低K^(+)条件下罗布麻对盐胁迫的光合响应机制  

Photosynthetic response of Apocynum venetum to salt stress under low K^(+)condition

作　　者：崔彦农 夏曾润 贾文[1] 柴薇薇[1] 王文颖[1] 王锁民[1] CUI Yannong;XIA Zengrun;JIA Wen;CHAI Weiwei;WANG Wenying;WANG Suomin(State Key Laboratory of Grassland Agro-ecosystems/Key Laboratory of Grassland Livestock Industry Innovation,Ministry of Agriculture and Rural Affairs/College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,Gansu,China;Key Laboratory of Se-enriched Products Development and Quality Control,Ministry of Agriculture and Rural Affairs/National-Local Joint Engineering Laboratory of Se-enriched Food Development/Ankang R&D Center for Se-enriched Products,Ankang 725000,Shaanxi,China)

机构地区：[1]草地农业生态系统国家重点实验室/农业农村部草牧业创新重点实验室/兰州大学草地农业科技学院,甘肃兰州730020 [2]农业农村部富硒产品开发与质量控制重点实验室/富硒食品开发国家地方联合工程实验室/安康市富硒产品研发中心,陕西安康725000

出　　处：《草业科学》2022年第5期922-929,共8页Pratacultural Science

基　　金：国家自然科学基金项目(31730093、31971405);陕西省创新能力支撑计划项目(2018TD-021、2018PT-31)。

摘　　要：罗布麻(Apocynum venetum)对盐渍环境具极强的适应能力。前期研究发现罗布麻为典型钾高效植物,且大量吸收钠离子(Na(+))和钾离子(K^(+))以提高叶片渗透调节能力是其适应盐胁迫的重要生理机制,但有关该植物对低K^(+)和盐渍环境的光合响应机制尚未见报道。通过盆栽试验研究了低钾(0.01 mmol·L^(−1) K^(+))和正常钾(2.5 mmol·L^(−1) K^(+))供应条件下,盐处理(50和200 mmol·L^(−1) NaCl)对罗布麻幼苗叶片光合气体交换参数、PSⅡ光化学活性及光能分配的影响。结果显示,未添加NaCl时,低钾处理对罗布麻净光合速率(P_(n))、叶绿素荧光和吸收光能的分配均无影响。在两个供钾水平下,添加50或200 mmol·L^(−1) NaCl均显著降低了P_(n)、气孔导度(G_(s))、蒸腾速率(T_(r))和胞间CO_(2)浓度(C_(i)),提高了气孔限制值(L_(s))(P<0.05);200 mmol·L^(−1) NaCl处理显著降低了PSⅡ最大光化学效率(F_(v)/F_(m))、潜在光化学活性(F_(v)/F_(o))、实际光电子产率(Φ_(PSⅡ))、激发能量捕获效率(F_(v')/F_(m'))及光化学猝灭(qP)(P<0.05),表明罗布麻光合速率在轻度盐胁迫下主要受气孔因素的限制,在重度盐胁迫下同时受气孔因素与非气孔因素的限制。同时,盐胁迫下罗布麻可通过提高叶片水分利用效率以抵御气孔限制。此外,200 mmol·L^(−1) NaCl处理下,罗布麻叶片通过增加热耗散以减轻光能过剩对光合系统的危害。研究结果为进一步明晰罗布麻的抗逆机制提供了理论依据。Apocynum venetum can adapt to saline environments.Previous studies have found that A.venetum is a typical K^(+)-efficient species,and the large absorption of Na+and K^(+)to enhance the leaf osmotic adjustment ability is an important physiological strategy for this species to adapt to salt stress.However,the photosynthetic response of A.venetum to low-K^(+)and saline environments has not yet been investigated.In this study,the effects of 50 and 200 mmol·L^(−1) NaCl treatment on the photosynthetic gas-exchange parameters,PSⅡphotochemical efficiency,and absorbed light allocation in A.venetum under low K^(+)(0.01 mmol·L^(−1))and normal K^(+)(2.5 mmol·L^(−1))conditions were investigated using a pot experiment.The results showed that low-K^(+)supplementation had no effect on the net photosynthetic rate(P_(n)),chlorophyll fluorescence kinetics,or absorbed light allocation when NaCl was not supplied.Under both low and normal K^(+)conditions,compared with the control,both 50 and 200 mmol·L^(−1) NaCl treatments significantly decreased the P_(n),stomatal conductance(G_(s)),transpiration rate(T_(r)),and intercellular CO_(2) concentration(C_(i)),and increased stomatal limit values(L_(s))(P<0.05).Moreover,200 mmol·L^(−1) NaCl treatment also significantly reduced the maximal photochemical efficiency of PSⅡ(F_(v)/F_(m)),potential activities of PSⅡ(F_(v)/F_(o)),actual photochemical efficiency of PSⅡ(Φ_(PSⅡ)),excitation capture efficiency by PSⅡ(F_(v')/F_(m')),and photochemical quenching(qP)(P<0.05).These results indicate that the photosynthesis of plants was inhibited by stomatal factors under slight salt stress but by both stomatal and non-stomatal factors under severe salt stress.Furthermore,A.venetum could cope with stomatal limitation under salt stress by improving its leaf water use efficiency.In addition,A.venetum was able to enhance leaf heat dissipation to relieve the damage to the photosynthetic system resulting from light redundancy under the 200 mmol·L^(−1) NaCl treatment.These results pr

关 键 词：土壤盐渍化 光合作用 叶绿素荧光 光能分配 NACL 钾离子 罗布麻 

分 类 号：S563.7[农业科学—作物学]