BIO330H5 Lecture 1: BIO330 1
Document Summary
Water potential in non-saline soil is close to zero - slightly negative. How do plants maintain: lowering osmotic. Xylem tissue is under a negative pressure. Water moves from: from lower to higher water potentials. When a plant find themselves short on water, they response by closing the stomata (reducing water loss) But cannot do that for long because eventually stops photosynthesizing. Pressure is dropping internally, plant becomes droopy. As water leaves, the structure deflates like a balloon. Once watered again, will return its normal structure. However, if the plant remains with no water irreversible wilting. Cells start to die because they cannot meet their energetic demands, metabolic needs, etc The only way to recover is for it to create new ones. The only way to avoid this is to maintain a lower leaf water potential than soil. As water leaves leaf cells, solutes become concentrated, osmotic pressure lowers and pressure in the cell decreases as well.
