Effect of acid-stress on growth and nutrient absorption of different maize genotypes

Growth and nutrient characteristics of N,P and K in different maize inbred lines with tolerance to acid-stress were studied at stages of seedling,shooting and flowering in a pot experiment.The results showed that nutrient characteristics of N,P and K of maize genotypes varied under acid-stress at different growing time.In the periods of seedling,shooting and flowering,the efficiency of uptake and accumulation of N,P and K of acid-tolerance genotypes were higher than those in acid-sensitive genotype.The mechanism of the tolerance to acid-stress represents not only higher uptake efficiency but also stronger ability of utilization and the reallocation and reutilization.The nutrient mechanism of tolerance to acid-stress may differ with growth stages.We found that N utilization efficiency was one of contributors to acid tolerance at seedling stages. To flowering stage,stronger ability of the reallocation and reutilization of P and K contributed to adaptation to acid-stress.The investigation of relative dry weight also suggested that there were remarkable differences in responses to acid stress among various maize genotypes.With the development of crop growth,the acid-stress symptom of medium acid-sensitive genotype was aggravated, but it had little effect on the acid-resistant genotypes even in acid soil of pH 4.6 for acid-tolerance genotype Z01.The growth characteristics and the dry matter weight of the acid-sensitive genotype,compared to medium acid-sensitive genotype,were more significantly influenced by acid stress.