刺桐叶部特征与其对刺桐姬小蜂抗性的关系

Relationship between the Leaf Morphostructure of Coral Trees and Their Resistance to Quadrastichu erythrinae

依据刺桐不同品系叶片的形态和解剖特征,结合其对刺桐姬小蜂(Quadrastichu erythrinae)的抗性表现,探讨二者的相互关系,对于揭示植食性昆虫与寄主植物的相互关系,选育抗虫刺桐品系并推广种植具有重要意义。研究结果表明:刺桐高感品系的叶片形状、厚度与高抗和中抗品系存在显著差异,可作为抗性鉴定的依据之一。从叶表微观形态来看,高抗品系上表皮不存在气孔器,上、下表皮的表皮细胞形状、大小均匀一致,排列致密,细胞间隙很小,表面密被霜状蜡质层保护,不利于刺桐姬小蜂侵入和产卵的构造;从叶片横切面结构上看,高感刺桐品系的栅栏组织、海绵组织、维管束鞘、上下表皮显著薄于高抗品系,且各内部组织细胞体积较大、排列疏松,不能有效抵御刺桐姬小蜂侵入与危害。同时,刺桐东方变种(Erythrina variegate var orientalis)HA1是高感品系,应禁止调运和引种;本地刺桐(E.variegate)HA2具有很强的抗虫性,宜于推广种植。

Relationship between plant-feed insects and hosts was studied by morphostructure and anatomy structure of leaves to discuss the relationship between coral trees and its resistance to Quadrastichu erythrinae, and to single out the highest resistance lines to generalize. The results showed that there was a remarkable difference on the leaf shape and thickness of coral trees between highly susceptible lines, middle and high resistance lines, which were regarded as the evidence of evaluating their resistance. Observed from micro-morphology on the leaf surface of the highest resistance lines, there was symmetrical epidermis cells in size and shape which arranged tightly with little intercellular space on the surface, and covered by wax layer which looked like a frost. Observed from cross section of the leaves of the highest resistance lines, the thickness of palisade tissue, spongy tissue, vascular bundle, upper epidermis and lower epidermis were all thinner than those of middle or high resistance lines, and internal-tissues were made up of bigger cells loosely, which could not prevent Q. erythrinae from invading and damaging. In addition, E.variegata could be generalized in practice because of it＇s highest resistance, while E. variegate var orientalis must be prohibited to be allocated and transported because of it＇s most susceptible to Q. erythrinae.