Define the term 'stress' for plants. Discuss briefly the two types of stress encountered by plants.

(N/A) In plant biology,'stress' refers to any external condition that negatively impacts the plant's growth,development,or productivity. These conditions deviate from the optimal range required for normal physiological processes.
The two main types of stress are:
$1$. Abiotic Stress: These are non-living environmental factors that cause stress,such as drought (water deficit),salinity (high salt concentration),extreme temperatures (cold or heat),and heavy metal toxicity.
$2$. Biotic Stress: These are stresses caused by living organisms,such as pathogens (bacteria,fungi,viruses),pests (insects),and competition from weeds.