Question

In fall, the leaves of trees transition from green to an array of reds, oranges, and yellows. How will this change impact photosynthesis? Be sure to mention the effect on the light reactions and the Calvin cycle.

Answer 1

Plant make the food through photosynthesis which convert carbon di oxide and water to sugar by the use of sunlight,the energy comming from sunlight captured by chlorophyll, the sugar produced by the dark reaction of calvin cycle transported around the treevand stored in the leaves, so if plant kept away from sunlight it turns to yellow/orange just like in winter less sunlight, chlorophyll is not produced but the pigment which is responsible for yellow/orange is carotene found in carrot also found in leaves in growing season as the green colour fades the yellow carotene remains and low tempreture destroy the chlorophyll which results the transition from green to yellow.As a tree falls its leaves in winter, a layer of cells form across the base of the leaf stalk which restricts the movement of sugars(which is produced by dark reaction) back into the body of the tree. Concentrated in the leaf, sugars react with proteins in the cell sap to produce anthocyanin, a purply red pigment that causes apples to turn red and black grapes purple. Crucially, the production of anthocyanin is boosted by sunlight, drought and temperatures staying above freezing.