Luo Shixiao, Zhang Dianxiang, Renner Susanne S
South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou 510650, China.
Ann Bot. 2006 Aug;98(2):459-64. doi: 10.1093/aob/mcl121. Epub 2006 May 30.
Oxalis debilis is a South American tristylous species that is currently naturalizing in China. Based on field observations and herbarium data a report is made on its pollination, morph frequencies, pollen viability, seed set and chromosome number. In addition, a new chromosome count for the species in Africa is provided.
Field observations were conducted in six provinces in south-east China. Flower visitors were recorded and nectar sugar was measured with a refractometer. The species' compatibility system was determined by carrying out experimental self- and cross-pollinations on bagged inflorescences. Stigma receptivity and pollen viability was determined using the MTT test.
Populations of O. debilis in China contain either the mid-style-length morph or the short morph, but not both. Pollination is by nectar- and pollen-foraging bees; pollen viability is low; and seed set in natural and experimentally self- or cross-pollinated flowers is extremely low. Chromosome counts indicate that O. debilis contains diploid and tetraploid forms in its native as well as introduced range, which does not support a previous hypothesis that the predominant vegetative reproduction in this species is an escape from pentaploidy.
酢浆草是一种原产于南美洲的三型花柱植物，目前正在中国归化。基于实地观察和标本馆数据，对其授粉、形态频率、花粉活力、结实率和染色体数目进行了报告。此外，还提供了该物种在非洲的新染色体计数。
在中国东南部的六个省份进行了实地观察。记录访花者，并使用折射仪测量花蜜糖分。通过对套袋花序进行实验性自花授粉和异花授粉来确定该物种的交配系统。使用MTT试验确定柱头可授性和花粉活力。
中国的酢浆草种群只包含中型花柱形态或短型花柱形态，而非两者兼具。授粉由采集花蜜和花粉的蜜蜂完成；花粉活力较低；自然状态下以及实验性自花授粉或异花授粉的花朵结实率极低。染色体计数表明，酢浆草在其原生分布区和引入分布区均包含二倍体和四倍体形式，这并不支持之前的一个假设，即该物种主要的营养繁殖是为了逃避五倍体状态。
