A STUDY ON THE TISSUES DIFFERENTITION OF THE STEM OF EUCOMMIA ULMOIDES OLIV.

Tien Lanhsing;Hu Zhenghai, (Department of Biology, Northwestern University)  

The present paper observes and describes the differentiation of theprimary structure and the process of secondary growth occuring in the stemof Eucommia ulmoides. The stem apex of Eucommia ulmoides consists ofone-layered tunica and corpus. The differentiation of primary structure ofthe stem begins with the ground meristem which involves the cotex and thepith, while at the ring of procambium, the first primary vascular tissuesdifferentiate in three or four separate strands. At the successively laterstages of development as more and more of the strands may be differentia- ted in the vascular region. the primary vascular tissues have developedinto rings as a result. According to Esau, the primary vascular system ofthe stem of Eucommia ulmoides is a traces system, while at the same timethe structure of the stem nodes prossess the features of unilacunar gap andone trace. When the primary structure has completed its differentiation inthe stem of Eucommia ulmoides, the epidermis begins to be transformedphellogen, producing first periderm. At the same time, cell division takesplace in the vascular cambium as well, thus producing the secondary vascu-lar tissues. Before the growth season comes to a close, the secondarystructure has become the principal part of the stem of Eucommia ulmoides.

【Key Words】：

Download(CAJ format) Download(PDF format)

CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.