Decrease In Fresh Weight Research Articles

2-Keto-L-Gulonic Acid Enhances Cold Stress Tolerance in Arabidopsis thaliana via Augmentation of Ascorbic Acid Biosynthesis and Antioxidant Defense Systems

Cold stress severely impairs plant growth, development, and yields. L-ascorbic acid (ASA), a crucial antioxidant, is pivotal in mitigating stress-induced damage. Previous research found that 2-keto-L-gulonic acid (2KGA), a precursor of ASA in its industrial production, effectively enhances the endogenous ASA content in plants. We hypothesized that 2KGA might alleviate chilling stress and tried to verify it through a cultivation experiment of Arabidopsis thaliana. The results demonstrate that the application of 2KGA significantly increased ASA content (24.58%) and up-regulated ASA biosynthetic genes in Arabidopsis at 4 °C for 24 h. Furthermore, 2KGA alleviated the decrease in fresh weight (17.05%) and total chlorophyll content (15.85%) caused by low temperatures. The contents of proline, soluble sugar (SS), soluble protein (SP), and the activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were significantly increased under the 2KGA treatment at low temperatures, while the malondialdehyde (MDA) content was reduced. Moreover, 2KGA up-regulated the ICE-CBF-COR signaling pathway in response to cold stress. These collective findings strongly support the involvement of 2KGA in enhancing cold tolerance in Arabidopsis, presenting an innovative approach for agricultural practices aimed at enhancing crop resilience to environmental stresses.

Foliar spraying with amino acids and their chitosan nanocomposites as promising way to alleviate abiotic stress in iceberg lettuce grown at different temperatures

We analyzed the effects of foliar spraying with amino acids, chitosan (CHS) and nanocomposites (NCs) of chitosan with the amino acids proline, l-cysteine and glycine betaine (CHS-Pro NCs; CHS-Cys NCs, CHS-GB NCs, respectively) on the changes in the physiological and biochemical parameters of iceberg lettuce grown at the control temperature (20 °C) and under chilling conditions (4 °C). The physicochemical parameters of the phospholipid monolayers (PLs) extracted from plants showed the effects of the treatments on the properties of the monolayers, namely, the packing density and flexibility. We observed increased accumulation of proline at 4 °C, and differences in the concentrations of sugars in most of the analyzed variants were a consequence of the lowered temperature and/or the use of organic compounds. A temperature of 4 °C caused a significant increase in the l-ascorbic acid level compared with that at 20 °C. Differences were also found in glutathione (GSH) content depending on the temperature and treatment with the tested organic compounds. CHS NCs loaded with Pro and GB were effective at increasing the amount of phenols under stress temperature conditions. We noted that a significant increase in the antioxidant activity of plants at 4 °C occurred after priming with Cys, CHS-Cys NCs, Pro and CHS-Pro NCs, and the CHS nanocomposites were more effective in this respect. Both low-temperature stress and foliar spraying of lettuce with various organic compounds caused changes in the activity of antioxidant enzymes. Two forms of dismutase (SOD), iron superoxide dismutase (FeSOD) and copper/zinc superoxide dismutase (Cu/ZnSOD), were identified in extracts from the leaves of iceberg lettuce seedlings. The application of the tested organic compounds, alone or in combination with CHS, increased the amount of malondialdehyde (MDA) in plants grown under controlled temperature conditions. Chilling caused an increase in the content of MDA, but some organic compounds mitigated the impact of low temperature. Compared with that of plants subjected to 20 °C, the fresh weight of plants exposed to chilling decreased. However, the tested compounds caused a decrease in fresh weight at 4 °C compared with the corresponding control samples. An interesting exception was the use of Cys, for which the difference in the fresh weight of plants grown at 20 °C and 4 °C was not statistically significant. After Cys application, the dry weight of the chilled plants was greater than that of the chilled control plants but was also greater than that of the other treated plants in this group. To our knowledge, this is the first report demonstrating that engineered chitosan–amino acid nanocomposites could be applied as innovative protective agents to mitigate the effects of chilling stress in crop plants.

Paradise by the far-red light: Far-red and red:blue ratios independently affect yield, pigments, and carbohydrate production in lettuce, Lactuca sativa.

In controlled environment agriculture, customized light treatments using light-emitting diodes are crucial to improving crop yield and quality. Red (R; 600-700 nm) and blue light (B; 400-500 nm) are two major parts of photosynthetically active radiation (PAR), often preferred in crop production. Far-red radiation (FR; 700-800 nm), although not part of PAR, can also affect photosynthesis and can have profound effects on a range of morphological and physiological processes. However, interactions between different red and blue light ratios (R:B) and FR on promoting yield and nutritionally relevant compounds in crops remain unknown. Here, lettuce was grown at 200 µmol m-2 s-1 PAR under three different R:B ratios: R:B87.5:12.5 (12.5% blue), R:B75:25 (25% blue), and R:B60:40 (40% blue) without FR. Each treatment was also performed with supplementary FR (50 µmol m-2 s-1; R:B87.5:12.5+FR, R:B75:25+FR, and R:B60:40+FR). White light with and without FR (W and W+FR) were used as control treatments comprising of 72.5% red, 19% green, and 8.5% blue light. Increasing the R:B ratio from R:B87.5:12.5 to R:B60:40, there was a decrease in fresh weight (20%) and carbohydrate concentration (48% reduction in both sugars and starch), whereas pigment concentrations (anthocyanins, chlorophyll, and carotenoids), phenolic compounds, and various minerals all increased. These results contrasted the effects of FR supplementation in the growth spectra; when supplementing FR to different R:B backgrounds, we found a significant increase in plant fresh weight, dry weight, total soluble sugars, and starch. Additionally, FR decreased concentrations of anthocyanins, phenolic compounds, and various minerals. Although blue light and FR effects appear to directly contrast, blue and FR light did not have interactive effects together when considering plant growth, morphology, and nutritional content. Therefore, the individual benefits of increased blue light fraction and supplementary FR radiation can be combined and used cooperatively to produce crops of desired quality: adding FR increases growth and carbohydrate concentration while increasing the blue fraction increases nutritional value.

Silver Nanoparticles Reduce the Toxic Effects of Cadmium on Datura stramonium Callus Culture

Cadmium (Cd) is one the most toxic metals harmful for both animals and plants. In this study, we test whether silver nanoparticles (AgNPs) can protect plants from cadmium toxicity. AgNPs treatments (0 and 100 μg/L) were applied to Datura stramonium calli grown in different cadmium metal environments (0, 150, 300, 450, and 600 μM). Cd application led to a decrease in fresh weight (FW), dry weight (DW), relative water content (RWC), total chlorophyll content (Chl.T), tolerance index (Ti), and bioaccumulation factor (BCF). The Cd treatment increased the hydrogen peroxide (H2O2), catalase (CAT), and guaiacol peroxidase (GPX) contents and Cd accumulation (Cd con). These results show the positive role of AgNPs in protecting the callus cultures from oxidative stress. The AgNPs pretreatment improved the growth of tissue cultures compared to nontreatment, increasing FW, DW, RWC, and Chl.T; the highest CAT and GPX activities were detected in the AgNPs pretreatment condition; and AgNPs pretreatment improved Ti and BCF, despite increased Cd. Also, this treatment caused a decrease in H2O2. Based on these results, we propose AgNPs as an effective agent to reduce the toxic effects of Cd metal on D. stramonium.

Effect of plant growth promoting rhizobacteria on the vase life of gerbera flowers

In this study, the effects of three different bacterial isolates added to the vase solution on the vase life were investigated. All three bacterial isolates significantly increased the vase life of gerbera cut flowers. While the vase life of the flowers in the control solution was 3 days, this period reached up to 11 days in the flowers kept in the vase containing bacteria. Daily water uptake decreased with increasing time in vase in all treatments. Although there were some differences between treatments in terms of daily water uptake, it has been determined that bacteria application does not have a significant effect on water uptake. The relative fresh weight decreased with increasing time in the vase. For example, in the solution containing Z7 bacteria, which allows the flowers to live the longest, the flower weight, which was 89 g on August 11, decreased day by day and decreased to 68 g on August 23. Bacteria applications slowed the rate of decrease in fresh weight. Bacillus cereus found to be more effective than other bacterial isolates in slowing fresh weight decrease.

Morpho-physiological characterization and metabolic profiling of rice lines for immunity to counter Helminthosporiumoryzae

Heliminthosporium oryzae is a necrotrophic fungal pathogen that effect rice crops grown on millions of hectares. We evaluated nine newly establishing rice lines and one local variety for resistance against H. oryzae. Significant (P ≤ 0.05) differences in response to pathogen attack were recorded in all rice lines. Maximum disease resistance was recorded in Kharamana under pathogen attack as compared to uninfected plants. A comparison of decline in shoot length revealed that Kharamana and Sakh experienced minimum lost (9.21%, 17.23%) in shoot length respectively against control while Binicol exhibited highest reduction (35.04%) in shoot length due to H. oryzae attack. Post-infection observations of shoot fresh weight revealed 63% decline in Binicol and declared it as the most susceptible rice line. Sakh, Kharamana and Gervex exhibited minimum fresh weight decrease (19.86%, 19.24% and 17.64% respectively) as compared to other lines under pathogen attack. Maximum chlorophyll-a contents were recorded in Kharamana under control and post pathogen attackconditions. Following the inoculation of H. oryzae, SOD was increased up to 35% and 23% in Kharamana and Sakh. However, minimum POD activity was recorded in Gervex followed by Swarnalata, Kaosen and C-13 in non-inoculated and pathogen-inoculated plants. Significant decrease in ascorbic acid contents (73.7% and 70.8%) was observed in Gervex and Binicol that later contributed in their susceptibility to H. oryzae attack. Pathogen attack caused Significant (P ≤ 0.05) changes in secondary metabolites in all rice lines but minimum total flavonoids, anthocyanin and lignin were observed in Binicol in uninfected plants and attested its susceptibility to pathogen. In post-pathogen attack conditions, Kharamana showed best resistance against pathogen by exhibiting a significantly high and maximum value of morpho-physiological, and biochemical attributes. Our findings suggest that tested resistant lines can be further explored for multiple traits including molecular regulation of defense responses to breed immunity in rice varieties.

English

Soil salinity is one of the most significant stressors limiting plant productivity in the world's irrigated and cultivated agricultural lands. Plants have a wide range of adaptations and mitigation strategies to overcome salinity effects. It is possible to mitigate the effects of salt stress by the development of resistant cultivars and more efficient use of available resources. However, these methods are time-consuming and costly. Solutions to salinity issues need to be developed that are both straightforward and inexpensive, as they will likely only be implemented temporarily. In this study, the effects of the different salinity levels (Control, 20mM, 40mM, 60mM, 80mM, and 100mM) on citrus rootstocks were determined. In the citrus growing regions, the sour orange, trifoliate orange, and Carrizo citrange were the three most popular rootstocks. As a result of the present study, the sour orange was found to have the lowest decline in plant height (13.36%), leaf area (31.19%), and root length (8.13%), while the trifoliate orange had the lowest decrease in fresh weight of the plant (6.82%) and root (4.42%). Trifoliate orange was shown to have the highest levels of catalase activity, whereas superoxide dismutase and peroxidase activities were found to be highest in Carrizo citrange and sour orange, respectively. The highest concentration of plant nutrients was found in the Carrizo citrange. Therefore, sour orange was discovered to be more salinity tolerant in terms of morphological traits, physiological qualities, biochemical composition, and plant nutrition than trifoliate orange and Carrizo citrange. For areas with high salt levels, growing citrus on sour orange rootstock may be a viable alternative

Selenium Uptake by Lettuce Plants and Se Distribution in Soil Chemical Phases Affected by the Application Rate and the Presence of a Seaweed Extract-Based Biostimulant

To tackle selenium (Se) malnutrition, biofortification is among the proposed strategies. A biostimulant application in soils is thought to support a plant’s growth and productivity. Biofortification with Se(VI) may lead to a leaching hazard due to the high mobility of Se(VI) in the soil environment. In this study, the effect of the application of two Se(VI) rates—5 and 10 mg kg−1 soil—and a biostimulant on the Se uptake by lettuce plants and on the Se(VI) distribution in soil fractions following the plants harvest, was investigated. Phosphorus (P) and sulfur (S) concentrations in plants were also determined. A high Se(VI) rate suppressed plant growth, leading to a significant fresh weight decrease from 12.28 to 7.55 g and from 14.6 to 2.43 g for the control and high Se(VI) without and with biostimulants, respectively. Impaired plant growth was verified by the SPAD, NDVI and NDRE measurements. The significantly highest Se concentration in plants, 325 mg kg−1, was recorded for the high Se(VI) rate in the presence of the biostimulant. Compared to controls, the low Se(VI) rate significantly decreased P and increased the S concentrations in plants. The post-harvest soil fractionation revealed that, in the presence of the biostimulant, the Se(VI) soluble fraction increased from 0.992 to 1.3 mg kg−1 at a low Se(VI) rate, and decreased from 3.T85 to 3.13 mg kg−1 at a high Se(VI) rate. Nevertheless, at a low Se(VI) rate, 3.6 and 3.1 mg kg−1 of the added Se(VI) remained in the soil in less mobile forms, in the presence or absence of the biostimulant, respectively. This study indicated that the exogenous application of Se in soil exerted dual effects on lettuce growth and Se availability, depending on the level of selenate applied.

Seed-Borne Erwinia persicina Affects the Growth and Physiology of Alfalfa (Medicago sativa L.).

Seed-borne Erwinia persicina can be transmitted globally via alfalfa (Medicago sativa L.) seed trade, but there is limited information about the impact of this plant-pathogenic bacterium on alfalfa plants. In this study, strain Cp2, isolated from alfalfa seeds, was confirmed by whole-genome sequencing to belong to E. persicina. Subsequently, the effects of Cp2 on alfalfa growth and physiology were evaluated by constructing a rhizosphere infection model. Strain Cp2 had a strong inhibitory effect on the elongation and growth of alfalfa roots, which was very unfavorable to these perennial plants. Furthermore, an increased number of leaf spots and yellowing symptoms were observed in plants of the Cp2 group from day 10 to day 21 and the strain Cp2 was re-isolated from these leaves. Correlation between growth and photosynthetic parameters was analyzed and the significant decreases in fresh weight and root and plant lengths in the Cp2 group were related to the marked reduction of chlorophyll b, carotenoid, transpiration rate, and stomatal conductance of leaves (r > 0.75). In addition, nine physiological indicators of root, stem, and leaf were measured in the plants 21 days after treatment with Cp2. The physiological response of root and leaf to Cp2 treatment was stronger than that of stem. The physiological indicators with the greatest response to Cp2 infection were further explored through principal component analysis, and superoxide dismutase, peroxidase, ascorbate peroxidase, and soluble protein showed the greatest changes in roots, stems, and leaves (P < 0.001). Among tissues, the commonality was the change of soluble protein. Therefore, soluble protein is speculated to be a physiological marker during alfalfa–E. persicina interactions. These findings indicate that once E. persicina spreads from alfalfa seeds to the rhizosphere, it can invade alfalfa roots and cause disease. This study demonstrates that this plant pathogenic bacterium may be a potential threat to new environment when they spread via seed trade and these “dangerous hitchhikers” warrant further attention, especially in the study of bacterial diseases in pasture-based production systems.

Selenium improved antioxidant response and photosynthesis in fragrant rice (Oryza sativa L.) seedlings during drought stress.

Drought stress substantially influences the growth and development of many crops. The present study was conducted to investigate the effects of exogenous selenium on the growth, photosynthesis and antioxidant response of fragrant rice seedlings under drought stress. In a pot experiment, fragrant rice seedlings were subjected to drought stress (soil water potential was controlled at - 0.025 ± 5MPa) and foliar application of selenium (Se) at 0, 10, 30, and 50μmol L-1. Rice seedlings not exposed to drought stress and Se were used as control. Exposure of fragrant rice seedlings to drought stress resulted in significant (P < 0.05) decrease in fresh weight, dry weight, plant height and stem diameter relative to the control. Total chlorophyll, chlorophyll a, chlorophyll b and carotenoid were 20.54-27.24%, 20.82-26.83%, 19.45-29.07% and 21.49-29.17% lower with drought stress treatment compared to CK. Drought stress also significantly (P < 0.05) decreased net photosynthetic rate and soluble protein content. However, Se treatments (30 and 50μmol L-1) substantially improved fresh weight and dry weight of fragrant rice seedlings under drought stress. Net photosynthetic rate, activities of antioxidant enzymes (GPX, SOD and CAT) and soluble protein content in rice seedlings under drought stress improved due to Se treatment. Higher transcript levels of antioxidant-related genes (GPX1, GPX4, CATA and CATC) were also observed with Se treatment.

INHIBITION OF RED CHILIES RIPENING PROCESS AT FRESH WEIGHT AND TOTAL CARBOHYDRATE CONTENT BY RED LIGHT

The research was conducted in a factorial experiment with factor A: far-red light treatment with 2 levels: control (without far-red light), and treatment (far-red light). Factor B was a time of observation with 3 levels: 4, 6, 8 days after wrapping. Wrapping each detached fruit in a combination of four layers of blue-colored plastic, one layer of green-colored plastic, and two layers of red-colored plastic resulted in a red light treatment. Transmission measurement of that plastic combined with a spectrophotometer at wavelength 700-735 nm was 75%. To deter fresh weight, each fruit was weighted with an analytical balance. Total soluble carbohydrate content was determined by the phenol-sulfuric method and counted based on the glucose standard curve (mg/gram tissue). Analysis of variance was conducted at a 5% significant level, and if the interaction was significant, then continued with simple effect determination at a 5% significant level by the F test. The fresh weight average of the soluble carbohydrate content of treated fruits was higher than the control. The fresh weight of chili fruits was relatively constant during observation of both treated and controlled fruits. The total soluble carbohydrate content average relatively did not differ between treated and control fruits. Total soluble carbohydrate content was increased 6 days after treatment and decreased 8 days after treatment. The result of this research concluded that red light inhibited the ripening process of chili fruits by slowing the decrease of fresh weight.

Pre- and/or Postharvest Silicon Application Prolongs the Vase Life and Enhances the Quality of Cut Peony (Paeonia lactiflora Pall.) Flowers.

Peony is an important ornamental plant and has become increasingly popular for cut flower cultivation. However, a short vase life and frequent poor vase quality severely restrict its market value. The study described herein was conducted to investigate the effects of silicon application on the vase life and quality of two cut peony (Paeonia lactiflora Pall.) cultivars, ‘Taebaek’ and ‘Euiseong’. For pre- and/or postharvest silicon application, four experimental groups based on treatments were designed. With silicon treatment, the relevant growth attributes, including the shoot and leaf lengths, stem and bud diameters as well as the leaf width were all remarkably increased. In the postharvest storage, the addition of silicon to the holding solution in the vase was able to significantly extend vase life, delay fresh weight decrease, and improve vase quality, as characterized by the antioxidant enzyme activities and mechanical stem strength. Taken together, silicon application, regardless of the approach, was able to effectively prolong the vase life and enhance the quality of cut peony flowers.

Changes in growth, yield and nutrient status of nine vegetables grown onto a soil substrate with two-phase olive mill waste sludge addition

The present experimental work was carried out in order to evaluate changes in growth, yield and nutrient status of nine vegetables grown on soil substrates with four doses (0%, 2.5%, 5% and 10% v/v) of a two-phase olive mill waste (OMW) sludge as an alternative strategy of their handling. Growth results showed that under 2.5% OMW, zucchini and cucumber mini plants tended to increase their total plant fresh weight (FW) whereas cucumber long and large-sized tomato presented the opposite trend. Under 5% OMW, watermelon, cucumber mini and zucchini presented the lowest total plant FW change whereas pepper and large-sized tomato the greatest decrease. Under 10% OMW addition, large-sized tomato and pepper, followed by watermelon, showed the greatest total plant FW decrease whereas all plum tomato plants under 10% OMW died at the end of the experiment. Yield results showed that among the vegetables tested, melon followed by large-sized tomato, plum tomato and cucumber long presented higher yield increase, eggplant the lowest one whereas watermelon produced no fruits. Based on the fact that yield gathers the greatest commercial interest for vegetable cultivation, we could assume that the addition of either 2.5% OMW for the majority of vegetable tested (except eggplant and watermelon) or 5% for melon, plum tomato, large-sized tomato and cucumber long could provide a sustainable alternative methodology for OMW management. Regarding plant nutrient status, the majority of the nutrient element concentrations determined revealed their non-significant change.

English

β-expansin 2 (EXPB2) gene induces drought tolerance in different plant species including maize. Different epigenetic mechanisms like DNA methylation, histone modification and RNA interference affect the gene activities under stress conditions. DNA methylation, an important epigenetic mechanism, could be involved in the regulation of ZmEXPB2 gene under drought stress in maize. Plants of drought sensitive variety „Jalal‟ were grown till 4th leaf stage under well-watered conditions. At 5th leaf stage, plants were divided in two groups i.e., well-watered (100% water holding capacity) or drought stress (0% water holding capacity for 15 days). Plants subjected to drought stress showed clear signs of stress by significant decrease in fresh weight of whole plant, 6th leaf length, stunted secondary root growth and increased primary root length. DNA methylation profile of three regions (denoted as -1.7 k, -1.3 k and -0.8 k) in the promoter of ZmEXPB2 gene, of root DNA, were evaluated. Under well-watered conditions, heterogeneity in DNA methylation profile along the promoter sequence was observed. Regions -1.7 k and -1.3 k were methylated whereas the region -0.8 k was nonmethylated. After the comparison of DNA methylation profile of well-watered and drought stress plants, no change in -1.7 k and -0.8 k regions was observed. However, the -1.3k region had significant decrease in the DNA methylation at symmetric cytosine sites i.e., cytosine-guanine (CG) dinucleotides and cytosine-adenine/cytosine/thymine-guanine (CHG where H = A, C or T) trinucleotide and significant increase at asymmetric cytosine sites (CHH) under the stress condition. In addition, significant increase in the gene expression of ZmEXPB2 under drought was also observed. In conclusion, drought stress conditions induce DNA hypomethylation at CG, and CHG sites and DNA hypermethylation at CHH sites in the middle region of the promoter of ZmEXPB2 gene. This shift can be associated with the up regulation of ZmEXPB2 gene which in turn increased primary root length as a plant stress response mechanism. © 2021 Friends Science Publishers

Interactive effects of salinity and drought stress on photosynthetic characteristics and physiology of tomato (Lycopersicon esculentum L.) seedlings

Sufficient quantity and quality of water are essential for vegetable production.Evaluating the individual and combined effects of drought and salt stress on plant establishment may help inform management of plant production in terms of stabilizing yield. This study investigates the effects of drought and salt stress on plant growth, nutrition elements, and select physiological parameters of tomato (Lycopersicon esculentum L. cv. H2274) through a pot experiment under greenhouse conditions. Drought stress was applied to tomato seedlings at 3 different levels of irrigation: D0 (control), D1, and D2 at 100%, 75%, and 50% field capacity, respectively. Salinity stress was applied at 3 different doses S0, S1, and S2 at 0 mM, 100 mM, and 150 mM NaCl, respectively. The effects of salinity, drought and their co-occurring stresses on growth, physiological and photosynthetic properties of tomato seedlings were statistically significant. Photosynthetic rate (Pn), stomatal conductance (gs), chlorophyll reading value (CRV), and plant dry weight (DW) decreased with salt and drought treatments. However, electrolyte leakage (EL) of the leaves increased with increasing salt and drought treatments. Fresh weight (FW) of the tomato seedlings decreased 67% under the 150 mM NaCl treatment (S-2), and decreased 69% under severe drought (D2); however, the interactive effects of these two treatments together (S2D2) resulted in an 80% decrease in FW. Furthermore, dry weight (DW) decreased 80% in the S2D2 treatment compared to the control. In general, both drought and salinity altered the mineral nutrient composition by decreasing N, P, K, Fe, Ca and Z content of the tomato seedlings, but Na, B and Cl content increased. These results show that effects of salinity and drought on tomato seedlings were less detrimental for plant establishment than the combined effects of the two stresses together.

Overexpression of Rice Genes OsNRT1.1A and OsNRT1.1B Restores Chlorate Uptake and NRT2.1/NAR2.1 Expression in Arabidopsis thaliana chl1-5 Mutant

Nitrogen uptake by plants is a key step for efficient nitrogen use, which affects plant growth and yield. Arabidopsis thaliana gene NRT1.1 was identified as a transporter related to nitrate (NO3−) signaling and uptake. In rice, three orthologs of NRT1.1, named OsNRT1.1A, OsNRT1.1B, and OsNRT1.1C, have been identified. This study evaluated the potential of OsNRT1.1A, OsNRT1.1B, and OsNRT1.1C in NO3− signaling and uptake through overexpression in the Arabidopsis chl1-5 mutant. The expression of OsNRT1.1A, OsNRT1.1B, and OsNRT1.1C was evaluated in the roots and shoots of rice cultivated with NO3− or NH4+. OsNRT1.1A was expressed in the roots and shoots cultivated with NO3− and NH4+. OsNRT1.1B was expressed predominantly in roots of rice cultivated with NO3−, while the expression of OsNRT1.1C was low in roots and shoots. Arabidopsis chl1-5 plants were transformed by the floral dip method using Agrobacterium tumefaciens to overexpress OsNRT1.1A and the alternative splicing product named OsNRT1.1As, OsNRT1.1B, and OsNRT1.1C. The chlorate test showed the ability of OsNRT1.1A, OsNRT1.1B or OsNRT1.1C to take up chlorate, as evidenced by the decrease in fresh weight. The OsNRT1.1B lineages presented higher toxicity to chlorate. Gene expression analyses showed that the insertion of OsNRT1.1A and OsNRT1.1B into Arabidopsis chl1-5 induced the expression of NRT2.1 and NAR2.1. OsNRT1.1As overexpression did not significantly affect the expression of NRT2.1 and NAR2.1. The results show the differential ability of NRT1.1 orthologs in rice to take up chlorate and signal the expression of other nitrate transporters, which may affect the efficiency of nitrogen utilization and its uptake.

Substrate and Plant Genotype Strongly Influence the Growth and Gene Expression Response to Trichoderma afroharzianum T22 in Sugar Beet.

Many strains of Trichoderma fungi have beneficial effects on plant growth and pathogen control, but little is known about the importance of plant genotype, nor the underlying mechanisms. We aimed to determine the effect of sugar beet genotypic variation on Trichoderma biostimulation. The effect of Trichoderma afroharzianum T22 on sugar beet inbred genotypes were investigated in soil and on sterile agar medium regarding plant growth, and by quantitative reverse transcriptase-linked polymerase chain reaction (qRT-PCR) analysis for gene expression. In soil, T22 application induced up to 30% increase or decrease in biomass, depending on plant genotype. In contrast, T22 treatment of sterile-grown seedlings resulted in a general decrease in fresh weight and root length across all sugar beet genotypes. Root colonization of T22 did not vary between the sugar beet genotypes. Sand- and sterile-grown roots were investigated by qRT-PCR for expression of marker genes for pathogen response pathways. Genotype-dependent effects of T22 on, especially, the jasmonic acid/ethylene expression marker PR3 were observed, and the effects were further dependent on the growth system used. Thus, both growth substrate and sugar beet genotype strongly affect the outcome of inoculation with T. afroharzianum T22.

Biochemical Response of Oakleaf Lettuce Seedlings to Different Concentrations of Some Metal(oid) Oxide Nanoparticles

Nanoparticles (NPs) significantly modify the physiological functions and metabolome of plants. The purpose of the study was to investigate the effect of CeO2, Fe2O3, SnO2, TiO2, and SiO2 nanoparticles, applied in foliar spraying of oakleaf lettuce at concentrations 0.75% to 6%, on the antioxidant enzyme activity and content of non-enzymatic antioxidants, chlorophyll pigments, fresh weight (FW) and dry weight (DW). It was found that 3% Fe2O3-NPs caused a 27% decrease in fresh weight compared to control plants. Fe2O3-NPs caused an increase in dry weight (g 100 g−1 FW) when compared to the control for all concentrations, but total DW (g per plant) was similar for all NPs treatments. Significant increases in chlorophyll a + b content after treatment with 1.5% and 6% SiO2-NPs, 3% Fe2O3-NPs, and 3% TiO2-NPs were noted. Fe2O3-NPs caused a significant increase in the activity of ascorbate peroxidase, guaiacol peroxidase, and catalase (only for 3% Fe2O3-NPs). SnO2-NPs decreased ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) activity (for all tested concentrations) but increased catalase (CAT) activity when a 3% suspension of these NPs was applied. The level of glutathione (GSH) increased due to application of all metal/metalloid oxides, with the exception of SnO2-NPs. When all concentrations of TiO2-NPs were applied, L-ascorbic acid increased significantly, as well as increasing at higher concentrations of SiO2-NPs (3% and 6%) and at 0.75% and 3% Fe2O3-NPs. SiO2-NPs and TiO2-NPs significantly elevated the carotenoid and total phenolic content in treated plants compared to the control. The total antioxidant capacity of plants treated with 3% CeO2-NPs was almost twice as high as that of the control.

Genotype-Dependent Differences between Cereals in Response to Manganese Excess in the Environment

Industrial and agronomic activities lead to oversupply and accumulation of elements in the environment. Relatively little is known about mechanisms of manganese (Mn) triggered stress. In this study, different cultivars of popular cereals wheat, oat, and barley were investigated for their response to excessive Mn. Manganese ions (MnCl2) at 5 and 10 mM were applied to the grains and then to the media on which the plants grew until they developed their first leaf. It was performed ICP MS aiming to understand the mechanism of manganese stress in susceptible and resistant cultivar. Under Mn-stress a decrease in fresh weight of plants was observed, also differences in water content in first leaves, an increase in superoxide dismutases (SOD) and peroxidases (POX) activity, and a significant rise in catalase (CAT) was only characteristic for barley. Increasing Mn concentration resulted in enhancing of manganese superoxide dismutase (Mn-SOD) and copper, zinc superoxide dismutase (Cu/Zn-SOD) bands intensity. The increase in proline content, depending on a balance between pyrroline-5-carboxylate synthase (P5CS), ornithine-d-aminotransferase (OAT), and proline dehydrogenases (PHD) activities, indicated osmotic disorders in all plants and differentiated the studied cereals. Microscopic observations of changes in the structure of plastids and starch accumulation in Mn presence were particularly visible in sensitive cultivars. The study ranked the tested cereals in terms of their tolerance to Mn from the most tolerant wheat through barley and the least tolerant oats.

Phytotoxicity of Class B aqueous firefighting formulations, Tridol S 3 and 6% to Lemna minor

Abstract Phytotoxicity of Class B aqueous firefighting concentrates, Tridol-S 3%, and Tridol-S 6% to Lemna minor were studied using the parameters such as the frond number, biomass production in terms of dry weight, chlorophyll content and proline accumulation. Decrease in fresh weight, dry weight, and chlorophyll pigments; increase in proline content suggested that both the firefighting concentrates are potentially toxic to L. minor. Relative growth rate (RGR) also showed a similar pattern of toxicity with the corresponding increase in test concentrations of both the compounds. The EC50 values show Tridol-S 3% was more toxic than Tridol-S 6% in terms of frond number and dry weight. From our findings, it is clear that L. minor is highly sensitive to the exposure of firefighting foams, and is suitable for its use as an indicator organism for assessing the aquatic toxicity of aqueous firefighting foams. This study clearly suggests that the migration of Tridol AFFF into aquatic environments is likely to have detrimental effects on the aquatic flora. To the best of our knowledge, this study constitutes the first report on the phytotoxicity of firefighting concentrates, Tridol-S 3% and Tridol-S 6% to Lemna minor L.