Phosphorus and nitrogen resorption from different chemical fractions in senescing leaves of tropical tree species on Mount Kinabalu, Borneo
Phosphorus and nitrogen resorption from different chemical fractions in senescing leaves of tropical tree species on Mount Kinabalu, Borneo
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DOI：
10.1007/s00442-017-3938-9
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发表时间：
2017-09
期刊：
影响因子：
2.7
通讯作者：
Yuki Tsujii;Y. Onoda;K. Kitayama
中科院分区：
文献类型：
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作者：
Yuki Tsujii;Y. Onoda;K. Kitayama
养分吸收是植物降解有机化合物并从衰老组织中吸收养分的过程，是植物在营养贫乏的环境中增加生长和适应能力的关键功能。生长在低磷土壤上的热带树木尤其被认为具有很高的磷再吸收效率(Pre，即在绿叶中全磷脱落之前从衰老的叶片中吸收的磷的百分比)。然而，这种更大的PRE背后的生化机制仍然不清楚。在这项研究中，我们测定了来自三个磷有效性不同的地点的22个树种的绿叶和衰老叶的易溶、核酸、脂肪和残留物中的磷浓度。基纳巴鲁，婆罗洲。Pre在24%到93%之间变化，并且在来自贫磷地点的物种中更高。磷素吸收速率以脂类部分、核酸部分最大，易溶部分和残渣部分最低。对于Pre含量较高的物种，残留组分的P再吸收速率相对较高，与其他不稳定组分的吸收率相当。这表明，生活在贫磷环境中的树种通过改善顽固性化合物的降解来增加PRE。这项研究表明，植物对有机化合物的选择性降解取决于环境条件，这是导致Pre变化的一个关键机制。
Nutrient resorption, a process by which plants degrade organic compounds and resorb their nutrients from senescing tissues, is a crucial plant function to increase growth and fitness in nutrient-poor environments. Tropical trees on phosphorus (P)-poor soils are particularly known to have high P-resorption efficiency (PRE, the percentage of P resorbed from senescing leaves before abscission per total P in green leaves). However, the biochemical mechanisms underlying this greater PRE remain unclear. In this study, we determined the P concentration in easily soluble, nucleic acid, lipid and residual fractions for green and senescent leaves of 22 tree species from three sites, which differed in P availability, on the lower flanks of Mt. Kinabalu, Borneo. PRE varied from 24 to 93% and was higher in species from the P-poor site. P-resorption rate was greatest from the lipid fraction, the nucleic acid fraction, and lowest in the easily soluble fraction and the residual fraction when all the species were pooled. For species with higher PRE, P-resorption rate of the residual fraction was relatively high and was comparable in magnitude to that of the other labile fractions. This suggests that tree species inhabiting P-poor environments increased PRE by improving the degradation of recalcitrant compounds. This study suggests that plants selectively degrade organic compounds depending on environmental conditions, which is a key mechanism underlying the variation of PRE.