苏打盐碱胁迫对甜高粱叶片结构及抗性指标的影响

为确定以Na2CO3和NaHCO3为主要成分的苏打盐碱胁迫对甜高粱叶片结构及抗性影响,研究了盐碱胁迫下甜高粱品种314B和M-81E叶片结构与幼苗生理指标的变化。结果表明:针对应试的两个甜高粱品种,苏打盐碱胁迫可极显著减小叶片厚度、中脉厚度和最大导管直径,极显著增加叶片上下角质层及下表皮厚度(P<0.01)。增加叶绿体中淀粉粒和嗜锇滴颗粒数,且发生叶绿体被膜和基质分离现象;使线粒体内膜上嵴数量减少,甚至消失。株高和茎基周长均比对照极显著减小,叶绿体色素极显著增加(P<0.01);叶片质膜相对透性和脯氨酸含量极显著升高,品种间丙二醛含量的变化差异较大。过氧化物酶(POD)活性和过氧化氢酶(CAT)活性均极显著升高,超氧化物歧化酶(SOD)的活性极显著降低(P<0.01)。比较叶片结构和抗性生理指标变化可知,品种M-81E比314B抗盐碱性强。

Effects of Saline-sodic Stress on the Blade Structure and Resistant Indexes in Sweet Sorghum(Sorghum bicolor L.Moench)

Sorghum(Sorghum bicolor L.Moench) crop has been considered relatively more salt tolerant than other cereals and has the potential as a grain and fodder crop in saline and alkaline soils.However,only a few of the cultivars can thrive under high levels of salinity.Genetic improvement of Sorghum bicolor for salt tolerance is of importance due to limited arable land and increasing salinity coupled with population pressure.The objective of this study was to investigate the effect of saline-sodic stress(mainly composed of Na2CO3 and NaHCO3) on the blade structure and evaluate the salinity tolerance of two selected sorghum cultivars(314B and M-81E).The results showed that the leaf thickness,midrib thickness and bigger vessels diameter of the two sweet sorghum seedlings were significantly decreased under saline-sodic stress,while the upper epidermis thickness,lower epidermis thickness,upper stratum corneum thickness and lower stratum corneum thickness were significantly increased compared with the control group(P<0.01).Results further indicated that starch grain and osmophilic globule number in chloroplast were significantly increased(P<0.01),and the matrix was separated from the chloroplast envelope.In the mitochondria,the number of ridge in the inner coat appeared to decrease and even disappear.The plant height and stem base perimeter were reduced dramatically,whereas the chloroplast pigment was signally increased(P<0.01).The relative permeability in leaf plasmalemma and the content of proline was increased(P<0.01),and the content of MDA was different between 314B and M-81E.The activity of POD and CAT was significantly increased and SOD was decreased(P<0.01),under salt-affected soil conditions compared with control.Based on above data,it was concluded that the M-81E is much resistant to saline-sodic stress than 314B.In conclusion,sweet sorghum tolerates saline-sodic stress through the changes of the leaf structure and the physiological substances and the resistance is varied among different varieties.