On Photosynthetic Characteristics of Siji Pomelo

The photosynthetic characteristics of leaves in 7 year old guanximiyou pomelo variety under field conditions are studied. The results are as follows:(1) The diurnal variation of net photosynthetic rate( Pn ) of peripheral leaves in sunny days presented bimodal carve.In overcast days, the daily change of Pn had one peak , The diurnal variation of Pn of inner leaves showed the one peak or indention carve.(2) Analyze Pn in maximal and average of Pn : Pn 10 Pn 6 Pn 11 Pn 7 Pn 8.(3) Among shoots in different months, there are differences in the responses of leaves Pn to light intensity and CO 2.The light compensate (Lcp) and saturated (Lsp) point of leaves was 17.42～78.31 μmol/m 2·s and 1 378～1 821 μmol/m 2·s respectively,the apparent quantum efficiency between 0.019 73 and 0.050 98; the CO 2 compensate (Ccp) and saturated (Csp) point was 52.54～97.31 μmol/mol and 800～961 μmol/mol respentively,the carboxying efficiency between 0.020 39 and 0.053 40,which indicates that sijiyou take on obvious character of C 3 type plant.(4) The proper temperature of photosynthesis are 24～32 ℃.(5) There are different relativity between Pn and the physio ecological factors in different means