Boron (B) is essential for vascular plants. Rapeseed (Brassica napus) is the second leading crop source for vegetable oil worldwide, but its production is critically dependent on B supplies. BnaA3.NIP5;1 was identified as a B-efficient candidate gene in B. napus in our previous QTL fine mapping. However, the molecular mechanism through which this gene improves low-B tolerance remains elusive. Here, we report genetic variation in BnaA3.NIP5;1 gene, which encodes a boric acid channel, is a key determinant of low-B tolerance in B. napus. Transgenic lines with increased BnaA3.NIP5;1 expression exhibited improved low-B tolerance in both the seedling and maturity stages. BnaA3.NIP5;1 is preferentially polar-localized in the distal plasma membrane of lateral root cap (LRC) cells and transports B into the root tips to promote root growth under B-deficiency conditions. Further analysis revealed that a CTTTC tandem repeat in the 5’UTR of BnaA3.NIP5;1 altered the expression level of the gene, which is tightly associated with plant growth and seed yield. Field tests with natural populations and near-isogenic lines (NILs) confirmed that the varieties carried BnaA3.NIP5;1^Q allele significantly improved seed yield. Taken together, our results provide novel insights into the low-B tolerance of B. napus, and the elite allele of BnaA3.NIP5;1 could serve as a direct target for breeding low-B-tolerant cultivars.

The objectives were to determine whether two peanut cultivars show different tolerance to calcium (Ca) deficiency. The seedlings of cultivars LH11 and YZ9102 at first trifoliate leaf stage were transplanted in nutrient solution for 28 days with 0.01 and 2.0 mmol/L Ca treatments. Low Ca supply did not affect plant growth, root length and surface area of YZ9102, whereas decreased plant biomass, root length and surface area of LH11 seedlings that appeared necrosis in shoot tip. YZ9102 plant had higher Ca concentration and more Ca distribution to leaves than LH11. Under limited Ca condition, LH11 appeared net Ca²⁺ effluxes in the zones of 0.2 ∼ 1.5 mm from root apex, while YZ9102 roots maintained net Ca²⁺ influxes. Peanut cultivar YZ9102 seedlings had longer roots and higher capacities of Ca uptake and Ca translocation to shoots than LH11, which might be account for higher tolerance to Ca deficiency compared with LH11.

Combining organic and chemical fertilizers is a sustainable strategy for vegetable production. However, there is limited research concerning the risks associated with heavy metals (HMs) in greenhouse systems with long-term location application. A three-year investigation, conducted from 2021 to 2023, explored a fifteen-year field experiment with combinations of chemical fertilizer (CH), corn straw (SW) and pig manure (PM). Five treatments were evaluated: excessive fertilization (high CH and PM), conventional fertilization (normal CH), organic–inorganic fertilization (3/4CN + 1/4PN, 2/4CN + 2/4PN and 2/4CN + 1/4PN + 1/4SN). This study evaluated the risks associated with heavy metals (HMs) by analyzing and quantifying their concentrations in soil and cucumber fruits, as well as by calculating the bioconcentration factors (BCFs), the geo-accumulation index (Igeo), and both the non-carcinogenic and carcinogenic risks. The results indicated that excessive fertilization (CF) increased the concentrations of Cu and Zn in fruits, as well as the Igeo values of Cu, Zn, and Cd, and the non-carcinogenic Cu risk, while decreasing the BCFs of Cu and Zn. Organic–inorganic fertilization also elevated the Igeo values of Cu and Zn. Redundancy analyses confirmed a positive correlation between the soil concentrations of Cu and Zn and higher levels of available phosphorus contents (48.4%), alongside a lower pH (4.9%). The concentrations of Cu, Zn, and Cd in both soil and cucumber fruits increased linearly with the duration of application and amount of input. Although the combined application of CH with PM or SW did not significantly elevate the non-carcinogenic or carcinogenic risks associated with most heavy metals, the carcinogenic risks of Cd and As emerged as potential risk factors after 15 years of organic–inorganic fertilization. Utilizing a combination of CH with PM and SW as a fertilizer management strategy can effectively address both the control of heavy metal inputs in the facility and the safety and quality of cucumbers.

Soil phosphorus (P) can be divided into inorganic P (Pi) and organic P (Po). Microorganisms play essential roles in soil P transformation. However, there are many ways to detect P transformation, and the relationship between P forms and microorganisms under long-term fertilization is largely unclear. In this study, soil P forms were analyzed by a chemical sequential fractionation method and solution ³¹P nuclear magnetic resonance (³¹P-NMR) technique. Phospholipid fatty acid (PLFA) contents were measured by gas chromatography as the characterization of soil microbial community structures. The objective was to determine the changes of soil P forms and associated microbial community composition in mollisol with long-term fertilization. We sampled soil from a field experiment with 26-year-old continuous maize (Zea mays L.) cropping in Northeastern China. Three fertilization treatments were selected as chemical fertilization (NPK), NPK with crop straw (NPKS), and NPK with manure (NPKM). As shown in ³¹P-NMR spectra, orthophosphate accounted for 62.8–85.8% of total extract P. Comparison to NPK and NPKS treatments, NPKM application notably increased the concentrations of Po, Olsen-P, orthophosphate, orthophosphate monoester, and total P. Soil P fractions including resin-Pi, NaHCO₃-P, NaOH-P, and HCl-P, especially Pi fractions, were enhanced by NPKM. The amounts of total PLFAs and PLFAs in bacteria, Gram-positive (G⁺) and Gram-negative (G⁻) bacteria, actinomycetes, and fungi were high in NPKM-treated soil. The percentages of PLFAs in bacteria and fungi in total soil PLFAs were 56.8% and 9.7%, respectively, which did not show any significant difference among the treatments. NPKM increased the proportions (%) of PLFAs in G⁺ bacteria, and NPKS increased the proportions (%) of G⁻ bacteria in total PLFAs. The composition of soil microbial community was found to be significantly affected by soil total carbon and pH. There was a close relationship between HCl-Pi, NaHCO₃-Po, orthophosphate, and pyrophosphate with anaerobe, aerobes, and G⁺. Manure addition directly increased soil available P concentrations, and indirectly acted through the alterations of anaerobe, aerobes, and G⁺. It is concluded that long-term NPKM application would lead to the accumulation of labile P and moderately labile P in mollisol through the activity of soil microbes.