Zanetti Marcilio, Dayrell Roberta L C, Wardil Mariana V, Damasceno Alexandre, Fernandes Tais, Castilho Alexandre, Santos Fernando M G, Silveira Fernando A O
Bioma meio Ambiente LTDA, Nova Lima, Brazil.
Departamento de Genética, Ecologia e Evolução, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Front Plant Sci. 2020 Dec 8;11:599496. doi: 10.3389/fpls.2020.599496. eCollection 2020.
Cangas (ironstone outcrops) host a specialized flora, characterized by high degree of edaphic endemism and an apparent lack of natural history knowledge of its flora. Due to intense pressure from iron ore mining this ecosystem is under threat and in need of restoration. We studied seed functional traits that are relevant for restoration, translocation and conservation in 48 species from cangas in eastern Amazon. Were determined the thermal niche breadth, classified seed dormancy and determined methods to overcome it, determined the effect of seed storage on germination, tested the association between germination traits and functional groups, and tested whether seed traits are phylogenetically conserved. We found a broad interspecific variation in most seed traits, except for seed water content. Large interspecific variation in the temperature niche breadth was found among the studied species, but only four species, showed optimum germination at high temperatures of 35-40°C, despite high temperatures under natural conditions. Only 35% of the studied species produced dormant seeds. Mechanical scarification was effective in overcoming physical dormancy and application of gibberellic acid was effective in overcoming physiological dormancy in five species. For the 29 species that seeds were stored for 24 months, 76% showed decreases in the germination percentage. The weak association between germination traits and life-history traits indicate that no particular plant functional type requires specific methods for seed-based translocations. Exceptions were the lianas which showed relatively larger seeds compared to the other growth-forms. Dormancy was the only trait strongly related to phylogeny, suggesting that phylogenetic relatedness may not be a good predictor of regeneration from seeds in cangas. Our study provides support to better manage seed sourcing, use, storage and enhancement techniques with expected reduced costs and increased seedling establishment success.
坎加斯（铁矿石露头）拥有独特的植物群落，其特点是土壤特有性程度高，且对其植物群落的自然历史知识明显缺乏。由于铁矿石开采的巨大压力，这个生态系统受到威胁，需要恢复。我们研究了与亚马逊东部坎加斯地区48种植物的恢复、迁移和保护相关的种子功能性状。测定了热生态位宽度，分类了种子休眠并确定克服休眠的方法，测定了种子储存对发芽的影响，测试了发芽性状与功能群之间的关联，并测试了种子性状是否在系统发育上保守。我们发现，除种子含水量外，大多数种子性状存在广泛的种间变异。在所研究的物种中，温度生态位宽度存在较大的种间变异，但尽管自然条件下温度较高，只有4个物种在35 - 40°C的高温下显示最佳发芽。在所研究的物种中，只有35%产生休眠种子。机械擦伤在克服物理休眠方面有效，赤霉素处理在克服5个物种的生理休眠方面有效。对于储存24个月的29个物种的种子，76%的发芽率下降。发芽性状与生活史性状之间的弱关联表明，没有特定的植物功能类型需要特定的基于种子的迁移方法。例外的是藤本植物，与其他生长形式相比，它们的种子相对较大。休眠是唯一与系统发育密切相关的性状，这表明系统发育相关性可能不是坎加斯地区种子再生的良好预测指标。我们的研究为更好地管理种子来源、使用、储存和增强技术提供了支持，有望降低成本并提高幼苗建立成功率。
