Carbon assimilation and habitat segregation in resurrection plants: a comparison between desiccation- and non-desiccation-tolerant species of Neotropical Velloziaceae (Pandanales)
Carbon assimilation and habitat segregation in resurrection plants: a comparison between desiccation- and non-desiccation-tolerant species of Neotropical Velloziaceae (Pandanales)
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DOI：
10.1111/1365-2435.12462
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发表时间：
2015-12-01
影响因子：
5.2
通讯作者：
Oliveira, Rafael S.
中科院分区：
文献类型：
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作者：
Alcantara, Suzana;de Mello-Silva, Renato;Oliveira, Rafael S.
1.干燥耐受性是某些生物体表现出的使其含水量与干燥空气的含水量平衡并在重新建立供水时恢复的能力。这在被子植物中是一种普遍但罕见的策略，大多数耐干燥（DT）的物种仅限于热带岩石露头。这种有限的生态范围是由于低生产力造成的竞争潜力弱，这是由于植物干燥时发生的碳同化的时间限制。然而，很少有研究解决这个问题的被子植物已经进行。我们调查了坎波斯红辣椒中20种干燥耐受性不同的Velloziaceae物种。Campos rupestres是一个生态区，其特点是在巴西中部/东南部沿着山脉的岩石基质上生长特殊的植被，海拔900米以上。它被认为是一个新热带热点和DT维管植物和Velloziaceae的主要多样性中心。在这里，我们测试了碳同化率，功能性状和物种栖息地是否证实了假设的生产力和耐干燥性之间的权衡。所有物种在雨季表现出相似的光合速率，在旱季，只有DT物种表现出急剧下降，他们的代谢。非耐脱水（NT）物种大于DT的（即。e.更大的最大株高;茎体积）。DT的相对冠层面积和茎干物质含量低于NT，而叶片磷浓度高于DT。其余的形态功能性状评价没有这些组之间的变化。DT种主要分布在裸露的岩石土壤中，而NT种则分布在深层的桑迪土壤中.我们的研究结果支持的假设，在被子植物的耐干燥性和生产力之间的权衡，并建议DT策略可能只会演变和持久的栖息地，严重的生长限制，由于干旱限制竞争更富有成效的物种。
1. Desiccation tolerance is the ability that some organisms show to equilibrate their water content with that of dry air and recover when water supplies are re-established. This is a widespread although rare strategy in angiosperms, and most desiccation-tolerant (DT) species are restricted to tropical rock outcrops. Such restricted ecological range is attributed to weak competitive potential caused by low productivity, due to the temporal limitation in carbon assimilation that occurs when plants desiccate. However, few studies addressing this question in angiosperms have been conducted.2. We investigate 20 species of Velloziaceae of campos rupestres that differ in their desiccation tolerance. Campos rupestres is an ecoregion characterized by particular vegetation growing on rocky substrates that occurs along mountains in central/south-eastern Brazil, above 900 m a.s.l. It is considered a Neotropical hotspot and the main centre of diversity for DT vascular plants and the Velloziaceae. Here, we tested whether carbon assimilation rates, functional traits and species habitats corroborate the hypothesized trade-off between productivity and desiccation tolerance.3. All species showed similar photosynthetic rates during the wet season; in the dry season, only DT species showed drastic decrease in their metabolism. Non-desiccation-tolerant (NT) species are larger than DT ones (i. e. greater maximum plant height; stem volume). Relative canopy area and stem dry-matter content were lower in DT compared to NT, while leaf phosphorous concentration was higher in DT. The remaining morphofunctional traits evaluated did not vary between these groups. DT species occupied mainly exposed rock soils, while NT species occurred in deep, sandy soil habitats.4. Our results support the hypothesis of a trade-off between desiccation tolerance and productivity in angiosperms and suggest that DT strategy may only evolve and persist in habitats where severe growth limitations due to drought limit competition from more productive species.