盐碱胁迫下水稻齐穗期剑叶光响应特性的研究

采用LI-6400P型光合仪测定了盐碱胁迫下水稻品种吉优1号齐穗期剑叶的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)对不同模拟光强的响应。结果表明,无论是盐碱胁迫还是非盐碱胁迫,水稻剑叶的Pn、Gs、Tr在低光强(0～200μmolphotonm-2s-1)下随光强的增加呈直线上升趋势,而Ci呈直线下降趋势;在中光强(200～800μmolphotonm-2s-1)下Pn、Gs、Tr随光强增加上升趋缓,而Ci缓慢降低;在高光强(>800μmolphotonm-2s-1)下Pn、Gs、Tr均达到最大值,并保持平衡或略有下降,而Ci降到最低并保持平衡。但与非盐碱胁迫相比盐碱胁迫使Pn、Gs、Tr、Ci整体下降。盐碱胁迫降低了水稻的光饱和点和光补偿点。

Studies on Light Response Characteristics of the Flag Leaves at Full Heading Time of Rice under Saline-alkali Stress

The physiological characteristics of flag leaves of rice variety "Jiyou 1" at full heading time under saline alkali stress,such as net photosynthesis rate (Pn),stomatal conductance (Gs),transpiration rate (Tr),intercellular CO2 and concentration (Ci) were measured with LI-6400 Potable Photosynthesis System under simulated light intensities from 0 to 200 μmol photon m-2s-1.The results showed that in any case Pn,Gs and Tr increased sharply as the light intensity enhanced from 0 to 1 500 μmol photon m-2s-1,whereas Ci decreased significantly.Pn,Gs and Tr increased slowly and Ci reduced slowly as the light intensity enhanced from 200 to 800 μmol photon m-2s-1.As the light intensity exceeded 800 μmol photon m-2s-1,Pn,Gs and Tr reached maximum respectively and tended to dynamic balanced or decreased slightly,while Ci reduced to minimum and kept a balance.Compared with the control,Pn,Gs,Tr and Ci of saline alkali stressed rice entirely decreased.The light saturation point and light compensation point of photosynthesis were significantly lowered under saline alkali stress.