烤烟漂浮育苗中烟苗的基本生长规律

2000-2001年,以NC89为供试品种,采用商品基质和育苗专用肥,进行烤烟漂浮育苗基本生长规律的研究。结果表明:在苗床期内,烟苗的茎高、单株根鲜重和茎鲜重在生育期内呈现持续增加趋势;茎围、单株根干重和茎干重在生育期内呈现先缓慢增加后迅速增加趋势;螺旋根发生率在苗床期内的变化是大十字期迅速增加而后基本趋于稳定。烟苗的根、茎、叶、全株中干物质积累均呈S型曲线,且相关性达到极显著水平。在小十字期和大十字期,烟苗各器官的干物质分配规律是叶>根>茎;在七叶一心期和成苗期,烟苗各器官的干物质分配规律是叶>茎>根。叶片内叶绿素含量、NR酶活性、SOD酶活性、根系活力均呈递增趋势;烟苗叶片中INV酶活性在整个苗床期内基本处于一个相对稳定的状态。与烤后烟叶中主要化学元素含量相比,烟苗体内的N,K,Ca,Mg特别丰富,尤其是小十字期。

Studies on Basical Growth Rules of Flue-cured Tobacco Seedlings in the Floating System

Experiments on basical growth rules of flue- cured tobacco seedlings in the floating system were carried out with NC 89 and commercial medium and fertilizer during 2000 - 2001. The results as follows. Plant height,stem fresh weight and root fresh weight of single plant took on continuously increasing trend during the whole tobacco seedlings' stages; stem circumference and root dry weight and stem dry weight took on slowly increasing trend and rapidly increasing trend in early stage and late stage of tobacco seedlings respectively; the change of spiral-root formation percentages was having a rapidly increasing trend during 4 leaves stage and kept a basically steady trend then. The accumulation of dry matter in seedlings' root,stem, leaf and the whole plant were shaped on logistic curve and arrived at positive relevance level during the whole growth stage. The distribution of dry matter in each organ was leaf > root > stem in 2 - 3 leaves stage and was leaf > stem > root in 3 - 4 leaves stage. The studies also showed,the chrolophyll content,SOD arid NR activity of tobacco seedlings leaves and root vitality all presented a gradually increasing trend in whole growth stages; the change of INV activity in leaves kept a relative steady state basically in the whole tobacco seedlings growth stages. N,K,Ca,Mg contents of tobacco seedlings were richer than those of flue-cured tobacco in the field, especially two to three leaves stage.