Universidade Federal de Uberlândia, Instituto de Biologia, 38402-020 Uberlândia, MG, Brasil.
Ann Bot. 2012 Aug;110(3):667-79. doi: 10.1093/aob/mcs125. Epub 2012 Jun 28.
Apomictic plants are less dependent on pollinator services and able to occupy more diverse habitats than sexual species. However, such assumptions are based on temperate species, and comparable evaluation for species-rich Neotropical taxa is lacking. In this context, the Melastomataceae is a predominantly Neotropical angiosperm family with many apomictic species, which is common in the Campos Rupestres, endemism-rich vegetation on rocky outcrops in central Brazil. In this study, the breeding system of some Campo Rupestre Melastomataceae was evaluated, and breeding system studies for New World species were surveyed to test the hypothesis that apomixis is associated with wide distributions, whilst sexual species have more restricted areas.
The breeding systems of 20 Campo Rupestre Melastomataceae were studied using hand pollinations and pollen-tube growth analysis. In addition, breeding system information was compiled for 124 New World species of Melastomataceae with either wide (>1000 km) or restricted distributions.
Most (80 %) of the Campo Rupestre species studied were self-compatible. Self-incompatibility in Microlicia viminalis was associated with pollen-tube arrest in the style, as described for other Melastomataceae, but most self-incompatible species analysed showed pollen-tube growth to the ovary irrespective of pollination treatment. Apomictic species showed lower pollen viability and were less frequent among the Campo Rupestre plants. Among the New World species compiled, 43 were apomictic and 77 sexual (24 self-incompatible and 53 self-compatible). Most apomictic (86 %) and self-incompatible species (71 %) presented wide distributions, whilst restricted distributions predominate only among the self-compatible ones (53 %).
Self-compatibility and dependence on biotic pollination were characteristic of Campo Rupestre and narrowly distributed New World Melastomataceae species, whilst apomictics are widely distributed. This is, to a certain extent, similar to the geographical parthenogenesis pattern of temperate apomictics.
无融合生殖植物对传粉者服务的依赖性较小，能够占据比有性种更多样化的栖息地。然而，这些假设是基于温带物种的，而对新热带地区丰富的分类群缺乏可比的评估。在这种情况下，Melastomataceae 是一个主要的新热带被子植物科，有许多无融合生殖的物种，在巴西中部岩石露头的富含特有种的 Campos Rupestres 植被中很常见。在本研究中，评估了一些 Campos Rupestres Melastomataceae 的繁殖系统，并调查了新世界物种的繁殖系统研究，以检验无融合生殖与广泛分布相关，而有性种的分布区域则较为有限的假设。
使用人工授粉和花粉管生长分析研究了 20 种 Campos Rupestres Melastomataceae 的繁殖系统。此外，还为 124 种具有广泛（>1000 公里）或受限分布的新世界 Melastomataceae 物种编制了繁殖系统信息。
在所研究的 Campo Rupestre 物种中，大多数（80%）为自交亲和的。Microlicia viminalis 的自交不亲和性与花粉管在花柱中受阻有关，这与其他 Melastomataceae 描述的情况相同，但大多数分析的自交不亲和物种在无论授粉处理如何，花粉管都能生长到子房。无融合生殖的物种表现出较低的花粉活力，在 Campos Rupestre 植物中的频率较低。在所汇编的新世界物种中，有 43 种为无融合生殖，77 种为有性生殖（24 种自交不亲和，53 种自交亲和）。大多数无融合生殖（86%）和自交不亲和物种（71%）分布广泛，而仅限于自交亲和物种（53%）的分布受限。
自交亲和性和对生物传粉的依赖是 Campos Rupestre 和分布狭窄的新世界 Melastomataceae 物种的特征，而无融合生殖的物种分布广泛。这在一定程度上类似于温带无融合生殖的地理部分生殖模式。
