干旱胁迫对C3植物天山猪毛菜叶片C4光合酶和δ^13C值的影响  

Changes in C photosynthetic enzymes andδ^13C values of C desert plant Salsola junatovii Botsch.under soil drought stress

作　　者：闻志彬[1] 夏春兰 王玉兰 WEN Zhi-bin;XIA Chun-lan;WANG Yu-lan(Key Laboratory of Biogeography and Biological Resources under Chinese Academy of Sciences,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,Xinjiang,China;University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]中国科学院新疆生态与地理研究所,中国科学院干旱区生物地理与生物资源重点实验室,乌鲁木齐830011 [2]中国科学院大学,北京101408

出　　处：《干旱区研究》2020年第4期993-1000,共8页Arid Zone Research

基　　金：新疆维吾尔自治区自然科学基金面上项目(2016D01A074)资助。

摘　　要：以藜科猪毛菜属具有代表性的C3荒漠半灌木植物天山猪毛菜(Salsola junatovii Botsch.)为研究对象,采用盆栽控水试验设置正常水分与轻度、中度和重度3种胁迫处理,测定不同程度干旱胁迫下叶片含水量、4种C4光合酶[磷酸烯醇式丙酮酸羧化酶(PEPC)、NADP-苹果酸酶(NADP-ME)、NAD-苹果酸酶(NAD-ME)和磷酸烯醇式丙酮酸羧激酶(PEPCK)]的活性以及蛋白表达量、稳定碳同位素比值(δ^13C值);同时测定6个野外不同年平均降水量地区叶片的δ^13C值,明确不同干旱胁迫对天山猪毛菜C4光合酶和δ^13C值的影响;探讨天山猪毛菜是否会通过增强C4途径的表达来适应干旱胁迫。结果显示:(1)植物叶片含水量随干旱胁迫的加剧而降低;(2)4种光合酶,仅有PEPC和NAD-ME受到干旱胁迫的影响。这两种酶的活性和蛋白表达量变化趋势基本一致,它们均随着干旱胁迫程度的加剧先增加,并在中度干旱胁迫达到最大值,然后在重度干旱胁迫下急剧下降。NADP-ME活性、PEPCK活性及其蛋白表达量均不受干旱胁迫的影响;(3)尽管在轻度和中度干旱胁迫下天山猪毛菜叶片δ^13C值升高,并在中度干旱胁迫下δ^13C值最高,但在胁迫处理下δ^13C值仍处于C3植物范围内;野外样品叶片的δ^13C值表明,年降水量相对较少的3个地区样品δ^13C值高。Salsola junatovii Botsch.is a typical C3 desert subshrub,belonging to the genus Salsola L.of the family Chenopodiaceae.It was used to investigate the changes of four C4 photosynthetic enzymes,including phosphoenolpyruvate carboxylase(PEPC),NAD-malic enzyme(NAD-ME),NADP-malic enzyme(NADP-ME),and phosphoenolpyruvate carboxykinase(PEPCK),as well asδ^13C values in response to soil drought stress(including mild,moderate,and severe drought stress).A study ofδ^13C values in samples from six different precipitation areas was performed to understand the transition of photosynthetic carbon assimilation pathway from C3 to C4 under soil drought stress.The results were as follows:(1)leaf water content decreased due to increasing drought stress,(2)in these four photosynthetic enzymes,only PEPC and NAD-ME activities were affected by drough stress.Changes in activities and relative protein levels of PEPC and NAD-ME were consistent.They increased by increasing drought stress and reached the maximum values under moderate drought stress.Then,they decreased sharply under severe drought stress conditions.The activity of NADP-ME,and the activity and relative protein level of PEPCK were not affected by drought stress,and(3)theδ^13C values increased under the mild and moderate drought stress and reached the maximum values under moderate drought stress conditions.Theδ^13C values belonged to the range of C3 plants under drought stress,and theδ^13C values of samples from the three areas with relatively low annual precipitation were higher.

关 键 词：光合碳同化途径 C3荒漠植物 干旱胁迫 C4光合酶 天山猪毛菜 

分 类 号：Q945.78[生物学—植物学]