Assessing the relevance of an enhanced root growth due to the activity of rhizobacteria for plant phosporus uptake under low P supply

植物根际促生菌以不同的方式帮助植物在次优磷供应下生长。它们增加了根际磷的有效性，并能诱导增强的根系生长，使植物能够利用更大的土壤体积。目的是评估肠杆菌属菌株（E.（1）这两个过程中，哪一个更重要。玉米的根生长动力学将在根盒中确定，根盒允许每天查看根。此外，还将在不同P和接种水平下的田间试验中量化根生长。E. radicincitans增加磷土壤溶液浓度将在培养研究与土壤不同的主要磷源。此外，培养和未培养植物根际土壤的磷分级与非培养土壤相比，揭示了P主要是由E。根癌最后，所有的数据的领域，盆，和孵化实验将用于模拟吸附过程，土壤运输和吸收。这给出了关于增强的根生长和/或P增溶的相关性的信息，用于在次优的P供应下更好地植物生长。

Plant growth promoting rhizobacteria help plants to grow at sub-optimal P supply in different ways. They increase P availability in the rhizosphere and they can induce an enhanced root growth which enables plants to exploit larger soil volumes. The objective is to assess for an Enterobacter strain (E. radicincitans) which of these processes is of more importance. Root growth dynamics of maize will be determined in rhizoboxes which allow a daily view on the roots. Furthermore, root growth will also be quantified in field experiments at different P and inoculation levels. The ability of E. radicincitans to increase P soil solution concentration will be investigated in incubation studies with soils differing in their main P source. Additionally, a P fractionation of rhizosphere soil of incubated and non-incubated plants in comparison to bulk soil reveals which P form is mainly solved by E. radicincitans. Finally, all the data of the field, pot, and incubation experiments will be used for modelling sorption processes, soil transport, and uptake. This gives information about the relevance of enhanced root growth and/or P solubilization for a better plant growth at sub-optimal P supply.