首页   按字顺浏览 期刊浏览 卷期浏览 STEM FORMATION FROM A SUCCULENT LEAF: ITS BEARING ON THEORIES OF AXIATION
STEM FORMATION FROM A SUCCULENT LEAF: ITS BEARING ON THEORIES OF AXIATION

 

作者: Paul B. Green,   Kenton E. Brooks,  

 

期刊: American Journal of Botany  (WILEY Available online 1978)
卷期: Volume 65, issue 1  

页码: 13-26

 

ISSN:0002-9122

 

年代: 1978

 

DOI:10.1002/j.1537-2197.1978.tb10829.x

 

出版商: Wiley

 

数据来源: WILEY

 

摘要:

The radial symmetry of shoots and roots arises from a center of symmetry within the apical meristem. When a lateral axis forms at a distance from the tip, a new center of radial symmetry must arise. We have studied the biophysics of this kind of transformation in the epidermal layer of the succulentGraptopetalumwhere a stem “regenerates” from organized leaf tissue. Study of the epidermal cell pattern (with scanning electron microscopy) shows that reorganization involves neither a cellular pre‐pattern blocked out by oriented cell divisions nor a callus‐like stage where cell files, expansion direction, and primary cell wall cellulose orientation are randomized throughout. Rather, developmental events are a function of initial position. In regions of geometrical compatibility between parent axis and prospective lateral, there is little or no modification of files, expansion, or cellulose. In regions requiring 90° changes in orientation, cellulose orientation (studied with polarized light) conforms to the new symmetry first. This is followed later by changes in the surface growth pattern and in the cell division pattern. The early establishment of a circumferential cellulose pattern in the epidermal layer could account for both the cylindrical shape of the new axis and the subsequent rearrangement of directional growth and cell file pattern.

 

点击下载:  PDF (3203KB)



返 回