密度、留叶数及其互作对烤烟光合特性及经济性状的影响

Effects of Density, Leaf Number Remained and Their Interaction on Photosynthetic and Economic Characters of Flue-Cured Tobacco

采用双因素随机区组试验，研究密度、留叶数及其互作对烤烟（云烟97）光合特性、经济性状的影响。结果表明，密度、留叶数及其互作对烤烟光合特性、经济性状产生显著影响，且留叶数效应较大，密度和互作效应较小。同一留叶数下，随密度增加，光合速率（Pn）、气孔导度（Gs）、胞间 CO2浓度（Ci）、蒸腾速率（Tr）、叶绿素含量均表现出先升高后降低的趋势；低、中密度下，Pn、Gs、Ci、Tr、叶绿素含量随留叶数增加，均逐渐升高，高密度下则先升高后降低。不同处理的光、CO2响应曲线类型均相同，但曲线参数存在差异，低、中密度下，随留叶数增加，最大Pn逐渐升高，高密度下则先升后降。相同密度下，烤烟产量、产值均随留叶数增加而显著上升；留叶数一定时，随密度增大，产量呈上升趋势，但产值先升后降。综合分析，密度16500株/hm2、留叶23片/株效果最好；理论适宜密度、留叶数范围分别为17093～17665株/hm2、21.3～23.1片/株。

A field experiment was conducted using two-factor randomized complete block design to investigate the effects of density （D）, number of leaves remained （L） and their interaction on photosynthetic characters and economic traits of flue-cured tobacco （cv Yunyan 97）. The results showed that D, L and their interaction had significant effects on photosynthetic characters and economic traits of flue-cured tobacco, and the responses from the D were greater than those from L and their interaction. Under same L condition, Pn, Gs, Ci, Tr and chlorophyll content increased first and then declined as D increased. As for the low and medium D conditions, with L increasing, Pn, Gs, Ci, Tr and chlorophyll content increased gradually, but they increased first, and decreased later under high D conditions. In addition, light and CO2 response curve type from all treatments were the same, but response curve parameters were different. With L increasing, maximum Pn rised gradually under low and medium D conditions, while increased first, and decreased later under high conditions. With L increasing, both yield and output value increased significantly under seam D conditions;under seam L conditions, yield rised gradually, but output value increased firstly and then declined, when D increased. On the consideration of comprehensive analysis, effect of 16500/23 treatment was best; and theoretically the appropriate D and L for Yunyan 97 were 17093-17665 plant/ha and 21.3-23.1 leaves/plant respectively.