Question

3. Compare and contrast sun leaves vs. shade leaves. Your answer should include the leaf area, leaf thickness, extent of the vascular system, and photosynthetic rates. 4. Discuss some ways that plants can modify leaves to prevent water loss 5. Explain why transpiration is sometimes called an "unavoidable evil". 6. Describe the role ABA plays in stomatal closure. Include a detailed description of how the stomata close (i.e. which ions are involved? what are the steps?).

Answer 1

2 . Sun leaves Shade leaves i) Leaf area Smaller in area | Larger in area (6) Leaf color Lighter green Darker green I due to the presence in color because of chlorophyll (2) of abundant pigment chlorophyll pignent. (1) heal thickness | Thicker Thinner (iv) extent of Sun Leaves receives vascular Jabundant Sunlight, Vascular System (with more layers is less of chlorophyll. Ivascular system lis more extensive Low (v) photo synthetic | Higher extensive. System rates

1. Leaves modification some plants modify leaves to protect from cater loss in the following ways, (i) stomata: plants prevent water loss by closing their Stomata. Small leares have less stomata when compared to large leares this adaptation also helps in preventing watu loss () Thick cuticles reduces the water loss From Leat Surface (%) Guard cells reduces the water loss By controlling the stomate closure and opening

(iv) Leares modified in the form of aspires (ox) Scale leares prevents water loss and act as defense. (g) Cactus. () Thickness of leaves, some leaves are thicker which helps in storage of water. 5) Transpiration - unavoidable evil. In transpiration, small amount of water is absorbed by the roots of the plant. The remaining water is evaporated from the leares, stem and flowers into the atmosphere. The riesulting water loss is unavoidable because the leaves of the stomata will be open for carrying out photosynthesis. The co, enters the leaves through stormata.

with the help of sunlight releases oxygen in the atrosphere. If there ie o excess. water does, the guard celle regolete it, by controlling the stornete closure and opening. C) ABA (Abscibie acid) – Hormone click plays an important role in closing of Stomata during the times of drought plants -> ABA (Abecisic acid ) in guard cells. During stomata closure drought Condition prevents acta loss

Guard cells swollen shrunken stomata open Stomata closed Requires potassium ions Requires calcium and ABA: