Physiological changes in epiphytic plants under stress

[Ravi]

Abiotic factors : light & water.
High light intensity and water deficit contribute to stress.
Changes are : switching over to CAM metabolism.
CAM: craussulacean acid metabolism for survival.
CAM (syn) CAM photosynthesis : a carbon fixation pathway to adapt to arid conditions
The stomata remain shut during day to minimise evapotranspiration and open during the night to collect CO2.
Light stress: excess light absorbed more than required for photosynthesis , “ excess light”. Expressed by a ratio photon flux density and photosynthesis high ,as a protective mechanism photo inhibitor process turned on. Photo chemical inactivation mostly PSII is triggered, CAM is one of the means for epiphytic plant survival and adaption to inappropriate light & water conditions .
Survival of plants like Phalaenopsis, the low light intensity orchids, depends upon how quickly they can adapt to the changing environment.
There is formula for photon flux density which is beyond the scope.
References:
Abstracts from Asian journal of plant sciences.
Wikipedia.
alan.ece.gatech.edu>ECE4833>lectures

Orchids also have a role in the balance of eco system of the forests