排序方式: 共有1条查询结果,搜索用时 0 毫秒
1
1.
An estimate of photorespiration is obtained from the relationshipbetween the net exchange of CO2 of the leaf and the internalCO2 concentration, i.e. within the mesophyll intercellular spaces.The latter is obtained by calculation, taking into account thecombined epidermal and boundary-layer resistances between thebulk atmosphere and the mesophyll intercellular spaces. Thelinear part of this relationship (at low CO2 concentrations)is extrapolated to zero internal concentration, at which noneof the intercellular photorespired CO2 is available for reassimilation.The calculated output of CO2 under such conditions providesan estimate of photorespiration, but, by failing to take intoaccount intracellular reassimilation of photorespired CO2 underestimatesactual photorespiration. As the slope of this linear relationshiprepresents the mesophyll (intracellular) resistance to CO2 uptake,this procedure was used to recalculate published data on effectsof light intensity and of oxygen concentration on net photosynthesis.The analysis showed that increased oxygen concentration anddecreased light intensity reduced photosynthesis largely byincreasing mesophyll resistance to CO2 uptake. It is suggestedthat the CO2 compensation point () is a function of both photorespiration(L) and mesophyll resistance (rm): = L. rm. 相似文献
1