摘要
通过分析不同盐分处理60 d胡杨幼苗的光响应特征。结果表明:①在0～3 500μmol·m-2·s-1光强范围,各处理幼苗的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)均随光强增加逐渐增大,而胞间CO2浓度(Ci)呈相反趋势;不同光强下幼苗的Pn、Gs、Tr、Ci和WUE均值均随盐浓度增大而减小;低盐浓度处理(0.5 mol·L-1)条件下,幼苗通过气孔调节提高WUE,降低盐分对幼苗的损伤;高盐处理(2 mol·L-1),气孔基本失去调节能力,出现了Tr相对较低、WUE相对较高的现象,而幼苗的Pn均值降低了约75%,幼苗的光合代谢受到严重抑制。②随盐浓度增大,胡杨幼苗的最大净光合速率(Pnmax)、表观量子效率(α)、暗呼吸速率(Rd)和光饱和点(LSP)逐渐降低,光补偿点(LCP)逐渐增加,盐分抑制了幼苗对光的吸收、利用和转换能力。
As the dominant species of the riparian forests along the Tarim River in Xinjiang,northwest China,Populus euphratica plays an important role in maintaining the functions of riparian ecosystem. Recent embankments along the river have altered the soil,water and salinity conditions of the riparian zones,which is expected to impact the survival and growth of P. euphratica seedlings as well as the regeneration of the riparian forests. In order to assess the potential effects of these alterations on P. euphratica,the photosynthesis of P. euphratica seedlings under different soil salinity gradients was explored. The results indicated that the net photosynthetic rate（ Pn）,stomatal conductance（ Gs）,transpiration rate（ Tr） and water use efficiency（ WUE） of the seedlings were increased with the increase of the photosynthetically active radiation（ PAR） in a range of 0- 3 500 μmol·m^- 2·s^- 1,whereas the change of intercellular CO2concentration（ Ci） was reverse. Photosynthesis of seedlings was restrained,which was evidenced by the decrease of the mean values of Pn,Gsand Trunder the mild salinity stress（ 0. 5 mol·L^- 1）.However,the WUE of seedlings was high to reduce water loss through regulating stomatal closure. Under severe salinity stress（ 2 mol·L^- 1）,the Tr of seedlings was significantly decreased due to the insensitive stomatal regulation to light,and the average of Pnwas decreased by about 75%. With the increase of salinity,the maximal net photosynthetic rate（ Pnmax）,light-saturation point（ LSP）,dark respiration rate（ Rd） and apparent quantum yield（ α）of the seedlings were gradually decreased,but the light compensation point was gradually increased. The results suggested that the capability of light absorption,utilization and conversion of the seedlings was restrained under salinity stress.
出处
《干旱区研究》
CSCD
北大核心
2014年第4期728-733,共6页
Arid Zone Research
基金
国家自然基金项目(41171095)
国家"973"项目(2013CB429905)
科技支撑计划项目(2013BAC10B01)
关键词
胡杨幼苗
盐胁迫
光合—光响应曲线
Populus euphratica seedling
salinity stress
photosynthesis-light response curve
