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Artemisia annua L. is a medicinal plant appreciated for the production of artemisinin, a molecule used for malaria treatment. However, the natural concentration of artemisinin in planta is low. Plant nutrition, in particular phosphorus, and arbuscular mycorrhizal (AM) fungi can affect both plant biomass and secondary metabolite production. In this work, A. annua plants were ino- culated or not with the AM fungus Funneliformis mosseae BEG12 and cultivated for 2 months in controlled conditions at three different phosphatic (P) concentrations (32, 96, and 288 µM). Plant growth parameters, leaf photosynthetic pigment concentrations, artemisinin production, and mineral uptake were evaluated. The different P levels significantly affected the plant shoot growth, AM fungal colonization, and mineral acquisition. High P levels negatively influenced mycorrhizal colonization. The artemisinin concentration was inversely correlated to the P level in the substrate. The fungus mainly affected root growth and nutrient uptake and significantly lowered leaf artemisinin concentration. In conclusion, P nutrition can influence plant biomass production and the lowest phosphate level led to the highest artemisinin concentration, irrespective of the plant mineral uptake. Plant responses to AM fungi can be modulated by cost–benefit ratios of the mutualistic exchange between the partners and soil nutrient availability. [ABSTRACT FROM AUTHOR]

Traditional soybean (Glycine max L.) breeding has improved seed yield in high-input agricultural systems, under high nitrogen (N), phosphorus (P) and potassium (K) supply. The seed yield improvements under non-P supply and the seed protein and mineral content dilution by yield improvement were evaluated in 18 soybean cultivars released from 1995 to 2016 in south-east China. Soybean varieties were grown under rainfed conditions in the field under 0 and 35 kg P ha−1 in four sites: Dafang and Shiqian in the growing season of 2017 and Dafang and Puding in the 2018 season. The seed yield, seed protein content and nine seed nutrition concentration were examined. Soybean seed yield increased with the year of release at rates of 5.5–6.7 g m−2 year−1 under 35 kg P ha−1 and 3.9–4.8 g m−2 year−1 under non-P supply in the four experiments. The increase resulted from increases in the number of filled-pods and total seed number rather than from single seed weight and number of seeds per pod. Seed protein content and seed nutrition concentration has not changed with the year of release under 0 and 35 kg P ha−1. Grain yield was positively correlated with the seed Fe concentration. The cultivar superiority of seed yield, seed P, Zn and Ca concentration was negatively correlated with their static stability coefficient. Traditional soybean breeding increased yield under both P and non-P supply, without affecting seed protein content and mineral concentrations. A trade-off between high seed yield and seed P, Zn and Ca concentration and their stability under different environments was shown. Whether traditional soybean (Glycine max L.) breeding can improve seed yield in low-input agricultural systems was not well known. In this study, we found: (1) traditional soybean breeding increased yield under both P and non-P supply, without affecting seed protein content and mineral concentrations; (2) a trade-off between high seed yield and seed P, Zn and Ca concentration, as affected by different environments. Both the yield improvement and the tolerance to low nutrition can be improved by soybean breeding. [ABSTRACT FROM AUTHOR]

Although phosphorus (P) is known to reduce zinc (Zn) uptake by roots and root-to-shoot translocation, how this interaction is affected by changes in root morphology and arbuscular mycorrhizae (AM) are poorly understood. The current study determined the effects of P application rate (0, 25, 50, 100, 200, and 400 kg P ha −1 ) on Zn uptake by roots and root-to-shoot translocation in a high-yielding winter wheat system on calcareous soil. Root dry weight (RDW), root length density (RLD), and root surface area (RSA) significantly increased as P application increased from 0 to 50 kg ha −1 but were unaffected by rates >50 kg ha −1 . Zn accumulation (mg m −2 or μg m −2 ) by roots at flowering increased with application of 25 and 50 kg P ha −1 but slightly decreased with application of 100–400 kg P ha −1 . Zn accumulation in roots and in shoots at flowering and grain yield at maturity were positively correlated with RDW, RLD, and RSA. Root Zn accumulation was increasing with increased AM colonization from low AM (<10%) to 30% AM colonization. Whereas, continuously increasing AM colonization induced root Zn accumulation decrease, which may be mainly due to the decrease of root dry weight affected by P deficiency. P application rate did not significantly affect the ratio of Zn concentrations in roots vs. shoots or the ratio of Zn accumulation in roots vs. total Zn accumulation in the plant, indicating that Zn translocation from roots to shoots is not the primary factor limiting Zn concentrations in grain. These results indicate 1) that P application affects the Zn accumulation of wheat by affecting Zn uptake by roots and 2) that the changes in Zn uptake by roots and Zn accumulation following P application reflect changes in root morphology and AM colonization of roots. [ABSTRACT FROM AUTHOR]

Modified clays are being increasingly used as P-inactivation agents for lake eutrophic control. However, the interaction of P with these material amended sediments still remain unclear. This study investigates the P sorption and supply from the thermally treated calcium-rich attapulgite amended eutrophic lake sediments as well as the ecological safety of material addition. The results indicated that P sorption on material amended sediment can be well fitted by a modified Langmuir model. Material addition can greatly enhance the P sorption capacity of lake sediment and lower the zero equilibrium P concentration ( EPC 0 ), which can turn lake sediment from a source to a pool. P sorption on raw and material amended sediment generally decreases with an increase of the water pH value. But material amended sediment still can adsorb a large amount of P even in very alkaline conditions resulting from algal blooms. Furthermore, P sorption on amended lake sediment was less influenced by NO 3 − and HCO 3 − than by SO 4 2− to a moderate degree and by SiO 3 − to a much larger degree. The results of diffusive gradients in thin films (DGT) measurement indicated the ability of P supply from lake sediment was largely inhibited by material addition. This was due to sediment mobile P had been transformed into stable Ca-P. A toxicity study indicated that material additions can increase pH value in lake sediment and can cause a toxic effect on benthic organisms when a large addition of material is involved, but this would be greatly attenuated in the field. The results of this study indicated that thermally treated calcium-rich attapulgite has the potential to be used as a P-inactivation agent for lake eutrophication control. [ABSTRACT FROM AUTHOR]

Although the interaction between phosphorus (P) and zinc (Zn) in crop production has long been a focus of plant nutrition research, the effects of P on the Zn content of cereal crops remains unclear, especially in intensive agricultural systems with high rates of P application and low levels of available Zn. The current study of a high-yielding winter wheat system on the North China Plain compared the effects of P application (0, 25, 50, 100, 200, and 400 kg ha −1 ) on yield, biomass accumulation, Zn accumulation, Zn uptake during all crop stages, and Zn remobilization. In two growing seasons (2011–2012 and 2012–2013), the results indicated that P application significantly increased wheat grain yield and shoot biomass. Phosphorus application also significantly increased the P concentration and decreased the Zn concentration in shoots. Phosphorus application increased P accumulation (kg ha −1 ) throughout the growing season but the effect of P application on Zn accumulation (g ha −1 ) depended on crop stage. Zn accumulation increased with increasing P application rates at the jointing stage. Zn accumulation at the flowering and maturity stage increased with application of 25 and 50 kg P ha −1 but decreased with application of 100–400 kg P ha −1 in both cropping seasons. The Zn harvest index and the ratio of pre-anthesis to post-anthesis Zn accumulation were not greatly affected by P application rate. Zn remobilization into grain increased with application of 0–50 kg P ha −1 but then decreased with the further application of 50–400 kg P ha −1 in both cropping seasons. Overall, the effects of P application on Zn nutrition depended on P rate and crop stage. Lower P application rates (<50 kg ha −1 ) increased Zn accumulation especially after the flowering stage and increased Zn remobilization to grain. High rates of P (>50 kg ha −1 ), in contrast, significantly decreased Zn accumulation and remobilization in this high-yielding winter wheat system. The results indicate that optimal P management in intensive agricultural systems is needed to ensure both high wheat yields and high levels of Zn in grain required for human nutrition. [ABSTRACT FROM AUTHOR]