Root/Shoot Allocation and Root Architecture in Seedlings: Variation among Forest Sites, Microhabitats, and Ecological Groups1
Root/Shoot Allocation and Root Architecture in Seedlings: Variation among Forest Sites, Microhabitats, and Ecological Groups1
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DOI：
10.1111/j.1744-7429.2003.tb00586.x
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发表时间：
2003-09
期刊：
影响因子：
--
通讯作者：
H. Paz
中科院分区：
文献类型：
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作者：
H. Paz
本文分析了4种新热带森林木本植物幼苗根系质量分配和根系形态的变异规律及其与环境因子的关系。在森林中，我探索了根系特征对水分或养分有效性不同地点的反应。在每一片森林里，我探索了物种对不同微生境的可塑性反应：林隙和林下。此外，我通过比较不同演替类群的物种(对光的需求[22 spp.])来探索根和地上部性状的生活史相关性的证据。或耐荫[27种])萌发型(具有光合子叶或后备子叶的物种)。在每个森林地点，挖掘了10到20种树种的幼树。林下条件下共采集到55种，林隙中也采集到31种。从每一株幼苗中，确定了六种形态比例。土壤资源最低的林地，其根系分配比例较高。最贫瘠的部位根系细长，旱季最长的部位根系较深。不同萌发类型的苗木性状差异不显著。耐荫树种比需光树种分配更多的根，形成更厚的根。强光树种对生境的可塑性反应强于耐荫树种，光合子叶树种的可塑性低于光合子叶树种。总体而言，这些结果表明，在新热带物种中，幼苗的根分配和根形态反映了植物在地理和小生境尺度上对水分或养分可获得性的调整。此外，由于不同物种在根的分配和根的形态上的差异，表明生活史对光环境的专化性。
ABSTRACT I analyzed patterns of variation in root mass allocation and root morphology among seedlings of woody species in relation to environmental factors in four Neotropical forests. Among forests, I explored the response of root traits to sites varying in water or nutrient availability. Within each forest, I explored the plastic response of species to different microhabitats: gaps and understory. Additionally, I explored evidence for life history correlation of root and shoot traits by comparing species differing in their successional group (light-demanding [22 spp.] or shade tolerant [27 spp.]) and germination type (species with photosynthetic cotyledons or species with reserve cotyledons). At each forest site, young seedlings from 10 to 20 species were excavated. A total of 55 species was collected in understory conditions and 31 of them were also collected in gaps. From each seedling, six morphological ratios were determined. Allocation to roots was higher in forest sites with the lowest soil resources. Roots were finer and longer in the most infertile site, while roots were deeper in the site with the longest dry season. Seedling traits did not differ between germination types. Shade tolerant species allocated more to roots and developed thicker roots than light-demanding species. Light-demanding species showed stronger plastic responses to habitat than shade tolerant species, and species with photosynthetic cotyledons showed lower plasticity than species with reserve cotyledons. Overall, these results suggest that among Neotropical species, root allocation and root morphology of seedlings reflect plant adjustments to water or nutrient availability at geographic and microhabitat scales. In addition, life history specialization to light environments is suggested by differences among groups of species in their allocation to roots and in their root morphology.