Abstract: Chenopodium quinoa is a traditional crop in South America with its high nutritional value and strong environmental adaptability,while its adaptability in arid area of northwest China needs to be further studied.Ecological stoichiometry is the study of the elemental composition of organisms (mainly C,N,P) and their relationships,and it can be used to reflect the characteristics of organisms and their relationship with environment.The changes of contents of carbon (C),nitrogen (N) and phosphorus (P) and stoichiometric ratio at different phonological phases of C.quinoa were studied in a field trial in the Hexi Corridor.The organic carbon (OC) content hardly changed with the change of phenological phases,while the contents of total nitrogen (TN) and total phosphorus (TP) decreased significantly.There was no difference of OC content among organs,while the contents of TN and TP were significantly different with higher values in leaves and spikes.The C∶N and C∶P tended to increase with the plant growth,while N∶P decreased at first and then increased significantly.The C∶N and C∶P in roots and stems were higher than those in leaves and spikes,while N∶P in leaves was higher.The contents and stoichiometric ratios of C,N and P of C.quinoa were significantly affected by phenological phases and organs,showing the very close links with the growth and accumulation rate of dry matter.

Key words: Chenopodium quinoa, phenology, functional organ, ecological stoichiometry, Hexi Corridor