碱性盐胁迫对偃麦草苗期生长的影响

Effects of saline-alkaloid stress on the seedling growth and physiological characteristics of Elytrigia repens

采用不同浓度(0、20、40、60、80、100和120mmol·L^(-1))碱性盐混合溶液(NaCl、Na_2SO4、NaHCO_3和Na_2CO_3)处理偃麦草新品种"农菁7号"(Elytrigia repens Nong Jing No.7),测定其幼苗存活率、株高和生物量,旨在明确盐碱胁迫对偃麦草幼苗生长的影响和碱性盐胁迫下偃麦草叶片叶绿素、游离脯氨酸、可溶性糖、丙二醛(MDA)、超氧化物酶(SOD)活性,以探讨偃麦草主要生理指标对盐碱胁迫的响应规律。结果表明,碱性盐胁迫可降低偃麦草幼苗存活率、株高及生物量,当溶液浓度≥80mmol·L^(-1)后幼苗存活率显著下降(P<0.05)。株高和生物量与碱性盐溶液浓度均呈极显著的负相关关系(P<0.01)。偃麦草叶绿素含量随碱性盐胁迫浓度的增加呈现出先增加后降低的趋势,在80mmol·L^(-1)时达到最大值。游离脯氨酸、MDA和SOD均随胁迫浓度的增加而增加。碱性盐胁迫对偃麦草苗期的生长发育产生不利的影响,为了适应盐碱环境,偃麦草各种生理生化指标都会进行相应的调节。

Soil salinization is a serious worldwide problem which causes heavy losses of agriculture production.Plants with higher salt tolerance has been considered as a best way to control the saline soil.In the present study,the effects of saline-alkaloid stress on growth including the survival rate,plant height and biomass and biochemistry including chlorophyll,proline,soluble sugar,MDA and SOD activities of Elytrigia repens new variety ＂Nong Jing No.7＂were studied.The results showed that the survival rate,plant height and biomass of E.repens decreased under saline-alkaloid stress.The survival rate significantly decreased（P〈0.05）under treatment over 80mmol·L^-1 concentration of saline-alkaloid.There was a very significant negative relationship（P〈0.01）between saline-alkaloid concentration and plant height and biomass.The chlorophyll content increased and then decreased with saline-alkaloid concentration increased which reached peak under treatment of80mmol·L^-1.The contents of soluble sugar and MDA and SOD activities increased with saline-alkaloid concentration increased.All these results showed that saline-alkaloid stress had negative effect on the seedling growth of E.repens,and the physiological and biochemical indexes of E.repens changed to adapt to the salinealkaloid environment.