白蜡虫7种寄主植物叶片解剖结构与寄主选择性的关系

用石蜡切片法在显微镜下观察白蜡虫Ericerus pela(Chavannes)]7种寄主植物叶的解剖结构。结果表明,寄主植物的叶脉、表皮、栅栏组织、海绵组织、维管束解剖结构及数量性状特征在属、种间存在显著差异。7种寄主植物中,华南小蜡(Ligustrum calleryanum Decne.)和白蜡树(Fraxinus chinensis Roxb.)表皮被毛,华南小蜡表皮毛浓密,白蜡树表皮毛稀疏,其它寄主植物表皮无毛;女贞树(Ligustrum lucidum Ait.)栅栏组织、海绵组织和叶脉的厚度最厚、维管束直径最大,其它寄主植物相对较小。因此,叶片表面光滑、叶脉发达、叶片肥厚是白蜡虫优良寄主植物的重要解剖学特征。7种寄主植物中脉和侧脉发达,近轴面凹陷,远轴面突起,肉脉包埋在叶肉中,推测叶脉突起和凹槽可能是白蜡虫固定位点选择的关键线索。

Relationship between Leaf Anatomical Structures of Seven Host Plants and Host- selection by Ericerus pela (Chavannes )

Main vein, lateral vein and minor vein of seven host plants leaves of Ericerus pela (Chavannes) were sectioned with paraffin sectioning method. Under the NikonE800 microscope, numerous observations were made, including leaf thickness, midrib, culticle, palisade tissue and spongy tissue, diameter of vascular bundle, ratio of palisade tissue to spongy tissue, and ratio of leaf thickness to midrib thickness. Results showed that there were significant differences among genus and species of quantitative characters or anatomical structures of Ligstrum, Fraxinus and Chionanthus. Among seven host plants, the leaves of Fraxinus chinensis Roxb. and Ligstrum calleryanum Decne. have trichomes. Ligustrum lucidum Ait. had the maximum diameter of vascular bundle and the thickest of vein, spongy tissue and palisade tissue. Therefore, it may be important anatomical features of superior host plants of E. pela that leaf surfaces were smooth with well-developed veins and thick lamina. Moreover, well-developed main and lateral veins formed protrude on the abaxial surfaces and groove on the adaxial surfaces, however, a network of minor veins was present in the lamina of the leaf and these were too small to be visibly raised on either the lower or upper surfaces. We speculated that grooves and protrudes of main or lateral veins provided key cues for settling-sites selection of E. pela.