Study On Differences Of Phosphorus Efficiency And Mechanism Of Different Peanut Genotypes

Screening P-efficient peanut variety, utilizing fully abundant phosphorus resource and solving the problem of peanut P-deficiency were studied. It is very important to economize resources, avoid pollution and impr efficient or continuing development in agriculture. Seedling pot experiment was conducted to screen phosphorus efficiency and inefficiency peanut from the 42 varieties tested. Pot experiments and simulative experiments was used to study phosphorus uptake, translocation and utilization of different peanut varieties, affect on peanut efficiency and inefficiency under different soil types and uptake other elements under short of P. the differences in mechanism among different P-efficient peanut varieties was probed. The main results are as followed:l.The results in seedling screening experiments showed that dry weight, P content and accumulation under P-deficiency condition were significantly lower than normal. There were differences to tolerant to P-deficiency in relative dry weight, relative P content and accumulation under all treatments. Based on cluster analysis, the 42 peanut varieties could be classified into four types.2.Relative dry weight and relative P accumulation of P-efficient variety were higher than those of P-inefficient peanut variety at flowering. P-efficient variety was more sensitive to P than P-inefficient variety and was affected by P in seeds. Flowering could be thought as best stage screening P-efficiency or deficiency peanut varieties. Relative yield and harvest coefficient of P-efficiency variety were higher than those of P-inefficiency variety.3.There were differences in phosphorus uptake, translocation and utilization among different P-efficient and inefficient peanut varieties. P uptake and relative P accumulation of P efficient variety were higher than those of P inefficient variety. There was the same pattern of P uptake amount at flowering, podding and maturity. Economic utilization ration and the ability of P-efficiency variety to transport P from roots to aerial parts were stronger than those of P-inefficient variety.4.N content, K content, N and K accumulation of plant under P-deficiency condition were lower than those of normal condition. There was no obvious difference in N content or K content among varieties. Relative N accumulation and relative K accumulation ofP-efficient variety were higher than those of P-inefficient variety under P-deficient or sufficient treatments.5.Total root length, root fresh weight, root volume, ration between root and shoot, total uptake area and active uptake area of P deficient condition were higher than those of normal, but there was no obvious difference between P efficient and inefficient peanut varieties. Root showed a higher affinity to P than normal, and the affinity to P of P-efficiency variety was higher than that of P-inefficient variety under P-deficient condition. P deficient condition could decrease root membrane permeability, reduce P exosmosis and increase net uptake velocity for P. Furthermore, root secreted more H+ and made the soil acidify under P deficient condition.6.APA secreted by root of P-deficient treatment was higher than that of normal under P-deficiency stress, but the difference was no regular among varieties. There was no peak on APA secreted by root of P-efficient variety. APA in leaves was a little higher than that of normal, APA in under leaves was also higher than that in upper leaves.7.P-efficiency or inefficiency of peanut was relative to the size of seed, variety of big seeds was more P-efficient and variety of middle or small seeds was P-inefficient. Because big seed stored more P, and was benefit to growth. Thus, which had a better absorption in mineral material.