盐胁迫对二色补血草光合生理生态特性的影响

以黄河三角洲贝壳堤岛贝壳沙为基质,及该岛上生长的优势草本植物二色补血草幼苗为材料,用不同浓度的NaCl溶液(0,50,100,200,300mmol/L)模拟盐胁迫处理30d,探讨二色补血草光合生理生态特性对盐胁迫的响应特征。结果表明:二色补血草对盐胁迫和光合有效辐射(PAR)具有较强的适应能力,在盐浓度为50～100mmol/L条件下,其净光合速率(Pn)、瞬时水分利用效率(WUE)、表观光能利用效率(LUE)、羧化效率(CE)、光饱和点(LSP)、表观量子效率(AQY)均达到最高值,光补偿点(LCP)最低,表明其在此盐分范围内,利用光的能力较强,光照生态幅最宽。当盐分浓度为300mmol/L时,其Pn、WUE、LUE、CE、LSP和AQY显著下降,LCP升高,Pn、Tr、Gs、WUE、LUE、CE对PAR的响应曲线与对照差异较大,即高盐胁迫加重了二色补血草对光的敏感性;WUE、LUE、CE的最优PAR和盐分范围存在一定的差异,低PAR下有利于光能的利用,中PAR下有利于水分的利用,高PAR下有利于CO2的利用;WUE对盐分的适应范围最大,CE其次,LUE最小。

Photosynthetic Characteristics of Limonium bicolor under Salt Stress

An experiment with shell sand was carried out to study the effects of NaCl stress on the characteristics of photosynthesis in Limonium bicolor.Five different concentrations of NaCl were applied:0,50,100,200,300 mmol/L for 30 d.The results showed as follows:(1)Under 50,100 mmol/L NaCl stress,the net photosynthesis rate (P_n),instantaneous water use efficiency (WUE),apparent light use efficiency (LUE),carboxylation efficiency (CE),light saturation point (LSP),apparent quantum efficiency (AQY) all reached maximum value,which showed Limonium bicolor has a strong ability to adapt to salt stress and light intensity.The most wide ecological amplitude of light was observed.The minimum of light compensation point (LCP) was observed.(2)P_n,WUE,LUE,CE,LSP and AQY decreased,but LCP increased with NaCl stress being 300 mmol/L.The light response curves of P_n,T_r,G_s,WUE,LUE,CE were different from control significantly,which showed that the higher the NaCl stress was,the more sensitive of characteristics of photosynthesis in L.bicolor were about light density.Its ability to use light intensity decreased.The ecological amplitude of light became narrow.The optimal range of PAR for WUE,LUE,CE is different,which is low PAR,middle PAR,high PAR.WUE has the maximum ability to adapt to salt stress,CE second,LUE minimum.