Boron Deficiency Research Articles

Genetic variation of BnaA3.NIP5;1 expressing in the lateral root cap contributes to boron deficiency tolerance in Brassica napus.

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;1Q 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.

DIAGNOSIS AND REMEDY OF BORON DEFICIENCY IN VALENCIA ORANGE TREES UNDER TWO DIFFERENT SITES CONDITIONS.

This study was carried out during three consecutive (2016/019) experimental seasons on 15- year-old fruitful Valencia orange trees (Citrus sinensis L. Osbeck) Olinda cv., budded on Volkamer lemon rootstock, grown in reclaimed soil at two sites (South of El Tahreer& West of Al Nubaria regions) under drip irrigation system (Nile water) and subjected to the same cultural practices. This work aim to study the role of Boron in fruitful Valencia orange trees during the 1st season through an exploratory study at the 1st season ( phase ”I”), then using foliar application of different Boron sources (Boric acid at 1% ; Boron / Molybdenum compound at 1% ; Mulase “CM” at 3ml / L., and Boric acid at 1% + Mulase “ CM” at 3ml / L. and control treatment, at the suitable stage to compensate Boron deficiency during the other two seasons (phase “II”). Results indicated that, there is a fluctuation in Leaf Boron content(ppm) from one site to another during the phase “I” of the study for both sites, whereas, at the 1st site seemed to be constant during the most samples (from 10 to 20 ppm) and slightly reduction ( 50 ppm) for October sample. On the other hand, leaf Boron content under “Site II” conditions was higher (from 30 to 40 ppm) than the site”I” (from 10 to 20 ppm).Moreover, it has increased during February (up 30 ppm), then sharply reduced at the March sample (

Genome-wide identification of Brassicaceae B-BOX genes and molecular characterization of their transcriptional responses to various nutrient stresses in allotetraploid rapeseed

BackgroundB-box (BBX) genes play important roles in plant growth regulation and responses to abiotic stresses. The plant growth and yield production of allotetraploid rapeseed is usually hindered by diverse nutrient stresses. However, no systematic analysis of Brassicaceae BBXs and the roles of BBXs in the regulation of nutrient stress responses have not been identified and characterized previously.ResultsIn this study, a total of 536 BBXs were identified from nine brassicaceae species, including 32 AtBBXs, 66 BnaBBXs, 41 BoBBXs, 43 BrBBXs, 26 CrBBXs, 81 CsBBXs, 52 BnBBXs, 93 BjBBXs, and 102 BcBBXs. Syntenic analysis showed that great differences in the gene number of Brassicaceae BBXs might be caused by genome duplication. The BBXs were respectively divided into five subclasses according to their phylogenetic relationships and conserved domains, indicating their diversified functions. Promoter cis-element analysis showed that BBXs probably participated in diverse stress responses. Protein-protein interactions between BnaBBXs indicated their functions in flower induction. The expression profiles of BnaBBXs were investigated in rapeseed plants under boron deficiency, boron toxicity, nitrate limitation, phosphate shortage, potassium starvation, ammonium excess, cadmium toxicity, and salt stress conditions using RNA-seq data. The results showed that different BnaBBXs showed differential transcriptional responses to nutrient stresses, and some of them were simultaneously responsive to diverse nutrient stresses.ConclusionsTaken together, the findings investigated in this study provided rich resources for studying Brassicaceae BBX gene family and enriched potential clues in the genetic improvement of crop stress resistance.

Is it possible to detect boron deficiency in eucalyptus using hyper and multispectral sensors?

Boron (B) is an essential element whose deficiency results in rapid inhibition in the growth of plants, acting on their meristematic growth. Real-time monitoring of B fertilization in eucalyptus is helpful for guiding precision diagnosis and efficient management of plant boron nutrition. This research hypothesizes that different boron levels alter the reflectance of different wavelengths in eucalyptus. In this context, the objective of this study was to identify spectral ranges that can be used to monitor the boron status in eucalyptus plants. The experiment was carried out in a greenhouse, in which the treatments consisted of increasing boron levels in the form of boric acid (17% of B), whose levels varied from deficit to toxicity. Thus, five treatments were established: no boron, 1, 10, 20, and 40 mg/dm3 of boron. The remote sensing data used were bands, heights, and vegetation indices calculated after obtaining the spectral curves in each treatment. Our findings show that it is possible to accurately distinguish the boron levels in eucalyptus using hyper and multispectral bands. The 350–371 nm spectral range can be used for detecting boron-deficient plants. Plants with adequate boron levels can be identified by using the 426–444 nm, 1811–1910 nm, 1948–2115 nm, and 2124–2208 nm spectral ranges. Finally, the 425–475 nm spectral range can be used to find boron-toxicity plants.

Quantifying the boron demand of Pelargonium graveolens for optimum biomass yield and quality of essential oil under field conditions

Deficiency and toxicity of micronutrient boron (B) play a critical role in plant productivity. In this study, the evaluation of B supplementation on biomass and essential oil (EO) yield of rose-scented geranium (Pelargonium graveolens L.) and its distribution at different application rates (2.5, 5.0, and 7.5 kg ha−1) was performed in a field trial during the growing season of two consecutive years 2017–18 and 2018–19. Boron uptake, plant biomass, and EO yield along with EO constituent in leaves were determined at different time scales. Application of B significantly improved the biomass yield of P. graveolens and at B-II treatment (5.0 kg ha−1 dose) highest biomass and EO yield was recorded, however, B-III treatment (7.5 kg ha−1) demonstrated toxicity symptoms like the decline in protein and chlorophyll content and an increase in proline and stress enzymes (SOD, CAT) in plant leaves. The effects of B on EO constituents varied with the different developmental stages of P. graveolens. Furthermore, the application of B at 5.0 kg ha−1 acts as a stimulant in upgrading the quality and quantity of EO with improved main aroma constituent’s P. graveolens than the control without modulating odor quality i.e., citronellol:geraniol (C:G) ratio. Hence, the study revealed a balanced level of B as a crucial parameter for the enhanced productivity with the improved economic return of P. graveolens.

Organoboron Compounds: Effective Antibacterial and Antiparasitic Agents.

The unique electron deficiency and coordination property of boron led to a wide range of applications in chemistry, energy research, materials science and the life sciences. The use of boron-containing compounds as pharmaceutical agents has a long history, and recent developments have produced encouraging strides. Boron agents have been used for both radiotherapy and chemotherapy. In radiotherapy, boron neutron capture therapy (BNCT) has been investigated to treat various types of tumors, such as glioblastoma multiforme (GBM) of brain, head and neck tumors, etc. Boron agents playing essential roles in such treatments and other well-established areas have been discussed elsewhere. Organoboron compounds used to treat various diseases besides tumor treatments through BNCT technology have also marked an important milestone. Following the clinical introduction of bortezomib as an anti-cancer agent, benzoxaborole drugs, tavaborole and crisaborole, have been approved for clinical use in the treatments of onychomycosis and atopic dermatitis. Some heterocyclic organoboron compounds represent potentially promising candidates for anti-infective drugs. This review highlights the clinical applications and perspectives of organoboron compounds with the natural boron atoms in disease treatments without neutron irradiation. The main topic focuses on the therapeutic applications of organoboron compounds in the diseases of tuberculosis and antifungal activity, malaria, neglected tropical diseases and cryptosporidiosis and toxoplasmosis.

Artan Dozlarda Bor Uygulamasının Antep Fıstığı (Pistacia vera L.) Çeşitlerinin Yeşil Aksam Bor Konsantrasyonu ve Diğer Besin Elementlerinin Alımı Üzerine Etkisi

Antep fıstığı (Pistacia vera L.) son yıllarda Akdeniz ve Güneydoğu Anadolu bölgesinde giderek artan oranda bitki deseni içerisinde yer almaya başlayan bir bitki türüdür. Toprak ve çevre faktörleri bakımından bor (B) noksanlığının yaygın olabileceği bu bölgelerde bitkilerin özellikle B noksanlığına duyarlı Antep fıstığının B ile beslenme düzeyinin belirlenmesi oldukça önemlidir. Bu noktadan hareketle bu araştırma kapsamında büyüme dönemi olarak karagöz patlamasının %20 ve meyvenin mercimek büyüklüğü döneminde olduğu iki farklı dönemde yapraktan artan dozlarda B (%0; %0,2; %0,4; %0,6 ve %0,8) uygulamasının Antep fıstığı bitkisinin yeşil aksam B konsantrasyonu ve besin elementleri üzerine etkisi araştırılmıştır. Bu amaçla, bahçe koşullarında iki Antep fıstığı çeşidinin (Uzun ve Kırmızı) yetiştirildiği üretim alanlarındaki deneme tesadüf blokları deneme planına göre yürütülmüştür. Araştırma sonucunda bitki çeşitlerinin ve uygulanan gübre dozlarının, B konsantrasyonuna önemli düzeyde etkisinin olduğu belirlenmiştir. Bitki çeşitlerine göre tüm B uygulamaları altında B konsantrasyonunun Uzun çeşidine (%8,3) göre Kırmızı (%21) çeşidinde daha yüksek olduğu, ortalama B konsantrasyonunun Kırmızı çeşidinde 200,3 mg kg-1 iken, Uzun çeşidinde ise 176,3 mg kg-1 olduğu belirlenmiştir. Artan dozlarda B uygulaması ile bitkinin yeşil aksamındaki B konsantrasyonunun arttığı, bu artışların (%36,8) kontrole göre sadece %0,6 B doz uygulamasında istatistiksel olarak önemli düzeyde olduğu belirlenmiştir. Bor uygulamasının analizi yapılan makro (N, K) ve mikro (Zn, Fe, Mn) element konsantrasyonları üzerinde ise istatistiksel olarak önemli sayılabilecek bir etkisi saptanmamıştır.

Incidence of GLMD-Like Symptoms on Grapevines Naturally Infected by Grapevine Pinot gris virus, Boron Content and Gene Expression Analysis of Boron Metabolism Genes

Grapevine Pinot gris virus (GPGV) is considered to be a causal agent of Grapevine Leaf Mottling and Deformation (GLMD) disease that has been reported worldwide through the grapevine-growing regions. Seven grapevines that were collected from a vineyard in the Czech Republic were tested for the presence of GPGV in leaf and phloem tissues. Each of the seven grapevines was infected by GPGV, from which sic symptoms were mostly shown without a typical mottling. The phylogeny based on RNA-dependent RNA polymerase and movement/coat protein sequences indicated the same origin of the GPGV isolates. The GPGV titer was the highest in the grapevines with the highest GLMD-like symptoms; however, some of the grapevines with milder GLMD-like symptoms had a lower GPGV titer than the asymptomatic grapevine. Soil analysis showed uneven boron content in the direct vicinity of the grapevines, while the boron content in the grapevines was more, even showing no boron deficiency. The quantitative analysis of selected gene expressions associated with boron efflux and transport only partially explained the boron content in the soil and grapevines and only in the grapevines growing in soils with the highest or lowest boron contents. The VvBor2 and VvNIP5 genes had a higher expression and VvNIP6 had a lower expression in the grapevine growing in the soil with the lowest boron content, while a low expression of VvBor1 and VvBor2 was observed in the grapevine that was grown in the soil with the highest boron content.

Chemical and molecular scale speciation of copper, zinc, and boron in agricultural soils of the Canadian prairies

The general incidence of copper (Cu), zinc (Zn), and boron (B) deficiencies in soils of the Canadian prairies may be related to identifiable, highly variable, inherent soil attributes. The objective of this study was to investigate the variability of selected properties and their relationship with the bioavailability, forms, and distribution of Cu, Zn, and B in a range of prairie soils. The nature of these micronutrient distributions were evaluated by measuring extractable concentrations, supply rates, and by separation into various chemical pools through sequential extraction and spectroscopic speciation analyses. Soil pH was found to be the least variable property [coefficient of variation (CV) < 13%], whereas carbonate content was the most variable (CV > 130%). The Cu and B availability showed strong negative correlation with the sand content in all soils. Path coefficient results indicated that organic carbon had the highest positive direct effect on availability and supply of Cu and B in Grey soils. Extractable Zn was positively correlated with organic carbon content of Brown and Dark Brown soils. Overall, high sand content and low organic matter were identified as important soil properties contributing to the deficiency of Cu, Zn, and B. The major proportion of Cu, Zn, and B was found in the recalcitrant residual fraction (59%–88%), with the smallest proportions in labile soluble, exchangeable forms (2%–8%). The X-ray absorption near edge structure revealed that Cu and Zn associated with carbonate minerals were dominant forms of these micronutrients present in all soils. Chemisorption is likely a major process regulating the bioavailability of Cu and Zn in prairie soils.

Influência da adubação bórica na cultura do feijoeiro

A cultura do feijão em nosso país além de participar de maneira expressiva no cenário econômico que engloba a cadeia do agronegócio, exerce uma função cultural bastante intensificada por ser um dos símbolos básicos da alimentação da população e importante fonte de proteína. O Brasil destaca-se no ranking mundial como um dos principais países produtores e consumidores de feijão (Phaseolus vulgares L). Esta cultura pode ter sua produtividade limitada pelo baixo teor de Boro (B) encontrada em parte dos solos brasileiros cultivados, onde os níveis adequados deste nutriente varia de 1,0 a 1,2 mg dm-3. Com isso, pode existir a necessidade de se fazer a adubação para superar a limitação na produtividade por deficiência de Boro no solo e na planta. As plantas absorvem B na forma de ácido bórico. Ao longo dos anos o nível tecnológico empregado na produção do feijão vêm aumentando significativamente, neste sentido diversas pesquisas tem sido direcionadas para práticas de manejo que gerem rentabilidade e produtividade dessa cultura. Essa revisão tem por objetivo discorrer sobre a relevância da adubação bórica na cultura do feijoeiro e identificar em quais estádios de desenvolvimento essa adubação seria crucial para o ciclo da planta, assim como levantar a resposta à adubação bórica das principais variáveis agronômicas estudadas.

The mitigation effect of boron on the occurrence of osteoporosis in ovariectomized rats

<p indent="0mm">In recent years, unhealthy lifestyles and diet habits have resulted in poor bone growth and development, as well as bone metabolism disorders in adolescents. At the same time, bone metabolism disorder represented by osteoporosis has become the second disease that threatens human health after cardiovascular disease. The bone metabolism disease is a persistent problem in the livestock husbandry and pet industry, which has caused the death and elimination of livestock and poultry and has brought huge economic losses. Therefore, bone metabolic diseases not only threaten human health, but also seriously affect the economic benefits of the pet industry and livestock husbandry. While people focus on the prevention of animal bone metabolism diseases, they mainly focus on various vitamins and major elements, but ignore the trace element “boron” with a wide range of uses. Boron is a non-metal element, and its unique physical and chemical properties make it widely involved in the metabolic regulation activities of human and animal bodies. It promotes the immune function, antioxidant capacity, mineral and hormone metabolism, growth and production performance of animals, especially in bone metabolism which is essential trace element. A large number of studies have shown that boron deficiency will not only lead to bone dysplasia and even deformity, but also lead to bone structural changes, and disorders in bone formation and bone repair. Appropriate boron supplementation has positive effects on bone development and bone maintenance of humans and animals. In this study, the ovariectomized (OVX) rats were selected to establish an osteoporosis model, and the effects of boron on osteoporosis were studied by boron supplementation in drinking water during 22 weeks. Through the microscopic observation of the femoral metaphysis tissue structure in different periods (the 9th and 22nd week after boron supplementation), boron could slow down but not completely prevent the occurrence of osteoporosis. For a long time after the rats’ ovaries were removed, the removal of the ovaries resulted in severe estrogen deficiency in rats. Although studies have shown that boron has an estrogen-like effect and could make up for the lack of estrogen, but not completely replace estrogen. Boron could inhibit the TRAP activity and reduce the bone resorption process, but the bone metabolism including bone resorption and bone formation of the OVX rat has also entered a steady state, ALP activity was still decreased and the osteogenesis effect was weakened. In addition, boron supplementation maintained the content of the serum Ca, P and Mg in the OVX rats, and those three elements mainly derived from the bone minerals of the skeletal system. Therefore, the rat body has been in a state of losing Ca, P, and Mg for a long time, and bone minerals loss will lead to osteoporosis if it goes on. The improvement of antioxidant capacity in OVX rats in the boron supplementation groups could slow down the damage of oxidative stress to osteoblasts and osteocytes, inhibit the differentiation and proliferation of osteoclasts, reduce the damage to the skeletal system, and delay the occurrence of osteoporosis. Therefore, boron could slow down but not completely prevent the occurrence of osteoporosis in OVX rats.

Physiological and proteomic analysis reveals the impact of boron deficiency and surplus on alfalfa (Medicago sativa L.) reproductive organs

Boron (B), an essential element for increasing seed yield and germinability in alfalfa (Medicago sativa L.), plays a vital role in its reproductive processes. However, effects of B stress on physiological and proteomic changes in reproductive organs related to alfalfa seed yield and germinability are poorly understood. In order to gain a better insight into B response or tolerance mechanisms, field trials were designed for B deficiency (0 mg B L−1), B sufficiency (800 mg B L−1), and B surplus (1600 mg B L−1) application during alfalfa flowering to analyze the proteomics and physiological responses of alfalfa ‘Aohan’ reproductive organs. Results showed that B deficiency weakened the stress-responsive ability in these organs, while B surplus reduced the sugar utilization of ‘Aohan’ flowers and caused lipid membrane peroxidation in ‘Aohan’ seeds. In addition, four upregulated stress responsive proteins (ADF-like protein, IMFP, NAD(P)-binding Rossmann-fold protein and NAD-dependent ALDHs) might play pivotal roles in the response of ‘Aohan’ reproductive organs to conditions of B deficiency and B surplus. All of the above results would be helpful to understand the tolerance mechanisms of alfalfa reproductive organs to both B deficiency and B surplus conditions, and also to give insight into the regulatory role of B in improving seed yield and germinability in alfalfa seed production. In summary, B likely plays a structural and regulatory role in relation to lipid metabolism, carbohydrate metabolism, amino acid metabolism, and signal transduction, thus regulates alfalfa reproductive processes eventually affecting the seed yield and germinability of alfalfa seeds.

УСЛОВНО ЭССЕНЦИАЛЬНЫЕ МИКРОЭЛЕМЕНТЫ В ПИТАНИИ ВЕГЕТАРИАНЦЕВ И ВЕГАНОВ: ФТОР, КРЕМНИЙ, БРОМ, БОР

A brief review of the physiology of conditionally essential trace elements and their status among vegetarians and vegans is presented. To date, the biological role of conditionally essential trace elements has been studied much worse than the role of essential trace elements and, especially, macroelements. Nevertheless, they perform a number of important functions in the human body, and the development of their deficiency may lead to unpleasant consequences. Fluorine plays an important role in calcium-phosphorus metabolism and bone tissue development. In addition, it is necessary to maintain normal oral flora. With its deficiency, the risk of osteoporosis development increases while the resistance of tooth enamel to bacterial damage decreases. Despite the evidence that vegetarians are more likely to develop caries than omnivores, it is premature to conclude that they are poorly supplied with fluoride, primarily because drinking water is still the main source of fluoride. The most studied function of silicon is its involvement in the collagen synthesis. Thus, with silicon defi-ciency, the formation of connective tissue, including the organic matrix of the bones, is disturbed. Despite the fact that silicon is mainly found in plant foods, vegans should be mindful about its status, since they have an increased risk of osteopenia and osteoporosis. There is a lack of data on the physiological significance of bromine. Presumably, it is involved in the activa-tion of certain digestive enzymes, inhibitory processes in the nervous system. Although vegetarians and vegans seem to consume less bromine than omnivores, they are probably at a higher risk of intoxication with this element. This is due to the fact that bromine-containing pesticides are actively used in agriculture and can accumulate in plants. Vegetarians and vegans consume more plant foods. The situation is aggravated by the fact that bromine accumulates more actively against the background of iodine deficiency, which is often observed in these population groups. Boron plays a role in the glucose and lipid metabolism, as well as in the vitamin D, calcium and phosphates exchange, thus participating in the formation of an inorganic matrix of bones. It is unlikely that vegetarians and vegans have an increased risk of developing nutritional deficiency of boron compared to omnivores. However, considering data on a higher risk of vitamin D and calcium deficiency and osteoporosis, monitoring and correction of boron status can affect the prevalence of metabolic disturbances in bone tissue among vegans.

Reproductive development and pollen-stigma interaction in sunflower plants receiving boron deficient and toxic supply

To study the effect of boron deficiency and toxicity on the reproductive development and pollen-stigma interaction in sunflower (Helianthus annuus var. Sungold), plants were raised in sand culture under glass house condition till maturity at 0.033 (deficient), 0.33 (sufficient) and 3.3 (toxic) mg B L−1 supply. The effect of deficiency and toxicity of boron on the number, size and weight of inflorescence, anther size, pollen producing capacity (PPC) of an anther and pollen viability were determined. Enzymes peroxidase, acid phosphatase and esterase and protein were cytochemically localized on the stigmatic surface of disk floret. As compared to control plants (0.33 mg B L−1 supply) development of inflorescence was not only delayed but also poor under boron deficiency and toxicity. Pollen grains produced under boron deficiency and toxicity had reduced size with low viability. Histochemical localization of proteins showed marked decrease in concentration on the stigmatic surface of plants receiving deficient and toxic boron supply. Cytochemical localization of peroxidase enzymes on the stigmatic surface showed increased activity whereas a decrease in acid phosphatase and esterase activity was observed suggesting poor pollen stigma interaction under boron stress condition which might be the cause of poor fertilization.

BnaA02.NIP6;1a encodes a boron transporter required for plant development under boron deficiency in Brassica napus

Boron (B) is an essential micronutrient for the plant normal growth. In Arabidopsis, NIP6;1 is a boric acid channel required for the proper distribution of boric acid, especially in the nodal regions of shoots. BnaA02.NIP6;1a, a homologous gene of AtNIP6;1 in Brassica napus, was reported to play a key role in B transport activity. However, little is known about the other functions of BnaA02.NIP6;1a in Brassica napus. In this study, we found that BnaA02.NIP6; 1a was localized in both plasma membrane and cytoplasm, which was different from that in Arabidopsis. The transgenic Arabidopsis plant containing a BnaA02.NIP6;1a promoter driven GUS reporter gene displayed strong GUS activity in roots, stems, leaves, especially in buds and open flowers, which are different from the expression pattern from its homologous gene in Arabidopsis. Silencing BnaA02.NIP6;1a repressed vegetative growth under B-deficient condition in Brassica napus. More importantly, knockdown of BnaA02.NIP6;1a in rapeseed resulted in the reduction of boron accumulation in the flower under boron deficiency and lead to severe sterility, which has not yet been reported before. Furthermore, nip6;1 mutant in Arabidopsis only showed the loss of apical dominance phenotype under boron deficiency at reproductive stage, whereas BnaA02.NIP6;1 RNAi lines exhibited large amounts of abnormal development of the inflorescence as compared with the wild type under boron limitation. Taken together, our results demonstrate that BnaA02.NIP6;1a encodes a boron transporter required for plant development under boron deficiency in Brassica napus, which shows its novel and diverse function in rapeseed compared with model plant Arabidopsis.

Capsaicinoids and mineral composition of peppers produced under nutrient deficiencies

The aim of the present study was to verify the effect of the nutritional stress caused by macronutrient and boron deficiencies on the biosynthesis of capsaicinoids and the mineral nutrient contents of dry Capsicum annuum fruits. The experiments were carried out in a shade house at Campos dos Goytacazes/RJ, Brazil, in sand fertigated with a nutrient solution, in randomized blocks applying an 8x2 bifactorial scheme, with eight treatments [Complete treatment and applying the element omission technique for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S) and boron (B)], and two fruit harvesting dates, with four replications. Pepper fruits produced under potassium deficiency displayed increased capsaicin contents, whereas sulfur deficiency decreased capsaicin contents. Capsaicin contents were different depending on the harvesting dates, ranging from 0.369 to 1.224 mg g−1.

Characterization and use efficiency of sparingly soluble fertilizer of boron and zinc for foliar application in coffee plants

Deficiencies of boron and zinc occur in coffee plantations despite the many fertilizer sources offered by the industry for the agriculture. Sparingly soluble fertilizers (SSF) have been used in several countries for many years. However, their effectiveness when applied to leaves is highly contested, and information about their use efficiency is still lacking. Experiments were set up to characterize the SSF of B and Zn according to particle size of fertilizers, and the spreading and retention of the particles in the leaf, comparing SSF (calcium borate, Zn oxide, and Zn borate) with soluble sources (boric acid and Zn sulfate) in four doses (mg.L-1): Experiment I (B 0, 130, 260, and 520), Experiment II (Zn 0, 200, 600, and 1,800), and experiment III (B 0, 43, 129, and 387, and Zn 0, 200, 600, and 1,800), to supply B and Zn for coffee plants. Microparticles of the SSF were found adhered to coffee leaves, and the Zn oxide was the one with the smallest particle size. SSFs were effective at increasing the Zn and B leaf concentrations in coffee. Dry matter of coffee increased 15% with applications of 270 mg.L-1 of B as calcium borate and 384 mg.L-1 of B as boric acid. Foliar application of Zn oxide at the dose of 1,800 mg.L-1 of Zn increased the leaf areas of the plants. High doses of Zn sulfate caused toxicity to coffee plants due to high saline concentrations. The microparticles found retained on the surface of the coffee leaves increased leaf concentration of B and Zn, which explained variations in the dry matter measurements and show the potential of the SSF for the development of fertilizers to improve the availability of micronutrients to coffee.

High Content of Boron in Curative Water: From the Spa to Industrial Recovery of Borates? (Poland as a Case Study)

Boron minerals are a sought-after raw material. The European Union’s total dependence on imported borates means that this has been a critical material since 2014. Due to the increased use of borates in modern economies, data on the predicted boron demand in the coming years indicate that it may become a critical element on a global scale. Formerly, the high boron content in groundwater was the basis for qualifying it as medicinal water (boric water). Nevertheless, the current information on the potential toxicity of boron and the narrow margin between deficiency and toxicity of boron in the human body has caused a tightening of the limits of this element in water intended for human consumption. For this reason, metaboric acid has lost its position as a specific component of curative waters. However, despite the fact that boron is not currently a specific component of curative waters, it is found in measureable concentrations in Polish medicinal water considered therapeutic based on other valuable specific components. High boron content in curative water may be the cause of the problems in some spas when obtaining certificates confirming the therapeutic properties of waters. Literature data indicate that waters with high boron content (above 25 mg/L) should not be freely available for drinking in pump rooms and other places in health resorts. To identify the situation with Polish health resorts, the content of boron in 248 curative water samples was analyzed. In 154 of these samples, the boron concentration was relatively low and did not exceed 5 mg/L. However, in the remaining 94 samples, the boron content exceeded 5 mg/L, and 38 samples had boron content exceeding 30 mg/L. Ten of the 248 samples of curative water had a boron concentration above 100 mg/L, which may be a potential source of boron for industrial recovery. The highest concentration of boron was noticed in a water sample from the Wysowa health resort and was 187.6 mg/L. Unfortunately, most of water intakes with a high concentration of boron (above 100 mg/L) are low-yielding wells. Based on the data collected, Rabka appears to be the best candidate for small-scale boron production in terms of boron content and water resources values.

MtNIP5;1, a novel Medicago truncatula boron diffusion facilitator induced under deficiency

BackgroundLegumes comprise important crops that offer major agronomic benefits, including the capacity of establishing symbiosis with rhizobia, fixing atmospheric N2. It has been proven that legumes are particularly susceptible to boron (B) stress, which leads to important yield penalties. Boron (B) deficiency or toxicity in plants causes the inhibition of growth and an altered development. Under such conditions, the participation of two distinct protein families (the major intrinsic protein family MIP and the Boron transporter family BOR) is required to minimize detrimental effects caused by B stress. However, in legumes, little is known about the transport mechanisms responsible for B uptake and distribution, especially under deficiency.ResultsA Medicago truncatula protein, MtNIP5;1 (Medtr1g097840) (homologous to the Arabidopsis thaliana AtNIP5;1) was identified as a novel legume B transporter involved in B uptake under deficiency. Further analyses revealed that this M. truncatula aquaporin expression was boron-regulated in roots, being induced under deficiency and repressed under toxicity. It localizes at the plasma membrane of root epidermal cells and in nodules, where B plays pivotal roles in symbiosis. Furthermore, the partial complementation of the nip5;1–1 A. thaliana mutant phenotype under B deficiency supports a functional role of MtNIP5;1 as a B transporter in this legume model plant.ConclusionsThe results here presented support a functional role of MtNIP5;1 in B uptake under deficiency and provides new insights into B transport mechanisms in legume species.

Crescimento e rendimento da cultura do trigo com aplicações de boro

A deficiência do micronutriente boro (B) se destaca pelos prejuízos relativos à formação e qualidade da colheita, sendo importante a compreensão de seu manejo e de sua aplicação no cultivo de grãos. O objetivo do estudo foi avaliar o crescimento e o rendimento da cultura de trigo em resposta a doses e formas de aplicação de boro. O estudo foi conduzido em casa de vegetação, em Cascavel, Paraná, Brasil. O delineamento experimental foi o de blocos casualizados, e os quatro tratamentos avaliados foram: testemunha sem adição de B; fertilização via sulco (octaborato de sódio 20,5% de B, 1,0 kg.ha-1); fertilização via foliar (octaborato de sódio 2% de B, 150 mL.ha-1) e fertilização via sulco mais foliar (1,0 kg.ha-1 de octaborato de sódio 20,5% de B + foliar 150 mL.ha-1 de octaborato de sódio 2% de B). Foram avaliados o comprimento do sistema radicular e da parte aérea, bem como massa seca da planta e rendimento de grãos. A fertilização com B via sulco e foliar proporcionou incremento de 56,5% no rendimento de grãos em relação às plantas que não receberam esse micronutriente. A aplicação de B favoreceu o crescimento e rendimento do trigo, sendo recomendada sua aplicação via sulco e via foliar na adubação da cultura.