Govt Exams
The source in phloem transport is any photosynthetically active tissue, primarily mature leaves, which produce and load photosynthates into sieve tubes.
Stomatal oscillation refers to the dynamic opening and closing of stomata in response to changing environmental conditions to maintain optimal gas exchange while reducing water loss.
Some C3 plants show facultative CAM characteristics under severe drought stress, temporarily shifting to CAM metabolism to conserve water.
The cytochrome b6f complex transfers electrons between PSII and PSI while simultaneously pumping H+ ions into thylakoid lumen for chemiosmosis.
Ethylene accumulates in leaf petioles during water stress, promoting abscission layer formation, leading to leaf shedding. ABA increases ethylene production.
Wilting occurs when transpiration rate exceeds the water absorption rate by roots, even with adequate soil water, due to environmental stress or damaged vascular tissue.
Turgor pressure in sieve tubes is involved in phloem transport, not xylem transport. Water transport in xylem is driven by root pressure, capillarity, and transpirational pull.
In the Z-scheme, electrons from PSI reduce NADP+ to NADPH with the help of ferredoxin and NADP reductase enzyme.
Km (Michaelis constant) is the substrate concentration at half Vmax, and it inversely represents enzyme affinity for substrate. Lower Km means higher affinity.
Guttation occurs due to root pressure being high at night (stomata closed), causing water exudation through hydathodes at leaf tips.