Responses of different genotype Fagopyrum tataricum seedlings to low phosphorus stress

To explore the responses of Fagopyrum tataricum to low phosphorus(P) stress, a potting experiment was conducted to examine the agronomic traits and physiological characters of four genotypes of F. tataricum at the seedling stage under different P treatment(P1, 2 mmol/L, CK; P2, 1 mmol/L; P3, 0.2 mmol/L). Results showed that with increasing P stress:(1) Plant height, stem diameter, leaf area, dry weight of shoots and roots, average root diameter, root surface area, and root volume decreased for all genotypes, whereas the length of the main root and most root-shoot ratios increased. To some extent, the amplifications of different genotypes were significantly different.(2) Chlorophyll content, soluble protein content, and root activity decreased, whereas root superoxide dismutase(SOD) activity, peroxidase(POD) activity, acid phosphatase activity, soluble sugar content, and free proline content all increased, and the increase was greater in low-P tolerant cultivars than that in low-P sensitive F. tataricum.(3) Total P content and P accumulation per plant decreased, whereas P use efficiency increased. Therefore, to adapt to low-P environments, the low-P tolerant cultivars absorbed and utilized soil P by root growth and higher acid phosphatase, maintained stronger photosynthetic capacity by higher chlorophyll content, and reduced membrane lipid peroxidation damage by higher antioxidant enzyme(e.g., SOD and POD) activity.