Soil phosphorus availability determines the preference for direct or mycorrhizal phosphorus uptake pathway in maize
Soil phosphorus availability determines the preference for direct or mycorrhizal phosphorus uptake pathway in maize
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DOI：
10.1016/j.geoderma.2021.115261
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发表时间：
2021
期刊：
影响因子：
6.1
通讯作者：
Lin Zhang;Qun Chu;Jianwei Zhou;Z. Rengel;G. Feng
中科院分区：
文献类型：
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作者：
Lin Zhang;Qun Chu;Jianwei Zhou;Z. Rengel;G. Feng
植物如何平衡从环境中获取资源的不同策略是生物学和生态学的基本问题。菌根植物对磷的吸收可分为直接途径和菌根途径。目前尚不清楚DP和MP之间是否存在权衡，以及植物如何管理这两种途径的选择和/或差异贡献。我们使用32 P标记技术来量化三种玉米基因型在Olsen P值为4.5，8和50 mg kg−1（分别代表低，次优和高P供应）时两种途径的P吸收。计算了磷吸收的偏好指数（MP贡献与DP贡献之比）、基于磷转运蛋白的偏好指数、C投资指数（菌丝长度与根长度之比）和基于磷效率的偏好指数。我们的研究结果表明，玉米植株更喜欢MP在次优土壤有效磷，因为无论是C投资指数和磷效率为基础的优先指数是最大的磷供应。地上部磷含量与磷吸收偏好指数呈显著正相关，表明地上部磷需求决定了DP和MP之间的权衡。总之，在玉米磷素吸收方面，对DP或MP的偏好随着土壤有效磷水平的变化而变化。这些发现可以用来更好地管理菌根真菌，以提高农业作物在土壤中的可持续性与次优的磷供应。
How plants balance different strategies to acquire resources from the environment is a basic question in biology and ecology. Phosphorus (P) uptake by mycorrhizal plants comprises direct pathway (DP) and mycorrhizal pathway (MP). It is unknown whether there is a trade-off between DP and MP and how plants govern selection and/or differential contributions of the two pathways. We used32P labelling technique to quantify P uptake by both pathways in three maize genotypes differing in P acquisition at Olsen P values of 4.5, 8 and 50 mg kg−1, representing low, suboptimal and high P supplies, respectively. We calculated the preference index of P uptake (ratio of MP contribution to DP contribution), P-transporter-based preferential index, C investment index as (ratio of hyphal length to root length), and the P-efficiency-based preferential index. Our results showed that maize plants preferred MP at the suboptimal soil available P because both the C investment index and the P-efficiency-based preferential index were greatest at that P supply. Shoot P content showed a significant relationship with the P uptake preference index, suggesting shoot P demand governed the trade-off between DP and MP. In conclusion, the preference for DP or MP regarding P acquisition in maize shifts with changes in soil available P level. These findings could be harnessed to better manage mycorrhizal fungi to enhance the sustainability of agricultural crops in soils with suboptimal P availability.