Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Plant Biol (Stuttg). 2012 Jan;14(1):208-15. doi: 10.1111/j.1438-8677.2011.00474.x. Epub 2011 May 31.
The Brazilian Atlantic Forest is a typically multi-layer tropical forest, while cerrado (savanna) is a patchy habitat with different physiognomy. Despite these differences, both habitats have high light heterogeneity. Functional traits of Dalbergia nigra and D. miscolobium from the Atlantic Forest and cerrado, respectively, were evaluated under shade (25% of full sunlight) and full sunlight in a nursery experiment. We hypothesised that both species should benefit from high phenotypic plasticity in relation to light. Plasticity was estimated using the relative distance phenotypic index (RDPI). D. miscolobium had lower shoot growth under both light conditions, suggesting it has low competitive capacity in the forest environment, which could explain its limited ability to expand over areas of Atlantic Forest. The studied species exhibited photoprotection strategies under high light and improved light capture under low light. Stomatal conductance, ETR(max) (maximum electron transport rate), PPFD(sat) (saturating photosynthetically active photon flux density), chlorophyll and carotenoid content had higher RDPI than stem morphological traits. Although both species showed considerable phenotypic plasticity, D. miscolobium had higher RDPI for eight of 11 evaluated traits. This high plasticity could be one of the factors that explain the occurrence of this species in a wide range of environmental conditions, from open grassland to dense woodlands, and it could also reflect its adaptation to high light. D. nigra also had considerable plasticity and good growth performance in both shade and full sunlight, but its absence in areas of cerrado suggests that factors other than light limit its occurrence in these habitats.
巴西大西洋森林是一种典型的多层次热带森林，而塞拉多（热带稀树草原）则是一种具有不同外貌的块状栖息地。尽管存在这些差异，但这两种栖息地的光照异质性都很高。在苗圃实验中，我们评估了大西洋森林和塞拉多的分别来自黑黄檀和交趾黄檀的功能性状在遮荫（25%全日照）和全日照下的表现。我们假设这两个物种都应该从与光相关的高表型可塑性中受益。使用相对距离表型指数（RDPI）来估计可塑性。在两种光照条件下，D. miscolobium 的芽生长较低，这表明它在森林环境中的竞争能力较低，这可以解释它在大西洋森林地区的扩张能力有限。研究物种在高光下表现出光保护策略，并在低光下提高光捕获能力。气孔导度、最大电子传递速率（ETR(max)）、饱和光合有效光子通量密度（PPFD(sat)）、叶绿素和类胡萝卜素含量的 RDPI 高于茎形态特征。尽管这两个物种都表现出相当大的表型可塑性，但 D. miscolobium 在 11 个评估特征中有 8 个具有更高的 RDPI。这种高可塑性可能是该物种在从开阔草原到茂密林地等广泛环境条件下存在的因素之一，也可能反映了它对高光的适应。D. nigra 在遮荫和全日照下都具有相当大的可塑性和良好的生长表现，但它在塞拉多地区的缺失表明，除了光照之外，还有其他因素限制了它在这些栖息地的存在。
