寄生植物锁阳茎的发育解剖学研究

锁阳茎的初生分生组织由原表皮、基本分生组织以及在基本分生组织中呈波浪式环状排列的原形成层束组成。茎的增粗是由于呈波浪式环状排列的维管束,其“波浪”上下幅度逐渐增大,即从“浪”的基部到“浪”顶端维管束数目由4个逐渐增加到10－12个。维管束数目不断增加是由于：（1）由髓射线薄壁细胞反分化产生分生组织束,分生组织束活动产生新的维管束;（2）维管束中分化出一列或几列薄壁细胞,导致该维管束被分化出的薄壁细胞分成2－3个独立的维管束。

Developmental anatomy studies on the stem of Cynomorium songaricum

Primary meristem of Cynomorium songaricum Rupr.is composed of protoderm,ground meristem and procambium strands that line a wavelike ring in the ground meristem.As the diameter of the stem increases,the range of the "wave" rises correspondingly,that is the number of the bundles from the bottom to top of the wave increases from 4 to 10-12.The reasons for the increase suggested in this paper,are as the following:(1) the parenchymous cells of pith ray turn into meristem strands and the meristem strands form new vascular bundles;(2) a vascular bundle can be separated into 2-3 independent vascular bundles by one or two row parenchymous cells split from the vascular.