入侵植物薇甘菊种群年龄的解剖学特征

对不同年龄薇甘菊(Mikania micrantha)茎的解剖观察发现,不同年龄的薇甘菊茎的解剖学特征存在差异,具体表现在:1年生的薇甘菊茎是初生结构;2年生的薇甘菊出现次生生长;3年生的薇甘菊茎次生生长继续进行,原先棱角处由于整体生长缓慢,出现凹陷现象,初生生长的表皮被周皮取代;4年生的薇甘菊茎开始出现退化现象,皮层内叶绿体降解,表皮沉积物明显;5年生薇甘菊茎的周皮开始脱落,出现明显的干裂碎片;6年生薇甘菊植株的茎内髓心大量沉积单宁类物质,初生韧皮部已经脱落,次生韧皮部产生的周皮已经死亡,开始脱落,整体呈现功能丧失状态。

Anatomical Features of Population Age for Invasive Species Mikania micrantha

It is found that there are differences in the anatomical characteristics of Mikania micrantha of different ages through the anatomy observation on the stem of Mikania micrantha of different ages. The differences are as follows: the annual stem is primary structure; the biennial stem shows secondary growth; the stem secondary growth continues in the third year, and because of the slowness of holistic growth, hollows appear on the primary edges, and epidermis is replaced by periderm; in the fourth year, the stem begins to degenerate, and chloroplast in the cortex is degraded, and the sediment of epidermis becomes obvious; in its fifth year, the periderm of stem begins to abscise, and presents obvious dry fragments; in its sixth year, volumes of tannins accumulate in the boxed-heart of stem, and primary phloem has already abscised, and periderm which origins from the secondary phloem is already dead and becomes to abscise, in a word, the stem is losing its function.