Question

.During autumn, the leaves of the plants turn red and fall, resulting in complete defoliation of the trees. Which mechanism is taking place?
Dormancy
Senescence
Photoperiodism

Answer 1

We have studied autumn leaf senescence in a free-growing aspen (Populus tremula) by following changes in pigment, metabolite and nutrient content, photosynthesis, and cell and organelle integrity. The senescence process started on September 11, 2003, apparently initiated solely by the photoperiod, and progressed steadily without any obvious influence of other environmental signals. For example, after this date, senescing leaves accumulated anthocyanins in response to conditions inducing photooxidative stress, but at the beginning of September the leaves did not. Degradation of leaf constituents took place over an 18-d period, and, although the cells in each leaf did not all senesce in parallel, senescence in the tree as a whole was synchronous.............

Answer 2

photo periodism is the mechanism which helps the plants to turn red and fall durining autumn season

Answer 3

thanx

Answer 4

always welcome......