Increasing the pH of acid soils is a well-recognized means of improving their fertility; however, the effects that plants impose on rhizosphere soils in response to this change are not well understood. This research sought to investigate changes in phosphorus (P) availability in the rhizosphere of blue lupin (Lupinus angustifolius) in response to an increase in pH. Blue lupin plants were grown in rhizoboxes using two contrasting acid soils at their native pH (5.3 and 4.7) and treated with lime to increase their pH to 6.3 in a replicated trial. Measurements of localized acid phosphomonoesterase activity and P flux were made next to lateral root segments using a combination of zymography and diffusive gradient in thin films (DGT). Rhizosphere and bulk soils were tested for pH, organic anions, exchangeable aluminium (Al), labile P and phosphomonoesterase activity. Root morphological traits, root and shoot yields and shoot nutrient concentrations were also recorded. Profiles of DGT-P fluxes across lateral roots showed mobilization of P in the soil with the higher organic P content, and depletion in the other. The extent of acid phosphomonoesterase activity in the rhizosphere decreased with soil pH increase. Shoot P uptake was strongly correlated with fine root length and total organic anions in the rhizosphere. The proportion of thin roots decreased at pH 6.3 compared to the native pH, whereas that of thick roots increased. Soil pH increase to 6.3 using lime negatively affects the P acquisition by blue lupin due to the reduction of organic anion exudation, fine root length and the extent of acid phosphomonoesterase activity in the rhizosphere.

Soil pH effects on phosphorus mobilization in the rhizosphere of Lupinus angustifolius

High level of zinc triggers phosphorus starvation by inhibiting root-to-shoot translocation and preferential distribution of phosphorus in rice plants.

Transcriptome analysis reveals the molecular mechanism of boron deficiency tolerance in leaves of boron-efficient Beta vulgaris seedlings.

Biodegradable Polymer Nanocomposites Provide Effective Delivery and Reduce Phosphorus Loss during Plant Growth

Oilseed flax is one of the most important oil crops in China. With the improvement of people's living standards and the deepening knowledge of the nutritional value of oilseed flax, the demand and economic value of oilseed flax are increasing, and the cultivated area in China is expanding. However, the grain yield of oilseed flax is lower than other oil crops. It varies significantly from year to year, combined with a lower degree of mechanization, which has greatly limited the healthy development of the flax industry. Some of the effects of agronomic measures on productivity and water use efficiency of oilseed flax are reviewed in this paper. The major agronomic strategies for the productivity of oilseed flax were presented based on fertilization, plant density, irrigation, cropping pattern and weed control. Future research should investigate the effect of silicon and potassium fertilizers on the mechanism of lodging resistance of oilseed flax, the effects of diversified cropping systems (strip intercropping and crop rotation) on high and stable productivity and efficient utilization of resources. 

Agronomic cultivation measures on productivity of oilseed flax: A review

Effect of balanced application of boron and phosphorus fertilizers on soil bacterial community, seed yield and phosphorus use efficiency of Brassica napus.

Rapeseed (Brassica napus L.) is highly susceptible to boron (B) and phosphorus (P) deficiencies, yet knowledge of how these two essential elements interact to contribute to plant growth and crop yield is limited. To this end, a pot experiment with three P application rates (5, 75, and 150 mg P2O5 kg-1 dry soil) and two B application rates (0.25 and 1 mg B kg-1 dry soil) was conducted. The results showed that high P combined with high B optimized plant growth and facilitated P distribution forward to seeds compared with high P and low B combination at the maturity stage. Under low P conditions, low B supply was more beneficial for P absorption at seedling and bolting stages and increased P distribution ratio in seeds at the maturity stage, resulting in higher photosynthetic efficiency and growth parameters than low P and high B combination. Interestingly, high B supply could upregulate the expression of the P-starvation-induced gene BnaC3.SPX3 and P transport genes in roots under low P conditions, so low B-facilitated P absorption appears to be a BnaPHT1s-independent process. Significant differences of B and P interaction on the seed yield, net photosynthetic rate, and total P absorption and distribution at the maturity stage between two cultivars might reflect the distinct genotypic properties. Overall, our findings highlight the importance of balanced B and P nutrition which acts synergistically to modulate growth and yield formation of B. napus either in nutrition deficiency or sufficiency.

Boron and Phosphorus Act Synergistically to Modulate Absorption and Distribution of Phosphorus and Growth of Brassica napus.

BnaC4.BOR1;1c is required for B acquisition in Brassica napus (B. napus) under low B stress. This study aimed to reveal the B regulatory mechanism of BnaC4.BOR1;1c and its physiological roles in B translocation from roots to shoots and B distribution in shoots. Transgenic Arabidopsis plants expressing GUS (β-glucuronidase) under different promoters were generated and the mRNA, and GUS activity was quantitatively measured. The in-situ PCR and immunohistochemistry in B. napus were performed to investigate BnaC4.BOR1;1c expression pattern and localization. Furthermore, assays of B transport and distribution in wild type B. napus and BnaC4.BOR1;1c RNAi lines were carried out to elucidate its physiological roles. Results showed that BnaC4.BOR1;1c mRNA abundance is negatively correlated with B availability, which was mediated by the 29 nt sequence in the 5′ terminal region of 5’-UTR. Besides, the 5’-UTR simultaneously regulates protein expression level, most probably depending on the translation efficiency. BnaC4.BOR1;1c mainly localizes on the plasma membrane of vascular bundle cells in roots and shoots with a polar localization manner that is probably beneficial to B xylem loading in roots and B unloading from xylem to phloem in vascular bundle of shoots. Short-term 10B uptake analysis demonstrates that BnaC4.BOR1;1c preferentially distributes B to developing leaves and flowers under B deficiency. This study reveals combined regulatory action of mRNA abundance and translation efficiency mediated by the 5’-UTR in BnaC4.BOR1;1c in response to B availability and its physiological role in preferential B acquisition in developing tissues of B. napus.

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Vascular tissue-specific expression of BnaC4.BOR1;1c, an efflux boron transporter gene, is regulated in response to boron availability for efficient boron acquisition in Brassica napus

Zhe Zhao

Papers

Effect of balanced application of boron and phosphorus fertilizers on soil bacterial community, seed yield and phosphorus use efficiency of Brassica napus.

Boron and Phosphorus Act Synergistically to Modulate Absorption and Distribution of Phosphorus and Growth of Brassica napus.

Vascular tissue-specific expression of BnaC4.BOR1;1c, an efflux boron transporter gene, is regulated in response to boron availability for efficient boron acquisition in Brassica napus

Boron mediates nitrogen starvation-induced leaf senescence by regulating ROS production and C/N balance in Brassica napus