define the term "stress" for plants. discuss briefly the two types of stress encountered by plants .

Any change in the surrounding environment may cause disruption to homeostasis. Environmental modulation of homeostasis is defined as biological stress. Thus, plant stress implies any adverse effect on the physiology of a plant. It can be divided into two primary categories :-
1) ​Abiotic stress- It ​is a physical or chemical insult that the environment may impose on a plant disrupting homeostasis.
2) ​Biotic stress- It ​is a biological insult to which a plant may be exposed during its lifetime.