Botanist's Lens: Life Sans Senescence
Maidenhair tree (Ginkgo biloba)
Senescence is the last stage of plant development. Leaf buds grow into a leaf, mature and during senescence, the last stage occurs where it withers, falls and leaves the plant. Senescence and abscission (natural cutting off of plant part from the plant) together help in falling of leaves, flowers and fruits.
Without abscission how would the apple fall down from the tree? Then how would, Newton still discover gravity? Senescence and abscission are timed sequences that, even though they lead to death of a tissue, they are a key process for the plant to live on. Without fruits falling off, how would the seeds wither away? Without leaves withering in a timely manner, the plant would loose crucial building blocks to live on. Life sans senescence and abscission wouldn't be good for plants.
Maple 'Sango Kaku' (Coral Bark Maple)
Autumn senescence in plants is an important process in deciduous eastern forests. It is initiated by change in photoperiod first than change in temperature. Lower temperatures accelerate the green pigment chlorophyll degradation, but the onset is certainly due to change of day light hours. Senescence is a programmed process in which the plant almost reclaims its building blocks from the leaves, before they wither and fall away.
"Leaf senescence is induced as part of plant development but can also be prematurely induced as a result of environmental changes or harvesting. Premature senescence leads to reduced yield and quality of crops and this is likely to be of increasing concern in times of climate change and parallel population growth." - Source