混合盐胁迫对刺槐和绒毛白蜡根系生长及其解剖结构的影响

Effects of mixed salt stress on the root growth and natomical structure of Robinia pseudoacacia and Fraxinus velutina

以刺槐和绒毛白蜡为研究对象,设置不同浓度的NaCl和Na_2CO_3混合盐胁迫,对比两种植物的生物量分配、盐敏感指数和盐耐受指数的差异,制作石蜡切片观察盐胁迫对根系结构的影响。结果表明:随着盐胁迫程度的增加,刺槐和绒毛白蜡的生长均受到抑制;低浓度(0.2%)的盐胁迫对刺槐的生物量有促进作用,盐敏感指数和耐受性指数最高,而绒毛白蜡在中盐浓度下(0.4%)耐受性最高,在高盐浓度下(0.8%)敏感性较高;在混合盐胁迫下,绒毛白蜡根系周皮比例增加程度大于刺槐,而皮层比例增加程度低于刺槐,绒毛白蜡根系中维管束比例减小,而刺槐趋势相反。说明在盐胁迫下刺槐和绒毛白蜡采取不同的耐盐策略。

The biomass allocation,salt sensitive index and salt tolerance index were compared between Robinia pseudoacacia and Fraxinus velutina under the mixed salt stress with different concentrations of NaCl and Na2CO3.The paraffin sections were made to observe the effect of salt stress on the root structure.The results showed that the growth of both R.pseudoacacia and F.velutina were suppressed with the increase of salt stress.The biomass of R.pseudoacacia increased at the low concentration of salt stress(0.2%),meanwhile R.pseudoacacia performed the highest salt sensitive index and tolerance index.F.velutina performed the highest tolerance index in the moderate salt concentration(0.4%)and stronger sensitivity under high salt concentration(0.8%).The root periderm proportion of F.velutina was higher than that of R.pseudoacacia’s in the mixed salt stress,while the cortex ratio increased less than R.pseudoacacia.The vascular bundle proportion of F.velutina root was reduced,while the opposition trend was observed in R.pseudoacacia.Under salt stress,R.pseudoacacia and F.velutina have different salt tolerance strategy.