Faculty of Bioresources and Food Industry, Besut Campus, Universiti Sultan Zainal Abidin, 22300 Besut, Terengganu, Malaysia.
School of Biological Sciences, University of Aberdeen, Aberdeen, UK.
Tree Physiol. 2018 Nov 1;38(11):1752-1760. doi: 10.1093/treephys/tpy082.
Aluminium (Al) accumulation is a common trait expressed in at least 60 plant families and particularly prevalent in tropical woody plants. However, the functional significance and genetic or physiological controls on Al accumulation are currently unknown. We tested the hypothesis that differential expression of Al accumulation among wild populations of the Al-accumulating tropical shrub Melastoma malabathricum L. is associated with habitat-related variation in total and exchangeable soil Al concentrations. Mature leaves and seeds were sampled from 20 populations of M. malabathricum growing in six habitats across Peninsular Malaysia, and soil was collected from each site. The seeds were grown in hydroponic solutions comprising 50% Hoagland's solution amended with Al in the form of 1.0 mM AlCl3 to test the hypothesis that differential expression of foliar Al accumulation is an inherited trait. Foliar Al concentrations varied significantly among populations, but were not consistently different among plants growing in different habitats and showed no relationship to total or exchangeable Al concentrations in soils collected at the 20 sites. Mean foliar Al concentration in wild plants was positively correlated with foliar calcium (Ca) concentrations, and with total soil nitrogen (N), Ca and magnesium (Mg) concentrations, across the 20 populations, and Al addition increased foliar concentrations of phosphorus, Ca, Mg and potassium in seedlings. The differential expression of Al accumulation in M. malabathricum populations is uncoupled to local variation in soil Al concentrations, but may be sensitive to local soil-related variation in the availability of other macro-nutrients, in particular N, Ca and Mg. Further research on the factors controlling Al uptake should focus on the plasticity of this trait within populations of Al accumulators and interactions with micro-habitat variation in the availability of the macronutrient cations.
铝（Al）积累是至少 60 个植物科中普遍存在的特征，尤其在热带木本植物中更为普遍。然而，目前尚不清楚铝积累的功能意义以及遗传或生理控制因素。我们检验了以下假设：在富含铝的热带灌木皱叶酸模（Melastoma malabathricum L.）的野生种群中，铝积累的差异表达与总土壤和可交换土壤铝浓度的栖息地相关变化有关。从马来西亚半岛六个栖息地的 20 个皱叶酸模种群中采集成熟叶片和种子，并从每个地点采集土壤。将种子种植在包含 50％Hoagland 溶液的水培溶液中，并用 1.0 mM AlCl3 的形式添加铝，以检验叶片铝积累的差异表达是一种遗传特征的假设。叶片铝浓度在种群之间存在显著差异，但在不同栖息地生长的植物之间没有差异，并且与 20 个地点采集的土壤中的总土壤或可交换的铝浓度没有关系。野生植物的平均叶片铝浓度与叶片钙（Ca）浓度呈正相关，与总土壤氮（N），Ca 和镁（Mg）浓度在 20 个种群中呈正相关，并且 Al 加增加了幼苗叶片磷，Ca，Mg 和钾的浓度。皱叶酸模种群中铝积累的差异表达与土壤铝浓度的局部变化无关，但可能对其他大量营养元素（尤其是 N，Ca 和 Mg）的可用性的局部土壤相关变化敏感。对控制铝吸收的因素的进一步研究应集中在积累者种群中该特征的可塑性及其与大量营养元素阳离子可用性的微生境变化的相互作用上。
