Relation1 between the photosynthesis of Paris polyphylla var.yunnanensis and the environmental factors

Light compensation point, saturation light intensity,CO2 compensation point carbozylation efficiency and the effect of temperature and humidity on the photosynthetic rate of Paris polyphylla var.yunnanensis were studied with the photosynthesis analysis system and in the phytotron.It shown light compensation point,CO2 compensation point and carbozylation efficiency was 5.7?μmol/(m2·s),65?μmol/mol and 0.029?5 respectively,but the saturation light intensity was not monitored even if the photosynthetic active radiation increased from 0 to 2?000?μmol/(m2·s) and the optimal radiation was from 750 to 2?000?μmol/(m2·s).The net photosynthetic rate increased with CO2 concentration increasing,the CO2 concentration over normality would enhance utilization efficiency of light energy in photosynthesis.When the leaf temperature increased from 11℃ to 20℃ the net photosynthetic rate increased,but it increased from 20℃to 35℃,the rate decreased.The optimal temperature was from 16℃ to 28℃.When relative humidity went up from 20% to 85%,the net photosynthetic rate increased.The optimal humidity was above 75%.