Class 12th Biology 2017 Set1 Outside Delhi Board Paper Solution
Describe the inter-relationship between productivity, gross primary productivity and net productivity.
Primary production is defind as the amount of biomass or organic matter produced per unit area over a period of time by plant during photosynthesis. It is expressed in terms of weight or energy.
The rate of biomass production is called productivity. It is expressed in terms of g-2 yr-1 or (Kcal m-2) yr-1 to compare the productivity of different ecosystem.
It can be divided into gross primary productivity (GPP) an net primary productivity (NPP)
GPP is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is utilised by plants in respiration. Gross primary productivity minus respiration losses (R) is the net primary productivity (NPP).It is the weight of the organic matter stored by the produces in a unit area/volume per unit time.
GPP - R = NPP
Net primary productivity is the available biomass for the consumption to heterotrophs.
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