Abstract

The root soil interaction affects the fractionation and bioavailability of nutrients in the rhizosphere and, in turn, the uptake and accumulation of nutrients by plants. In this study, a greenhouse experiment using Thomson Navel Orange (Citrus sinensis (L.) Osbeck.) grafted on three rootstocks [Swingle Citrumelo (SC), Sour Orange (SO), and Troyer Citrange (TC)] was conducted in mildly acidic soil. Eighteen months after transplanting in the pots, the i) P acquisition efficiency (PAE) in these plants; ii) rhizosphere effects on some biological characteristics, including dissolved organic Carbon (DOC), fungi and bacteria populations, microbial biomass P (MBP), and alkaline (AlP) phosphatase, and iii) the fractions of P in the rhizosphere soils were determined. Results of the study showed that the TC and SO promoted scion P uptake and increased PAE. The rhizospheric condition of SO rootstock induced significant promotion (P < 0.05) in all biological properties compared to other rootstocks. Living roots of SO markedly modified biological properties in the rhizosphere soil and therefore affected P bioavailability. Moreover, the rhizosphere effects on the chemical fractions of P were under rootstock control. The lowest organic P was measured in SO-grafting, whereas the lowest amounts of exchangeable P and residual P in the rhizosphere soils were measured in TC- grafting. The contents of P associated with Fe and Al compounds were lower in the SO and TC rhizosphere than in the SC rhizosphere soil. This study provides insights into the adaptive mechanisms of Thomson Navel Orange grafted on three rootstocks to phosphorus deficiency.

中文翻译：

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不同吸磷效率柑橘砧木根系活性对根际土壤磷含量及部分生化特征的影响

摘要

根系土壤相互作用影响根际养分的分离和生物利用度，进而影响植物对养分的吸收和积累。在本研究中，使用汤姆森脐橙 ( Citrus sinensis) 进行的温室试验(L.) Osbeck.) 嫁接在三个砧木上 [Swingle Citrumelo (SC)、Sour Orange (SO) 和 Troyer Citrange (TC)] 在弱酸性土壤中进行。移栽到盆中 18 个月后，i) 这些植物中的磷获取效率 (PAE)；ii) 根际对一些生物特性的影响，包括溶解有机碳 (DOC)、真菌和细菌种群、微生物生物量 P (MBP) 和碱性 (AlP) 磷酸酶，以及 iii) 确定了根际土壤中 P 的比例。研究结果表明，TC 和 SO 促进了接穗 P 的吸收并增加了 PAE。SO 砧木根际条件诱导显着促进（P <0.05) 与其他砧木相比，所有生物学特性。SO 的活根显着改变了根际土壤中的生物特性，因此影响了磷的生物有效性。此外，根际对磷化学成分的影响受砧木控制。在 SO 嫁接中测得的有机磷最低，而在 TC 嫁接中测得的根际土壤中交换性磷和残留磷含量最低。SO和TC根际土壤中与Fe和Al化合物相关的P含量低于SC根际土壤。这项研究提供了对嫁接在三个砧木上的汤姆森脐橙对缺磷的适应机制的见解。