Effects of nitrogen forms on nitrogen uptake and allocation and andrographolide components accumulation in Andrographis paniculata

Subjects: Biology >> Botany >> Applied botany submitted time 2024-05-15 Cooperative journals: 《广西植物》

JIAN Shaofen LIN Yang WAN Si ZHONG Chu LIU Han

Abstract： 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. Plants use inorganic and organic N sources from soil, and N form is a key factor affecting the active ingredients and their contents in medicinal plants. However, the utilization characteristics of different N forms by medicinal plants and the impact on active ingredients remain to be investigated. With nitrate nitrogen (NN), ammonium nitrogen (AN), amide nitrogen (urea, UN) and amino acid nitrogen (glycine, GN) as sole N source and combining 15N isotope tracing and physiological and biochemical analysis, this study aimed to clarify the characteristics of N uptake and utilization and its effect on the accumulation of andrographolide components at different growth stages (rapid growth stage, jointing stage, budding stage, flowering stage) of Andrographis paniculata. The results were as follows: (1) N content in leaves and roots decreased gradually with the growth period, and it was lower in the NN treatment. (2) The absorption rate of N was higher in the vegetative growth period, and rapidly decreased in the reproductive growth period. The absorption rate of AN, UN and GN was higher than that of NN in A. paniculata. (3) The allocation ratio of N in leaves was decreased, while the allocation ratio of N in stems was increased at budding stage. In comparison to the NN treatment, AN, UN, and GN treatments reduced N allocation ratio in leaves, but increased the ratio in stems and roots 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. However, the allocation of leaf N in the carboxylation system in UN and AN treatment was reduced at budding stage and flowering stage, 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 leaves, stems and roots, N uptake rate, and N allocation ratio in leaves and roots, while they were significantly positively correlated with N allocation ratio in stems. The opposite was true for 14-deoxyandrographolide. Taken together, the results indicate that the vegetative growth period is the main period 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.

 Hits 598  Downloads 300  Comment 0