Essential Element For Plants Research Articles

The transcription factor Dof3.6/OBP3 regulates iron homeostasis in Arabidopsis.

Iron is an essential element for plants. Iron uptake by plants is highly regulated, but the underlying mechanism is poorly understood. Using a truncated fragment of the iron deficiency-responsive bHLH100 gene promoter, we screened the Arabidopsis transcription factor yeast one-hybrid (Y1H) library and identified the DOF family protein, OBP3, as a crucial component of the iron deficiency-signaling pathway. OBP3 is a transcriptional repressor with a C-terminal activation domain. Its expression is induced by iron deficiency. The transgenic lines that overexpress OBP3 exhibited iron overload and premature leaf necrosis, while the obp3 mutant was less tolerant of iron deficiency. It was discovered that OBP3 directly targets the Ib subgroup of bHLH gene promoters. OBP3 interacts with the bHLH transcription factor ILR3 (IAA-LEUCINE RESISTANT3), and their interaction enhances the DNA-binding ability and transcriptional promoting activity of OBP3, resulting in the positive regulation of iron deficiency-response genes. In addition, the E3 Ligase BRUTUS facilitates 26S proteasome-mediated degradation of OBP3 protein to prevent excessive iron uptake in plants. In conclusion, our research emphasizes the vital role of OBP3 in regulating plant iron homeostasis.

Plant functional type and peat properties determine elemental transfer in boreal mire vegetation

Uptake of elements into plants is an integral part of many environmental impact assessments. Typically, the plant uptake is determined using an empirical soil-to-plant transfer factor (CR). The elemental concentrations in plants are expected to vary with plant species and plant functional type (PFT), but also according to soil and element properties. Specifically, the uptake of essential elements is regulated, and likely less related to soil concentrations than the uptake of non-essential elements. In this study, the impact of PFT, species and environmental factors on the CR of mire plants was tested. The plants included in the study were four common boreal peatland species (Andromeda polifolia, Vaccinium oxycoccus, Eriophorum vaginatum and Carex rostrata) sampled from 40 minerogenic mires along an age gradient.The results show that while plant species and PFT (heathers and sedges) are the main determinants of the CR value, also environmental factors, such as peat C:N ratio, are important. Further, concentrations of essential elements in plants were only weakly correlated to peat concentrations, whereas the correlation was stronger for non-essential elements and elements utilized at trace amounts.The results of this study verify that CR values may vary substantially between peatland plant species and PFTs. Further, the results suggest that it is relevant to include effects of PFTs on CR and among-species variation in environmental impact assessments. This is because the PFT may have a large impact on the exposure pathways to humans, which could, for example, be berries or animal feed, and also due to the uncertainties of the composition of the future vegetation communities. Since CR varies systematically with several soil properties, there may be potential for adjusting the CR values for expected environmental changes, and thereby reduce the uncertainties of empirical CR values determined from a broad range of environmental conditions.

TOTAL NITROGEN CONTENT IN SEDIMENTS IN THE MANGROVE AND CRAB CONSERVATION AREA OF TARAKAN CITY

Nitrogen in sediments is an essential element for plants that play a role in the process of photosynthesis and stimulate growth. This study aims to examine the total Nitrogen (N) content in sediments based on differences in depth in the Mangrove and Crab Conservation Area of Pamusian Village, Tarakan City. The method used in the research is quantitative descriptive method by describing the content of Nitrogen (N) in sediments based on differences in depth at each research station and determining the location of sampling points for sampling using purposive sampling method. Sediment sampling was carried out at 3 station points, namely the Pamusian River flow area, the watchtower area and the area near residential areas. Sediment sample testing was carried out at the Soil Laboratory of the Faculty of Agriculture, Borneo University of Tarakan. The results of this study showed that the Nitrogen (N) content in sediments in the Mangrove and Crab Conservation Area of Pamusian Village at a depth of 10 cm ranged from 0.25 - 0.32%, a depth of 20 cm ranged from 0.19 - 0.24%, and a depth of 30 cm ranged from 0.14 - 0.20%. The highest total nitrogen content is at a depth of 10 cm and the station that has the highest total nitrogen content is station 3.

Phosphate Turnover in Various Parts of Nodulated Soybean (Glycine max (L.) Merr.) Plants and the Relation to the Xylem Transport

Phosphorus is a major essential element in plants, and the absorption and transport of P are related to crop growth and productivity. Phosphate (Pi) is absorbed in the roots and transported to the shoot. Plants store surplus Pi in the vacuoles. The characteristics of Pi storage and turnover in various parts of the nodulated soybeans might be related to plant growth and P-use efficiency. This research focused on the changes in the Pi concentrations and Pi contents in each part of young soybean plants grown in Pi-sufficient (50 μM Pi) or Pi-deficient (0 μM Pi) conditions. Also, the Pi flux rate in xylem sap from roots to shoot was determined. The growth of the plants was the same after 7 days of Pi-sufficient and Pi-deficient treatments. During the Pi-deficient period, the Pi concentrations in the roots, leaves, and stems decreased significantly but did not deplete. The decrease in Pi concentration in nodules was much slower than the other parts. After the re-supply of 50 μM Pi in the solution, the Pi concentration increased only a little in each part of the Pi-deficient plants. The Pi concentration and Pi flux in the xylem sap quickly responded to the changes in the Pi concentration in the culture solution.

Localization of the MTP4 transporter to trans-Golgi network in pollen tubes of Arabidopsis thaliana.

Zinc (Zn) is an essential element for plants. Numerous proteins in different cellular compartments require Zn for their structure and function. Zn can be toxic when it accumulates in high levels in the cytoplasm. Therefore, Zn homeostasis at tissue, cell, and organelle levels is vital for plant growth. A part of the metal tolerance protein (MTP) / Cation Diffusion Facilitator (CDF) transporters functions as Zn transporters, exporting Zn from the cytosol to various membrane compartments. In Arabidopsis thaliana, MTP1, MTP2, MTP3, MTP4, MTP5, and MTP12 are classified as Zn transporters (Zn-CDF). In this study, we systematically analyzed the localization of GFP-fused Zn-CDFs in the leaf epidermal cells of Nicotiana benthamiana. As previously reported, MTP1 and MTP3 were localized to tonoplast, MTP2 to endoplasmic reticulum, and MTP5 to Golgi. In addition, we identified the localization of MTP4 to trans-Golgi Network (TGN). Since MTP4 is specifically expressed in pollen, we analyzed the localization of MTP4-GFP in the Arabidopsis pollen tubes and confirmed that it is in the TGN. We also showed the Zn transport capability of MTP4 in yeast cells. We then analyzed the phenotype of an mtp4 T-DNA insertion mutant under both limited and excess Zn conditions. We found that their growth and fertility were not largely different from the wild-type. Our study has paved the way for investigating the possible roles of MTP4 in metallating proteins in the secretory pathway or in exporting excess Zn through exocytosis. In addition, our system of GFP-fused MTPs will help study the mechanisms for targeting transporters to specific membrane compartments.

Transcriptional analysis of the molecular response of Arabidopsis to manganese stress and recovery

Manganese (Mn) is an essential element for plants and plays a role in various metabolic processes. However, excess manganese can be toxic to plants. This study aimed to analyze the changes in various physiological activities and the transcriptome of Arabidopsis under different treatments: 1 mmol/L MnCl2 treatment for 1 day or 3 days, and 1 day of recovery on MS medium after 3 days of MnCl2 treatment. During the recovery phase, minor yellowing symptoms appeared on the leaves of Arabidopsis, and the content of chlorophyll and carotenoid decreased significantly, but the content of malondialdehyde and soluble sugar increased rapidly. Transcriptome sequencing data shows that the expression patterns of differentially expressed genes exhibit three major models: initial response model, later response model, recovery response model. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis identified several affected metabolic pathways, including plant hormone signal transduction mitosolysis activates protein kinase (MAPK) phytohormone signaling, phenylpropanoid biosynthesis, ATP binding cassette transporters (ABC transporter), and glycosphingolipid biosynthesis. Differential expressed genes (DEGs) involved in phenylpropanoid biosynthesis, ABC transporter, and glycosphingolipid biosynthesis, were identified. Sixteen randomly selected DEGs were validated through qRT-PCR and showed consistent results with RNA-seq data. Our findings suggest that the phenylpropanoid metabolic pathway is activated to scavenge reactive oxygen species, the regulation of ABC transporter improves Mn transport, and the adjustment of cell membrane lipid composition occurs through glycerophospholipid metabolism to adapt to Mn stress in plants. This study provides new insights into the molecular response of plants to Mn stress and recovery, as well as theoretical cues for cultivating Mn-resistant plant varieties.

Effect of various phosphorus levels on the extraction of Cd, the transformation of P, and phosphorus-related gene during the phytoremediation of Cd contaminated soil

Phytoremediation has emerged as a common technique for remediating Cd pollution in farmland soil. Moreover, phosphorus, an essential element for plants, can alter the pectin content of plant cell walls and facilitate the accumulation of Cd in plant tissues, thereby enhancing phytoremediation efficiency. Therefore, pot experiments were conducted in order to investigate the effect of phosphorus levels on Cd extraction, phosphorus transformation and phosphorus-related genes during phytoremediation. The results revealed that an optimal application of suitable phosphate fertilizers elevated the soil's pH and electrical conductivity (EC), facilitated the conversion of soil from insoluble phosphorus into available forms, augmented the release of pertinent enzyme activity, and induced the expression of phosphorus cycling-related genes. These enhancements in soil conditions significantly promoted the growth of ryegrass. When applying phosphorus at a rate of 600 mg/kg, ryegrass exhibited plant height, dry weight, and chlorophyll relative content that were 1.27, 1.26, and 1.18 times higher than those in the control group (P0), while the Cd content was 1.12 times greater than that of P0. The potentially toxic elements decline ratio and bioconcentration factor were 42.86% and 1.17 times higher than those of P0, respectively. Consequently, ryegrass demonstrated the highest Cd removal efficiency under these conditions. Results from redundancy analysis (RDA) revealed a significant correlation among pH, total phosphorus, heavy metal content, phosphorus forms, soil enzyme activity, and phosphorus-related genes. In conclusion, this study suggests applying an optimal amount of suitable phosphate fertilizers can enhance restoration efficiency, leading to a reduction in soil Cd content and ultimately improving the safety of crop production in farmlands.

Selenium-Induced Enhancement in Growth and Rhizosphere Soil Methane Oxidation of Prickly Pear.

As an essential element for plants, animals, and humans, selenium (Se) has been shown to participate in microbial methane oxidation. We studied the growth response and rhizosphere methane oxidation of an economic crop (prickly pear, Rosa roxburghii Tratt) through three treatments (Se0.6 mg/kg, Se2.0 mg/kg, and Se10 mg/kg) and a control (Se0 mg/kg) in a two-month pot experiment. The results showed that the height, total biomass, root biomass, and leaf biomass of prickly pear were significantly increased in the Se0.6 and Se2.0 treatments. The root-to-shoot ratio of prickly pear reached a maximum value in the Se2 treatment. The leaf carotenoid contents significantly increased in the three treatments. Antioxidant activities significantly increased in the Se0.6 and Se2 treatments. Low Se contents (0.6, 2 mg/kg) promoted root growth, including dry weight, length, surface area, volume, and root activity. There was a significant linear relationship between root and aboveground Se contents. The Se translocation factor increased as the soil Se content increased, ranging from 0.173 to 0.288. The application of Se can improve the state of rhizosphere soil's organic C and soil nutrients (N, P, and K). Se significantly promoted the methane oxidation rate in rhizosphere soils, and the Se10 treatment showed the highest methane oxidation rate. The soil Se gradients led to differentiation in the growth, rhizosphere soil properties, and methane oxidation capacity of prickly pear. The root Se content and Se translocation factor were significantly positively correlated with the methane oxidation rate. Prickly pear can accumulate Se when grown in Se-enriched soil. The 2 mg/kg Se soil treatment enhanced growth and methane oxidation in the rhizosphere soil of prickly pear.

Morphophysiology of Punica Granatum L. under microalgae biomass stimulation

The use of microalgae has been proeminent in agricultural scenario, because it is an alternative product considered extremelly productive, which contains essential elements for plants. Thus, this study aimed to evaluate the morphophysiology of Punica granatum L. seedlings treated with Spirulina platensis and Scenedesmus sp. nanoparticles in controlled environment. The research was carried out at the of Federal University of Campina Grande, Pombal-PB, using a completely randomized design with five replications. The factorial scheme (2 x 4) was adopted, represented by two types of microalgae (Spirulina platensis; Scenedesmus sp.) and four doses of application (0, 5, 10 and 15%). Growth evaluations happened at 135 days after planting, verifying the number of leaves and branches and shoot length. The physiological parameters evaluated were gas exchanges, chlorophyll ‘a’ fluorescence, electron transport rate, stationary fluorescence, maximum fluorescence yield after light adaptation and quantum efficiency of PSII. Shoot length and number of branches had rises at doses of 6 and 15%. Number of leaves was induced in seedlings at dose of 8% with Spirulina platensis. Stomatal conductance and internal CO2 concentration increased in seedlings sprayed with Spirulina platensis. extract of Scenedesmus sp. improved the stationary fluorescence and quantum efficiency of PSII in pomegranate seedlings.

Impacto da mudança de uso da terra nos estoques de nitrogênio em plintossolo de cerrado

ABSTRACT The land use changes and different management forms promote modifications in soil organic matter (SOM), which imply the yield and sustainability of agricultural systems. SOM provides essential elements for plants, such as Nitrogen (N), one of its main constituents, and is also an indicator of soil quality. This study aimed to evaluate the dynamics of N levels and stocks in the soil of Plinthosol in the state of Tocantins, Brazil, under different uses (eucalyptus, corn, and pasture) compared to a natural ecosystem of Cerrado sensu stricto. Therefore, six trenches were opened in each study area to collect soil samples at 0-10, 10-20, 20-30, 30-40, and 40-50 cm soil layers, determining the contents and stocks (0-50 cm) of total N in the soil by dry combustion. The means were compared by the Tukey test at a 5% error probability level. N-S contents and stocks of the evaluated systems did not differ statistically from the reference area, except the eucalyptus area, which presented a higher average content, specifically in the 0-10 cm layer, and a higher average stock, considering the entire layer evaluated (0- 50cm). N-S stocks decreased in the following order across different land uses: eucalyptus > corn = pasture = Cerrado, probably indicating the effectiveness of the arboreal component in incorporating N-S as well as the importance of adopting conservation management practices that prioritize greater input and stabilization of organic matter in the soil.

Función de los hongos micorrícicos y las bacterias solubilizadoras de fosfatos en la absorción de elementos esenciales y metálicos en las plantas en suelos contaminado con metales pesados

The objective of this study was to compare the effect of different types of inoculants (control, vesicular arbuscular mycorrhizae fungi [VAMF], phosphate-solubilizing bacteria [PSB], and co-inoculant [VAMF-PSB]) on root colonization, plant growth, macronutrient (P and N) uptake, and metal element uptake under heavy metal-contaminated soil conditions. Three species of vegetable plants, namely tomato (Solanum lycopersicum L. cv. Ratna), red chili (Capsicum annuum L. cv. Gada), and hot chili (Capsicum frutescens L. cv. Pusaka Brengolo), were grown in heavy metal (Zn, Ca, Ni and Cd) –contaminated soil for eight weeks. Plants co-inoculated with VAMF-PSB showed significantly higher root colonization by VAMF as well as P and N concentrations in shoot and root than plants inoculated with only VAMF or PSB; consequently, the plant biomass also increased. In heavy metal-contaminated soil, VAMF colonization and PSB application could significantly improve the essential metal concentration (Cu and Zn) in the shoot, although there were no significant effects on the roots. On the contrary, co-inoculation with VAMF-PSB could significantly decrease Cd and Ni concentrations in the shoot, although Cd and Ni concentrations did not show a significant difference in the root. The concentrations of Cu, Zn, Cd, and Ni were higher in the roots than in the shoots of the three plant species tested. The type of inoculant used in this study selectively discriminated between plant essential (Cu, Zn) and non-essential elements (Cd, Ni).

Comparative Study on the Effect of Urine from Pregnant and Non-Pregnant Women and Algafer LPF Plus on the Length of Epicotyl to the Germinating Corn (Zea Mays) Seeds in Hydroponics

This study was conducted to analyze the effect of urine from pregnant and non-pregnant women and Algafer LPF Plus on the germination rate of Corn (Zea mays) seeds in hydroponics by determining the length of epicotyl in various percentage concentrations of urine and Algafer. There were four (4) treatments used namely: T1 (0.75%), T2 (5%), T3 (10%), and T4 as control. Treatment was done by allowing the plants to grow in water culture and adding different concentrations of the test solution in every test system. A total of fifteen (15) seedlings per replicate were considered and the average length of epicotyl was taken. The data were then subjected to a 3X4 Factorial Analysis of Variance (ANOVA) and Duncan’s Multiple Range Test (DMRT). Results of the study indicated that the rate of germination increases at a 10% level concentration of urine from pregnant and non-pregnant women, whereas in Algafer, concentrations in T2 (5%) and T3 (10%) caused seed rotting. Among the three test solutions, both urines from pregnant and non-pregnant women have been shown to cause growth by promoting cell elongation on epicotyl. DMRT for both urines of pregnant and non-pregnant women revealed that T3 (10%) was significantly different from the other treatment means. In Algafer LPF Plus, DMRT revealed that T2 and T3 were not different from each other, likewise with T1 and T4. These findings indicated that certain components in urine are essential to the germination of corn seeds. The presence of these essential elements in plants plays a vital role in attaining earlier and greater growth. The waste product, therefore, excreted by the kidney can now be used as an inexpensive substitute for fertilizers for faster germination at the proper concentration.

Cyanobacterial elicitors as efficient plant growth promoters affect the biomass and metabolic profiles of four species of Mentha L.: A comparative study

Medicinal and aromatic plants contain compounds with industrial and therapeutic applications; among which genus Mentha L. has special economic importance. The present investigation aimed to evaluate the ability of cyanobacterial strains as bio-elicitors on biomass production, as well as the quality and quantity of essential oils of four species of Mentha (M. spicata L., M. piperita L., M. aquatica L., and M. pulegium L.). Following the seedling growth test, two cyanobacterial strains, Wollea vaginicola ISB89 and Nostoc spongiaeforme var. tenue ISB91, were selected as potential bio-elicitors. Then, the growth of plants under 1% cyanobacterial suspensions was assessed by measuring growth factors including length and weight of plants, and leaf area after 90 days of planting. Moreover, the amount of essential oils of plants and their constituents were evaluated. According to the results, both cyanobacterial elicitors significantly increased plant biomasses and essential oils yield. There was a direct relationship between cyanobacterial auxins and biomass and essential oil of Mentha spp.; in this way, Wollea with a higher level of auxins and cations provides essential elements for plants. Therefore, plants treated with Wollea exhibited more growth and essential oil promoting features compared to Nostoc treatments. The most important terpenoids in essential oils of investigated species belong to oxygenated monoterpenes with 79–91% contents; including Piperitenone, Menthol, and Menthone. In M. piperita, the amount of Menthone, as one of the principal constituents of essential oil, increased under cyanobacterial elicitors (115–137%). For M. spicata the enhancement of Piperitenone (46–96%), and for M. pulegium, the increase of neo-Menthol (17–115%) was remarkable. Based on the results, two cyanobacteria strains are considered as a rich source of natural compounds and phytohormones which can be used to increase the yield and essential oil production of studied economically important plant species.

Boron contamination and related health risk assessment in the soils collected from olive groves in İzmir province, Türkiye

Although boron (B) is an essential element for plants, high levels are also toxic. In this respect, pollution of soils by B may pose a serious problem for ecosystem and human health. On the other hand, studies evaluating the ecological and human health risks that may arise due to B contamination in agricultural soils are limited. In this study, it was aimed to determine the B pollution degree of the soils taken from the olive groves of İzmir province, which is approximately 180 km away from the B deposits in the Bigadiç district. In addition, the factors affecting boron adsorption and availability were discussed and the ecological and health risks of boron were evaluated. For this, soil samples were collected at depths of 0–30 cm from 118 olive groves and their B, Al, Fe, pH and organic matter contents were determined. The mean B content (47.08 mg/kg) of the study area was comparable to world-soil average B concentration (42 mg/kg). Also, B had a “low potential ecological risk” in the study area according to the ecological risk index results. On the other hand, based on the results of contamination factor (Cf) and enrichment factor (EF), “moderate contamination” and “significant enrichment” were found in the study area for B. These findings indicated that the B content in the study area is mainly related to the soil parent material, but irrigation water also contributes slightly to B content. Correlation analysis results suggested that Al and Fe contents of the soils in the study area may have an effect on B adsorption. The results of health risk assessment indicated non-carcinogenic effects are not expected for adults and children exposed to soil B content by ingestion, dermal contact and inhalation.

EFFECT INTERACTION OF SULFATE (SO4 2-) DAN CHROMATE (CrO4 2-) ON GROWTHAND CR6+ACCUMULATION IN Tagetes erecta L.

Chromium is a heavy metal that is toxic, bioaccumulative, persistent, and cannot be decomposed in the environment. The Cr6+ ion is a chromium ion that has the highest toxicity among other chromium ions, so its presence in the environment is hazardous for plants, animals, and humans. Sulfur is an essential element for plants, whose presence can reduce Cr6+ concentrations in the terrestrial environment by inhibiting the uptake of Cr6+ by plants. Tagetes erecta is a bioremediation agent plant that can remediate land polluted with Cr6+ waste. In this research, we studied the growth of T. erecta in media polluted with Cr6+ and sulfate and its ability to accumulate of Cr6+. Several parameters observe in this experiment, i.e. growth parameters, namely plant height, number of leaves, number of flowers measured at the end of the study, dry weight, root length, and Cr6+ concentration estimated using the diphenylcarbasid method. The results showed that the plant height of T. erecta. was not significantly different, and sulfate addition did not affect plant height. The addition of sulfate affected the number of leaves and flowers, dry weight of root shoots, root length, and Cr6+ content in T. erecta. polluted with Cr6+. so that in these parameters, there was a significant difference in the addition of Cr6+ and sulfate on growth of T. erecta and its ability to Cr accumulation.

Bioactive compounds in cruciferous sprouts and microgreens and the effects of sulfur nutrition.

Cruciferous sprouts and microgreens are a good source of bioactive compounds for human health since they are rich in glucosinolates, polyphenols, carotenoids, vitamins, etc. Sulfur-containing bioactive phytochemicals called glucosinolates are attractive to humans owing to its cancer chemoprevention. They mainly exist in cruciferous vegetables. Sulfur is one of the essential elements for plant and is also an indispensable component of glucosinolates. In this paper, the nutritional value of cruciferous spouts and microgreens is summarized, along with the effects of sulfur nutrition on bioactive phytochemical compounds of cruciferous sprouts and microgreens, especially glucosinolates. The review aims to provide nutritious information so that people may consume cruciferous sprouts and microgreens wisely, and to offer helpful cues for the research on cruciferous sprouts and microgreens products. This article is protected by copyright. All rights reserved.

Review of Inexpensive Adsorbents for Removing Boron from Aqueous Solutions

Boron is one of the essential elements for plants, animals, and humans, but its excess poses a great risk to life. Therefore, it is necessary to effectively remove boron from various boron-containing aqueous solutions to reduce damage to living things. There have been many studies on the adsorbent for removing boron from the boron-containing aqueous solution, but many of them are expensive or cannot be industrialized or commercialized, so they remain in the laboratory stage. Reducing the cost of adsorbent and realizing commercialization can be said to be the key links to successfully solving the problem of boron removal from an aqueous solution. The purpose of this review is to conduct a comprehensive analysis of inexpensive adsorbents used for boron removal from industrial wastewater and drinking water and to discuss future research directions. This article summarizes the development and utilization of inexpensive adsorbents, including inorganic materials, natural materials, and wastes. The limitations of performance, applicable conditions, sources, et al., of inexpensive adsorbents currently developed and utilized were analyzed, and future research directions were discussed. Most inexpensive adsorbents have a limited range of use, and compared to organic materials, inorganic materials have very low adsorption performance. The development of adsorbents using natural materials or waste is not active. Therefore, further research is needed to improve the performance of inorganic adsorbents, develop environmentally sustainable and efficient adsorbents, and recycle adsorbents.

The Arabidopsis Target of Rapamycin kinase regulates ammonium assimilation and glutamine metabolism.

In eukaryotes, a target of rapamycin (TOR) is a well-conserved kinase that controls cell metabolism and growth in response to nutrients and environmental factors. Nitrogen (N) is an essential element for plants, and TOR functions as a crucial N and amino acid sensor in animals and yeast. However, knowledge of the connections between TOR and the overall N metabolism and assimilation in plants is still limited. In this study, we investigated the regulation of TOR in Arabidopsis (Arabidopsis thaliana) by the N source as well as the impact of TOR deficiency on N metabolism. Inhibition of TOR globally decreased ammonium uptake while triggering a massive accumulation of amino acids, such as Gln, but also of polyamines. Consistently, TOR complex mutants were hypersensitive to Gln. We also showed that the glutamine synthetase inhibitor glufosinate abolishes Gln accumulation resulting from TOR inhibition and improves the growth of TOR complex mutants. These results suggest that a high level of Gln contributes to the reduction in plant growth resulting from TOR inhibition. Glutamine synthetase activity was reduced by TOR inhibition while the enzyme amount increased. In conclusion, our findings show that the TOR pathway is intimately connected to N metabolism and that a decrease in TOR activity results in glutamine synthetase-dependent Gln and amino acid accumulation.

Effect of Three Boron Concentrations in Soil on Growth and Physiology in Sweet Cherry Trees.

Boron (B) is an essential element for plants. B availability depends on the physical and chemical characteristics of the soil and the quality of irrigation water. Under natural conditions, both toxic and deficit concentrations can occur and should be managed for crop production. However, the range between deficiency and toxicity is narrow. The objective of this study was to determine the response of cherry trees to deficient (0.04 mg kg-1), adequate (1.1 mg kg-1), and toxic (3.75 mg kg-1) B concentrations in the soil by measuring growth, biomass, photosynthetic parameters, visual symptoms, and morphological changes. Plants treated with a toxic dose had more spurs and shorter internodes than those treated with adequate and deficient doses. The white root weight (50.5 g) at low B concentrations had the most roots compared with the adequate (33.0 g) and toxic (22.0 g) concentrations. The stem weight and biomass partitioning were higher for white roots and stems at B-deficient and -adequate doses than at toxic doses. The net photosynthesis (Pn) and transpiration rate (E) were significantly higher in plants with adequate concentrations of B. Stomatal conductance (Gs) was higher in B-deficient plants. Morphological and visual differences were observed between treatments. The results showed that it is essential to adequately manage B in cherry crops to avoid the adverse effects of both low and toxic concentrations.

The use of selenium for controlling plant fungal diseases and insect pests.

The selenium (Se) applications in biomedicine, agriculture, and environmental health have become great research interest in recent decades. As an essential nutrient for humans and animals, beneficial effects of Se on human health have been well documented. Although Se is not an essential element for plants, it does play important roles in improving plants' resistances to a broad of biotic and abiotic stresses. This review is focused on recent findings from studies on effects and mechanisms of Se on plant fungal diseases and insect pests. Se affects the plant resistance to fungal diseases by preventing the invasion of fungal pathogen through positively affecting plant defense to pathogens; and through negative effects on pathogen by destroying the cell membrane and cellular extensions of pathogen inside plant tissues after invasion; and changing the soil microbial community to safeguard plant cells against invading fungi. Plants, grown under Se enriched soils or treated with Se through foliar and soil applications, can metabolize Se into dimethyl selenide or dimethyl diselenide, which acts as an insect repellent compound to deter foraging and landing pests, thus providing plant mediated resistance to insect pests; moreover, Se can also lead to poisoning to some pests if toxic amounts of Se are fed, resulting in steady pest mortality, lower reproduction rate, negative effects on growth and development, thus shortening the life span of many insect pests. In present manuscript, reports are reviewed on Se-mediated plant resistance to fungal pathogens and insect pests. The future perspective of Se is also discussed on preventing the disease and pest control to protect plants from economic injuries and damages.