伯乐树不同发育阶段叶片表面附属结构特征

利用石蜡切片及电子显微镜扫描技术，对伯乐树（Bretschneidera sinensis）不同发育阶段的叶表面表皮毛、角质层、乳突和气孔器4种附属结构进行了观察。结果显示：伯乐树叶的上、下表面和叶脉处分布着单细胞或多细胞的单列表皮毛，表皮毛的密度随着叶片的生长发育逐渐稀疏；叶片上表面覆盖着条纹状的角质层；叶片的下表面有鲜花状乳突，密度随叶片的生长逐渐稀疏；气孔仅见于下表面，气孔器类型为无规则型。伯乐树和叠珠树叶片具有相似的乳突结构，结合形态学、解剖学及分子证据，在一定程度上显示了伯乐树与叠珠树科可能存在较密切的关系；叶表面附属结构的特点反映了伯乐树对环境的长期适应。

Features of Leaf Appendages of Bretschneidera sinensis in Different Development Stages

Leaf appendages (trichome, cuticle, papillae, stomatal apparatus) of Bretschneidera sinensis in different development stages were observed by paraffin section and scanning electron microscopy (SEM). The results showed that there were epidermal trichomes composed of one or several cells in a row on both leaf epiderms and veins. The density of the trichomes decreased with leaf development. The upper epiderm was covered with striated cuticles. The lower epiderm was covered with flower-like papillae and the density also decreased with the development of leaf. The stomatal apparatus were anomocytic and found only on lower epidermis. By possessing similar papillae, combined with morphological, anatomical and molecular evidence, the close relationship between Bretschneidera sinensis and Akaniaceae was inferred. The characters of leaf appendages of Bretschneidera sinensis reflect its long-term adaption to environment.