涝害对芝麻根系生长及光合特性的影响

Effects of Waterlogging on Root Growth and Photosynthetic Characteristics of Sesame Seedlings

以抗涝性不同的芝麻(Sesamum indicum L)品种2541和鄂芝2号为材料,在4片真叶期进行涝害处理48h,探讨了涝害与芝麻生长发育及光合参数、叶绿素荧光参数等指标之间的关系。结果表明:(1)涝害导致根系生长缓慢,侧根数减少,不耐涝品种鄂芝2号表现尤其明显。(2)涝害处理后2品种最大荧光(Fm)、开放PSⅡ中心的量子效率(Fv/Fm)、PSⅡ潜在活性(Fv/F_0)和叶绿素含量(Chl)均下降,初始荧光(F_0)则升高。品种2541除Fv/F_0与对照相比达显著水平外,其他荧光参数均与对照未达显著水平。(3)叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)均下降,水分利用效率(WUE)提高,且耐涝品种2541变化幅度较小,到撤水后15d恢复到与对照相当。可见,品种的抗性与光合参数、叶绿素荧光参数以及侧根数量密切相关。

Two sesame(Sesamum indicum L)accessions,ZZM2541 and Ezhi-2,with different tolerance to waterlogging,were selected as test materials and the seedlings at the 4-true leaf stage were treated by waterlogging for 48 h.The relationships between waterlogging damages and growth,photosynthetic parameters and chlorophyll fluorescence parameters were also explored to provide theoretical basis for screening the waterlogging resistant sesames.The results showed that(1)the waterlogging stress induced slow-growing of roots and reduction of adventitious roots in both accessions,especially for the susceptive Ezhi-2.(2)All of the average values of maximum fluorescence yield(Fm),quantum efficiency of open PSⅡcentres(Fv/Fm),initial fluorescence(Fv/F_0)and chlorophyll content(Chl)decreased in both accessions after suffering to the waterlogging stress.There were no significant differences of chlorophyll fluorescence parameters(excluding the Fv/F_0)of ZZM2541 compared with the control.(3)The less reduction of mean photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs)were observed in the leaves of waterlogged ZZM2541 than in waterlogged Ezhi-2(compared to controls),and the leaves of Ezhi-2 showed a higher water use efficiency(WUE)after the removal of waterlogging.The results indicated that the tolerance to waterlogging of sesame accessions was closely related to the photosynthetic parameters,chlorophyll fluorescence parameters and number of adventitious roots.