一氧化氮对水分胁迫下苹果砧木新疆野苹果光合与生理特性的影响

摘要

以10叶龄的新疆野苹果(M.sieversii (L edeb) Roem.)实生苗为研究材料,采用盆栽控水的研究方法,于中度水分胁迫(含水量为土壤最大持水量的45％～55％)条件下,外源喷施一氧化氮(NO),测定净光合速率(Pn)等光合特性指标、SOD等抗氧化酶活性以及Pro等渗透胁迫物质含量,探讨外源一氧化氮对水分胁迫下苹果砧木生理特性的影响.结果表明:相比于对照,外源NO处理(180～210 μmol·L-1)减缓了水分胁迫下新疆野苹果叶片中MDA和Pro含量、电导率、胞间二氧化碳浓度以及POD活性的升高趋势,并能延缓净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、SOD与CAT酶活性的下降速率,且具有明显的浓度效应;190 μmol· L-1的NO处理效果最佳,相比于对照,Pn、Gs、Tr、SOD及CAT活性分别上升了28.73％、32.94％、33.33％、14.24％、25.38％;a、POD活性、Pro含量、REC及MDA含量分别下降了18.68％、40％、78.72％、49.06％、26.47％;适当浓度NO处理能够激活水分胁迫下新疆野苹果幼苗的抗氧化酶系统,并可以保护细胞膜系统,增强细胞光合性能,从而提高其耐旱性.%The study aims to explore physiological effects of exogenous nitric oxide (nitric oxide,NO) on apple rootstocks under water stress and to clarify the differences of photosynthetic,physiological and biochemical indexes of apple rootstock after different concentrations of exogenous NO treatments.The 10-leaf age of M.sieverii (Ledeb) Roem seedlings were tested as experiment materials,and the pot experiment which combined with artificial water control was carried.In the moderate water stress (water content is 45％ ～ 55％ of the soil field capacity) conditions,after spraying exogenous NO,the photosynthetic rate (Pn) and other photosynthetic characteristic indexs,antioxidant enzymes activity such as SOD and the content of osmotic stress substances such as Pro were measured by pot experiment.Compared with the control,exogenous NO slowed the upward trend of MDA and Pro content,conductivity,intercellular CO2 concentration and POD activity under water stress,and cut the decreasing rate of Pn,stomatal conductance (Gs),transpiration rate (Tr),SOD and CAT activity.It was detected a significant effect of concentration,with 190μ mol· L-1 NO having the largest effect.Pn,Gs,Tr,SOD and CAT activities increased by 28.73％,32.94％,33.33％,14.24％,25.38％;Ci,POD activity,Pro content,REC and MDA contents were decreased by 18.68％,40％,78.72％,49.06 ％,26.47 ％.Appropriate concentrations of NO treatment can activate M.prunifolia seedlings of antioxidant system,protect the cell membrane system and enhanced cell photosynthetic performance under water stress.