Q.What are the physiological effects of plants facing drought condition?

Step 1. Drought stress arises when a period without appreciable rainfall reduces soil water content to the point where the plant suffers water deficiency, and this produces a cascade of physiological effects.

Step 2. A decrease in cellular growth and in the synthesis of cell-wall components causes cells to become smaller in size, and nitrogen fixation (along with nitrogen reduction) decreases because the activity of certain enzymes involved in these processes is reduced.

Step 3. Rising abscisic acid levels close the stomatal apparatus down to a minimum, which sharply reduces the rate of transpiration.

Step 4. Protochlorophyll formation is inhibited and the photosynthetic process declines as a result, while levels of the amino acid proline increase as part of the plant's osmotic-adjustment response to water shortage.

Step 5. Respiration and the translocation of assimilates both decrease, and the resulting water loss increases the activity of hydrolytic enzymes, which go on to destroy RNA and disrupt protein structure. …

List the sequence of physiological effects drought produces, as given in the ch …

• Naming only 'wilting' as the effect of drought without describing the underlying hormonal (ABA) and metabolic (photosynthesis, respiration) changes that cause it. …