种植密度对烟草主茎中化学成分运输与储存的影响

为探究不同种植密度对烟草主茎形态结构及茎中化学成分运输、贮存的影响，以烤烟品种NC55为材料，采用田间小区试验，设不同种植密度，对单株生物量、主茎形态结构、大量元素和非结构性碳水化合物含量进行研究。结果表明，高密度处理降低了烟株各器官尤其是叶片的生物量，烟株茎围为4.28~7.55 cm，节距为1.41~6.13 cm，低密度处理的茎围为4.83~10.00 cm，节距为1.26~4.95 cm。化学成分分析表明，自顶部向下主茎中氮磷钾含量呈降低的趋势，可溶性糖、蔗糖和淀粉含量呈增加趋势。低密度处理显著增加了主茎皮层和髓中全氮、全磷的含量，降低了下部髓中全钾的含量。低密度处理增加了皮层中非结构性碳水化合物，而降低其在髓中含量。低密度处理增加了主茎中全氮、全磷的运输贮存，增加了非结构性碳水化合物的运输，减少其贮存。种植密度通过改变主茎形态结构与器官占比等改变了主茎中大量元素与非结构性碳水化合物的运输与贮存能力，是调整烟草源-流-库关系的重要手段。

Effects of Planting Density on Transportation and Storage of Chemical Components within Tobacco Stem

In order to study the effects of different planting densities on morphological structure of tobacco main stem and the transportation and storage of chemical components in the stem, flue-cured tobacco NC55 was used as the material to study the biomass, main stem morphological structure, macronutrients and non-structural carbohydrate content under different planting density treatments in a field experiment. The results showed that the biomass of different organs, especially leaves were reduced by high density treatment. The stem circumference of tobacco treated by high density was 4.28-7.55 cm, the pitch was 1.41-6.13 cm, the stem circumference of tobacco treated by low density treatment was 4.83-10.00 cm, the pitch was 1.26-4.95 cm. Chemical composition analysis showed that the contents of nitrogen, phosphorus and potassium in the main stem decreased from top to bottom, while the contents of soluble sugar, sucrose and starch increased. Under low density treatment, the contents of nitrogen and phosphorus in cortex and pith of main stem were significantly increased and the content of potassium in bottom pith was significantly reduced. Under low density treatment, the contents of soluble sugar, sucrose and starch in the cortex of main stem were increased, and the non-structural carbohydrates in pith were reduced. Low density treatment increased the transportation and storage of nitrogen and phosphorus in the main stem, increased the transportation of non-structural carbohydrates and reduced the storage of non-structural carbohydrates. Planting density changed the transportation and storage capacity of macronutrients and non-structural carbohydrates in the main stem through the morphological structure of the main stem and the proportion of organs, etc. As a result, planting density is an important method to regulate the relationship between source, flow and storage of nutrients in tobacco.