外源蔗糖对NO_3^-胁迫下叶用莴苣碳氮代谢的影响  

Effect of Exogenous Sucrose on Nitrogen and Carbon Metabolism of Lettuce Under NO_3^- Stress

作　　者：常丽丽[1] 廖宗文[2] 陈日远[1] 刘厚诚[1] 宋世威[1] 孙光闻[1] 

机构地区：[1]华南农业大学园艺学院,广东广州510642 [2]华南农业大学资源与环境学院,广东广州510642

出　　处：《北方园艺》2016年第1期10-15,共6页Northern Horticulture

基　　金：现代农业产业技术体系专项基金资助项目(CARS-25-C-04)

摘　　要：以意大利生菜(Lactuca sativa L.‘Yidali’)为试材,采用水培方法,以常规营养液(7.5mmol/L NO_3^-)培养,以叶面喷施清水作为对照(CK),在75mmol/L NO_3^-胁迫下,通过叶面喷施0mmol/L(T1)、3mmol/L(T2)的蔗糖,测定地上部鲜重、干重、硝酸盐、铵态氮(NH_4^+)、可溶性糖、蔗糖、硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)、蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)、全氮含量及全氮积累量等指标,研究外源蔗糖对NO_3^-胁迫下叶用莴苣碳氮代谢的影响。结果表明:在整个生长期,T1处理叶用莴苣的生长受到显著的抑制,外加蔗糖处理可以缓解NO_3^-胁迫对叶用莴苣生长的抑制,其中在第3、4次取样时缓解作用较明显;与T1处理相比,T2处理显著提高了叶用莴苣中可溶性糖、蔗糖含量,提高了SS、SPS的活性,并随着生长时间的延长而逐渐提高,在第3、4次取样时表现较明显;与T1处理相比,T2处理显著提高了全氮的积累量,在第3次取样时表现较明显;在第4次取样时显著提高NR活性,降低了硝酸盐、NH_4^+含量;同时,外源蔗糖略提高了植株中GDH和GS活性。Lactuca sativa L.‘Yidali＇was used as materials,the influences of exogenous sucrose（0,3mmol/L）on nitrogen and carbon metabolism in lettuce（Lactuca sativa L.‘Yidali＇）cultivated in nutrient solution under 75mmol/L NO_3-stress were investigated.With conventional nutrient solution（7.5mmol/L NO_3-）and foliar spraying water as control（CK）.The shoot fresh weight,shoot dry weight,nitrate content,ammonium N content,contents of soluble sugar and sucrose,activity of nitrate reductase（NR）,glutamic dehydrogenase（GDH）,glutamine synthetase（GS）,activities of sucrose synthase（SS）,sucrose phosphate synthase（SPS）,total N content and accumulation of total N were determined in this study.The results showed that,the growth of lettuce were significantly restrained under 75mmol/L NO_3-stress at the whole growth stage,exogenous sucrose could alleviate the suppression of the 75mmol/L NO_3-stress on the growth of lettuce,the best effect were observed at the third,fourth sampling.Compared with the T1 treatment,contents of soluble sugar,sucrose in leaves of lettuce were significantly increased,the activities of SS,SPS were enhanced with the time of the growth increase gradually,the best effect were observed at the third and fourth sampling.Accumulation of total N was enhanced by T2,it was obvious at the third sampling.The activity of NR was significantly improved and nitrate and NH_4＋content reduced significantly at the fourth sampling.And the activities of GDH,GS increased slightly treated with exogenous sucrose.

关 键 词：蔗糖 NO3-胁迫 叶用莴苣 碳代谢 氮代谢 

分 类 号：S636.2[农业科学—蔬菜学]