外源独脚金内酯对油菜苗期干旱胁迫的缓解效应

Alleviation effects of exogenous strigolactone on growth of Brassica napus L.seedling under drought stress

为了探究外源独脚金内酯(SLs)对油菜苗期干旱胁迫的缓解效应,以甘蓝型油菜品种中双11为材料进行盆栽试验,研究了0.18μmol/L SLs灌根处理对正常供水和干旱胁迫下油菜长势、光合速率、抗氧化系统和渗透调节物质的影响。研究表明,外源SLs能有效缓解干旱胁迫对油菜苗期生长的抑制作用,与干旱胁迫相比,SLs处理后干物质积累量增加了21.13%,总叶绿素含量和叶片净光合速率分别提高9.37%和90.65%,可溶性糖和脯氨酸含量分别增加26.53%和25.28%;超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等酶活性分别提高12.58%,12.04%和12.61%;抗氧化物质抗坏血酸(ASA)和还原型谷胱甘肽(GSH)含量分别增加14.15%和18.96%,抗坏血酸/脱氢抗坏血酸(ASA/DHA)、还原型谷胱甘肽/氧化型谷胱甘肽(GSH/GSSG)比值提高;活性氧水平显著降低,过氧化氢(H2O2)含量和超氧阴离子自由基(O2·-)产生速率分别下降了11.18%和15.28%,有效减少叶片丙二醛(MDA)的积累,减轻因干旱胁迫导致的膜系统损伤。综上,SLs处理能加快干旱条件下油菜叶绿素合成速度,提升叶片光合能力,提高叶片抗氧化能力,促进油菜苗期生长,有效提高油菜苗期抗旱性。

In order to reveal the alleviating effect of exogenous strigolactone(SLs)on drought stress in rape seeding stage,a pot experiment with Zhongshuang 11(Brassica napus L.)was conducted to study the effects of 0.18μmol/L SLs on growth,photosynthetic rate,antioxidant system and osmotic regulators in rapeseed under well water supply and drought stress.The results showed that exogenous SLs could effectively alleviate the inhibition of drought stress on growth of rapeseed seedlings.Compared with drought stress,SLs treatment effectively increased the dry matter accumulation by 21.13%.The chlorophyll content and net photosynthetic rate of leaves increased by 9.37%and 90.65%,respectively.Moreover,the soluble sugar and proline content increased by 26.53%and 25.28%,respec⁃tively.The activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)increased by 12.58%,12.04%and 12.61%,respectively.The contents of antioxidant ascorbic acid(ASA)and glutathione(GSH)increased by 14.15%and 18.96%,respectively.The ratios of ASA/DHA and GSH/GSSG increased either.The levels of reac⁃tive oxygen species decreased significantly,the hydrogen(H2O2)content and superoxide anion radical(O2·-)produc⁃tion rate decreased by 11.18%and 15.28%,respectively,and effectively reduced the malondialdehyde(MDA)con⁃tent in leaves and alleviated membrane damage caused by drought stress.In conclusion,SLs treatment can acceler⁃ate the chlorophyll synthesis rate,enhance photosynthetic capacity and antioxidant capacity of leaves,promote the growth of rapeseed seedlings,and effectively improve the drought resistance in rape seedlings stage.