揭膜和不揭膜对烤烟叶片结构的影响

采用石蜡切片的方法研究了不同覆盖处理的烤烟叶片解剖结构。研究结果表明，揭膜和不揭膜主要影响到中下部叶片的厚度，7月28日测定时，揭膜的叶片厚度比不揭膜的处理提高了25.88%，叶片厚度的增加主要是海绵组织厚度和栅栏组织厚度的增加。不揭膜的烤烟叶片的栅栏组织厚度变化比较有规律，均是随着叶位的上升而变薄；而揭膜的叶片到第二次测定时是中间的叶片最厚，下部叶片栅栏组织厚度与上部叶相差不大，说明揭膜后烤烟叶片的发育期提前了。所以，要根据黑龙江烟区的气候特点，在夏季气温较高时，适时揭膜。

Effects of Polyethylene Mulch on Anatomical Structure in Leaves of Flue-Cured Tobacco

This study was conducted, using the method of slices of paraffin wax, to investigate anatomical structures in leaves of flue -cured tobacco treated with applying polyethylene mulch and taking off polyethylene mulch after transplanting. The result showed that applying polyethylene mulch plays an important role in middle and bottom stalk tobacco leaves. The leaf thickness treated with polythene mulch was higher by 25.88%than taking off polyethylene mulch, measuring on July 28th. The increase of leaf thickness was mainly caused by the thickness of sponge and palisade parenchyma. The leaf thickness for palisade parenchyma treated with polythene mulch changed regularly, the thickness of leaf decreased with rising of the leaf position. However, the thickness in middle stalk position of tobacco was thicker than upper and bottom stalk, which was measured on July 28th. These results indicated that leaves treated with taking off polyethylene mulch developed earlier. It is suggested that taking off polyethylene mulch at proper time is a good practice to improve leaf quality and yield in tobacco production, according to climate characters in Heilongjiang province.