尾穗苋轴器官异常结构的研究

尾穗苋轴器官中存在多轮呈同心环状排列的异常维管束和其间的结合组织。异常维管束外韧型。两相邻轮的异常维管束由３－６层切向溥壁结合组织细胞分隔；同一轮两相邻异常维管束间被３－９列径向结合组织细胞所间隔，其外侧轮径向结合组织细胞壁趋向厚壁木质化。从根到茎，异常维管束的轮数趋于减少，而径向结合组织细胞的厚壁木质化程度增加。此外，茎的异常次生结构的内方存在２－３轮是散生的维管束在横切面上，散生维管束排成５－７组小环状，每７－１１个维管束排列成一小环状。

ANOMALOUS STRUCTURE IN THB AXIS OF AMARANTHUS CAUD.ATUS

AnomaIous secondary structure which is composed of many rings of concentric enomalous bundles embedded in conjunctive tissue occurs in the axis of Amaranthus caudatus.The anomalous bundles belong to collateral type.There are 3 to 6 layers of tangential conjunctive parenchyma tissue calls between two rings of anomalous bundles.And within the same ring,the bundles are separated by 3 to 9 files of radial coyjunctive parenchyma or thick-walled and lignified tissue cells. From the root to the stem,the number of rings of anomalous bundles tends to dlcrease, and the thick-walled,lignified degrees of radial cojunctive tissue cells to increase. In addition, 2-3rings of central vascular bundles are appearance to be scattered. As seen in cross section,the scattered bundles are usually arranged in 5-7 small rings,and each ring consists of 7-11 bundles.