Accumulation of phosphate in leaves as external environmental phosphate concentrations increase has been observed across the plant kingdom. The excess storage of anions, such as phosphate, has various metabolic trade-offs, including a corresponding influx of counter-ions to maintain charge balance and/or the reduction in organic acid content to maintain internal pH. The leaves and roots of four hybrid poplar genotypes were tested for differences in metabolic response to increasing external phosphate and further effects on patterns of anion resorption among hybrid poplar and willow were explored. Organic acid concentrations increased or remained constant across treatments, suggesting that metabolic adjustments were made in response to greater influxes of inorganic cations rather than a response to increasing phosphate. During senescence, the hybrid poplar Tristis had higher sulfate and organic acid resorption, while hybrid willow, AAFC-5, had higher phosphate resorption proficiencies, suggesting differing anion remobilization mechanisms. Furthermore, phosphate accumulation was shown to continue well after bud-set in poplar hybrids, which may contribute to the low phosphorus resorption efficiency. This indicates that closely related species, with similar growth strategies, show preferential resorption toward different nutrients.

中文翻译：

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辨别磷酸盐状态对杂种杨代谢的影响。

在整个植物界中，观察到随着外部环境磷酸盐浓度增加，叶片中的磷酸盐积累。阴离子（例如磷酸盐）的过量存储具有各种代谢折衷，包括相应的抗衡离子流入以保持电荷平衡和/或有机酸含量降低以保持内部pH。测试了四种杂种杨树基因型的叶和根在增加的外部磷酸盐代谢反应方面的差异，并探索了对杂种杨树和柳树中阴离子吸收模式的进一步影响。在整个处理过程中，有机酸浓度增加或保持恒定，这表明代谢调节是响应于更多的无机阳离子流入而做出的，而不是响应于磷酸盐的增加。在衰老期间 杂种杨Tristis具有较高的硫酸盐和有机酸吸收能力，而杂种杨（AAFC-5）具有较高的磷酸盐吸收能力，表明阴离子的固定机制不同。此外，显示出在杨树杂种芽芽定植后磷酸盐累积持续良好，这可能导致磷吸收效率低。这表明具有相似生长策略的密切相关物种显示出对不同养分的优先吸收。