海桑和无瓣海桑叶片结构的比较研究

为了探讨外来植物无瓣海桑的潜在危害,采用石蜡切片法对海桑(Sonneratia caseolaris Engl.)、无瓣海桑(S.apetala B.Ham)叶片进行了解剖学研究。实验结果显示,两种植物的叶片均为等面叶;中脉维管束为周韧维管束;具4级侧脉,第1级侧脉为半周韧维管束;成熟叶片叶肉组织具发达的贮水薄壁细胞,具含单宁成分的薄壁细胞,具晶体细胞和石细胞;盐腺由表皮细胞发育而成,可分为3个发育阶段。作为外来植物的无瓣海桑,其中脉维管束具微弱形成层,叶脉维管组织比海桑更发达;贮藏组织中含单宁细胞、晶体细胞较多;栅栏组织含叶绿体多于海桑等特点,使其比海桑对环境具有更大的适应性。因此,无瓣海桑有可能成为入侵植物。

Comparative Study on the Leaf Structures of Sonneratia caseolaris and S. apetala

This study investigated the potential endanger of alien plant Sonneratia apetala. The leaf structures of S.caseolaris and S.apetala were studied by paraffin sectioning under a light microscope. Results showed that both S.caseolaris and S.apetala had isobilateral leaves; the midrib vascular bundle was amphicribral; the leaves had four veins, with the primary vein having a semi-amphicribral vascular bundle; the mesophyll of the mature leaves had aqueous tissues, crystal cells, tannin cells and stone cells; the salt glands were developed from the epidermis cells of the leaves, experiencing three periods. As an alien plant species, compared with S.caseolaris, S.apetala had a faint cambium, better-developed vascular tissues, more crystal and tannin cells in the storage tissues, and more chloroplasts in the palisade. Furthermore, S.apetala had obviously better ecological adaptability than S.caseolaris. Thus, S.apetala may become an invasive plant.