Search

Soil phosphorus (P) availability is a crucial factor determining primary productivity in terrestrial ecosystem. Plant functional traits and microbes under P‐deficient conditions can respond positively to increase soil P bioavailability. Whether and/or how the fine‐root traits (FRTs) of deep‐rooted desert species affect the rhizosphere and bulk soil community of phoD‐harbouring bacteria and thus improve the availability of soil P, however, remains unclear.We conducted a three‐year artificial outdoor pot experiment of P supply using Alhagi sparsifolia Shap. (hereafter Alhagi) to address this gap. Fine‐root samples from 1‐ and 3‐year‐old Alhagi seedlings and samples of the rhizospheres and bulk soil were collected. High‐throughput sequencing, sequential extraction and root system scanning were used to determine soil phoD‐harbouring bacteria community, Hedley‐P fractions and the FRTs.Fine‐root surface area (RSA), specific root length, foliar Mn concentration (indicating the quantities of root carboxylates that are released) and acid phosphatase (APase) activity were significantly higher in the no‐P supply compared with the high‐P supply conditions. APase activity was significantly higher by 27%, but the foliar Mn concentration was remarkably lower by 26%, in the 3‐ than the 1‐year‐old seedlings. The rhizospheric concentrations of labile P, moderately labile P, inorganic P and organic P in the no‐P supply condition were 5%, 11%, 10% and 21% higher, respectively, in the 3‐ than the 1‐year‐old seedlings. RSA and the foliar Mn concentration were dominated root predictors for the rhizospheric phoD‐harbouring bacteria community for the 1‐year‐old seedlings, whereas fine‐root P concentration was the dominated root predictor for the rhizospheric and bulk soil phoD‐harbouring bacteria communities for the 3‐year‐old seedlings. Soil water content, as the most dominant soil factor driving the variation of phoD‐harbouring bacteria community, notably could not be ignored. FRTs were the main factors that directly and positively determined rhizospheric phoD‐harbouring bacteria community and thus influenced soil P availability, but bulk soil phoD‐harbouring bacteria community were dominated by inorganic P concentration. The importance of fine‐root morphological traits to soil P availability gradually increased as the plants grew.Overall, our results emphasize the significance of rhizospheric phoD‐harbouring bacteria determined by the effect of FRTs on the bioavailability of soil P. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The process and function that underlie the assembly of root-associated microbiomes may be strongly linked to the survival strategy of plants. However, the assembly and functional changes of root-associated microbial communities in different desert plants in natural desert ecosystems are still unclear. Thus, we studied the microbial communities and diversity of root endosphere (RE), rhizosphere soil (RS), and bulk soil (BS) among three representative desert plants (Alhagi sparsifolia, Tamarix ramosissima, and Calligonum caput-medusae) in three Xinjiang desert regions {Taklimakan (CL), Gurbantünggüt (MSW), and Kumtag (TLF)} in China. This study found that the soil properties {electrical conductivity (EC), soil organic carbon (SOC), total nitrogen (TN) and phosphorus (TP), available nitrogen (AN) and phosphorus (AP)} of C. caput-medusae were significantly lower than those of A. sparsifolia and T. ramosissima, while the root nutrients (TN and TP) of A. sparsifolia were significantly higher compared to C. caput-medusae and T. ramosissima. The beta diversity of bacteria and fungi (RE) among the three desert plants was significantly different. The common OTU numbers of bacteria and fungi in three compartments (RE, RS, and BS) of the three desert plants were ranked as RS > BS > RE. The bacterial and fungal (RE) Shannon and Simpson indexes of C. caput-medusae were significantly lower as compared to those of A. sparsifolia and T. ramosissima. Additionally, bacterial and fungal (RE and RS) node numbers and average degree of C. caput-medusae were lower than those found in A. sparsifolia and T. ramosissima. Root and soil nutrients collectively contributed to the composition of root-associated bacterial (RE, 12.4%; RS, 10.6%; BS, 16.6%) and fungal communities (RE, 34.3%; RS, 1.5%; BS, 17.7%). These findings demonstrate variations in the bacterial and fungal populations across different plant species with distinct compartments (RE, RS, and BS) in arid environments. More importantly, the study highlights how much soil and plant nutrients contribute to root-associated microbial communities. [ABSTRACT FROM AUTHOR]

Coastal‐wetlands play a crucial role as carbon (C) reservoirs on Earth due to their C pool composition and functional sink, making them significant for mitigating global climate change. However, due to the development and utilization of wetland resources, many wetlands have been transformed into other land‐use types. The current study focuses on the alterations in soil organic‐C (SOC) in coastal‐wetlands following reclamation into aquaculture ponds. We conducted sampling at 11 different coastal‐wetlands along the tropical to temperate regions of the China coast. Each site included two community types, one with solely native species (Suaeda salsa, Phragmites australis and Mangroves) and the other with an adjacent reclaimed aquaculture pond. Across these 11 locations we compared SOC stock, active OC fractions, and soil physicochemical properties between coastal wetlands and aquaculture ponds. We observed that different soil uses, sampling sites, and their interaction had significant effects on SOC and its stock (p <.05). Reclamation significantly declined SOC concentration at depths of 0–15 cm and 15–30 cm by 35.5% and 30.3%, respectively, and also decreased SOC stock at 0–15 cm and 15–30 cm depths by 29.1% and 37.9%, respectively. Similar trends were evident for SOC stock, labile organic‐C, dissolved organic‐C and microbial biomass organic‐C concentrations (p <.05), indicating soil C‐destabilization and losses from soil following conversion. Soils in aquaculture ponds exhibited higher bulk density (BD; 11.3%) and lower levels of salinity (61.0%), soil water content (SWC; 11.7%), total nitrogen (TN) concentration (23.8%) and available‐nitrogen concentration (37.7%; p <.05) than coastal‐wetlands. Redundancy‐analysis revealed that pH, BD and TN concentration were the key variables most linked with temporal variations in SOC fractions and stock between two land use types. This study provides a theoretical basis for the rational utilization and management of wetland resources, the achievement of an environment‐friendly society, and the preservation of multiple service functions within wetland ecosystems. [ABSTRACT FROM AUTHOR]