摘要
研究镉(Cd)对大豆种子萌发和早期幼苗生长的胁迫伤害及外源水杨酸(SA)的缓解作用.以大豆品种"中黄13"为试验材料,采用纸间发芽法和水培法.研究Cd和外源SA对大豆种子萌发、种胚和幼苗抗氧化系统、幼苗光合特性、营养元素吸收转运和抗逆基因表达的影响.2.5 μmol L-1CdCl2胁迫诱发大豆种胚和幼苗氧化损伤,抑制幼苗对营养元素的吸收和转运、降低幼苗光合作用,进而抑制大豆种子萌发和早期幼苗的生长.添加50 μmol L-1 SA可减轻Cd对种胚和幼苗的氧化胁迫伤害,降低Cd在幼苗中的积累,促进幼苗对营养元素的吸收和转运、增强幼苗光合作用.Cd胁迫下,添加SA幼苗生长7 d,幼苗叶片H2O2、O2和 MDA含量分别比Cd胁迫处理降低46.31％、29.85％和37.89％.根系H2O2、O2-和MDA含量分别比Cd胁迫处理降低59.24％、46.30％和46.84％.幼苗叶中Cd含量比Cd胁迫处理降低63.50％,幼苗叶中Ca、Cu、Fe、Mg、Zn等元素含量比Cd胁迫处理分别增加84.45％、71.42％、192.50％、145.13％和141.20％,幼苗根中Ca、Cu、Fe、Mg、Zn 等元素含量比 Cd 胁迫处理分别增加 186.13％、453.51％、198.05％、131.39％和 112.50％,幼苗净光合速率(Pn)、PSⅡ最大光合效率(Fv/Fm)比Cd胁迫处理提高137.60％和24.99％.外源SA通过诱导上调大豆幼苗抗氧化系统基因表达,下调参与Cd转运蛋白基因DMT、IRT和MT1表达量,诱导抗氧化酶活性提高、降低幼苗对Cd的吸收,促进幼苗对营养元素的吸收和转运、增强幼苗光合作用,缓解Cd对大豆种子萌发和早期幼苗生长的胁迫伤害.
Abstract
This study investigated the impact of cadmium(Cd)stress on soybean seed germination and early seedling growth,and examined the potential alleviating effect of exogenous salicylic acid(SA).The experiment utilized the soybean variety'Zhonghuang 13'and employed both paper germination and hydroponic methods.Various aspects including the antioxidant sys-tem,photosynthetic characteristics,nutrient absorption and transport,and stress resistance gene expression were analyzed under the influence of Cd and exogenous SA.Results showed that 2.5 μmol L-1 CdCl2 stress led to oxidative damage in soybean em-bryos and seedlings,hindering nutrient absorption and transport as well as reducing photosynthesis,consequently inhibiting seed germination and early seedling growth.However,the addition of 50 μmol L-1 SA mitigated the oxidative stress caused by Cd,resulting in reduced Cd accumulation,enhanced nutrient absorption,and improved photosynthesis.Specifically,under Cd stress,the application of SA decreased the levels of H2O2,O2-,and MDA in both leaves and roots,while also reducing Cd content in the leaves and increasing the contents of essential elements such as Ca,Cu,Fe,Mg,and Zn.Moreover,the net photosynthetic rate(Pn)and maximum photosynthetic efficiency of PSⅡ(Fv/Fm)were significantly improved with SA treatment compared to Cd stress alone.Exogenous SA up-regulated the expression of antioxidant system genes in soybean seedlings while down-regulating the expression of Cd transporter genes DMT,IRT,and MT1.This led to an increase in antioxidant enzyme activity,a reduction in Cd absorption by seedlings,promotion of nutrient absorption and transport,enhancement of photosynthesis,and alleviation of stress damage caused by Cd during soybean seed germination and early seedling growth.
基金项目
山西省重点研发计划项目(201803D221011-5)
维普
万方数据