水因子对东北铁线莲光合特性的影响

Effects of water factor on photosynthesis of Clematis manshurica Rupr.

【目的】研究水因子对东北铁线莲光合特性的影响。【方法】采用室外盆栽法,在东北铁线莲生长季节设3种供水处理(312,468和624mm),研究水分供给量对东北铁线莲净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)、气孔限制值(Ls)和水分利用效率(WUE)日变化的影响。【结果】水分供给量为312,468和624mm时,Pn日均值为分别为2.83,4.05和3.56μmol/(m2.s),三者间差异显著(P<0.05);不同水分供给量东北铁线莲Pn出现了"光合午休"现象,呈明显双峰曲线。供水量为468mm处理东北铁线莲日平均Gs与供水量为312和624mm处理间存在显著差异(P<0.05)。供水量为312mm处理的日平均Tr和WUE与供水量为624mm处理间的差异极显著(P<0.01)。不同供水量对Ci和Ls日平均值均未产生显著影响。【结论】东北铁线莲的"光合午休"现象主要由非气孔因素引起;吉林省东北铁线莲规模种植区应选择在东北铁线莲生长季节降水量达468mm的地区。

【Objective】Effect of water supply on photosynthesis of Clematis manshurica Rupr.was stuied.【Method】The effects of water supply on net photosynthetic rate,stomatal conductance,intercellular CO2 concentration,transpiration rate and stomatal limitation value in the herbal plant C.manshurica were investigated.The herb was exposed to three water supply treatments,control,and mild,moderate,and severe water stress.The three treatments meant 312,468 and 624 mm total water supply distributed over the growth period in such proportion,which modeled the seasonal mean precipitation.【Result】The results showed that the daily average of Pn under the water supply of 312,468 and 624 mm was 2.83,4.05 and 3.56 μmol/（m^2·s）,respectively,and there were significant differences（P〈0.05）.Pn values of C.manshurica in different water supplies could be expressed as two-hump curves,reflecting a obvious middy depression at noon;there were significant differences（P〈0.05）of daily average Tr and WUE between water supply of 312 and 624 mm.However,there were no significant differences of daily average Ci and Ls under different water supplies.【Conclusion】The decrease in Pn during midday was mainly resulted from nonstomatal limitation.These results suggested that the production of C.manshurica in Jilin province should be arranged in the regions of precipitation ranging 468 mm.