Writes notes on following :

(a) Senescence (b) Abscission

(c) Quiescence (d) Vivipary.

(a) Senescence : Senescence is the process of  ageing in plants. It is the period between maturity and death.

(b) Abscission: It is the natural falling of leaves, foliage branches, fruits, floral parts etc.  

(c) Quiescence : It is the suspension of growth due to external factors. It is a period during which development is suspended. 

(d) Vivipary : It is the process when seeds germinate inside fruits which are still attached to the mother plant.