干旱胁迫对燕麦幼苗叶片光合特性及活性氧清除系统的影响  

Effects of drought stress on leaf senescence and the active oxygen scavenging system of oat seedlings

作　　者：吴雨涵 刘文辉[1] 刘凯强 张永超 WU Yu-han;LIU Wen-hui;LIU Kai-qiang;ZHANG Yong-chao(Key Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau,Academy of Animal and Veterinary Sciences of Qinghai University,Xining 810016,China)

机构地区：[1]青海省青藏高原优良牧草种质资源利用重点实验室,青海大学畜牧兽医科学院,青海西宁810016

出　　处：《草业学报》2022年第10期75-86,共12页Acta Prataculturae Sinica

基　　金：青海省科技厅重点实验室发展专项“青海省青藏高原优良牧草种质资源利用重点实验室”(2020-ZJ-Y03);国家现代农业产业技术体系(CARS-34);“昆仑英才乡村振兴人才”专项农业农村科技攻关团队资助。

摘　　要：为探究燕麦幼苗遭受干旱胁迫后叶片光合特性及活性氧清除系统的响应机制,本试验选用青海本地推广品种‘青燕1号’为研究对象,以PEG-6000模拟干旱胁迫环境,在不同干旱浓度(CK、P_(10)和P_(20))和不同干旱持续时间(4、7、10 d)处理下,研究燕麦幼苗干旱胁迫后对光合作用参数、叶绿素含量、类胡萝卜素含量、超氧阴离子含量、过氧化氢含量及酶类抗氧化剂和非酶抗氧化剂含量的影响,为青藏高原地区抗旱燕麦品种评价提供理论依据。研究表明:1)随着胁迫程度增加叶绿素含量(Chl)显著下降,超氧阴离子(O_(2)^(-))、过氧化氢(H_(2)O_(2))含量明显增加,净光合速率(P_(n))、蒸腾速率(T_(r))、胞间CO_(2)浓度(C_(i))、气孔导度(G_(s))、最大光化学效率(F_(v)/F_(m))和实际光化学效率(Φ_(psⅡ))明显下降,而初始荧光(F_(o))和非光化学淬灭(NPQ)显著增加。干旱胁迫能引起植株短时间内水分利用效率增加,但气孔关闭及光反应中心遭到破坏是光合性能减弱的主要原因。2)随胁迫浓度与胁迫时间增加酶类抗氧化剂超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)、抗坏血酸过氧化物酶(APX)先升高后降低,谷胱甘肽过氧化物酶(GPX)持续增加,而非酶类抗氧化剂在干旱胁迫下均显著高于对照。轻度胁迫下,‘青燕1号’燕麦主要通过酶类抗氧化剂清除活性氧毒害物质,而在重度胁迫下主要以非酶类抗氧化剂清除系统为主。This research investigated the responses of leaf senescence and the active oxygen scavenging system following water deficit stress in oats,in order to provide a theoretical framework for evaluation of drought-resistance of oat varieties used on the Qinghai-Tibetan Plateau.A popular local Qinghai oat variety,Qingyan No.1,was used in the experiment.Water deficit stress was simulated with PEG-6000 at two concentrations(P_(10) and P_(20))and a nil-PEG(CK)treatment was also included.These treatments were applied to plants for 4,7,or 10 days.The effects of drought stress on the photosynthesis parameters,chlorophyll content,carotenoid content,superoxide anion content,hydrogen peroxide content,antioxidant enzyme activities and non-enzymatic antioxidants were studied.It was found that:1)With increase in drought stress,the chlorophyll(Chl)content of oat seedlings decreased significantly;superoxide anion content(O_(2)−)and hydrogen peroxide(H_(2)O_(2))contents increased significantly;net photosynthetic rate(P_(n)),transpiration rate(T_(r)),intercellular CO_(2) concentration(C_(i)),stomatal conductance(G_(s)),maximum photochemical efficiency(F_(v)/F_(m)),and actual photochemical efficiency(Φ_(psII))decreased significantly;and chlorophyll initial fluorescence(F_(o))and the non-photochemical quenching coefficient(NPQ)increased significantly.Water deficit stress initially increased plant water use efficiency,but this effect was short-lived and stomatal closure and damage to light reaction centers were the main reasons for the weakening of photosynthetic performance under water deficit.2)With increase in PEG concentration,or duration of simulated water deficit stress,the activities superoxide dismutase(SOD),and related enzymes dehydroascorbate reductase(DHAR),glutathione reductase(GR),and ascorbic acid peroxidase(APX)increased initially and then decreased,while glutathione peroxidase activity(GPX)continued increasing.However,levels of non-enzymatic antioxidants of oats were significantly higher under drought stress than in co

关 键 词：干旱胁迫 燕麦 幼苗 

分 类 号：S544.9[农业科学—作物学]