PDF(Pubmed)
Abstract：
Davidia involucrata is a woody perennial and the only living species in the Genus Davidia. It is native to southern China where it holds cultural and scientific importance. However, D. involucrata is now an endangered species and its natural range includes low pH soils which are increasingly impacted by acid rain, nitrogen deposition and imbalanced nutrient cycling. The combination of these stresses also poses the additional risk of aluminum (Al) toxicity. Since the responses of D. involucrata to low pH and aluminum toxicity have not been investigated previously, a hydroponic experiment was conducted to examine the growth of one year old D. involucrata saplings after 50 d growth in a range of pH and Al conditions. Plant biomass, morphology, antioxidant enzyme activity, mineral concentrations and plant ecological strategy were compared at pH 5.8 and pH 4.0 without added Al (AlCl3) and in 0.1, 0.2 and 0.5 mM Al at pH 4.0. Our results showed that compared with pH 5.8, pH 4.0 (without added Al) not only inhibited root and shoot growth but also limited accumulation of nitrogen (N) and phosphorus (P) in leaves of D. involucrate. However, low Al concentrations (0.1 and 0.2 mM Al) at pH 4.0 partially restored the aboveground growth and leaf N concentrations, suggesting an alleviation of H+ toxicity by low Al concentrations. Compared with low Al concentrations, 0.5 mM Al treatment decreased plant growth and concentrations of N, P, and magnesium (Mg) in the leaves, which demonstrated the toxicity of high Al concentration. The results based on plant ecological strategy showed that D. involucrate decreased the competitiveness and favored its stress tolerance as pH changed from 5.8 to 4.0. Meanwhile, the competitiveness and stress tolerance of D. involucrata increased and decreased at low Al concentrations, respectively, and decreased and increased at high Al concentration, respectively. These trade-offs in ecological strategy were consistent with the responses of growth and antioxidant enzyme activity, reflecting a sensitive adaptation of D. involucrata to acid and Al stresses, which may aid in sustaining population dynamics. These findings are meaningful for understanding the population dynamics of D. involucrata in response to aluminum toxicity in acid soils.
摘要：
Davidia是多年生木本植物，是Davidia属中唯一的生物。它原产于中国南方，在那里具有文化和科学重要性。然而,天线莲现在是一种濒危物种，其自然范围包括低pH值的土壤，这些土壤越来越受到酸雨的影响，氮沉降和营养循环失衡。这些应力的组合还造成铝(Al)毒性的额外风险。由于马尾松对低pH和铝毒性的反应尚未被研究，进行了水培实验，以检查在一定pH和Al条件下生长50d后一岁的D.intenucrata树苗的生长。植物生物量,形态学,抗氧化酶活性，在不添加Al（AlCl3）的情况下，在pH5.8和pH4.0以及在pH4.0的0.1、0.2和0.5mMAl中比较了矿物质浓度和植物生态策略。我们的结果表明，与pH5.8相比，pH4.0（不添加Al）不仅抑制了根和芽的生长，而且限制了叶片中氮（N）和磷（P）的积累。然而,pH4.0时的低Al浓度（0.1和0.2mMAl）部分恢复了地上生长和叶片N浓度，表明通过低Al浓度减轻H毒性。与低铝浓度相比，0.5mMAl处理降低了植物生长和N的浓度，P,和叶子中的镁（Mg），这证明了高铝浓度的毒性。基于植物生态策略的结果表明，当pH值从5.8变化到4.0时，紫菜的竞争力降低，并且有利于其抗逆性。同时,在低铝浓度下，全花D的竞争力和抗逆性增加和减少，分别,并且在高Al浓度下减少和增加，分别。生态策略中的这些权衡与生长和抗氧化酶活性的反应一致，反映了马尾松对酸和铝胁迫的敏感适应，这可能有助于维持人口动态。这些发现对于了解酸性土壤中铝毒性反应中的全花D的种群动态具有重要意义。
