盐碱胁迫对枸杞幼苗生长与叶绿素荧光特性的影响

Effects of saline-alkali stress on the growth and chlorophyll fluorescence characteristics of Lycium barbarum seedlings

为深入了解盐碱胁迫下植物的生长发育情况,以宁夏1号枸杞为研究对象,采用盆栽控盐试验,设置完全营养土组(CK)、半营养土半盐碱土组(BK)和完全盐碱土组(AK)3个处理,测定枸杞幼苗的生长指标、叶片叶绿素荧光参数以及质子动力势参数,分析其变化规律。结果表明:低浓度盐碱胁迫(BK组)对枸杞幼苗的生长和叶片叶绿素含量并无显著影响,反而可能促进叶绿素的合成,而高浓度盐碱胁迫(AK组)则会抑制其生长,并使叶绿素含量显著降低;BK组和AK组枸杞叶片光系统Ⅱ(PSⅡ)光反应中心开放数目(q_(L))呈现先增加后减少的趋势,PSⅡ最大光化学量子产量(F_(v)/F_(m))在盐碱胁迫中后期显著下降(P<0.05),而非光化学猝灭系数(q_(N))显著升高(P<0.05);调节性能量耗散的量子产额(Y_(NPQ))随着胁迫时间的延长保持在一个较高的水平,而非调节性能量耗散的量子产额(Y_(NO))则在胁迫后期显著增加(P<0.05);类囊体质子传导率(g_(H^(+)))保持总体下降的趋势,电致变色带移衰退总幅度(ECS_(t))在略微降低后又显著升高(P<0.05);随着盐碱胁迫程度的加强,AK组各项生理指标较BK组波动更为剧烈,变化幅度更大,且与CK组的差异也更为显著。枸杞幼苗具有一定的耐盐碱能力,但较高浓度、长时间的盐碱胁迫仍会降低其光合作用效率,从而影响其正常生长。

It is of great importance to study the physiological response of crops under saline-alkali soil treatment.Such studies can aid the understanding of the growth and development of crops under abiotic stress,such as saline-alkali stress,while providing a reference for the selection of crops in regional saline-alkali soil research.Ningxia No.1 Lycium barbarum was selected as the research object in this study.A pot experiment was conducted by manipulating saline-alkali treatments;the treatments included the complete flowered soil group(CK),semi-saline-alkaline soil group(BK),and complete saline-alkaline soil group(AK).The growth indexes,chlorophyll fluorescence parameters,and proton dynamic parameters of L.barbarum seedlings were measured and analyzed.The results showed that low saline-alkali stress had no significant effect on the growth and chlorophyll content of L.barbarum and might actually promote chlorophyll synthesis(P<0.05);however,high saline-alkali stress could inhibit the growth of L.barbarum.The opening number(q_(L))of the PSⅡphotochemical reaction center in the AK and BK groups under saline-alkali stress increased initially and then decreased.The maximum photochemical quantum yield(F_(v)/F_(m))of PSⅡdecreased significantly in the middle and late stages(P<0.05),whereas non-photochemical quenching(q_(N))significantly increased(P<0.05).The quantum yield of the regulated energy dissipation(Y_(NPQ))remained at a high level with the increase in stress time,whereas the quantum yield of the unregulated energy dissipation(Y_(NO))increased significantly in the late period of the experiment(P<0.05).Under saline-alkali stress,H^(+)conductance in chloroplastic ATPase(g_(H^(+)))maintained an overall decreasing trend,whereas the electrochromic bandshift decay amplitude(ECS_(t))increased significantly after a slight decrease in the early stage.With the increase in saline-alkali degree,the AK group fluctuated more than the BK group,the range of changes was greater,and the difference between the AK and CK groups was also more significant.Overall,the seedlings of L.barbarum had saline-alkali tolerance;however,high concentration and long-term saline-alkali stress could damage their photosynthetic structure and reduce their photosynthetic efficiency and adaptability to light environment,thus affecting their normal growth.