How do different plants synthesize different foods of different tastes although they use the same starting materials?
APEKSHA K. DESHPANDE
Dharwad, Karnataka
Yes, different plants synthesize different food materials that taste differently. The commonest synthetic process taking place in plants is photosynthesis, wherein green plants produce carbohydrate (starch) using CO, water in presence of sunlight.
Initially glucose is produced and it is converted to starch and stored by the plant. Plants produce not only carbohydrates, but synthesize several other compounds such as proteins, oils, pigments, alkaloids, tannins, flavonoids , gums, resins, phytohormones, salts, phytochemicals etc.
Some of these compounds are used by the plants themselves but some will be stored in different parts of the plant. Proteins, phytochemicals, phytohormones are very essential for many metabolic activities that take place in plants. Plants do absorb phosphorus, nitrogen, several minerals from the soil using which they can synthesize the substances required for their growth, cell membrane synthesis etc.
Plants store the materials synthesized during their metabolic activity in different forms and circulate them to various parts of plant body to carry out other important functions. For example the pigments, essential oils, flavonoids will be circulated to parts like young leaves, fruits, flowers so as to help the plant in pollination, avoiding grazing animals, seed dispersal etc.
We, human beings are dependent on plants directly, indirectly (meat eaters) for our survival. We consume different plant parts such as grains, vegetables, leaves, spices, fruits, roots, stems etc in our daily life. In grains such as rice, wheat, stems like potato, colocasia (taro), sugarcane, roots like beetroot, sweetpotato the food is stored in the form of carbohydrates viz. starch, sugars. If it is stored in the form of starch it is bland in taste. If it is in the form of sugar as in Beets it tastes sweet.
Depending on the nature of foods stored the requirement of plant nutrients also varies. Though all green plants participate in photosynthesis and produce carbohydrates, the taste of the food varies because different plants store food in different forms.
Taste of the food we obtain depends on the chemical composition of the stored food material. The taste of the food also varies depending on plant part, age of the plant part and the geographical location, nutritional status of the plant.
Dr. T. BHAVANI
Bangalore
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This week’s question
AIDS is spread through blood transmission from infected persons. Though mosquitoes suck blood from the infected person, why is it not possible for mosquitoes to spread this disease?
Suresh Nayak, New Delhi
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