Changes in leaf photosynthesis of Citrus after winter
1993
Chen Zhihui | Jin Yongfeng | Ma Chunjuan (Zhejiang Agricultural Univ, Hangzhou (China). Dept. of Horticulture)
The experiment was carried out using a portable CO2 Infra-gas-analyser to measure leaf photosynthetic rates of Citrus unshiu after winter in Hangzhou. The photosynthetic rates of three leaf types (Spring, summer and autumn leaf of last year) of trees tended to increase, a phenomena of the recovery of leaf photosynthesis after winter. But the levels of photosynthetic rate were different with three leaf types, being highest in autumn leaf, lowest in spring leaf and intermediate in summer leaf. During the recovery of leaf photosynthesis, the fluctuation of leaf photosynthetic rates was obviously related to that of air temperatures. Furthermore, the recovery of photosynthesis was concurrent with the going-up of chlorophyll content in the leaf, and consequently an evident increase in leaf apparent quantum yield, though the carboxylation efficiency kept almost constant. The results presented show that the recovery of leaf photosynthetic capacity of citrus after winter was closely dependent on the regain of leaf capacity to use light energy
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