AP BIOLOGY

Detailed explanation-1: -As a result of transpiration, a suction force is created in the xylem vessel. This force causes water to be pulled up from the xylem in the roots to the stem and leaves. This pulling force is called transpirational pull.

Detailed explanation-2: -Lateral roots: Lateral roots grow outwards right under the soil surface. They absorb a lot of water and nutrients as well as anchoring the tree.

Detailed explanation-3: -Transpiration occurs when water vapour escapes from the pores of the leaves (stomata). This necessitates the employment of suction force in the xylem bundles, causing the water to rise. The increased pressure causes the plant to absorb more water.

Detailed explanation-4: -Root hairs form in the zone of differentiation and this is where they begin to poke out into the soil to absorb water and mineral nutrients. Root hairs greatly increase the root surface area and therefore increase the ability of a plant to absorb water and nutrients.

Detailed explanation-5: -When transpiration exceeds water absorption by the roots, the plant dehydrates. This usually happens each day with the plant rehydrating again each night. As the soil dries out this rehydration is not complete, resulting in the plant becoming water stressed (Figure 3).