盐旱胁迫对不同大豆品种(系)生长和光合特性的影响

Effects of Salt and Drought Stresses on Growth and Photosynthetic Characteristics of Different Soybean Varieties(Lines)

为明确盐、干旱及盐旱复合胁迫对不同大豆(Glycine max L.)品种(系)生长和光合特性等的影响,本研究以7个大豆品种(系)为材料,设置对照(CK,正常供水,75%田间最大持水量)、盐胁迫(S,土壤含盐量0.44%)、干旱胁迫(D,35%田间最大持水量)和盐旱复合胁迫(S+D,35%田间最大持水量,土壤含盐量0.44%)4个处理,采用盆栽方式,研究不同处理对大豆苗期生长、光合特性、叶绿素含量、叶绿素荧光参数和根系构型等31个指标的影响。结果表明,与对照相比,盐和盐旱复合胁迫均显著降低大豆幼苗的数字生物量、叶面积、归一化植被指数和叶片的叶绿素含量、暗反应最大荧光(Fm)、最大光化学效率(Fv/Fm)、PSⅡ的潜在活性(Fv/Fo)、实际光化学效率(ΦPSⅡ)、表观光合电子传递速率(ETR)、非光化学猝灭系数(NPQ),且在盐旱复合胁迫处理下降幅更大,干旱胁迫显著增加大豆幼苗的叶片角度和叶片投影面积;三种胁迫处理均明显降低大豆总根长、根表面积、根体积、根尖数、根分叉数、交叉数和光合速率、气孔导度、胞间CO_(2)浓度及蒸腾速率,且多数指标下降达显著水平,干旱胁迫处理的降幅小于盐和盐旱复合胁迫处理。综上可知,盐旱复合胁迫对大豆幼苗生长的影响最明显,盐胁迫次之,干旱胁迫最轻。由主成分分析和隶属函数综合评价结果得出,21C49为耐盐品系,蒙豆46为耐旱、耐盐旱复合胁迫品种,黑科68为盐敏感、旱敏感品种,龙垦330为盐旱复合胁迫敏感品种。

In order to determine the effects of salt stress,drought stress and their combination on growth and photosynthetic characteristics of different soybean(Glycine max L.)varieties(lines),7 soybean varieties(lines)were used as materials,and the pot experiment was conducted by setting four treatments including control(CK,normal water supply,75%of maximum field water capacity),salt stress(S,0.44%of soil salt content),drought stress(D,35%of maximum field water capacity)and salt-drought combined stress(S+D,35%of maximum field water capacity,0.44%of soil salt content).The effects of different treatments on 31 in-dicators of soybean seedlings such as growth parameters,photosynthetic characteristics,chlorophyll content,chlorophyll fluorescence parameters and root configuration were studied.The results showed that compared with CK,the digital biomass,leaf area,normalized vegetation index,leaf chlorophyll content,and some chloro-phyll fluorescence parameters including Fm,Fv/Fm,Fv/Fo,ΦPSⅡ,ETR and NPQ of soybean seedlings were significantly reduced under S and S+D treatments,especially under S+D treatment.Drought stress signif-icantly increased the leaf angle value and leaf projection area of soybean seedlings.The three stress treatments significantly reduced total root length,root surface area,root volume,root tip number,root bifurcation num-ber,cross number,photosynthetic rate,stomatal conductance,intercellular CO_(2)concentration and transpira-tion rate of soybean seedlings,and most of these indicators decreased to a significant level,but the reduction range under drought stress treatment was smaller than that under salt stress and their combination.In conclu-sion,the effects of salt and drought combined stress on soybean seedling growth were the most obvious,fol-lowed by salt stress and drought stress in order.According to the results of principal component analysis and membership function comprehensive evaluation,21C49 was a salt-tolerant line,Mengdou 46 was a variety re-sistant to drought stress and salt-drought combined stress,Heike 68 was a salt-sensitive and drought-sensitive variety,and Longken 330 was a variety sensitive to salt-drought combined stress.