植物营养与肥料学报2025，Vol.31Issue(3)：564-577,14.DOI:10.11674/zwyf.2024410
低温胁迫下黄瓜幼苗生长和氮素代谢对外源硝态氮供应水平的响应
Response of growth and nitrogen metabolism of cucumber seedlings to different exogenous nitrate nitrogen levels under low temperature stress
摘要
Abstract
[Objectives]We conducted a study on the growth and nitrogen metabolism characteristics of cucumber seedlings subjected to low temperature stress and varying exogenous nitrate(NO3--N)supply levels.Our objective was to elucidate the mechanisms cucumber employs to counteract abiotic stress and provide a theoretical foundation for the scientific management of nutrients in soilless cucumber cultivation.[Methods]For our hydroponic experiment,we utilized cucumber seedlings of the ʻXintaimiciʼ variety at the four-leaf-one-bud stage.Hoaglandʼs nutrient solution served as the base solution,and we prepared four treatment solutions with NO3--N concentrations of 0(N0),6 mmol/L(N6),12 mmol/L(N12),and 24 mmol/L(N24).The cucumber seedlings were grown in these solutions and exposed to low temperature stress conditions(15°C during the day and 10°C at night)for four days.Then the seedlings were harvested for the analysis of relative chlorophyll content(SPAD),biomass,activities of nitrogen metabolism and antioxidant enzymes,and the expression of genes related to nitrate nitrogen metabolism.[Results]Under low temperature,N24 treatment exhibited the highest SPAD values,soluble protein and proline content,the highest activities of nitrate reductase,glutamine synthetase,glutamate synthase and peroxidase,and the highest expressions of GS-1 and GS-2 both in roots and leaves.While N6 treatment exhibited the high dry weight and the activities of superoxide dismutase and catalase.In addition,N24 treatment was recorded the highest expression levels of nitrate nitrogen uptake and transport genes(NRT1s),nitrate reducing genes(NRs,NiR)and glutamate synthase genes(GOGATs)in root,which was consistent with the nitrate nitrogen content in root.While N6 treatment was recorded the highest expression levels of GOGAT-1-1,GOGAT-1-2,GOGAT-2-1 and GOGAT-2-2 in leaves.Under low temperature,N6,N12 and N24 treatments reduced the malondialdehyde contents in cucumber roots and leaves compared to N0.The principle component analysis results showed that N6 treatment achieved the top comprehensive scores in resisting low temperature stress.[Conclusions]Under low temperature and low exogenous NO3--N supply conditions,cucumber seedlings upregulate the expression of NRT1.2,NRT1.3,NRT1.9 and NRT1.10 to enhance the transport of NO3--N from roots to leaves,increase the activities of enzymes related to nitrogen assimilation,and maintain higher dry matter accumulation,thereby enabling normal growth and adaptation to low temperatures.However,under low temperature and high NO3--N supply conditions,cucumber seedlings up regulate the expression of NRT1s(NRT1.5,NRT1.8)genes in roots and increase NO3--N uptake,but the induced high activities of nitrogen assimilating enzymes are not conducive to dry matter accumulation.Overall,lower exogenous NO3--N supply levels(6 mmol/L)are beneficial for cucumber seedlings in resisting low temperature stress.关键词
低温胁迫/硝态氮/氮代谢酶活性/氮代谢基因表达/抗氧化系统Key words
low-temperature stress/nitrate nitrogen/nitrogen metabolism enzyme activity/nitrogen metabolism gene expression/antioxidant system引用本文复制引用
班甜甜,马超,李晓慧,陈卓,刘小翠..低温胁迫下黄瓜幼苗生长和氮素代谢对外源硝态氮供应水平的响应[J].植物营养与肥料学报,2025,31(3):564-577,14.基金项目
黔科合基础项目(ZK[2023]一般190) （ZK[2023]一般190）
黔科合平台人才项目[YQK(2023)25]. （2023）
