盐胁迫对红树植物红榄李幼苗叶绿体超微结构及光合荧光特性的影响  

Effects of salt stress on chloroplast ultrastructure and photosynthetic fluorescence characteristics of Lumni-tzera littorea(Jack)Voigt seedlings

作　　者：陈威 童宇艳 冯瑜 郝露露 张慧玉 岳丹斐 张颖 郑春芳 CHEN Wei;TONG Yuyan;FENG Yu;HAO Lulu;ZHANG Huiyu;YUE Danfei;ZHANG Ying;ZHENG Chunfang(Bureau of Natural Resources and Planning of Pingyang,Wenzhou 325400,Zhejiang,China;College of Life and Environmental Science,Wenzhou University,Wenzhou 325035,Zhejiang,China;School of Life Sciences and Technology,Lingnan Normal University,Zhanjiang 524048,Guangdong,China)

机构地区：[1]平阳县自然资源和规划局,浙江温州325400 [2]温州大学生命与环境科学学院,浙江温州325035 [3]岭南师范学院生命科学与技术学院,广东湛江524048

出　　处：《生态学杂志》2024年第3期716-723,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(32071503)资助。

摘　　要：探讨红榄李幼苗对盐胁迫的响应机制,为濒危红榄李保护提供理论依据。以红榄李幼苗为材料,研究了不同浓度NaCl(50、150、450、750 mmol·L^(-1))对红榄李植株叶片光合、荧光参数、光合色素变化、抗氧化酶活性、叶绿体超微结构及气孔特征的影响。150 mmol·L^(-1) NaCl处理下红榄李幼苗叶片净光合速率(Pn)、气孔导度(Gs)、潜在最大光能转换效率(Fv/Fm)、实际光能转换效率(ΦPSII)、总叶绿素(Chl)含量、类胡萝卜素(Car)含量、超氧化物歧化酶(SOD)活性及过氧化物酶(POD)活性等均显著高于其他处理。当NaCl浓度超过450 mmol·L^(-1)时,上述指标值均显著下降,而胞间CO_(2)浓度(Ci)、过氧化氢(H_(2)O_(2))含量、丙二醛(MDA)含量、超氧阴离子(O_(2)^(-·))产生速率等显著上升,其中,750 mmol·L^(-1) NaCl处理下植株叶片丙二醛(MDA)含量较150 mmol·L^(-1) NaCl增加56.58%。此外,当NaCl浓度为750 mmol·L^(-1)时,叶绿体的被膜界限逐渐模糊,淀粉粒和嗜锇颗粒增多膨大,基质、基粒片层逐渐松散变形,同时叶片气孔开张度变小,甚至关闭。以上结果表明,150 mmol·L^(-1) NaCl是红榄李幼苗植株生长发育的最适宜浓度。当NaCl浓度超过450 mmol·L^(-1)时,植株叶片抗氧化系统失衡,光合色素降低,气孔关闭,叶绿体超微结构受损。Exploring the response mechanisms of Lumnitzera littorea seedlings to salt stress can provide theoretical basis of protecting this endangered species.Here,we examined the effects of different concentrations of NaCl(50,150,450,750 mmol·L^(-1))on plant growth,leaf photosynthesis,fluorescence parameters,changes of photosynthetic pigments,antioxidant enzyme activities,chloroplast ultrastructure,and stomatal characteristics.The results showed that under 150 mmol·L^(-1) NaCl treatment,net photosynthetic rate(Pn),stomatal conductance(Gs),potential maximum light energy conversion efficiency(Fv/Fm)and actual light energy conversion efficiency(ΦPSII),contents of total chlorophyll(Chl)and carotenoid(Car),activities of superoxide dismutase(SOD)and peroxidase(POD)were significantly higher than those of other treatments.When the NaCl concentration exceeded 450 mmol·L^(-1),values of the above indices decreased significantly,while the intercellular CO_(2) concentration(Ci),contents of malondialdehyde(MDA)and hydrogen peroxide(H_(2)O_(2)),the production rate of superoxide anion(O_(2)^(-·))significantly increased.Leaf malondialdehyde(MDA)content under 750 mmol·L^(-1) NaCl exhibited 56.58%higher than that of 150 mmol·L^(-1) NaCl.In addition,under 750 mmol·L^(-1) NaCl stress,the boundary of chloroplast membrane was gradually blurred,and the starch particles and osmiophilic particles increased and expanded.More importantly,the matrix and grana lamella were gradually loose and deformed.Furthermore,the stomatal opening of leaves was reduced or even closed.Our results indicated that 150 mmol·L^(-1) NaCl was the optimal concentration for the growth and development of L.littorea seedlings.When NaCl concentration exceeded 450 mmol·L^(-1),photosynthetic capacity was reduced by inducing unbalance of antioxidant system,inhibiting the photosynthetic pigment synthesis,and preceding stomatal closure and damaging the chloroplast,which eventually led to plant wilting.

关 键 词：红榄李 盐胁迫 光合作用 抗氧化系统 叶绿体超微结构 

分 类 号：Q945.78[生物学—植物学]