甜瓜幼苗对KNO3+K2SO4混合盐胁迫的生理响应  

Physiological Response of Muskmelon Seedlings to KNO3-K2SO4 Mixed Salt Stress

作　　者：赵卫星[1] 常高正[1] 康利允[1] 高宁宁[1] 梁慎[1] 徐小利[1] 李海伦 王慧颖 李晓慧[1] ZHAO Wei-xing;CHANG Gao-zheng;KANG Li-yun;GAO Ning-ning;LIANG Shen;XU Xiao-li;LI Hai-lun;WANG Hui-ying;LI Xiao-hui(Instiute of Hoticulture,Henan Academy of Agricultural Sciences,Henan Zhengzhou 450002,China)

机构地区：[1]河南省农业科学院园艺研究所,河南郑州450002

出　　处：《西南农业学报》2020年第7期1423-1428,共6页Southwest China Journal of Agricultural Sciences

基　　金：国家西甜瓜产业技术体系建设项目(CARS-26);河南省科技攻关项目(162102110099)。

摘　　要：【目的】探明甜瓜幼苗对盐胁迫的生理响应机制,为耐盐性生理指标的筛选和盐胁迫的合理调控提供理论依据。【方法】以耐盐性甜瓜品种众云20和盐敏感甜瓜品种瑞雪8号为试材,比较了50、100、150、200 mmol·L-1的KNO3+K2SO4混合盐胁迫对甜瓜幼苗水分吸收、质膜透性、渗透调节物质及保护酶的影响。【结果】随混合盐浓度的增加,甜瓜幼苗地上部含水量逐渐降低;地下部分含水量及叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性先上升后下降;叶片丙二醛(MDA)、可溶性糖(SS)和可溶性蛋白(SP)含量逐渐上升;电导率(EC)和脯氨酸(Pro)含量先下降后上升。在低浓度盐胁迫下,甜瓜幼苗体内的SOD、CAT、POD等酶活性升高并积累大量的Pro、SS和SP,但随浓度的增加,细胞膜过氧化程度加重。与盐敏感品种相比,耐盐性品种叶片具有较高的SOD、CAT、POD活性和较低的MDA含量,并合成较多的Pro、SS和SP。通过相关性分析可知,甜瓜幼苗叶片SS、SP、MDA和地上部含水量与盐浓度呈显著相关性。【结论】甜瓜幼苗叶片SS、SP、MDA含量和地上部含水量对盐胁迫的响应起关键作用,可作为筛选耐盐性指标和调控混合盐分胁迫的重要因子。【Objective】The physiological response mechanism of muskmelon seedlings to salt stress was investigated to provide reference for screening physiological indexes of salt resistance and rational regulation of salt stress.【Method】The experiment was conducted to compare changes of water content in shoots and roots and membrane permeability,osmotic adjustment,antioxidant enzymes of leaves,by five treatments with various salt concentrations(0,50,100,150 and 200 mmol·L-1KNO3-K2SO4).【Result】Shoot water content of muskmelon seedlings decreased gradually,root water content and SOD,CAT,POD activities increased firstly and then decreased,malondialdehyde(MDA),soluble sugar(SS)and soluble protein(SP)contents increased gradually,electroconductibility(EC)value and proline(Pro)contents showed a decreasing-increasing trend,with the increasing concentration of salt.In the low concentration,muskmelon seedling could alleviate salt injury by increasing activities of SOD,CAT and POD,and accumulation massive Pro,SS and SP.When the concentration of salt stress exceed the self-regulating ability,muskmelon seedlings were harmed aggregately,for example peroxidation of membrane increased,electrolyte greatly leaked,and anti-oxidation system suppressed.Compared with the salt-sensitive cultivar,salt-enduring cultivar could enhance its resistance to salt stress by increasing activities of SOD,CAT and POD,decreasing MDA content,and composing more Pro,SS and SP.The result of correlation analysis showed that contents of SS,SP and MDA in leaves and water content in shoot were significantly correlated with salt concentration.【Conclusion】The contents of SS,SP and MDA in leaves and water content in shoot might play key roles to salt stress,which could be used as important factors to screen salt tolerance and regulate mixed salt stress.

关 键 词：甜瓜幼苗 盐胁迫 质膜透性 渗透调节 抗氧化酶 

分 类 号：S652[农业科学—果树学]