According to observation of the lower epidermis of the leaves of different insect-resistant Eucalyptus spp.by electronic scanning microscope, it was discivered as follows.In the leaves of a healthy plant, the length of stomata was negatively correlated with insect resistance and there was a close relationship between the value of grey and insect resistance.In the leaves of a plant In the susceptible strain damaged by insects, the stomata were extremely significantly longer than those in a healthy plant, but tended to shorten slowly in the high susceptible strain.When leaves were parasitized, the density of stomata significantly reduced in E.dunnii but insignificantly in E.grandis and E.urophylla ×E.tereticornis DH201-2.The relative height of waxy accumulation declined when damaged by the pest.The healthy leaves of high resistant and high susceptible strains were closely coverd with wax. The main vein cells were long and thin in high resistant strain, on the contrary, main vein was formed by thick and short cells in high susceptible strain.In the susceptible strain, the wax was film shaped.In damaged high susceptible strain, wax around stomata showed molten and covered the part of stomatal area.The main vein cells shortened and the boundaries of leaf margin were not clear.In the susceptible strain, wax spread outward and increased the porosity naked, the main vein cells mixed together, and there were sediments in the boundaries of leaf .It has been proved that the strains with high insect-resistance had leaves with short stomata and long main-vein cells.%应用电子扫描显微镜对不同抗虫品系桉树叶片的下表皮进行观察，结果表明：在健康的桉树叶片中，气孔的长度与抗虫呈负相关，灰度值与抗虫性存在一定关系。在受害植株中，中感品系受害叶片的气孔长度极显著大于未受害叶片，而高感品系则有缓慢缩小的趋势。受害后的叶片背面，气孔密度都略有减少，邓恩桉表现为极显著变化，巨桉QG8和巨圆桉DH201-2的变化不显著。蜡质的堆积圈的相对高度，在受害后都减低。在未受害叶片中，高抗、高感品系密被蜡质；高抗品系主脉细胞细长，主脉由粗短细胞组成；中感品系的蜡质呈薄膜状。高感品系植株的受害叶片气孔周围的蜡质晶体呈熔融状态，覆盖了部分气孔面积，受害主脉粗短，叶缘界限不清晰。中感品系的蜡质则向外熔融扩散，增大了气孔的裸露，主脉细胞融合，叶缘有沉淀物。研究结果表明，叶片的气孔长度短，主脉细胞细长的品系抗虫性较强。
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