杜仲含胶细胞发生和发育的研究

STUDIES ON THE INITIATION AND DEVELOPMENT OF GUTTA-CONTAINING CELLS OF EUCOMMIA ULMOIDES OLIV.

杜仲(Eucommia ulmoides Oliv.)茎皮层中的含胶结构是一种细丝状的分泌细胞。根据薄切片观察,其原始细胞出现在茎的原形成层分化出原生韧皮部最早的筛管分子时,它们是由一些皮层基本分生组织细胞通过纵向均等分裂、纵向不等分裂的子细胞,或者横向多次分裂后的末端细胞构成。在皮层基本分生组织停止分裂前,原始细胞可继续产生,其发生的位置无明显的规律性。此种原始细胞具有长宽比大、细胞核呈椭圆形和细胞质浓厚等特征,有别于周围细胞。以后,原始细胞的两端以插入生长方式迅速伸长,形成十分细长、两端膨大的丝状单细胞。在发育过程中,细胞质内逐渐合成和积累橡胶颗粒,随着橡胶颗粒增加,其细胞器逐渐退化。在成熟的含胶细胞中,细胞腔内充满橡胶颗粒,细胞核及其他细胞器解体,但其外仍有纤维素的细胞壁。

The gutta-containing structure in the cortex of a stem of Eucommia ulmoides is a fila- mentous,secretory cell.Observation of thin sections revealed that when the procambium of a stern differentiated into the earliest sieve elenents of protophloem,the initials cells appeared as daughter cells originated from a longitudinally equational or unequational divisions,or from the terminal cell formed by several transverse divisions of some cortical ground meriste- matic cells.Before the cells of the cortical ground meristem ceased to divide,the initial cells,. in an arbitrary position of origin,develops continuously.These initial cells were able to be- distinguished from the surrounding ceils by their large length/width ratio,the presence of ellip- ical nuclei and dense cytoplasm,etc.Later,both ends of the initial cells extended rapidly through intrusive growth,forming the very long,thin and filamentous unicell with two dilated terminations.During development,the gutta particles were gradually synthesized and accum- ulated in the cytoplasm,where as the organelles degenerated progressively.In the muture gutta-containing cell,the cell cavity was filled with gutta particles,the nucleus as well as other organelles was disintegrated leaving an intact fibrous cell wall.