Analysis On Difference In Phosphorus Efficiency And Physiological Mechanism And Their Correlation In Maize Inbred Lines

This pot experiment was carried out on 4 maize inbred lines (KH12, 478, Xin9005 and Wu312) at three stages (seedling, booting and maturity) under two P treatments, analyzing and studying on difference and correlation of phosphorus efficiency, as well as physiological mechanisms. The main results were summarized as follows:1. Under 3 stages and 2 P treatments, the phosphorus efficiencies of 4 maize inbred lines are steady. And KH12 is a high-efficient phosphorus genotype. Xin9005, Wu312 are low-efficient genotypes. 478 is medium. The higher phosphorus genotypes , the more biological field was produced.2. Under 2 P treatments, the main influence factor of phosphorus efficiency was phosphorus uptake efficiency, which showed more variation under LP than NP among the genotypes. P utilization efficiency and P transport efficiency showed little relationship with P efficiency. Meanwhile, P uptake efficiency is decided mainly by phosphorus uptake amount.3.According to difference of the root system morphology, low phosphorus condition made root radius and root volume reduced, while the ratio of root to shoot (R/S) increased. Meanwhile, the correlation of root radius, root volume and phosphorus efficiency are positive significantly. But the relationship of R/S ratio and phosphorus efficiency is unsteady. So R/S ratio can't be one of the indexes to evaluate P efficiency.4. Under 2 phosphorus treatments, A PA of the high P efficiency genotype (KH12) was higher significantly than the low P efficiency genotypes (Xin9005, Wu312). Under the low phosphorus condition, APA raised and had a most significant correlation relation with phosphorus efficiency.5. Low phosphorus condition also made ALPA activity in rhizosphere rise, the contents of soluble protein and soluble P in leaf reduce. Meanwhile, soluble protein content, soluble P content and APA had most significant positive correlation relations. So the higher P efficiency genotype (KH12), the higher APA, contents of soluble protein and soluble phosphorus were. But the difference of ALPA activity in rhizosphere is not significant among the genotypes.6. Low phosphorus condition also made N uptake amount, K uptake amount in the plant reduce. These two had most significant positive correlation with P uptake amount. Under 3 stages, 2 phosphorus levels, N uptake amount and K uptake amount of KH12 was higher than Xin9005 and Wu312 with low phosphorus efficiency significantly.7. Under low phosphorus treatment, the leaf chlorophyll content rose, but the difference among the genotype was not significant. It also caused leaf photosynthetic rate decrease, but the falling degree of 478 with high phosphorus efficiency was less than Wu312 with low phosphorus efficiency.