空心莲子草地下茎克隆繁殖特征

空心莲子草是一种原产于南美洲的苋科多年生草本植物,目前在许多地方已经成为一种危害十分严重的外来入侵植物。通过地下茎等营养器官进行无性繁殖是其主要繁殖方式。本文以空心莲子草的地下茎为实验材料,对其克隆繁殖特征进行了研究。研究结果表明:(1)地下茎的节是克隆繁殖的必要条件,节的有无决定克隆繁殖是否发生;(2)地下茎可以通过控制单位节上的出芽率来调节其克隆生长过程,从而使克隆繁殖结果更有利于整个种群的生长;(3)地下茎的粗细程度对其克隆繁殖也有显著影响。空心莲子草地下茎的单位节数与其单位节出芽率、无性系小株的高度和地上部分的节数之间存在密切联系。

The characteristics of clonal reproduction of rhizome from Alternanthera philoxeroides

Alternanthera philoxeroides(Mart.) Griseb is a perennial herb grown in South America naturally.However,it is regarded as a great harmful invasive weed in many regions over the world.Asexual reproduction by vegetative organs,such as rhizome,is its main reproductive way.The characteristics of clonal reproduction discussed in this paper is based on the experiment with rhizome of A.philoxeroides.The results show that:(1) the node of rhizome is prerequisite of its clonal reproduction;(2) rhizome can accommodate its clonal growth by controlling the ratio of buds/node;(3)the diameter of rhizome also has a distinct effects on its clonal reproduction.The ratio of buds/node is the highest in the rhizome segment with 1 node and the lowest in the rhizome segment with 4 nodes,but the morphological characteristics of ramets show a different result,i.e.the height and the node number of ramets is the lowest in the rhizome segment with 1 node and the highest in the rhizome segment with 4 nodes.While the ratio of buds/node is higher in the rhizome segment with thick node than thin ones.