Characteristic of growth and development of maize inbreds with different phosphorus efficiency under low-P stress

The effects of low-P stress on growth and development of 5 maize inbred lines with different phosphorus efficiency were evaluated at seedling,jointing,earing,silking stages under pot culture respectively.Seed yields was also investigated under the field condition.The results showed that there were remarkable different responses to low-P stress at different growing time among various maize genotypes.At seedling stage,the relative magnitude of plant dry matter weight and P-deficiency symptom of P-tolerance genotypes were markedly higher than those in P-sensitive genotype.As to jointing period,the P-deficiency symptom of P-sensitive genotype was aggravated,while there was still no P-deficiency symptom of P-tolerance genotypes.After entering reproductive growth phase,the dry matter weight of upper leaves and stem of the P-tolerant genotypes,compared to P-sensitive genotypes,was more significantly influenced by low-P stress.At the silking stage the response discrepancies of low-P stress of different inbreds take shape not only on plant dry matter weight,but also on plant height,diameter of stem,dry weight of stem,area and dry weight of functional leaves,and number of staminate flower branches.The relative magnitude of captioned parameters of P-tolerance genotypes was significantly higher that those of P-sensitive one.However,there were different biologic characteristics in different P-tolerant genotypes.Eventually,low-P stress decreased the economic yields of the inbred lines,but the P-resistant genotypes had higher relative seed yield compared to P-sensitive genotypes.Low-P stress prolonged the growing time and delayed tasselling,earing,pollen-shedding,silking of P-sensitive genotypes but it had little effect on the P-resistant genotypes.