空心莲子草无性繁殖体的大小及数量对其建群效应的影响

Influence of Size and Density of Alligator Weed Propagule Fragments on its Population Establishment

分别研究了不同大小的空心莲子草(Alternanthera philoxeroides(Mart.)Griseb.)地下茎片段(带1个节长度2cm、带2个节长度4cm、带3个节长度6cm)和肉质根片段(长度为0.2cm、1cm、3cm、5cm、7cm)在不同埋植密度(1根/盆、3根/盆、5根/盆、7根/盆、9根/盆)下的萌芽和幼苗生长。结果表明,随空心莲子草无性繁殖体(地下茎和肉质根)片段引入数量增加,每盆片段的萌芽数、幼苗的分枝茎节数以及植株的生物量显著增加;除0.2cm长的肉质根基本不能萌发外,随着无性繁殖体片段大小的增加,每盆片段的萌芽数和植株生物量显著增加;无性繁殖体片段的大小和数量交互作用对萌芽数和生物量具有显著的影响,对分枝茎节数无显著影响。这表明空心莲子草无性繁殖体片段越大、引入数量越多,其种群建立越易成功,入侵的风险就越大。

Different size of stem fragments of alligator weed (Alternanthera philoxeroides)(length of 2 cm with 1 node,length of 4 cm with 2 nodes,length of 6 cm with 3 nodes) and different length of root fragments (with length of 0.2,1,3,5,7 cm) were implanted accordingly in different density (1 fragment/pot,3 fragments/pot,5 fragments/pot,7 fragments/pot,9 fragments/pot).The sprouting and early growth of seedling of alligator weed were studied.The number of sprouts,branching node of the younglings and biomass significantly increased as the number of the fragments(underground stem fragment and root fragment) increased.In addition to the root fragments with length of 0.2 cm mostly could not sprout,the number of sprout and biomass significantly increased as the length of the fragments increased.The interaction of fragment size and number had a marked impact on the number of sprout and biomass,had no significant impact on the number of branching node.This shows that the larger the papagule fragments and the greater the introduction number of alligator weed,the more successful its population established,increased the risk of invasion.