大青山阳坡油松和山杏光合生理参数与土壤含水量的关系研究

Relationship between Soil Water Content and Photosynthetic Physiological Parameter of Pinus tabulaeformis and Prunus armeniaca in the Sunny Slope in Daqing Mountains

在大青山南麓浅山地带的阳坡造林地,使用Li-6400便携式光合测定仪对不同土壤水分处理下的油松和山杏苗木的光合生理参数进行了测定,研究了叶片净光合速率(Pn)、羧化效率(Ce)、蒸腾速率(Tr)、水分利用效率(WUE)对土壤含水量(SWC)的响应过程,并探讨了在不同土壤水状况下2个树种叶片光合作用的变化规律,最后确定了2个树种在大青山南麓阳坡适宜生长的土壤水分范围。研究表明:油松和山杏叶片Pn最高时的SWC临界值分别为17.9%和18.4%;Tr最高时的SWC临界值分别为18.7%和17.1%;维持叶片水分利用效率最高时的SWC临界值分别为14.66%和13.15%。选择维持最高叶片水分利用效率的SWC临界值和维持最高净光合速率的SWC临界值作为林木生长适宜的土壤水分范围,则油松和山杏生长适宜的土壤水分范围分别为14.66%～17.9%和13.15%～18.4%。

Li-6400 portable photosynthesis system was used to measure the photosynthetic parameters of Pinus tabulaeformis and Prunus armeniaca planted in the sunny slope in Daqing Mountains.The water use efficiency（WUE） was calculated according to WUC=Pn/Tr.The response processes of some parameters to SWC were studied,including net photosynthetic rate（Pn）,carboxylation efficiency（Ce）,transpiration rate（Tr）,water use efficiency（WUE）.The effects of different soil water stress on the photosynthesis and the fitting range of SWC of the two trees species were explored and got.The results showed that when the highest Pn was coming forth,corresponding thresholds of SWC to Pinus tabulaeformis and Prunus armeniaca were 17.9% and 18.4% respectively;when the highest Tr was coming forth,they were 18.7% and 17.1% respectively.The fitting ranges of SWC to Pinus tabulaeformis and Prunus armeniaca were 14.66%~17.9% and 13.15%~18.4% respectively.