HORTICULTURE

Detailed explanation-1: -Leaves are not all at the same angle to the sun. Some are horizontal, some vertical, some in between. Also, on some plant species, the leaf orientation changes throughout the day. Orientation to the sun is another adaptation to desert heat.

Detailed explanation-2: -Plants harvest energy from the sun with the help of chlorophyll and carotenoid, two photon-capturing molecules. But if the plants are exposed to too much sun, these molecules absorb more energy than they can handle and generate reactive species of oxygen that can destroy the plant.

Detailed explanation-3: -3 Leaf orientation. In contrast to leaf inclination, leaf orientation or azimuth (the angle formed clockwise from north to the horizontal projection of the leaf axis; Figure 4.4) is nearly random for many canopies and has received less attention. However, orientation can be important in determining Q interception.

Detailed explanation-4: -Reduced leaf size or change in leaf shape or color are common adaptations. Smaller leaves have less surface area exposed to the sun, lose less water and stay cooler than larger leaves. Gray leaves absorb less sun than dark green ones. Plants often lose leaves when suffering from extreme heat stress.