NEET BIOLOGY

Detailed explanation-1: -Temperature has very little affect on the shade of leaves; instead, it all comes down to the amount of sunlight. When fall arrives and the amount of daylight wanes, photosynthesis comes to a halt and chlorophyl dwindles.

Detailed explanation-2: -The changes in weather and daylight trigger a hormone that releases a chemical message to each leaf that it is time to prepare for winter. Over the next few weeks, abscission cells form a bumpy line at the place where the leaf stem meets the branch. And slowly, but surely, the leaf is “pushed” from the tree branch.

Detailed explanation-3: -Common deciduous trees in the Northern Hemisphere include several species of ash, aspen, beech, birch, cherry, elm, hickory, hornbeam, maple, oak, poplar and willow. In tropical and subtropical regions, deciduous trees include several species of acacia, baobab, roble, ceiba, chaca and guanacaste.

Detailed explanation-4: -Winter temperatures cause the production of auxin to slow down and this breaks the abscission layer, causing the leaves to detach from the trees. Losing leaves helps the tree to retain water during in the winter and means that it needs less energy to stay alive. The fallen leaves help to add nutrients to the soil.