflower	Fruits

Non-Vegetarian can have Eggs, Fish, Chicken along with the vegetarian diet.

Yes, but first you must check their label claim what amount of Carbohydrate is added. The super dark chocolate. 72% dark has 4 net carbs in it, 86% dark has 3 net carbs.

Some signs are: decreased appetite, bad breath, dry mouth, short-term fatigue, increased focus and energy, digestive issues. For acute diagnosis kindly consult your healthcare professional as these symptoms might be due to irregularities in your meal.

It depends what type of diet chart you have, if you cannot get your dietary requirements then you should get supplements. MCT is the most important fat source, and it is also available online. Make sure you check the carbohydrate level before using the ketofoods as per your diet. For more assistance consult your healthcare professional.

It’s hard at first. Looking at labels is important. There are brands out there that are keto friendly.

In starting you have to slowly increase the fat amount and decrease the carbohydrate amount. For further assistance consult your healthcare professional.

You can not withdraw once you have started your keto diet, because your metabolism is switched in to fat instead of carbohydrate. Sudden withdraw is risky and may lead to multiple organ failure. So, to withdraw, increase the carb slowly and reduce fat slowly in diet. Kindly consult your healthcare professional if you are willing to withdraw.

“Net carbs” and “impact carbs” are similar terms in ketogenic diets also in diabetic diet. These terms are introduced by food manufacturers as a marketing strategy, appearing on food labels to claim that the product contains less “usable” carbohydrate than is listed. Net carbs or impact carbs are the amount of carbohydrate that are directly absorbed by the body and contribute calories. They are calculated by subtracting the amount of indigestible carbohydrates from the total carbohydrate amount. Indigestible (unabsorbed) carbohydrates include insoluble fibres from whole grains, fruits, and vegetables; and sugar alcohols, such as mannitol, sorbitol, and xylitol commonly used in sugar-free diabetic food products. However, these calculations are not an exact or reliable science because the effect of sugar alcohols on absorption and blood sugar can vary. Some sugar alcohols may still contribute calories and raise blood sugar. The total calorie level also does not change despite the amount of net carbs, which is an important factor with weight loss..

/Disclaimer: The information provided in this article is just for having knowledge and information on General Health. Science Arena Does not claim any health benefits nor its authors in any form, all the data and information shown are based on the personal experience and reference health data taken from Health practitioner. [Not For Medicolegal Purpose]Educational Purpose Only/

To check your keto plan kindly consult your healthcare professional, do not take the diet with yourself, healthcare professional consult is recommended before you go for keto diet

Author Details

• Gautam Singh Rathore 
• Prathyusha Naresh

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Planting strategies in the dry climate

Modern living and globalization have brought up many changes in the environment. Changing lifestyle and over-dependence on combustible fuels resulted in carbon emissions and global warming. In developing economies, agriculture largely stands as a livelihood for the country's population. The present article throws light on the effect of drought on agriculture because of changing climatic patterns.

Agriculture and climate

Agriculture is a long-term process. It depends on multiple interactions with the environment right from sowing until obtaining the crop produce. Yield per hectare of the farm is dependent on the prevailing climatic conditions during the crop season. 

Temperature extremes and agriculture

Raising global temperatures and carbon emissions have already resulted in altered rainfall patterns, extreme temperatures, etc. Heat waves are the primary progression of elevating temperatures. 

Prolonged exposure to high temperatures is harmful to all living beings. Extended high-temperature exposure can cause serious damage particularly for plants in the phase of flowering. An extended exposure can cause changes in carbon assimilation and eventually growth rates. Climate deviations during flowering have a profound effect on fruit production which can bring severe losses to farmers cultivating cash crops.

Even short span temperature extremes can pose a severe threat to yield quality if they coincide with the critical developmental stages of crop. High temperatures are usually accompanied by high light intensities. Extreme light intensities beyond required levels damage the photosynthetic apparatus. So, even after the advent of ambient temperature and light intensities, the plant engages in the process of repairing rather than engaging in carbon assimilation and building biomass. 

In tropical and subtropical areas prevailing high temperatures are a global characteristic. Heat waves, reducing water availability have a combined effect further amplifying the existing severity.

Prolonged dry conditions accompanied by high temperatures can result in a severe condition termed Drought. Low or negligent precipitation along with extended high temperatures result in moisture loss from soil. Low soil moisture along with prevailing temperatures imposes abiotic water stress in plants. 

Plants adapted a multitude of physiological, morphological, and biochemical changes to cope with extreme conditions. 

Desert ephemerals 

Few plant species complete their lifecycle before the extreme climate arrives. These plants do not have any morphological structures to face drought, but they adapt rapid phenological development as an adaptation. 

They produce enough reproductive output in the form of seeds while few others maintain inactive underground structures that are not harmed by the existing harsh environment. 

On the advent of favorable conditions, the reproductive structures start a new generation and hence the species continues.

Some species adapt developmental plasticity to the environment. During the dry season they limit growth as a slow process. On the advent of wet conditions, they grow rapidly and produce large reproductive output.

Desert perennials 

Some arid area plants have a separate set of morphological adaptations. These are water savers having small leaf size or replacing the leaf count with thorns reducing water loss through transpiration. 

Few other desert plants are drought avoiders by maintaining a succulent lifestyle. They have a thick wax coating on the leaf surface and closed stomata to minimize water loss. 

Drought tolerance is an adaptive strategy that plants take as a physiological measure.

Impact on Crop plant physiology at a glance 

Living beings suffer from dehydration and overheat during dry environments. Plants are immobile and cannot run away to shade regions to protect from heat. However, they developed a multitude of adaptations to withstand drought conditions.

Plants developed a well-equipped hormonal system to communicate the existing localized stress to other parts so that the entire plant body gets ready to face the fight.

Plant hormone Abscisic acid (ABA) plays a key role in stress-mediated responses.

Plant roots sense water scarcity and an immediate synthesis of ABA takes place. Stomatal closure during high temperatures (usual noon times) is an ABA mediated response and is most intensely studied physiological adaptation.

ABA accumulation in guard cells causes an increase in calcium ions which leads to an imbalance in membrane potential. As a result, potassium ions leave guard cells into the surrounding mesophyll cells. Due to this series of ion uptake and efflux guard cells lose turgor and stomatal aperture shrinks otherwise called stomatal closure.

Stomatal closure reduces transpiration and thereby lowering pressure down the length of xylem tissues. Water is uptaken by roots because of existing negative pressures that run down the length of xylem. 

Plants lack “heart” which stands as a central pumping organ for the entire body in case of animals. The water loss through transpiration creates a negative pressure and thus roots tend to absorb water from the soil. Running over the principle of Cohesion-Tension theory water is transported to each cell throughout the plant via xylem vessels and tracheids. So, when the stomata are shut off, there is no or reduced water loss to the environment. 

Stomatal closure has an impact on growth too 

Though water loss is reduced, stomatal closure limits gaseous exchange which has a direct effect on carbon assimilation.

Usually plants grown in arid areas show stunted growth having reduced leaf size. Reduced leaf size is an adaptive feature so that only a small area is exposed to sunlight thereby less water can below. Reduced plant height, stem diameter, plant biomass has been reported in many plant species studied under drought when compared to those under normal conditions.

Rising temperatures pose a serious threat to the light-harvesting complex and photosynthetic enzymes causing a lowering photosynthetic output. This has a final impact on plant growth. 

Mastermind 

Most water is lost and the existing dehydrated interior can damage membranes and proteins. To protect the cellular proteins and membranes, plant cells accumulate small, highly soluble, non-toxic neutral molecules at molar concentrations. 

They are called osmolytes or osmoprotectants since they protect cellular protein structures by hydrogen bonding. Polyol hydroxyl groups of some osmolytes form hydrogen bonds with proteins of membrane bilayer helping in maintaining cell interior as well as cell turgor.

This strategy is not only to survive the existing stress but also helps plant cells to retain back their machinery once the drought is circumvented by normal conditions. 

What a mastermind!!! 

Drought stress induces accumulation of oxygen free radicals into the cellular interior which is entirely a different subject of discussion. Plants developed a well-defined antioxidative defense system to fight the drought-induced free radicals and maintain redox balance. 

The above-discussed strategies are adapted by plants that face an unexpected drought. However, there are other strategies adapted by plants to face the expected drought. Expected drought occurs in arid areas where plants living there.

Some species of plants developed special mechanisms to survive and continue performing carbon assimilation . This is known as the C4 pathway. It was first studied in the Crassulacean family. 

They perform gaseous exchange at night. When the surrounding temperatures reduce, carbon dioxide is fixed as Malic acid (a 4-carbon molecule) by enzyme PEP carboxylase and stored in vacuoles. During day time, malic acid is broken down to release CO2 which is accessible to enzyme RUBISCO to carry out further carbon assimilation.

C4 metabolism to increase food production

Global food needs are growing day by day and there is a dreadful need for studies that can increase food grain production. With increasing pollution and changing climatic conditions more research is being conducted in the aspects that can increase food production with existing conditions.

Few approaches have been discussed in our previous article. 

MODERN FARMING METHODS  

Apart from them, studies are also focussed on molecular aspects for installing the C4 pathway in C3 plants like rice in a manner to improve photosynthetic capacity.

The idea is that food crops having a C4 pathway can withstand arid conditions and continue their photosynthetic output. This can help plants to produce food grains even despite dry conditions, high temperatures, and even when stomata are closed there is no halt for carbon assimilation.

Genetic engineering (the science of manipulating organisms genes using biotechnology) has been employed and a set of genes regulating certain biochemical processes, leaf anatomy has been inserted and expressed in rice. Gene insertion and expression are not simply expecting expertise and knowledge from different fields like physiology, systems biology, molecular biology, metabolomics, plant breeding apart from genetic engineering, and biochemistry.

Photosynthesis in C3 plants is carried out in mesophyll cells while C4 plants have compartmentalization to perform photosynthesis. Carbon dioxide is fixed as 4-carbon compound oxaloacetate then converted to malate in mesophyll cells. Malate is transported to bundle sheath cells where it is converted to carbohydrates by the Calvin cycle (light-independent steps of carbon fixation). 

Chloroplasts are restricted only mesophyll cells (photosynthetic ground tissue of plant leaves) in C3 plants while they are distributed in both bundle sheath cells (tightly packed sheath of photosynthetic cells around vascular bundles) as well as mesophyll cells in C4 plants which make the two plan types very much different. Researchers increased the number and size of chloroplasts in bundle sheath cells of rice by overexpressing the chloroplast development genes in a cell-specific manner. 

Vein spacing is different in leaves of C3 and C4 plants. Veins are spaced closely in C4 plants than those in C3 plants. C3 plants have higher mesophyll cells that push the veins apart thus increasing vein space and reducing the vein density. Higher vein density allows only limited mesophyll cells thus the equal ratio of mesophyll cells and bundle sheath cells. 

Calvin cycle should be enhanced in bundle sheath cells while it should be reduced in mesophyll cells to install the C4 mechanism. For this RUBISCO activity is reduced in mesophyll cells and increased in bundle sheath cells to confine the Calvin cycle to bundle sheath cells. Simultaneously genes coding enzymes like β-carbonic anhydrase and Phosphoenolpyruvate carboxylase (PEPC) are overexpressed in mesophyll cells. 

However, this is only a summary of creating the rice cultivar with the C4 pathway but concerning the experimental part for bringing the plant from lab to field, it requires large data relating different genes, their functions, gene silencing, overexpression, gene source and finally field experiments. Before all, understanding plant responses to different stress stimuli and the genes responsible for particular response gains first place. Without complete knowledge of phenology, gene loci in different drought-tolerant species; advancement towards developing new cultivar would not have been possible. 

The socioeconomic impact brought by drought

Drought is an outcome of long period dry conditions. Arid areas have more effect on the social life of the population living there and semiarid regions grow in becoming arid. Long-period drought conditions result in famines and migrations. 

Low precipitation over extended periods reduces groundwater and diminishes surface water resources making the drought-stricken lands unfavorable for human living. 

Farmers tend to spend more money to dig wells, drill bore wells, and buy tankers of water because the precipitation levels are already low. The obvious and direct effect would be on the farm income and has an indirect strike over local economy returns as the entire social living is at stake. 

Forest fires are unstoppable due to prevailing dry conditions in forest areas. This poses a severe threat to the environment and entire wildlife living there are disturbed. The indirect effect would be on the people depending on forest products with an extent to their social life too.

Earth bears several species that have their uniqueness in interacting with the environment. Few are tolerant of harsh conditions while others are intelligent by escaping the harsh conditions. Every response is operated by a unique set of genes.

Advancements in bioinformatics and biotechnology have boosted up the studies in understanding as well as developing the “hardier” traits. 

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MODERN FARMING METHODS

Research and development in science and biotechnology have brought new approaches to farming that can withstand with polluting soils and changing lifestyles. New approaches for farming based on urban living has grown up. 

HYDROPONICS

The practice of growing plants in nutrient-enriched water (without soil) is called hydroponics. Because photosynthesis is the chief principle mechanism running behind in plants, and all that is needed for photosynthesis is sunlight, carbon dioxide, and nutrient supply through roots. 

In nature, plants uptake water and nutrients from the soil by the well-established deep root system. They depend on sunlight for photosynthesis and rely on atmospheric carbon dioxide for driving out the process of transforming light energy into chemical energy. 

In hydroponics plants are grown in water and roots have direct access to nutrients, so they do not have to grow longer and much of energy is diverted to the growth of leaves and aerial parts. 

With smaller roots and no need for farmland, hydroponics farm can be set in a greenhouse or even a balcony in concrete jungles also. 

Requirements for a hydroponic farm

All that is needed in hydroponics are a bunch of plastic troughs, pipes into which water enriched with nutrients are supplied and plants are grown in them. Greenhouse having the artificial light facility, pH monitoring devices, humidity measuring devices are all other accessory devices needed. Because the plants are grown on an entirely artificial setup, growers need to take extra care about plants. 

The root system is not well protruded and since the plants float in continuously circulated water, plants bearing larger aerial parts are not a better choice for hydroponics. Few growers use media like vermiculite, peat, Rockwool for supporting the root system. For plants bearing fruits special supporters may be installed at the time of setting up of hydroponics farm. 

Fast-growing plants like tomatoes, strawberries, lettuce, oregano, cilantro, spinach, basil, parsley and bell peppers produce greater results for farmers in hydroponics. Having a short life cycle and comfortable size ratio of aerial to root parts make them good returning species in hydroponics farms. 

Variants in hydroponics 

The main principle of hydroponics is that roots grow in water without a soil substratum. 

Basing on the size and purpose of the farm, water flow may be either static or continuous. 

Static water cultivation is the simplest one where water is maintained at a required level in troughs and roots are allowed to fall into it. Small scale farms have floating valves to adjust the water levels. This system needs a water reservoir to be covered with black plastic or aluminium foil to avoid exposure to sunlight. Sunlight induces the growth of alga in static water systems and this is a point of concern in hydroponics. 

Continuous flow hydroponics are those where nutrient solution flows continuously in the chamber containing suspended roots. A large tank containing nutrient solution is set at the bottom or one corner of the farm and nutrient solution is continuously pumped and allowed to flow through tubes. 

This set up needs expertise during construction and demands certain slopes in the channel for the easy and complete flow of nutrient solution.Proper channel slope along with enough channel length and right flow rate are design features in continuous flow hydroponics. 

Easy and random sampling (to check the pH or nutrient content) from any part of the farm is a main additional task for growers in continuous flow technique. This step ensures the proper distribution of nutrients along the length of flow channels. 

The level of the nutrient solution can be easily lowered when roots require aeration (to prevent waterlogging) in this system with the help of its accurate design. 

Subsets 

Keeping the hydroponics principle as main criteria two different subsets are in practice. Aeroponics and aquaponics are two variants of hydroponics.The basic principle lies the same. 

Aeroponics is a technique of growing plants with their roots placed in an environment saturated with nutrient solution. The plants are grown with efficient support systems having roots suspended in a nutrient solution saturated airtight chambers. There are spray jets for spraying a fine mist of nutrient solution periodically into the chamber containing roots. 

The only problem in hydroponics is that roots are waterlogged and suffer from suffocation, which is solved in aeroponics. The roots here face a cent percent oxygen availability. But the problem lies here itself. 

The aerosol maker otherwise called mister should be monitored periodically. The quantity of nutrient solution sprayed is largely dependent on the aerosol sprayer. If not, the roots will dry out and plants die. 

Aquaponics refers to raising fish and growing plants, both on the same farm within a closed-loop system. It is a sustainable farming technique where fish are grown in the circulating waters of hydroponics culture. 

These fish provide natural fertilizer for the plants that are broken down into simpler nutrients easily absorbable by the plant roots. Plants purify the water by absorbing dissolved nutrients in the water where the fish are growing. 

A small-scale farm for supplying vegetable needs for the family or local community is beneficial. Aquaponics farm on commercial-scale needs extra care concerning the maintenance of the tank. Checking the pH of water with stipulated intervals and physical observance on plant quality as well as fish is needed for proper maintenance of the commercial farm. 

Any stress faced by either of them can have an obvious impact on the life and quality of others. However, aquaponics is a better choice in terrestrial areas where people depend on imports for fish. Fresh fish devoid of fertilizers and chemicals are always a hot cake in the urban world. 

Problems faced by growers 

Hydroponics farms lie in a closed environment and plants rely on artificial light and humidity. The water input and nutrient content are all to be monitored. This is where the growers are caught with problems. 

Proper scientific knowledge and maintaining the balance of nutrients at different stages of the growth cycle of plants is needed. 

Hydroponic nutrient solutions are generally highly concentrated and water-soluble solutions that are dissolved in the right amount of water basing on tank size of the farm area. A disturbance in the balance of nutrients during various phases of growth cycles can lead to low productivity and also the death of cultivating plants. Both of them can swipe away the financial gains of farmers. 

Advantages 

Since hydroponics does not demand any specific crop area and do not need land restoration for setting up the farm, hydroponics is adapted even in urban areas by modern farmers. 

Because the plants are in no contact with soil and soil is a prime harbor for pathogens, hydroponic crops are pathogen-free. Hydroponic farms are in closed environments so the plants are pest-free. That too the plants are under continuous monitoring of pH and humidity. So, the growers are ensured with a handsome amount of financial gains in return for their investments. 

With its independence on natural sunlight and soil (since large of agricultural land lost fertility) hydroponics stands as one of the modern serves of current food needs. 

Hydroponics is operated in a closed environment and humidity is under strict control. It is dependent on artificial light and hence nutrient water used in hydroponics is less subjected to evaporation. Water loss due to evaporation is very less or negligible. Where, the word “Farming” poses some expectations of large water needs, hydroponics is something different. 

FARMING IN GREENHOUSES 

With changes in climatic conditions, switching to modern farming methods has become one good option for farmers. Rather than depending on the natural environment, greenhouses are one good approach for growers of vegetables, fruits and horticulture. 

Global warming is the burning problem now and has a combo effect. Changes in rainfall patterns, sunlight, raising temperatures, climate extremes are all outcomes of global warming. 

Agriculture depends on the existing environment and so erratic patterns in any of the climatic factors pose a serious issue to the output. Farmers adapt to modern techniques like farming in greenhouses or polyhouses. 

Greenhouses are the framed structures of transparent material over a large growing area. All conditions are controlled either partially or completely and monitored well.The main agenda is to maintain optimal growth conditions for plants rather than depending on the natural climatic factors. 

Polyhouses and greenhouses are almost the same with only a minute difference that Polyhouses have transparent polythene sheets as shelter while term greenhouses refer to those having either polythene sheets or transparent glass. 

Setting up a greenhouse 

Before a farmer starts cultivating in the greenhouse, a perfect plan for greenhouse set up is made. The place for greenhouse cultivation needs to be selected. And then the perfect design is selected based on the commodity being produced, that is either if the farmer is interested in producing vegetable crops or floriculture. The land is selected after the pH is checked and ensured with proper irrigation set up and drainage for leaving excess water. 

Setting up a greenhouse is a cost-effective process and hence farmers stand selective in crop to be cultivated. Greenhouses provide ambient conditions for growing small-sized herbs that can bear aerial products which are the final products for the market. It can be either vegetable or fruit crops like tomatoes, cucumbers, strawberries, bell peppers, and most cut flowers for floriculture gains. 

Maintaining internal conditions 

Greenhouses can be either partially artificial or completely artificial basing on infrastructure set up during construction. 

Vents are set up for aeration supply to maintain rich amounts of carbon dioxide and oxygen levels. Carbon dioxide is much needed for the growth of plants as it drives the photosynthesis which is much needed for growth. 

Vents may be used or sometimes artificial air supplies are used. This is basing on prevailing climatic conditions and phases of the crop for growing needs. 

Natural ventilation is set up with nets and ridges.Wind direction prevailing in the area is a prime factor to be concerned during the construction of naturally ventilated greenhouses. 

Ridges are planned and set up so that more natural wind can enter the farm. This lowers the dependence of farmers on artificial aeration set up and thus can lower the cost of farm maintenance. 

Mechanical ventilation is set using fans and cool pad fans. Mixing fansare set up for large farms. 

Artificial lights are the best choice for light to drive out photosynthesis in a long day favoring plants. They stand as the only option for daylight in low sunlight regions of the globe.Paraffin lamps can increase carbon dioxide levels in the greenhouse apart from providing light to drive photosynthesis on. 

Depleted carbon dioxide levels can hamper the growth of plants. So, an eye watch on levels of carbon dioxide is much needed. Few farms have carbon dioxide generators that depend on natural fuels which work in two ways. One that they produce carbon dioxide by burning and second that they raise the internal temperature in chilling nights. 

Shade controls like nets and shade screens are installed during construction itself. They help to reduce the length of daylight and also in reducing light intensity in hot summers where high daylight intensity harms the photosynthetic apparatus. 

This way they provide ambient conditions for short day favoring plants. These set up help in mimicking seasons and in producing unseasonal crops. 

High invested farms are availed with air conditioners for providing chilling temperatures for high-value crops. Natural fog is mimicked with over-head misting devices for extended winter-loving crops. 

Advantages 

Certain regions on globe face climate extremes like frosts, low daylight, extremes harsh temperatures, limited water supplies with arid temperatures, etc. Though the soil can support the growth of plants to some extent depending on naturally prevailing climatic factors brings bad fate to plants. Greenhouses are a better option for cropping in such areas. 

Because farming on fertile lands having ambient climatic conditions is becoming a problem nowadays, greenhouses can bring about a rise in farming lands in the current scenario. 

Utilizing whatever possible farm area with some human intervention can help to serve the existing and growing global food needs to some extent. 

Growing crops in a closed, controlled environment prevent their exposure from climatic extremes like chilling, frosting, drought, high-intensity sunlight, precipitation, scorching temperatures, insects and diseases. 

Since it has availability in monitoring and controlling the internal conditions within a greenhouse, farmers gain an opportunity of cultivating both seasonal and un-seasonal crops basing on the market demands. 

Year-round cultivation to satisfy floriculture and rest market demands is possible in greenhouse cultivation. Artificial lighting facility avails farmers to mimic the extended daylight for flowering phases in many floriculture farms. Chrysanthemum, Roses, Anthurium, Gladiolus are all popular cut flowers cultivated in greenhouses.

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Bacterial Transformation (Bacteria are Evolving Like viruses)-recall of Transforming Principle

In recent decades more studies were conducted to study the Bacteria and viruses, how they work, how they can be controlled and so on. The thing which is to be observed that bacteria are evolving at a high rate, they have adapted the evolutionary features of viruses. 

This was begun in the early 1920s when Frederick Griffith showed in his experiment that something is transforming in the non-virulent bacteria to make it virulent. At that time due to lack of technologies and resources he was unable to find which the responsible thing is making it happen. Later on, in the 1950’s it was validated and proven by Hershey and Chase that the DNA was responsible for this transformation.

Bacterial Transformation concerning Transforming Principle

This era is about advance genetics and proteomics where the medical experts are trying to cure the disease of their root cause concerning their origin. However we have far developed the CRISPR-CAS technology which is efficiently working but still it is unable to work in medical science.

Coming back to the medical Science we have developed about every medicine technique to cure the disease/illness caused by bacteria however when it comes to viruses especially in retroviruses it may take a decade to millenniums to find a cure. This is due to viruses do not have their own mechanism, they have only some part of bad DNA (junk DNA) which is functional in their hosts. Also they use host metabolism and machinery to work. On the other hand if we talk about bacteria’s they have a complete cell and have their own machinery/metabolism.

In case of illness caused by bacteria, medical science has to just focus on somehow interrupting bacterial machinery/metabolism to stop its functioning, whereas in the case of viral infection medical science has to find a way to eradicate the viral genome. 

These properties about viral infection or illness caused by viruses are now being adopted by most of the highly evolved bacteria. This is called bacterial genome transformation. Frederick Griffith in his experiments showed that a non-virulent strain of bacteria can become virulent if it gets the DNA of the Nucleus of the virulent bacteria.

Thus making the bacterial treatment complicated bacteria are now withstanding on most of the antibiotics. Government bodies are also taking necessary actions to prevent overuse or dosage of antibiotics because recent studies showed that most bacteria are now antibiotic-resistant.

An Overview of Griffith transforming principle

In his experiments, Griffith took two strains of bacteria one is Rough Strain (Virulent) and another is Smooth strain (Non-Virulent). As depicted in the below image he performed his experiment in the same pattern and drawn to this conclusion,

• When he injected heat-killed smooth strain (make non-virulent by killing them over high temperature) the mouse lives, whereas when the same is injected with the live rough strain the mouse died. He ended up that that may be DNA or Protein of the Smooth strain bacteria is acquired by Rough strain bacteria and it becomes virulent due to which mouse died.   
• Later on by Hershey and Chase it was proved that DNA was the transformed in Griffith experiment not protein form where we know that DNA is our genetics material.

Consequences of the Bacterial Transformation

Seeking to the present scenario, we have all the techniques and medication to fight against any bacterial illness, but the same is not available for illness caused by some latest or new viruses. However we can control the viral infections to some extent until they are at their last stage.

Recent researches are showing that most of the antibiotics are non-functional against microbes. This shows that microbes are now evolved enough to withstand antibiotics, the international health communities are advising people to not use antibiotics until unless recommended by the doctor. See the Notification at Indian Drug Regulatory Authority.

If the transformation occurs rapidly and at the brood spectrum then the infection rate is increased by double.

Controlling Bacterial Infection

Bacterial infection can be prevented or cured by taking some preventive measures below they are described:

Basic Sanitary Habits

Basic Sanitary habits are the hygiene-related habits that every individual must follow and apply in his/her daily routine to prevent any occurrence of microbial infection.

Now people are using Sanitizers and other alcohol-based products as a preventive measure which is more effective and quite susceptible. Below are the FAQs on Sanitizers and alcohol-based products:

FREQUENTLY ASKED QUESTIONS ABOUT SANITIZERS

How Sanitizers or Alcohol-based Products Work?

The sanitizer contains Alcohol as their active ingredient which may be of 70% or less in the concentration of Alcohol. Alcohol is used in the laboratories as a disinfectant due to its microbe killing properties; basically alcohol is absorbed by the bacterial cell in the lieu of cytoplasm by crossing the microbial cell membrane which water cannot cross easily, thus increasing the surface retention from inside of the bacterial cell. This causes the bursting of the microbial cell.

Does Sanitizers Effective Against Viruses?

Referring to my above question on how it works, Alcohol-based sanitizers are not effective against viruses except some flu viruses (Ref NCBI and NIH text on their website). This is because viruses do not have liquid filled inside their cell they are like small crystal-like structures/morphology. So alcohol cannot cross the membrane because to move inside/across the membrane an equal tension is must be created. If somehow it may cross it will not harm the viral genome thus having no impact on its viability.

However UV radiation exposure, heating water are effective against viruses but they cannot be used as sanitizers.

Does Regular use of Sanitizers cause any problem to my skin?

Yes, It may cause severe problems if overused. The most common skin manifestations of alcoholism are urticarial reactions, porphyria cutanea tarda, flushing, cutaneous stigmata of cirrhosis, psoriasis, pruritus, seborrheic dermatitis, and rosacea. (Ref: Skin diseases in alcoholics, by Kostović K, Lipozencić J. PMID: 15369644)

  

Taking Antibiotics (After Consulting The Doctor)

This is the medication part that only comes when you have symptoms or infected.

For any adverse or unwanted symptoms related to any query first consult your doctor before using any type of medication.

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