小麦体内钾含量变化特征及诊断叶、鞘位的研究

Studies on Characteristic of K Content of Winter Wheat and K Nutrition Diagnosis

利用盆栽试验研究了不同供钾水平下冬小麦在拔节期、孕穗期及抽穗期各部位钾素分布特征,并进行了不同部位含钾量与植株钾含量及成熟期吸钾量的相关分析。结果表明,小麦植株钾含量随生育期的进行逐渐降低,随土壤供钾水平的升高而升高。不同时期小麦各部位钾含量变化特征存在差异性。拔节期小麦叶片与叶鞘的含钾量随叶位由上至下逐渐降低,即1叶>2叶>3叶>4叶,2鞘>3鞘>4鞘,鞘降低幅度随供钾水平的升高而降低;孕穗期中低水平下小麦穗中含钾量最高,叶位间叶、鞘的含钾量呈由上至下逐渐降低的梯度变化,即1叶>2叶>3叶>4叶,1鞘>2鞘>3鞘>4鞘,而高钾水平下穗与各叶位的叶片含钾量无显著差异,2鞘的含钾量偏低;抽穗期中低钾水平小麦叶位间除1叶及1鞘含钾量明显较高,其他叶位间无明显差异。相关分析表明,3个时期植株钾素诊断在拔节期及孕穗期进行较好,1叶、2叶和3叶均可作为这两个时期植株钾素营养的诊断部位,1叶与4叶的含钾量比值可以作为植株钾素营养诊断指标。

Pot experiments with winter wheat were conducted to investigate K content characteristic of main growth stages of winter wheat in soil with different K fertility, and analyzed the correlations between different part K contents and whole plant K content, K uptake of maturity stage. The results showed that K content of wheat gradually reduced during whole growth period, and it increased with increasing soil K fertility. The characteristic of K content of wheat was different in different growth stages, jointing stage, the K content of leaf and sheath gradually reduced from upper leaf position to lower position, namely, 1st leaf〉 2nd leaf 〉 3rd leaf 〉 4th leaf, 2na sheath 〉 3rd sheath 〉 4th sheath, drop range of sheath reduced with rising soil K level, booting stage, in low and middle K level, K content of spike of wheat was highest, K contents of leaf and sheath gradually reduced from upper leaf position to lower position, namely, 1st leaf〉 2na leaf〉 3ra leaf〉 4th leaf,1st sheath 〉 2nd sheath 〉 3rd sheath 〉 4th sheath, in high K level, there was no significant difference between K content of spike of wheat and K content of different leaf position, K content of 2nd sheath was low; heading stage, K content of different leaf position had no significant difference, but for K content of I st was significantly higher. The correlation analysis showed that booting stage and jointing stage was the good stage for wheat K nutrition diagnosis, 1st leaf, 2nd leaf, 3rd leaf were the sampling parts of K nutrition diagnosis at booting stage and jointing stage. K content ratio of 1 st leaf and 4th leaf could be used for K nutrition diagnosis of wheat.