叶面喷施蔗糖对弱光胁迫下南瓜幼苗生长和光合特性的影响

为探究外源蔗糖对弱光胁迫下南瓜幼苗生长和光合特性的影响,以蜜本南瓜为材料,设置4个处理:正常光照(300μmol·m^-2·s^-1)下叶面喷施清水(CK),弱光(150μmol·m^-2·s^-1)下喷施清水(T0)、1%的蔗糖(T1)和2%的蔗糖(T2)。结果表明,与正常光照相比,弱光显著降低了南瓜幼苗的株高、茎粗、生物量、壮苗指数、比叶重等生长指标,以及荧光参数、净光合速率等光合指标。弱光下叶面喷施1%和2%的蔗糖提高了南瓜幼苗的株高、茎粗、生物量、比叶重、叶绿素含量、荧光参数和P_n-PPFD响应曲线及其参数等,其中喷施1%蔗糖增加幅度较大,地上部鲜质量、干质量、比叶重、叶绿素总含量、Fv/Fm、qP、TRO/RC、Ψo、AQY和P_(n max)分别比弱光处理显著增加了28.5%、40.6%、31.3%、5.7%、27.9%、37.5%、3.4%、14.3%、38.5%和34.3%,以上指标喷施2%蔗糖处理与1%蔗糖处理无显著差异。综上所述,弱光下喷施蔗糖可促进南瓜幼苗的生长并有效改善光和性能,且以1%蔗糖处理效果最好。

Effects of foliar spraying sucrose on growth and photosynthetic characteristics of pumpkin seedlings under weak light stress

To investigate the effects of exogenous sucrose on the growth and photosynthetic characteristics of pumpkin seedlings under weak light stress,we used Honey Pumpkin as the test material and set the following four treatment experiments:foliar sprayed with clear water(CK)under the normal intensity(300μmol·m^-2·s^-1),foliar sprayed with clear water(T0),1%sucrose(T1)and 2%sucrose(T2)under weak light intensity(150μmol·m^-2·s^-1).The results showed that,compared with normal light intensity,weak light intensity significantly reduced the growth indicators of pumpkin seedlings such as plant height,stem thickness,biomass,strong seedling index,and specific leaf weight,as well as photosynthetic indicators such as fluorescence parameters and P_n-PPFD response curves.Foliar spraying of 1%and 2%sucrose under weak light significantly improved the growth,leaf morphology,chlorophyll content,fluorescence parameters,and P_n-PPFD response curves and their parameters of pumpkin seedlings.In particular,the spraying of 1%sucrose increased the aboveground fresh/dry weight,specific leaf weight,total chlorophyll content,Fv/F_m,q_p,TRO/RC,Ψo,AQY and P_(n max) significantly by 28.5%,40.6%,28.6%,5.7%,27.9%,37.5%,3.4%,6.7%,38.5%and 34.3%.There was no significant difference between 2%sucrose spraying and 1%sucrose spraying for the above indicators.Spraying sucrose has a significant effect on the growth of pumpkin seedlings and effectively improve the photosynthetic performance under weak light intensity,in which 1%sucrose treatment has the better effect on the promotion of pumpkin growth and photosynthesis.