Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (5): 724-732.DOI: 10.17521/cjpe.2021.0226

• Research Articles • Previous Articles     Next Articles

Phenological dynamics of nitrogen, phosphorus and potassium stoichiometry in Chenopodium quinoa in northwest Yunnan, China

LI Zhao-Guang*, YANG Wen-Gao*, HE Gui-Qing, XU Tian-Cai, HE Qiong-Ji, HOU Zhi-Jiang, LI Yan, XUE Run-Guang**()   

  1. Institute of Alpine Economics and Botany, Yunnan Academy of Agricultural Sciences, Lijiang, Yunnan 674100, China
  • Received:2021-06-15 Accepted:2022-10-19 Online:2023-05-20 Published:2022-11-02
  • About author:First author contact:*Contributed equally to this work(Li ZG, lzg148@126.com; Yang WG, jinguwuqie@163.com)

Abstract:

Ams Nitrogen (N), phosphorus (P), and potassium (K) are key elements for plant growth and development. Exploring the ecological stoichiometry characteristics of N, P and K in different phenological stages is of great significance for understanding the physio-ecological processes such as nutrient limitation, resource absorption and utilization, and biomass allocation of plants.
Methods Here, we collected root, stem, leaf and spike samples of Chenopodium quinoa in different phenological stages, and measured the concentrations of N, P and K. We compared the differences of N, P, K contents and their ratios among roots, stems, leaves and spikes and among phenological stages, and analyzed their relationships with the biomass allocations.
Important findings (1) The mean N contents was 9.28, 12.22, 33.68, 31.28 mg·g-1 in the roots, stems, leaves and spikes, respectively. The breakdowns was 2.64, 3.71, 4.98, 5.68 mg·g-1 for P contents, and 25.63, 43.80, 74.08, 56.73 mg·g-1 for K contents, respectively. These resulted in mean N:P of 4.66, 4.20, 7.37, 5.70, N:K of 0.39, 0.31, 0.46, 0.62, and K:P of 13.77, 14.31, 16.82, 9.79 in the roots, stems, leaves and spikes, respectively. (2) The root, stem, and spike N, P and K and the leaf N and P contents decreased significantly with the phenological subsequences, reflecting the obvious dilution effect of biomass. On the contrary, the leaf K contents increased significantly with phenological subsequences, indicating an extremely strong drought resistance mechanism of C. quinoa under drought stress. The allocation ratios of N, P, K and biomass in the roots and stems kept stable, those in the leaves decreased, while those in the spikes increased with the phenological subsequences, indicating that the key resource allocation regulation of leaves and spikes occurred during the flowering stage. As the biomass increased in the filling stage, the nutrient elements gradually transferred to the spikes. (3) The variation source analysis revealed a greater contribution of organs to the variance of N, K contents and N:P, while a less one to the variance of P contents, than the phenological stages. (4) The allocation ratios of N, P, K and biomass were coupled among various organs. Specifically, the allocation ratios of root and leaf biomass showed a positive correlation with those of the root and leaf N, P and K, while a negative correlation with those of the spike N, P and K. The biomass allocation ratio of spike was positively correlated with spike N, P and K allocation ratios, while negatively correlated with root and leaf N, P and K allocation ratios. These results provided theoretical reference for further understanding of crop phenological character and guiding practical production in alpine regions.

Key words: ecological stoichiometry, phenological stage, Chenopodium quinoa, northwestern Yunnan of China