Phosphate-assisted phytoremediation of arsenic by Brassica napus and Brassica juncea: Morphological and physiological response

In this study, we examined the potential role of phosphate (P; 0, 50, 100 mg kg^?1) on growth, gas exchange attributes, and photosynthetic pigments of Brassica napus and Brassica juncea under arsenic (As) stress (0, 25, 50, 75 mg kg^?1) in a pot experiment. Results revealed that phosphate supplementation (P100) to As-stressed plants significantly increased shoot As concentration, dry biomass yield, and As uptake, in addition to the improved morphological and gas exchange attributes and photosynthetic pigments over P0. However, phosphate-assisted increase in As uptake was substantially (up to two times) greater for B. napus, notably due to higher shoot As concentration and dry biomass yield, compared to B. juncea at the P100 level. While phosphate addition in soil (P100) led to enhanced shoot As concentration in B. juncea, it reduced shoot dry biomass, primarily after 50 and 75 mg kg^?1 As treatments. The translocation factor and bioconcentration factor values of B. napus were higher than B. juncea for all As levels in the presence of phosphate. This study demonstrates that phosphate supplementation has a potential to improve As phytoextraction efficiency, predominantly for B. napus, by minimizing As-induced damage to plant growth, as well as by improving the physiological and photosynthetic attributes.     

Feasibility of Using Phytoextraction to Remediate a Compost-Based Soil Contaminated with Cadmium

Greenhouse and in-situ field experiments were used to determine the potential for phytoextraction to remediate soil contaminated with Cd from municipal solid waste (MSW) and sewage sludge (SS) compost application at a Peterborough (Canada) site. For the greenhouse experiment, one native (Chenopodium album) and three naturalized (Poa compressa, Brassica juncea, Helianthus annuus) plant species were planted in soil containing no detectable Cd (<1.0 μg·g^?1), and soil from the site containing low (5.0 ± 0.3 μg·g^?1 Cd), and high (16.5 ± 1.2 μg?g^?1 Cd) Cd concentrations. Plant uptake was low (root BAFs ≤0.5) for all species except P. compressa in the low Cd treatment (BAF 1.0). Only B. juncea accumulated Cd in its shoots, though uptake was low (BAF ≤0.3). For the field experiment, B. juncea was planted in-situ in areas of low and high Cd concentrations. Brassica juncea Cd uptake was low (root and shoot BAFs <0.2) in both treatments. Sequential extraction analysis indicated that Cd is retained primarily by low bioavailability soil fractions, and phytoextraction is therefore not feasible at this site. Though low Cd bioavailability has negative implications for Cd phytoextraction from MSW/SS compost-based soils, it may limit receptor exposure to Cd sufficiently to eliminate the potential for risk at this site.     

PLANT GROWTH REGULATORS ENHANCE GOLD UPTAKE IN BRASSICA JUNCEA

The use of plant growth regulators is well established and they are used in many fields of plant science for enhancing growth. Brassica juncea plants were treated with 2.5, 5.0 and 7.5 μM auxin indole-3-butyric acid (IBA), which promotes rooting. The IBA-treated plants were also sprayed with 100 μM gibberellic acid (GA₃) and kinetin (Kin) to increase leaf-foliage. Gold (I) chloride (AuCl) was added to the growth medium of plants to achieve required gold concentration. The solubilizing agent ammonium thiocyanate (1 g kg^?1) (commonly used in mining industries to solubilize gold) was added to the nutrient solution after six weeks of growth and, two weeks later, plants were harvested. Plant growth regulators improved shoot and root dry biomass of B. juncea plants. Inductively Coupled Plasma Optical Emission Spectrometry analysis showed the highest Au uptake for plants treated with 5.0 μM IBA. The average recovery of Au with this treatment was significantly greater than the control treatment by 45.8 mg kg^?1 (155.7%). The other IBA concentrations (2.5 and 7.5 μM) also showed a significant increase in Au uptake compared to the control plants by 14.7 mg kg^?1 (50%) and 42.5 mg kg^?1 (144.5%) respectively. A similar trend of Au accumulation was recorded in the roots of B. juncea plants. This study conducted in solution culture suggests that plant growth regulators can play a significant role in improving phytoextraction of Au.     

Assessment of Metal Uptake Capacity of Castor Bean and Mustard for Phytoremediation of Nickel from Contaminated Soil

The effect of increasing level of nickel (Ni) in soil was studied on biomass production, antioxidants, and Ni bioaccumulation and its translocation in castor bean (Ricinus communis) as well as Indian mustard (Brassica juncea) in similar agroclimatic conditions. The plants were exposed to 25, 50, 75, 100, and 150 mg Ni kg^?1 soil for up to 60 days. It was found that R. communis produced higher biomass during the same period at all the contamination levels than B. juncea, and reduction in fresh and dry weights due to the metal contamination in soil was significantly lower in R. communis than in B. juncea. Proline and malondialdehyde in the leaves increased with increase in Ni level in both the species, whereas soluble protein content was found decreased. A correlation between the protein and MDA contents in the leaves and Ni contamination levels revealed that higher r² values for protein and MDA were found in case of B. juncea, which indicates more toxic effects of the metal in this species. R. communis was found to have enhanced proline accumulation (higher correlation value, r²) at different Ni contamination levels. The bioaccumulation of Ni was higher in B. juncea on the basis of the per unit biomass; however, the total metal accumulation per plant was much higher in R. communis than in B. juncea during the same growing periods. The translocation of Ni from roots to shoots was higher in B. juncea at all Ni concentrations. R. communis appeared more tolerant and capable to clean more Ni from the contaminated soil in a given time and also in one crop cycle.     

Involvement of Asada-Halliwell Pathway During Phytoremediation of Chromium (VI) in Brassica juncea L. Plants

Brassica juncea (Indian mustard) L. plants were exposed to different concentrations (0.0, 0.1, 0.3 and 0.5 mM) of Chromium (Cr) and harvested after 30 and 60 days of sowing for the analysis of growth parameters, metal uptake and oxidative stress markers. Significant accumulation of Cr (VI) by B. juncea L. plants resulted in the reduced growth and modulations in the pool of various biochemical stress markers. The toxic effects of Cr (VI) on growth and other stress markers (protein content, lipid peroxidation and antioxidative enzymes viz.SOD, CAT, POD, APOX, GR, DHAR and MDHAR) in B. juncea L. were observed to be concentration and time dependent. Effect of Cr (VI) on biochemical parameters was differential and their maximum activities of SOD, POD, APX, GR, DHAR and lipid peroxidation were recorded at 0.5 mM concentration in 30 days old plants. Whereas, trend in the activities of most of the stress markers was reversed in 60 days old plants. The results obtained from the study suggested that Cr (VI) stress inhibited growth of B. juncea L. plants is directly interrelated with its accumulation and resulted in the modulation in activities of various stress markers.     

Changes in C–N metabolism under elevated CO2 and temperature in Indian mustard (Brassica juncea L.): an adaptation strategy under climate change scenario

The present study was performed to investigate the possible role of carbon (C) and nitrogen (N) metabolism in adaptation of Indian mustard (Brassica juncea L.) growing under ambient (370 ± 15 ppm) and elevated CO₂ (700 ± 15 ppm), and jointly in elevated CO₂ and temperature (30/22 °C for day/night). The key enzymes responsible for C–N metabolism were studied in different samples of Brassica juncea L. collected from ambient (AMB), elevated (ELE) and ELExT growth conditions. Total percent amount of C and N in leaves were particularly estimated to establish a clear understanding of aforesaid metabolism in plant adaptation. Furthermore, key morphological and physiological parameters such as plant height, leaf area index, dry biomass, net photosynthetic rate, stomatal conductance, transpiration, total protein and chlorophyll contents were also studied in relation to C/N metabolism. The results indicated that the C-metabolizing enzymes, such as (ribulose-1,5-bisphosphate carboxylase/oxygenase, phosphoenolpyruvate carboxylase, malate dehydrogenase, NAD-malic enzyme, NADP-malic enzyme and citrate synthase) and the N-metabolizing enzymes, such as (aspartate amino transferase, glutamine synthetase, nitrate reductase and nitrite reductase) showed significantly (P < 0.05) higher activities along with the aforesaid physiological and biochemical parameters in order of ELE > ELExT > AMB growth conditions. This is also evident by significant (P < 0.05) increase in percent contents of C and N in leaves as per said order. These findings suggested that improved performance of C–N metabolism could be a possible approach for CO₂ assimilation and adaptation in Brassica juncea L. against elevated CO₂ and temperature prevailing in climate change scenarios.     

Isolation of phytase-producing bacteria from Himalayan soils and their effect on growth and phosphorus uptake of Indian mustard (Brassica juncea)

Phytase-producing bacteria (PPB) is being investigated as plant growth promoting rhizobacteria (PGPR) to improve the phosphorus (P) nutrition and growth of plants grown in soil with high phytate content. Phytate is dominant organic P forms in many soils and must be hydrolyzed to be available for plants. Indian mustard (Brassica juncea) is a plant with economic importance in agriculture and phytoremediation, therefore biotechnological tools to improve growth and environmental stress tolerance are needed. In this study, we isolated and characterized PPB from Himalayan soils and evaluated their effect on growth and P uptake by B. juncea under greenhouse conditions. Sixty five PPB were isolated and based on phytate hydrolysis, three efficient PPB were chosen and identified as Acromobacter sp. PB-01, Tetrathiobacter sp. PB-03 and Bacillus sp. PB-13. Selected PPB showed ability to grow at wide range of pH, temperature and salt concentrations as well as to harbour diverse PGPR activities, such as: solubilization of insoluble Ca-phosphate (193–642 μg ml^?1), production of phytohormone indole acetic acid (5–39 μg ml^?1) and siderophore. Tetrathiobacter sp. PB-03 and Bacillus sp. PB-13 showed 50 and 70 % inhibition of phytopathogen Rhizoctonia solani, respectively. Greenhouse potting assay also showed that the bacterization of B. juncea seeds with Tetrathiobacter sp. PB-03 and Bacillus sp. PB-13 significantly increased the biomass and P content in 30 days old seedlings. This study reveals the potential of PPB as PGPR to improve the growth of B. juncea.     

Gold-nanoparticle induced enhancement in growth and seed yield of <Emphasis Type="Italic">Brassica juncea</Emphasis>

Experiments were carried out to determine the effect of Gold-nanoparticles on the growth profile and yield of Brassica juncea, under field conditions. Five different concentrations (0, 10, 25, 50 and 100 ppm) of Gold-nanoparticles were applied through foliar spray. Presence of Gold-nanoparticles in the leaf tissues was confirmed through atomic absorption spectroscopy. Various growth and yield related parameters, including plant height, stem diameter, number of branches, number of pods, seed yield etc. were positively affected by the nanoparticle treatment. Gold-nanoparticle treatment increased the number of leaves per plant; however the average leaf area was not affected. Optimal increase in seed yield was recorded at 10 ppm of Gold-nanoparticle treatment. Reducing as well as total sugar contents increased up to 25 ppm of Gold-nanoparticle treatment. Application of nanoparticles also improved the redox status of the treated plants. The results, for the first time, demonstrate successful use of Gold-nanoparticles in enhancing growth and yield of B. juncea, under actual field conditions and present a viable alternative to GM crops for ensuring food security.     

Can the use of natural biostimulants be a potential means of phytoremediating contaminated soils from goldmines in South Africa?

Biostimulants offer great potential in improving phytoremediation of contaminated soils. In the current greenhouse-based study, Brassica juncea seedlings grown on soils collected from Krugersdorp Goldmine and the adjourning areas (a Game Reserve and private farmland) were supplemented with different biostimulants (Kelpak® = KEL, vermicompost leachate = VCL, smoke-water = SW). Indole-3-butyric acid (IBA) was included in the study for comparative purposes because these biostimulants are known to enhance rooting. Prior to the pot trial, concentrations of elements in the three soil types were determined using Inductively Coupled Plasma-Optical Emission Spectroscopy. Plants were harvested after 105 days and the growth and concentrations of elements in the various plant organs were determined. TheB. juncea seedlings with and without biostimulants did not survive when growing in soil from the Krugersdorp Goldmine. The Game Reserve and private farmland soils supplemented with KEL produced the highest plant biomass and the lowest accumulation of metals in the organs of B. juncea. High concentrations (>13 000 mg kg^?1) of zinc and aluminium were quantified in the roots of IBA-supplemented soils from the Game Reserve. Generally, IBA and SW enhanced the phytoremediation of B. juncea due to elevated levels of elements that accumulated in their different organs.     

In vitro biochemical evaluation of cadmium tolerance mechanism in callus and seedlings of Brassica juncea

In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations of cadmium and compared for their respective tolerance to cadmium. Calli cultures were grown on Murashige and Skoog medium supplemented with α 6-benzyl aminopurine (200 µg L^?1, naphthalene acetic acid 200 µg L^?1) and 2,4-dichloro-phenoxy acetic acid (65 µg L^?1) while the seedlings grown on Hoagland's nutrient solution have been carried out. Cellular homeostasis and detoxification to cadmium in B. juncea were studied by analyzing the growth in terms of fresh weight and dry weight, lipid peroxidation, proline accumulation, and antioxidative enzymes (superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)). At 200 µM cadmium, callus and seedlings showed 73.61% and 74.76% reduction in tolerance, respectively. A significant increase in malondialdehyde (MDA) content was found in both calli and seedlings; however, the amount of MDA content was more in seedlings. Proline content increased on lower concentration of cadmium (up to 50 µM), and it further decreased (up to 200 µM). But the accumulation of proline was higher in callus cultures. The overall activity of antioxidative enzymes (SOD, CAT, and APX) was found to be higher in callus in comparison to seedlings of B. juncea. Callus and seedlings showed a significant (P?≤?0.5) increase in SOD activity in a concentration-dependent manner up to 50 µM cadmium concentration but decreased further. APX activity increased significantly at low cadmium levels but CAT activity decreased significantly throughout on increasing cadmium concentrations from 5 to 200 µM, respectively. Hence, it was observed that callus of B. juncea was more tolerant in comparison to seedlings exposed to equimolar concentrations of cadmium. Thus, from the present studies, it is concluded that calli were more tolerant toward cadmium-induced oxidative stress. Hence, it is suitable material for the study of cadmium tolerance mechanisms and for the manipulations within them for better understanding of cadmium detoxification strategies in B. juncea.     

Effect of bacterial inoculation of strains of pseudomonas aeruginosa,alcaligenes feacalis and bacillus subtilis on germination,growth and heavy metal (cd,cr, and ni) uptake of brassica juncea

Bacterial inoculation may influence Brassica juncea growth and heavy metal (Ni, Cr, and Cd) accumulation. Three metal tolerant bacterial isolates (BCr3, BCd33, and BNi11) recovered from mine tailings, identified as Pseudomonas aeruginosa KP717554, Alcaligenes feacalis KP717561, and Bacillus subtilis KP717559 were used. The isolates exhibited multiple plant growth beneficial characteristics including the production of indole-3-acetic acid, hydrogen cyanide, ammonia, insoluble phosphate solubilization together with the potential to protect plants against fungal pathogens. Bacterial inoculation improved seeds germination of B. juncea plant in the presence of 0.1 mM Cr, Cd, and Ni, as compared to the control treatment. Compared with control treatment, soil inoculation with bacterial isolates significantly increased the amount of soluble heavy metals in soil by 51% (Cr), 50% (Cd), and 44% (Ni) respectively. Pot experiment of B. juncea grown in soil spiked with 100 mg kg^?1 of NiCl₂, 100 mg kg^?1 of CdCl₂, and 150 mg kg^?1 of K₂Cr₂O₇, revealed that inoculation with metal tolerant bacteria not only protected plants against the toxic effects of heavy metals, but also increased growth and metal accumulation of plants significantly. These findings suggest that such metal tolerant, plant growth promoting bacteria are valuable tools which could be used to develop bio-inoculants for enhancing the efficiency of phytoextraction.     

Molecular marker-assisted breeding for improved Ogura cms restorer line (RfoRfo) and mapping of the restorer gene (Rfo) in Brassica juncea

Developing a fully functional hybrid system is a must for hybrid breeding in Brassica juncea. The B. napus Ogura cms hybrid system was transferred into B. juncea by the researchers at INRA, France. The B. juncea restorer (R) line (RfoRfo) exhibited poor vigor, low fertility and was black-seeded due to linkage drag. Our studies indicated that the Rfo gene in B. juncea R line was linked to the 5 C9 markers of B. napus (sN3553F, sS2285, sN3841, sN12905 and At5g58730) and 4 radish markers (At3g27100, At5g25080, At4g13720 and At5g06240) in addition to the 6 radish markers reported before (ScH03, ScA14, OPF3, BolJon, CAB and PGIint). These markers were used to screen for improved restorer plants in the three crosses of B. juncea restorer plant O39-16 (Rforf) × condiment var. Cutlass, O39-16 (Rforf) × canola B. juncea line C668 and O39-16 (Rforf) × resynthesized B. juncea line 15043. One improved homozygous R line VR441 (RfoRfo) with only 1 C9 marker sN12905 and 2 radish markers ScH03 and BolJon was successfully developed via marker-assisted selection in the cross O39-16 × 15043. VR441 had good seed-setting (average: 14.3 seeds/pod), strong growth vigor and was yellow-seeded. Linkage mapping revealed that the Rfo gene was introgressed into chromosome 9 of the A genome in B. juncea. The development of the improved R line VR441 has made the Ogura cms hybrid system fully functional in B. juncea. We are currently using the improved system for developing high yielding hybrid varieties in condiment and canola B. juncea.     

Brassica juncea tested on urban soils moderately contaminated by lead: Origin of contamination and effect of chelates

Urban garden soils are a potential repository of heavy metal pollution, resulting from either anthropogenic or geogenic origin. The efficiency of phytoextraction was compared on two garden soils with the same texture and topsoil Pb concentration (170 mg kg^?1) but not the same origin: one geogenic, the other anthropogenic. Two varieties of Brassica juncea were tested with citric acid (25 mmol kg^?1) or ethylenediaminetetraacetic acid (EDTA, 2.5 mmol kg^?1). Geogenic Pb was shown to be two times less available than anthropogenic Pb, as a result of which the phytoextraction efficiency was reduced by 59%. Pb mobility in the soil was solely enhanced with EDTA, which increased the Pb concentration in shoots of B. juncea by between 14 and 26 times in comparison with the control. The highest Pb concentration in shoots still remained low, however (i.e., 45 mg kg^?1 dry weight). Regardless of the chelates introduced, B. juncea 426308 accumulated roughly twice as much lead as B. juncea 211000, but only for the anthropogenic contaminated soil. Under these conditions, the amount of Pb accumulated by B. juncea (even when assisted by EDTA) was not high enough to envision achieving soil clean-up within a reasonable time frame.     

Phytoremediation of aspirin and tetracycline by Brassica juncea

With the increasing release of pharmaceutical drugs in the environment, research is in progress for investigating alternative methods for their remediation. Various studies have shown the phytoremediation potential of Brassica juncea for metals. The current study was aimed at evaluating the phytoremediation potential of B. juncea for two different pharmaceutical drugs i.e. aspirin and tetracycline in in-vitro conditions. The seeds of B. juncea were germinated and grown for a period of 28 and 24 days for aspirin and tetracycline, respectively. The study analyzed the remediation rate of B. juncea for the selected drugs in three different sets of varying concentration along with any phytotoxic effects exerted by the drugs on the seeds. Preliminary results showed that the average remediation rate of aspirin and tetracycline at the end of experiment was approximately 90% and 71%, respectively. As initial drug concentrations were increased in the media, the remediation rate also improved. However, at higher concentrations, the plants showed phytotoxicity as depicted by the decrease in shoot length of the germinated seeds. These preliminary results indicated that B. juncea could tolerate and remediate pharmaceutical drugs such as analgesics and antibiotics.     

Effect of Arsenic on Growth,Arsenic Uptake,Distribution of Nutrient Elements and Thiols in Seedlings of Wrightia arborea (Dennst.) Mabb.

Hydroponic experiments were conducted to investigate the effect of arsenic on seedlings of Wrightia arborea and Holoptelea integrifolia. Results revealed that W. arborea could tolerate much higher arsenic concentration than H. integrifolia. Therefore, further investigations were focused on W. arborea using higher arsenic concentrations (0.2–2.0 mM). Seedlings of W. arborea accumulated about 312–2147 and 1048–5688 mg/kg dry weight of arsenic in shoots and roots, respectively, following treatments with 0.2–1.5 mM of arsenic without exhibiting arsenic toxicity signs. However, arsenic at 2.0 mM caused decline in growth. Macronutrients content such as Ca, S (except at 2.0 mM), and K (only in root) increased while Mg, P, and K (shoot) decreased by arsenic treatments. However, the content of micronutrients was enhanced under arsenic treatments. Non-protein thiols (NP-SH) showed positive correlations with arsenic doses up to 0.2–1.5 mM but at 2.0 mM there was a decline in NP-SH thus suggesting important role of NP-SH in imparting arsenic tolerance. This study demonstrated that W. arborea that could tolerate arsenic concentrations up to 0.2–1.5 mM may be useful in arsenic phytoremediation programs.     

Foliar application of l-phenylalanine and ferulic acids to pea plants: induced phenylalanine ammonia lyase activity and resistance against Erysiphe pisi

Phenylalanine ammonia lyase (PAL) activity was measured using HPLC in pea leaves following exogenous application of l-phenylalanine and ferulic acid. Treatment with different concentrations (50, 100 and 150 ppm) of l-phenylalanine caused increased activity of PAL in comparison to the control. In pea leaves treated with 50 ppm l-phenylalanine, maximum PAL activity was observed after 72 h of treatment. Application of ferulic acid first reduced PAL activity at lower concentration (50 ppm) but increased at higher concentrations of the compound (100 and 150 ppm) in pea leaves as compared to the control. Maximum PAL activity was 0.19 nM cinnamic acid/min/g fresh wt. after 24 h at 50 ppm and then increased with time. Treatment with both the compounds significantly reduced conidial germination of Erysiphe pisi on pea leaves. They were equally effective at 100 and 150 ppm in reducing conidial germination. The conidial germination on l-phenylalanine-treated leaves was 26% after 24 h and that on ferulic acid-treated leaves was 34% as compared to the control (46%). Foliar application of different concentrations of l-phenylalanine increased the level of ferulic acid in the leaves of pea plants. Maximum accumulation of ferulic acid (79.3 and 83.5 μg/g fresh wt.) was observed following the application of l-phenylalanine after 24 h and 48 h, respectively. At 50 ppm, ferulic acid accumulation in pea leaves was 35.6 and 39.4 μg/g fresh wt. and 74.3 and 86.5 μg/g fresh wt. at 100 ppm.     

Exogenous application of L-phenylalanine and ferulic acid enhance phenylalanine ammonia lyase activity and accumulation of phenolic acids in pea (Pisum sativum) to offer protection against Erysiphe pisi

Phenylalanine ammonia lyase (PAL) activity was measured using HPLC in pea leaves following exogenous application of L-phenylalanine and ferulic acid. Treatment with different concentrations (50, 100, 150 ppm) of L-phenylalanine caused increased activity of PAL activity in comparison to control. In pea leaves treated with 50 ppm L-phenylalanine, maximum PAL activity was observed after 72 h of treatment. Application of ferulic acid first reduced PAL activity at lower concentration (50 ppm) but it further increased at higher concentrations of the compound (100 and 150 ppm) in pea leaves compared to control. Minimum PAL activity was 0.19 nM cinnamic acid/min/g fresh wt after 24 h at 50 ppm and then increased with time. Treatment with both compounds significantly increased the accumulation of phenolic acids and salicylic acid and reduced conidial germination of Erysiphe pisi on pea leaves. They were equally effective at 100 and 150 ppm in reducing conidial germination. Conidial germination on L-phenylalanine-treated leaves was 26% after 24 h and that on ferulic acid treated leaves 34% compared to control (46%). Foliar application of different concentrations of L-phenylalanine increased the level of ferulic acid in the leaves of pea plants. Maximum enzyme activity in terms of the accumulation of cinnamic acid (79.3 and 83.5 μg/g fresh wt) was observed following the application of L-phenylalanine after 24 and 48 h respectively. At 50 ppm, cinnamic acid accumulation in pea leaves was 35.6 and 39.4 μg/g fresh wt and 74.3 and 86.5 μg/g fresh wt at 100 ppm.     

In vitro salt and thermal tolerance of fungal endophytes of Nicotiana spp. growing in arid regions of north-western Australia

Abstract

Endophytic fungal strains isolated from indigenous Nicotiana plants naturally growing in dry and hot regions of north-western Australia were characterised based on their tolerance to salinity and temperature. Sixty-eight fungal isolates were tested on eight levels (0.5 M, 1.0 M, 1.5 M, 2.0 M, 2.5 M, 3.0 M, 3.5 M and 4.0 M) of five different of salts solutions NaCl, KCl, MgCl₂, CaCl₂ and MgSO₄ and at various temperatures (25–50?°C). The salt adaptation test indicated that the fungal strains namely Aspergillus niger (E-202), A. ochraceous-A (E-134), Aurantiporus sp. (E-135), Cladosporium halotolerance (E-128), Pleurostomophora richardsiae (E-13) and Trichoderma sp. (E-185.1) were tolerant to higher concentrations of various salts. The most growth-limiting salt turned out to be MgCl₂ followed by the chaotrope CaCl₂. Responses to temperature tolerance revealed that most fungi tested could grow at 30?°C. About 50% all the fungi did not show any growth when the temperature was raised above 30?°C. When the temperature was raised up to 50?°C all the fungi failed to grow but the fungus Rasamsonia piperina (E-172). Endophyte strains identified could be promising candidates for future research in investigating the fungus–plant interactions and their roles in plant adaptation to inhospitable environments.     

Phytoremediation of Bisphenol A and Total Dissolved Solids by the Mangrove Plant,Bruguiera Gymnorhiza

Bruguiera gymnorhiza, an evergreen mangrove tree, is tolerant of bisphenol A (BPA) and has potential BPA removal capability. BPA is highly toxic to plants at high concentrations, wherein they exhibit damaged symptoms such as chlorosis, necrosis, and wilting. The LD₅₀ of BPA toxicity for this plant was statistically estimated to be 39.97 mg L^–1. B. gymnorhiza can reduce COD from 15408 ± 246 to 49 ± 30 mg L^–1 by (approximately 99% reduction of the initial value) and can reduce content to levels below the industrial effluent standard of Thailand (<120 mg L^–1) within 48 days. This plant can completely remove BPA from the solution within 51 days of treatment. Polysaccharides and organic acids were found in the solution and were caused by plant response to the toxicity of BPA. In addition, B. gymnorrhiza can also reduce total dissolved solids (TDS) and salinity in real wastewater. Therefore, B. gymnorrhiza has potential for removal of BPA and TDS in contaminated in wastewater.     

Nanosilica and jasmonic acid as alternative methods for control Tuta absoluta (Meyrick) in tomato crop under field conditions

Recently, Tuta absoluta became one of the major pests that attack commercial tomato globally. Field test was done to evaluate the effect of different concentrations of nanosilica (NS) and jasmonic acid (JA), and compared them with indoxacrb (recommended insecticide) on reduction of damage rate caused by T. absoluta larvae under field conditions. Nanosilica (600 ppm) and indoxacrb (0.25 cm³/L) had the highest efficiency to reduce the rate of mines in the leaves. Jasmonic acid at rate 1.141 μM/plant showed a good reduction of number of fruits damaged. Nanosilica with 600 ppm concentration and Jasmonic acid at rate 1.141 μM/plant is used to control T. absoluta in the field.