水培红豆杉根的形态解剖

Morphological and anatomical structure of hydroponic Yew root

采用石蜡切片技术和光学显微技术,对生长在土壤中和水生环境中红豆杉根进行形态与解剖结构比较研究。结果表明,水培红豆杉经诱导后生出了大量不定根组成的新根系。新生气生根外观稍细,表皮排列较紧密,具有较为明显的角质层,表面密被细长的根毛;水生根外观稍粗,表皮细胞角质层不清楚,根毛较稀疏且短。水生根的皮层细胞层次较气生根略多。气生根与水生根中央的维管柱,初生木质部与初生韧皮部束数与土生根类似,均为2束,但细胞组成较少,结构明显简单。水培红豆杉的根次生生长发生较迟,次生生长与次生结构均较弱,表皮脱落被一两层周皮所代替,而皮层保留时间较长。

In this paper, the paraffin section technique and optical microscopy were used to compare the morphological and anatomical structure of Taxus chinensis under the soil and hydroponic conditions. Results showed that hydroponic Taxus chinensis formed a large root system composed of a large amount of adventitious roots. The new adventitious air root had a slenderer appearance, more closely arranged epidermis, an obvious stratum corneum, and an intensive cover of slender adventitious root, while the aquatic root had a thick appearance, an unclear stratum corneum of epidermal cell wall, and thin and short root hairs. The aquatic root cortical cells had a little bit more layers than the adventitious root cells. The central vascular cylinder, the primary xylem and primary phloem bundle number of adventitious root and aquatic root were similar to the root in the soil with the bundle number being 2, but adventitious root and aquatic root had less cells and an obvious simple structure. Compared to the root in the soil, the secondary growth of hydroponic Taxus chinensis root occurred later and the secondary growth and the secondary structure were both relatively weak. The epidermis was replaced by two layers of periderm after the epidermis fell off, while the cortex was kept for a long time.