Effects of nitrogen forms on nitrogen uptake and allocation and andrographolide components accumulation in Andrographis paniculata
Nitrogen(N)is a mineral nutrient with the highest demand for plants,and it is also a vital abiotic factor that limits plant yield and quality.In order to clarify the utilization characteristics of different N forms of Andrograhis paniculata and its relationship with the accumulation of andrographolide content,with nitrate nitrogen(NN),ammonium nitrogen(AN),amide nitrogen(urea,UN)and amino acid nitrogen(glycine,GN)as sole nitrogen source and combining 15 N isotope tracing and physiological and biochemical analysis,the effects of nitrogen form on N uptake and distribution and andrographolide content at different growth stages(rapid growth stage,jointing stage,budding stage,flowering stage)of A.paniculata were studied.The results were as follows:(1)N contents in leaf and root decreased gradually with the growth stage,and it was lower in the NN treatment.(2)The uptake rate of N was higher in the vegetative growth stage,and rapidly decreased in the reproductive growth stage.The uptake rates of AN,UN and GN were higher than that of NN in A.paniculata.(3)The allocation ratio of N in leaf was decreased,while the allocation ratio of N in stem was increased at budding stage.In comparison to the NN treatment,AN,UN,and GN treatments reduced N allocation ratio in leaf,but increased the ratios in stem and root at this growth stage.(4)At rapid growth stage,the maximum carboxylation rate and maximum electron transport rate of photosynthesis were lower in the NN treatment,as well as the proportion of leaf N allocation in the carboxylation system and bioenergetics components.The allocation of leaf N in the carboxylation system in UN and AN treatments were reduced at budding and flowering stages,respectively.(5)AN,UN and GN increased andrographolide and dehydroandrographolide contents,and decreased 14-deoxyandrographolide content at budding and flowering stages,while neoandrographolide was slightly affected by N forms.(6)The contents of andrographolide and neoandrographolide were significantly negatively correlated with N contents in leaf,stem and root,N uptake rate,and N allocation ratios in leaf and root,while they were significantly positively correlated with N allocation ratio in stem.The opposite was true for 14-deoxyandrographolide.Taken together,the results indicate that the vegetative growth stage is the main stage for N uptake in A.paniculata,and that A.paniculata can better utilize AN,UN,and GN,and promote the accumulation of andrographolide components by optimizing N allocation.The results provide a theoretical reference for N management of A.paniculata.
万方数据
维普
