烟草不同基因型叶片钾积累特性及变异分析

利用5个烟草基因型对烟叶钾积累和干物质积累特性及其变异进行研究，结果表明，烟草叶片的相对钾含量随生育期推延逐步降低，生育后期有两个明显的下降高峰。移栽后75d至烟叶采收结束单株烟叶的相对钾含量平均下降率为41．83％，此期的干物质积累率平均为21．91％，干物质积累的“稀释效应”不能完全解释烟叶钾含量下降的原因。叶片钾含量特性分析表明，烟叶钾积累达到一定量后积累总量下降，5个基因型单株叶片钾积累量的下降比率在20．06％－42．24％之间，基因型间存在着显的差异。烟叶的钾积累量却是达到最高点后开始下降，总量减少，积累率为负值，在烟叶成熟期烟叶钾积累总量平均减少了27．45％，是烟草生育后期烟叶相对钾含量下降的重要原因之一。钾积累达到最大值的时间后移是烟草钾高效积累的一个特点。5个烟草基因型的溶液培养试验表明，烟株地上部绝对钾含量与根系总吸收面积和根系活跃吸收面积具有显的相关性（r=0.8413^*,r=0.7871^*)。地上部钾含是与根系总吸收面积相关显（r=0.7555^*)，但与根系活跃吸收面积相关性不大（r=0.4389)。提高烟叶钾积累量应特别重视培育一个强大的根系。采用12个烤烟基因型进行分析发现，在株高，单株叶数，茎围3个与钾含量有显相关的因素中，单株叶数和茎围对提高烟叶的钾含量有较大的直接效应。

Analysis on potassium accumulation characteristics and genetic variation in tobacco leaves

Five tobacco genotypes were used to study K accumulation and dry matter accumulation and their genetic variation in tobacco leaves Results obtained are as follows: relative K content in tobacco leaves was gradually reduced in the growing stage in flue\|cured tobacco genotypes The average of decrease percentage of relative K content in leaves of single plant was 41 83% and the average of dry matter accumulation was 21 91% in the period of 75th day after transplanting to harvest The diluted effect due to dry matter accumulation was not enough to explain the decrease of K content in tobacco leaves The analysis of K accumulation in tobacco leaves showed that the amount of K accumulation start to decrease when it reached a certain level The decrease percentage of K accumulation in five tobacco genotpes was 20 06%~42 24%, there was significant difference among them A typical feature of K\|high\|efficiency\|accumulation tobacco plant was that the period when the amount of K accumulation reached maximum was postponed In water culture experiment for 5 tobacco genotypes, results showed that there are significant correlation between K absolut content of tobacco leaves and total assimilative surface of root, and active assimilative surface of root The relationship between K content of tobacco leaves and active assimilation surface of root is not significant Significant correlation between K content of tobacco leaves and stalk heigh, leaf number per plant, stalk circumference was obtained in filed experiment for 12 tobacco genotypes Leaf number per plant, stalk circumference have greater immediate effect of increasing K content in tobacco leaves