不同生育期桔梗对钙、镁吸收规律和累积特性的研究

采用原子吸收光谱法对不同生育期桔梗各部位中的钙、镁含量和累积量进行了测定。结果表明:桔梗根部钙元素的累积量从现蕾期开始增高,开花期和种子期的钙元素累积量占根部全部钙元素累积量的75.8%。叶部钙元素的积累量开花期最高,为2.8 mg/株,苗期最低,为1.5 mg/株;茎部对钙元素的积累量也在开花期时最高,为11.6 mg/株。桔梗根部镁元素累积量在现蕾期最高,为6.5 mg/株。茎部镁元素累积量随着植株的生长呈下降状态,从苗期的3.7 mg/株降到种子期的1.0 mg/株。叶部镁的累积量一直呈缓慢增长,种子期最高,累积量仅为1.4 mg/株;由于桔梗整个生育期对镁、钙元素的需求量较低,因此,可在移栽前或现蕾期适当补充钙、镁等微量元素肥料即可满足桔梗对钙、镁的需求。

Study on Absorption Law and Accumulation Characteristics of Ca and Mg in Different Growth Periods of Platycodon grandiflorus

The content and accumulation amount of Mg and Ca in different growth periods of Platycodon grandiflorus were determined by atomic absorption spectroscopy .The results showed that the accumulation a-mount of Ca in root began to increase from the squaring stage;the Ca accumulated in blossom and seed forma-tion periods accounted for 75 .8%of all in root;the Ca accumulation in leaves was the highest in blossom peri-od as 2.8 mg per plant, but the lowest in seedling period as 1.5 mg per plant.The Ca accumulation in stem was also the highest in blossom period as 11 .6 mg per plant .The Mg accumulation in root was the highest in squaring period as 6 .5 mg per plant .The Mg accumulation in stem declined with the growth of plants , which decreased from 3.7 mg per plant in seedling period to 1.0 mg per plant in seed formation period .The accumu-lation of Mg in leaves always increased slowly , and the highest amount was only 1.4 mg per plant, which ap-peared in seed formation period .The Platycodon grandiflorus demanded lower Mg and Ca during the whole growth period , so appropriate supplement of Ca and Mg fertilizers before transplanting or in squaring period could meet the demand .