PDF(Pubmed)
Abstract：
The effect of floral traits, floral rewards and plant water availability on plant-pollinator interactions are well-documented; however, empirical evidence of their impact on flowering phenology in high-elevation meadows remains scarce. In this study, we assessed three levels of flowering phenology, i.e. population-, individual- and flower-level (floral longevity), in two nearby but contrasting (wet versus dry) sub-alpine meadows on Yulong Snow Mountain, southwestern China. We also measured a series of floral traits (pollen number, ovule number, and the ratio of pollen to ovule number per flower, i.e. pollen:ovule ratio [P/O]) and floral rewards (nectar availability and pollen presentation) as plausible additional sources of variation for each phenological level. Floral longevity in the wet meadow was significantly longer than that for the dry meadow, whereas population- and individual-flowering duration were significantly shorter. Our results showed a significant positive relationship between flowering phenology with pollen number and P/O per flower; there was no relationship with ovule number per flower. Further, we found a significant effect of flowering phenology on nectar availability and pollen presentation. Our findings suggest that shorter floral longevity in dry habitats compared to wet might be due to water-dependent maintenance costs of flowers, where the population- and individual-level flowering phenology may be less affected by habitats. Our study shows how different levels of flowering phenology underscore the plausible effects of contrasting habitats on reproductive success.
摘要：
花卉性状的影响，植物-传粉媒介相互作用的花卉奖励和植物水分可用性是有据可查的；然而，它们对高海拔草甸开花物候影响的经验证据仍然很少。在这项研究中,我们评估了三个水平的开花物候，即人口-，个人和花卉水平（花卉寿命），在玉龙雪山附近但形成对比的两个（湿与干）亚高山草甸中，中国西南部。我们还测量了一系列花卉性状(花粉数，胚珠数,和每朵花的花粉与胚珠数的比率，即花粉：胚珠比[P/O]）和花卉奖励（花蜜的可用性和花粉的呈现）作为每个物候水平的合理的额外变异来源。湿草甸的花卉寿命明显长于干草甸，而种群和个体开花持续时间明显较短。我们的结果表明，开花物候与花粉数和每花P/O之间存在显着的正相关；与每花的胚珠数没有关系。Further,我们发现开花物候对花蜜的可利用性和花粉的呈现有显着影响。我们的发现表明，与潮湿相比，干燥栖息地的花卉寿命较短可能是由于花卉的水分依赖性维持成本。种群和个体水平的开花物候可能受栖息地的影响较小。我们的研究表明，不同水平的开花物候如何强调对比栖息地对繁殖成功的合理影响。
