不同氮效率油菜苗期碳氮代谢差异  

Difference in carbon and nitrogen metabolism of rapeseed(Brassica napus L.)with contrasting nitrogen efficiency at seedling stage

作　　者：王玉乾 巢成生 代晶 沈欣杰[1] 李银水[1] 顾炽明 谢立华[1] 胡小加[1] 秦璐[1] 廖星[1] WANG Yu-qian;CHAO Cheng-sheng;DAI Jing;SHEN Xin-jie;LI Yin-shui;GU Chi-ming;XIE Li-hua;HU Xiao-jia;QIN Lu;LIAO Xing(Oil Crops Research Institute of Chinese Academy of Agriculture Sciences/Key Laboratory of Biology and Genetic Breeding of Oil Crops,Ministry of Agriculture and Rural Affairs,Wuhan 430062,China)

机构地区：[1]中国农业科学院油料作物研究所/农业农村部油料作物生物学与遗传育种重点实验室,湖北武汉430062

出　　处：《中国油料作物学报》2022年第3期589-601,共13页Chinese Journal of Oil Crop Sciences

基　　金：国家绿肥产业技术体系专项(CARS-22-05);国家重点研发计划项目(2016YFD0100202-5);中国农业科学院科技创新工程(CAASASTIP-2013-OCRI)。

摘　　要：为探究氮高效的机制,研究油菜苗期碳氮代谢规律,以两个氮效率差异显著的油菜种质(氮高效种质A294和氮低效种质A364)为材料,通过设置正常(CK,9.5 mmol/L)和低氮(LN,0.475 mmol/L)两个处理,比较不同氮效率油菜在根系形态、氮吸收转运同化、光合碳代谢生理指标以及碳氮代谢相关基因表达等方面的差异。结果表明,氮高效的A294在低氮胁迫下根系发达,植株生物量和氮累积量显著高于A364,前者根系吸收及向地上部转运氮的能力较强,而氮同化关键酶硝酸还原酶和谷氨酰胺合成酶活性在两个种质间无显著差异;同时,A294叶片SPAD值、光合色素含量、净光合速率及磷酸蔗糖合酶基因BnaSPS的表达均更高。进一步分析发现,低氮胁迫下A294根系中硝酸盐转运蛋白基因BnaNPF7.3的表达显著高于A364,而BnaNPF7.2b在A364根系的表达则显著高于A294;此外,A364可溶性糖含量的根叶比及根系中蔗糖合酶基因BnaSUS表达高于A294,说明低氮胁迫下氮高效油菜A294可以将更多的营养元素(氮)分配至地上部,使叶片保持较高的光合速率,为生物体构建提供保障;而氮低效油菜种质A364则倾向于将有限的营养元素(氮)分配在根系并维持其生长发育,同时其根系可溶性糖消耗占比高于A294,导致其根冠比高于A294。由此认为,油菜在响应外界氮缺乏胁迫时,氮素与能量物质(可溶性糖)的分配与消耗差异会影响叶片碳代谢(光合作用、蔗糖合成)速率,最终导致油菜苗期氮效率的差异。To better understand the mechanism underlying nitrogen efficiency of rapeseed(Brassica napus L.)at seedling stage,two accessions with contrasting N efficiency(A294 with high efficiency,and A364 with low efficiency)were applied on investigating their C and N metabolism.The differences in root morphology,N absorption,transport and assimilation,and physiological indices related to photosynthetic C metabolism and gene expressions involved were compared between the two accessions through hydroponics,under normal N(CK,9.5 mmol/L)and low N(LN,0.475 mmol/L)nutrient solutions respectively.Results showed that,N-efficient accession A294 had stronger root system,with significantly higher plant biomass and N accumulation amount than those of A364 under low N condition.The ability for N absorption and transportation of A294 were also greater.However,activities of nitrate reductase and glutamine synthetase had no significant differences in two accessions.SPAD value,photosynthetic pigment content,net photosynthetic rate,and sucrose phosphate synthase gene(BnaSPS)expression of A294 leaves were all higher than those of A364.Further analysis found that,under low N stress,the expression of nitrate transporter BnaNPF7.3 in A294 root was remarkably higher than that of A364,while BnaNPF7.2b expression was significantly lower than A364.Root to leaf ratio of soluble sugar content in A294 was significantly lower,as well as root expression of sucrose synthase gene(BnaSUS)than A364.It is indicated that,N-efficient rapeseed accession A294 could distribute more nutrient elements(N)to seedling shoots under N deficiency stress,maintaining higher photosynthetic rate in leaves to guarantee a stronger metabolism of organisms;whereas,A364 could tend to allocate more nutrient elements(N)in root to promote growth and development.At the same time,the ratio of soluble sugar consumption in A364 roots was higher,which lead to higher root/shoot ratio in A364.Therefore,the distribution and consumption of N and energy substances(soluble sugar)of rapeseed re

关 键 词：氮效率 油菜 苗期 低氮胁迫 碳氮代谢 

分 类 号：S565.4[农业科学—作物学]