桔梗不同生育期氮、磷、钾含量分布规律的研究

通过对一年生桔梗不同生育期栽培不同部位中N、P、K含量的测定，分析桔梗在不同生育时期对不同营养元素的需求状况。测定结果表明，桔梗茎部和叶片中的N含量随着植株生长而逐渐降低，整个生育期N元素含量分别降低了17.6%和23%。根部N含量呈上升趋势，整个生育期增长幅度为33.7%；P元素在桔梗各器官中的含量变化，在不同的生育期内有所不同。其中，根部P元素含量苗期最高为0.41%，开花期最低为0.34%，到种子期又提高到0.38%；根部K含量一直在增加，生育期内含量增加了0.24%。茎部和叶部K含量在现蕾期最低，分别为0.42%和0.51%。试验表明，苗期和开花期是N、P、K元素的需求旺盛期。

N, P and K Distribution Pattern of Platycodon in Different Growth Stages

In this study, through the determination N, P, K content of in the different parts of Platycodon in the different growth period,Analysis of demand conditions of various nutrients in different growth periods.Results showed that, N content in stem and leaves of Platycodon decreased gradually with the growth of plant, the content of N throughout the growing period were reduced 17.6% and 23%. N content in roots increased during the whole growth period, the growth rate was 33.7%;The content of P elements in various organs of Platycodon is different in each growth period.Among them, The P element content in roots is a maximum of 0.41% at the seedling stage,in the blossom period for a minimum of 0.34%, in the seed stage it is increased to 0.38%;The K content in roots has been increasing, the whole growth period increased by 0.24%. The lowest K content of stem and leaf in the Squaring stage, respectively 0.42% and 0.51%;Experiments show that, N, P, K elements is demanded strong in seedling stage and blossom stage.