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The purpose of this study was to examine the influence of 10 and 20 nm nanoparticles (AgNPs) on the growth and biochemical composition of microalga Porphyridium purpureum CNMN-AR-02 in two media which differ by the total amount of mineral salts (MM1 with 33.02 g/L and MM2 with 21.65 g/L). Spectrophotometric methods were used to estimate the amount of biomass and its biochemical composition. This study provides evidence of both stimulatory and inhibitory effects of AgNPs on different parameters depending on the concentration, size, and composition of the nutrient medium. In relation to the mineral medium, AgNPs exhibited various effects on the content of proteins (an increase up to 20.5% in MM2 and a decrease up to 36.8% in MM1), carbohydrates (a decrease up to 35.8% in MM1 and 39.6% in MM2), phycobiliproteins (an increase up to 15.7% in MM2 and 56.8% in MM1), lipids (an increase up to 197% in MM1 and no changes found in MM2), antioxidant activity (a decrease in both media). The composition of the cultivation medium has been revealed as one of the factors influencing the involvement of nanoparticles in the biosynthetic activity of microalgae. [ABSTRACT FROM AUTHOR]

Introduction: Corn is one of the most important crops in the cereal family, and after wheat, it has the largest cultivated area in the world. Among the types of corn, sweet corn seeds are sensitive to storage conditions due to their low starch content and poor seed vigor. Therefore, it is essential to understand their physiological and biochemical behavior during storage to prolong their longevity and prevent the loss of vigor. On the other hand, seed deterioration is a natural phenomenon, resulting in seeds losing their viability and quality even under optimal storage conditions. This undesirable phenomenon causes more damage, especially in sensitive seeds such as sweet corn. Part of this damage is related to the decrease in the speed and percentage of seed germination, which leads to a decrease in plant density and failure to achieve the desired density in the field, resulting in decreased crop yield. This experiment evaluated and tested the ability of seed priming with ascorbic acid to improve damage caused by sweet corn seed deterioration. Materials and methods: This experiment was carried out in the Laboratory of Seed Science and Technology, Faculty of Agriculture, BuAli Sina University, as a factorial in a completely randomized design with four replications. The seed used for the experiment was Chase variety. Wheat seeds deteriorated by accelerated aging method for 72 hours at 43 °C. Then, the deteriorated seeds were primed at 25°C with 1, 1.5 ml of ascorbic acid and distilled water for 18 hours. The studied traits included germination percentage, mean germination time, germination rate, vigor index, malondialdehyde content, soluble sugars, soluble proteins, and superoxide dismutase enzyme activity. Results: The results showed that vitamin priming of seeds with ascorbic acid improved the germination percentage, germination rate, vigor index, soluble sugars, soluble proteins, and activity of the antioxidant enzyme superoxide dismutase in deteriorated seeds. Among the examined traits, the mean germination time and malondialdehyde content of primed seeds decreased compared to non-primed ones. The concentrations of ascorbic acid used in mean germination time, germination rate, vigor index, and soluble sugars were not significantly different. However, it had a more favorable effect than hydropriming in improving the studied parameters of sweet corn seeds. While seed priming with a concentration of 1.5 mM ascorbic acid had the most significant effect on germination percentage, soluble proteins, malondialdehyde content, superoxide dismutase activity, and its difference with other priming treatments was significant. Even though seed priming with a concentration of 1.5 mM ascorbic acid had the greatest effect on the germination percentage, soluble proteins, malondialdehyde content, superoxide dismutase activity. However, its difference was significant from other priming treatments. It increased the percentage of germination, soluble proteins, and superoxide dismutase activity by 71, 85, and 44%, respectively, and decreased the content of malondialdehyde by 52.9%. Conclusion: Based on the results from this experiment, it can be concluded that applying ascorbic acid, especially the concentration of 1.5 mM, as the best priming treatment is recommended to recover the lost quality of deteriorated sweet corn seeds and improve their germination characteristics. [ABSTRACT FROM AUTHOR]

Calcium (Ca) is necessary for plant growth and stress resistance, which are essential for the successful cultivation of Panax quinquefolium L. (American ginseng). However, information about the physiology of Ca nutrition in this species is limited. Therefore, the objective of this study was to determine the effect of Ca on the growth and physiological performance of American ginseng. Two-year-old American ginseng plants were supplemented with the following Ca concentrations [Ca2+] in a hydroponic system: 0, 160.17, 320.34, 640.68, and 961.02 mg⋅L−1. Measurements included growth biomass accumulation, chlorophyll (Chl) content and fluorescence, photosynthetic parameters, antioxidant enzyme activity, root activity, and malondialdehyde content. Biomass, stem height, leaf area, maximum photochemical efficiency, and superoxide dismutase activity peaked at [Ca2+] of 640.68 mg⋅L−1. Actual photochemical efficiency, minimum saturating irradiance, photosynthetic rate, catalase and peroxidase activities, and root activity reached their maximum at [Ca2+] of 320.34 mg⋅L−1. Stem diameter and regulated thermal energy dissipation increased with [Ca2+]. The sum of nonregulated heat dissipation and fluorescence emission and malondialdehyde content decreased to a minimum at [Ca2+] of 320.34 mg⋅L−1. The Chl content reached a maximum at [Ca2+] of 160.17 mg⋅L−1, but the Chl a/b ratio increased with [Ca2+]; the actual photochemical efficiency and photosynthetic rate reached their maximum level at Chl a/b ratios of 2.04 and [Ca2+] of 320.34 mg⋅L−1. Therefore, the optimal [Ca2+] for American ginseng growth was 320.34 mg⋅L−1. Furthermore, an appropriate increase [Ca2+] in the growth medium may improve biomass accumulation, light energy utilization efficiency, and stress resistance in American ginseng.

Copyright of Acta Edulis Fungi is the property of Acta Edulis Fungi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present investigation focused on the role of calcium ascorbate (CaAsc) on tomato seedlings under low-temperature stress. Study was conducted by spraying aqueous solution of CaAsc at 0, 50, and 100 mM, on tomato seedlings with 5-7 true leaves in order to counteract the adverse impacts of chilling stress. One week after foliar application of CaAsc, all seedlings were exposed to a chilling temperature of 3±0.5 °C for six days (six hours per day) in a growth chamber. Loss of membrane integrity due to chilling stress led to oxidation of phenolic compounds by activation of peroxides (POD) and polyphenol oxidase (PPO) enzymes. Higher phenylalanine ammonia-lyase (PAL) activity, which is responsible for phenolic compounds accumulation, due to chilling temperature, has been considered as defense mechanism of chilling stress. The results revealed that application of 50 mM CaAsc ameliorated chilling injury of tomato seedling, which was associated with lower electrolyte leakage (16.2 %) and malondialdehyde (1.54 nmol g-1 FW) accumulation. Also, CaAsc-treated seedlings with 50 and 100 mM of CaAsc exhibited higher total phenols accumulation (36.2 and 28.4 mg pyrogallol g-1 FW, Respectively) which results from higher PAL enzyme activity concurrent with lower POD and PPO enzymes activity. Enhancing chilling tolerance in tomato seedling treated with 50 mM CaAsc by triggering phenols metabolism was associated with better seedling growth rate. [ABSTRACT FROM AUTHOR]

DOR: 98.1000/2383-1251.1399.7.1.13.1.1578.1610 Extended Abstract Introduction: Sweet corn (Zea mays var. saccharata) is a corn variety that is distinguished from other varieties due to the presence of genes that affect starch production in the endosperm. Given that the most of plants including sweet corn face with problems such as non- uniform germination and poor seed emergence in the early stages of germination. Thus, the use of organic stimulants is one of the ways to reduce the harmful effects of non-biological stresses, increase seed germination, uniform appearance and increase their yield and quality. The present study was carried out to investigate the effect of different concentrations of chitosan on seed germination and some biochemical traits of sweet corn under osmotic potential conditions. Materials and Methods: To investigate the effect of chitosan and osmotic stress on germination and biochemical parameters of sweet corn, a factorial experiment was conducted in a completely randomized design with four replications at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2017. The first factor was osmotic stress at 0, -3, -6, and -9 bar osmotic potentials and the second factor was pre-treatment at five levels of chitosan zero, 0.25%, 0.5%, 0.75% and 1% and one level of distilled water. The seeds were immersed in the desired solutions of chitosan for 3 hours at 25 °C and under dark conditions, and then the pre-treated seeds were germinated under standard germination condition. In each petri dish, 25 seeds were placed on a filter paper and osmotic potential was applied using polyethylene glycol 6000. Seed germination was carried out in the germinator at 25 ± 1 ° C for 7 days under dark conditions. The germination traits and biochemical traits were measured according to standard methods. Results: Osmotic stress reduced germination percentage and germination rate, seedling vigour length index, germination uniformity coefficient, allometric coefficient, and soluble protein content and also increased the mean germination time, proline, soluble sugar content and hydrogen peroxide. Pre-treatment of seeds with a concentration of 0.5% chitosan increased protein, proline, and soluble sugars content at all osmotic stress levels. At the osmotic stress levels, the highest and lowest levels of hydrogen peroxide respectively were observed in 0.5% chitosan treatment and distilled water treatment. The results showed that pre-treatment with 0.5% chitosan increased germination percentage and rate and seedling vigour length index, and also reduced the mean germination time and malondialdehyde. Pre-treatment of seed with zero and 1% chitosan led to reduction in some of the germination and biochemical traits in comparison with 0.25, 0.5, and 0.75% chitosan. Conclusions: The results showed that seed treatment with 0.5% chitosan could reduce the harmful effects of osmotic potential on some germination and biochemical traits in sweet corn seedlings and improve seedling growth. Highlights: 1-Chitosan increases the germination percentage and germination rate. 2-Chitosan increases soluble sugars, proline, and soluble protein. 3-Chitosan reduces the amount of malondialdehyde and hydrogen peroxide.

Common bean (Phaseolus vulgaris L.) is mostly cultivated on marginal soils where salinity is a key stress. The focus of the present study was to evaluate the efficiency of melatonin priming and hydro priming on germination, growth parameters, antioxidant defense system and tolerance threshold in seven common bean cultivars grown under different levels of salinity stress. The experiments were conducted as a factorial arrangement based on a completely randomized design with six replicates. The results showed that salinity levels decreased radicle and hypocotyl lengths, seedling vigor index, and salinity tolerance threshold under Petri dish conditions. However, melatonin priming alleviated the inhibitory effects of salinity and enhanced salt tolerance threshold of all the cultivars. The highest tolerance thresholds of Dorsa, Almas, Koosha, and Pak cultivars were obtained under 100 µM melatonin treatment, while in Sayad, Shekoofa, and Derakhshan, 20 µM melatonin caused higher thresholds. Results of the greenhouse experiment showed that melatonin priming increased salt tolerance threshold, but it reduced malondialdehyde content and hydrogen peroxide accumulation. It also induced a higher increase in relative shoot dry weight of the cultivar Dorsa than the other cultivars. The cultivars Dorsa and Shekoofa treated with 100 and 20 µM, respectively, maintained a lower MDA content and Na+ concentration and a higher K+/Na+ ratio in shoot and root, N concentration and salt tolerance threshold than the other cultivars under salinity stress. These results suggest that seed priming with melatonin enhances salinity tolerance by stimulating antioxidant activities, alleviating oxidative damage and enhancing plant dry weight. [ABSTRACT FROM AUTHOR]

Introduction/Objectives: Non-steroidal anti-inflammatory drugs (NSAIDs) are effective in reducing pain and inflammation in rheumatoid arthritis and other joint- and muscle-associated diseases. However, the extensive, long-term, and over the counter administration of NSAIDs may cause various side effects in the patients. In the present study, the chronological effect of NSAIDs on oxidative stress and antioxidant status in patients with rheumatoid arthritis was studied. Methods: The study included 100 female individuals categorized in four major groups: (1) control group consisting of age- and gender-matched healthy individuals, (2) NRA-NSAID individuals taking NSAIDs without any history of RA, (3) RA individuals with a history of RA but not taking NSAIDs, and (4) RA-NSAID individuals with chronic RA and taking NSAIDs for a long period. The sera of the participants were analyzed for the oxidative stress and antioxidant status. Results: The RA-NSAID group showed the significantly highest oxidative stress, in terms of malondialdehyde content and lipid-reducing ability as determined in thiocyanate and hemoglobin-induced linoleic acid systems. However, the free radical scavenging ability of the RA-NSAID group, against 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, superoxide, and 2,2-azino-bis-tetrazolium sulfate radicals, was found to be lower than those of the other study groups. The regression analysis of the experimental data showed a significant positive relationship between duration of NSAID intake and malondialdehyde production, lipid-reducing ability, and metal chelating ability in the RA-NSAID patients. The free radical scavenging abilities of the RA-NSAID group were negatively correlated with the duration of NSAID intake. Conclusions: The prolonged use of NSAIDs significantly increased the oxidative stress and decrease the antioxidant potential of both the RA patients and NRA individuals. The study provides awareness to the public particularly the RA patients regarding the risk of oxidative stress–associated abnormalities caused by the frequent and prolonged use of NSAIDs for temporary relief from pain. Key Points • The study presents the effects of long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) on antioxidant status of patients with rheumatoid arthritis. • The continuous administration of NSAIDs has been found to significantly increase the oxidative stress of the patients with rheumatoid arthritis as well as the individuals with no signs of rheumatoid arthritis. • The prolonged NSAID therapy also decreased the antioxidant potential of the patients with rheumatoid arthritis as well as the individuals with no signs of rheumatoid arthritis. • The study would be a significant and valuable contribution to the literature for the awareness regarding the use of NSAIDs. [ABSTRACT FROM AUTHOR]

Cell division cycle 37 (Cdc37) is an important cytoplasmic phosphoprotein, which usually functions as a complex with heat shock protein 90 (Hsp90), to effectively reduce the damage caused by heavy metals, such as cadmium (Cd), in aquatic animals. The high toxicity of Cd in aquatic systems generally has a deleterious effect on healthy farming of shrimps. In the present study, a novel Cdc37 gene from Penaeus monodon was identified and designated as PmCdc37. Following exposure to Cd stress, the expression levels of PmCdc37 were upregulated at the transcriptional level in both the hepatopancreas and hemolymph. RNA interference and recombinant protein injection experiments were carried out to determine the function of PmCdc37 in P. monodon following Cd exposure. To clarify the correlations between PmCdc37 and PmHsp90, the respective recombinant proteins were expressed in vitro, and the ATPase activity of PmHsp90, with or without PmCdc37, was assessed. Moreover, a pull-down assay was conducted to detect the correlation between PmCdc37 and PmHsp90. After analyzing the expression patterns of PmHsp90 following Cd challenge, whether PmHsp90 can promote the ability of PmCdc37 to resist Cd stress or not was investigated. The results showed that formation of a PmHsp90/PmCdc37 complex protected shrimp against Cd stress-induced damage. Moreover, we also confirmed that PmSOD is involved in Cd stress, and that the PmHsp90/PmCdc37 complex can regulate SOD enzymatic activity. PmSOD was involved in decreasing the MDA content in shrimp hemolymph caused by Cd stress. We concluded that during exposure to Cd, the PmHsp90/PmCdc37 complex increases SOD enzyme activity, and in turn decreases the MDA content, thereby protecting shrimp against the damage caused by Cd stress. The present studies contribute to understanding the molecular mechanism underlying resistance to Cd stress in shrimp.

Sugarcane often suffers from low-temperature stress in Guangxi, China. In this study, the cold tolerance potential of 20 new sugarcane varieties was evaluated on the basis of chlorophyll content (Chl), chlorophyll fluorescence parameters, plasma membrane permeability (PMP) and malondialdehyde (MDA) content, and visual scoring. The study was conducted at the experimental field of Fushui Field Station of Guangxi University. Following the period of cold stress, the Chl of sugarcane varieties decreased, while PMP and MDA contents increased. Moreover, the chlorophyll fluorescence parameters (Fo, Fm, Fv/Fm, Fv/Fo) also showed changes as a result of cold stress. However, these fluctuations significantly varied among different varieties. Likewise, the cold tolerance index (CTI) of the sugarcane varieties ranged from 0.03 to 0.76 depicting a great variability in the cold stress tolerance of varieties under evaluation. The correlation analysis of physiological indicators with cold tolerance parameters revealed that CTI was positively correlated with PMP and MDA and negatively correlated with Chl and its fluorescence parameters. Based on overall evaluation, eight varieties, viz. GUC44, CP88-1762, CP96-1257, GUC50, GX13-4201, GX13-4222, CP97-2730, and CP05-1762, were identified as a highly cold tolerant, while seven varieties were categorized as mild tolerant, five as susceptible, two as mild highly tolerant, and two as mild susceptible. This study offers an insight into physiological response of sugarcane against cold stress and an all-inclusive approach to screen sugarcane genotypes against this widespread issue of concern. Moreover, it is expected that this study will provide some promising sugarcane germplasm resources with better cold stress tolerance. [ABSTRACT FROM AUTHOR]

The present study was carried out with the aim of (i) evaluating the effect of chitosan (CTS) on the growth of durum wheat under salinity and (ii) examining CTS-regulated mechanisms of salinity tolerance associated with the antioxidant defense system. To achieve these goals, durum wheat seedlings were treated with CTS at different molecular weight, low (L-CTS, 50–190 kDa), medium (M-CTS, 190–310 kDa) and high (H-CTS, 310–375 kDa). The results obtained show that exposure to 200 mM NaCl reduced the shoot and the root dried biomass by 38% and 59%, respectively. The growth impairment induced by salinity was strongly correlated with an increase in the superoxide anion production (5-fold), hydrogen peroxide content (2-fold) and malondialdehyde (MDA) content (4-fold). Seedlings responded to the oxidative stress triggered by salinity with an increase in the total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant activity (TAA) by 67%, 51% and 32%, respectively. A salt-induced increase in the activity of the antioxidant enzymes superoxide dismutase and catalase (CAT) of 89% and 86%, respectively, was also observed. Treatment of salt-stressed seedlings with exogenous CTS significantly promoted seedling growth, with the strongest effects observed for L-CTS and M-CTS, which increased the shoot biomass of stressed seedlings by 32% and 44%, respectively, whereas the root dried biomass increased by 87% and 64%, respectively. L-CTS and M-CTS treatments also decreased the superoxide anion production (57% and 59%, respectively), the hydrogen peroxide content (35% and 38%, respectively) and the MDA content (48% and 56%, respectively) and increased the TPC (23% and 14%, respectively), the TFC (19% and 10%, respectively), the TAA (up to 10% and 7%, respectively) and the CAT activity (29% and 20%, respectively). Overall, our findings indicate that CTS exerts its protective role against the oxidative damages induced by salinity by enhancing the antioxidant defense system. L-CTS and M-CTS were the most effective in alleviating the adverse effect of NaCl, thus demonstrating that the CTS action is strictly related to its molecular weight.

To increase the thermotolerance of improved White Ponni (IWP), two quantitative trait loci (QTLs), qHTSF1.1 and qHTSF4.1, controlling spikelet fertility under high-temperature stress, were introgressed from Nagina 22 into IWP through marker-assisted breeding. The progenies were subjected to foreground selection of target QTLs using simple sequence repent markers RM431 and RM5757 linked to qHTSF1.1 and qHTSF4.1, respectively. At each generation, foreground selection with single target QTL or both QTLs was done together. The QTL-positive plants were forwarded to next generation by selfing. The F2:3 progenies were subjected to phenotypic analyses under high-temperature stress at the flowering stage. Chlorophyll stability index, malondialdehyde content, grain yield, and yield-related components of the F2:3 progenies were measured. The progenies IWP-295, IWP-277 and IWP-246 harboring both qHTSF1.1 and qHTSF4.1 showed higher fertility percentages under high-temperature stress at the flowering stage. These QTLs were responsible for maintaining membrane integrity and yield under elevated temperature conditions.

The present study was carried out to minimize postharvest problems of chilling injury during cold storage by the application of anti-chilling compounds, viz. salicylic acid (SA), sodium nitroprusside (SNP) and a nitric oxide donor (NO). For minimizing chilling injury symptoms summer squash (Cucurbita pepo L.) fruits were treated with salicylic acid (1.0–1.5 mM) and sodium nitroprusside(1.0–1.25 mM) followed by cold storage at 5±2ºCand 85–90% relative humidity. Among the used anti-chilling molecules, salicylic acid @1.0 mM provides the best results for minimizing chilling injury score (0.74) and proline content (333.87 μg/g) during cold storage. Fruits treated with 1.5 mM SA and 1.0 mM SNP showed a 37.42% and 27.42% lower electrolyte leakage as compared to control. In the case of malondialdehyde (MDA) content, 1.0 and 1.5 mM SA dose showed a ≈39% and ≈36% lower content than control. Higher fruit firmness (7.07 N) retention was found in 1.0 mM sodium nitroprusside and followed by 1.0 mM salicylic acid (6.96 N) treated fruits. Overall 1.0 mM salicylic acid followed by 1.0 mM sodium nitroprusside proves better for prevention of chilling injury and lower production of malondialdehyde content.

The present investigation was carried out with the aim to find out the beneficial effects of edible coating on postharvest quality of summer squash (Cucurbita pepo L.) under cold storage condition. In our experiments, different edible coatings, viz. gum arabic (5, 10 and 15%) and fruwash were used in order to minimize the excessive moisture loss during postharvest handling and storage. Among the treatments, gum arabic (10%) coating showed better colour retention in terms of Lvalue followed by fruwash treatment. Fruits coated with 10% gum arabic found best for minimizing water loss (more than 50%), respiration rate (≈21%) with higher fruit firmness (7.55 N) as compared with other treatments including control. After 12 days of storage, malondialdehyde content in 10% gum arabic treated fruits (0.141 nmol/g) was recorded significantly lower than control (0.183 nmol/g fruit weight). Highest proline content (235.05 μg/g fruit weight) was recorded in 10% gum arabic while, it was lowest (140.06 μg/g fruit weight) in control. Proline content was ≈68% higher in 10% concentration and ≈30% in 15% gum arabic treated fruit as compared with control after 12th days of storage. Overall 10% gum arabic coated summer squash fruits had better postharvest quality retention characteristics.

Excessive industrialization and the usage of pesticides plague the farming soils with heavy metals, reducing the quality of arable land. Assessing phytoavailability of cadmium (Cd) from growth medium to plant system is crucial and necessitates precise and timely monitoring of Cd to ensure food safety. Zinc (Zn) and silicon (Si) have singularly demonstrated the potential to ameliorate Cd toxicity and are important for agricultural production, human health, and environment in general. However, Zn-Si interaction on Cd toxicity alleviation, their effects and underlying mechanisms are still fragmentarily understood. Seven treatments were devised besides control to evaluate the single and combined effects of Zn and Si on the physio-biochemical attributes and ultrastructural fingerprints of Cd-treated rice genotypes, i.e., Cd tolerant “Xiushui-110” and Cd sensitive “HIPJ-1”. Supplementation of both Zn and Si promoted plant biomass, photosynthetic parameters, ionic balance, and improved chloroplast ultrastructure with minimized Cd uptake and malondialdehyde (MDA) content due to the activation of antioxidant enzymes in Cd stressed plants. The combined effects of 10 μM Zn and 15 μM Si on 15 μM Cd displayed a greater reduction in Cd uptake and root-leaf MDA content, while enhancing photosynthetic activity, superoxide dismutase (SOD) activity and root-leaf ultrastructure particularly in HIPJ-1, whilst Xiushui-110 had an overall higher leaf catalase (CAT) activity and a higher root length and shoot height was observed in both genotypes compared to the Cd 15 µM treatment. Alone and combined Zn and Si alleviation treatments reduced Cd translocation from the root to the stem for HIPJ-1 but not for Xiushui-110. Our results confer that Zn and Si singularly and in combination are highly effective in reducing tissue Cd content in both genotypes, the mechanism behind which could be the dilution effect of Cd due to improved biomass and competitive nature of Zn and Si, culminating in Cd toxicity alleviation. This study could open new avenues for characterizing interactive effects of simultaneously augmented nutrients in crops and provide a bench mark for crop scientists and farmers to improve Cd tolerance in rice.

Cucumber is a warm season crop that suffers from chilling injury at temperatures below 10°C. In recent years, jasmonates have been used for reduction of chilling injuries in plants. An experiment was, therefore, conducted to test whether methyl jasmonate (MeJA) application at various concentrations (0, 0.05, 0.1 and 0.15 mM) through seed soaking or foliar spray would protect cucumber seedlings, subjected to chilling stress. Results showed that MeJA application decreased chilling index, ion leakage, malondialdehyde content and hydrogen peroxide free radical and increased growth parameters, proline contents, chlorophylls contents and antioxidant activity. Although, seed soaking method provided better protection compared to foliar spray method, the highest cold tolerance was obtained with 0.15mM MeJA application in both application methods that caused low level of chilling index (1.67), malondialdehyde content (0.11 nm g-1 FW), hydrogen peroxide free radical (0.22 nm g-1 FW) and ion leakage (32.87%). In general, it may be concluded that MeJA could be used effectively to protect cucumber seedling from damaging effects of chilling stress at the early stages of growth.

In plants, lipoxygenases (LOXs) are involved in various processes, such as growth, development, and response to stress cues. In the present study, the expression pattern of six durum wheat LOX-encoding genes (TdLpx-B1.1, TdLpx-B1.2, TdLpx-A2, TdLpx-B2, TdLpx-A3 and TdLpx-B3) under hyperosmotic stress was investigated. With osmotic (0.42 M mannitol) and salt (0.21 M NaCl) stress imposed at the early stages of seedling growth, a strong induction of the TdLpx-A2 gene expression in the shoots paralleled an equally strong increase in the LOX activity. Enhanced levels of malondialdehyde (MDA) and increased rates of superoxide anion generation were also observed as a result of the stress imposition. Sequence analysis of the TdLOX2 encoded by the TdLpx-A2 gene revealed that it belonged to the type-1 9-LOX group. When overexpressed in E. coli, TdLOX2 exhibited normal enzyme activity, high sensitivity to specific LOX inhibitors, with 76% and 99% inhibition by salicylhydroxamic and propyl gallate, respectively, and a preference for linoleic acid as substrate, which was converted exclusively to its corresponding 13-hydroperoxide. This unexpected positional specificity could be related to the unusual TV/K motif that in TdLOX2 replaces the canonical TV/R motif of 9-LOXs. Treatment of seedlings with propyl gallate strongly suppressed the increase in LOX activity induced by the hyperosmotic stress; the MDA accumulation was also reduced but less markedly, whereas the rate of superoxide anion generation was even more increased. Overall, our findings suggest that the up-regulation of the TdLpx-A2 gene is a component of the durum wheat response to hyperosmotic stress and that TdLOX2 may act by counteracting the excessive generation of harmful reactive oxygen species responsible for the oxidative damages that occur in plants under stress.

The objective of the present work was to investigate the antioxidant enzyme activities and the occurrence of lipid peroxidation during storage of J. curcas seeds obtained from fruits at different maturity stages. Seeds extracted from fruits collected at three stages of maturity were used, i.e., yellow, brownish-yellow, and brown (dry fruits). The seeds were subsequently stored for 18 months in Kraft paper bags in a laboratory environment. Initially as well as every three months, the seeds were evaluated for germination and electrical conductivity, and the seed embryos were evaluated for lipid peroxidation; protein content; and superoxide dismutase, peroxidase, and ascorbate peroxidase enzyme activity at the same time points. In general, the seeds from the three stages of fruit maturity did not differ regarding germination throughout the entire period of storage, although a reduction in viability was observed after nine months of storage. The electrical conductivity increased during storage and was greater for the seeds obtained from brown fruits. There was a reduction in protein content and in enzyme activities in the seed embryo, except for superoxide dismutase. No relationship was observed between reduction in seed viability and lipid peroxidation. Thus, J. curcas seeds with high initial quality can be stored under environmental conditions for up to 9, 15 and 15 months for brown (dry), yellow and brownish-yellow fruits, respectively, without a significant reduction in germination but with a reduction in seed vigour. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of wetland plants in the treatment of coking wastewater, Oenanthe javanica (Blume) DC (OC), Artemisia selengensis Turcz. ex Bess. (AB), Echinochloa crusgalli (L.) Beauv. (EB), Brasenia schreberi J.F.Gmel. (BG), and Lythrum salicaria L. (LL) were used to remove ammonia–nitrogen and chemical oxygen demand (COD) from coking wastewater. Results showed high concentrations (> 30%, diluted by deionized water) of coking wastewater caused decreased photosynthetic rate, transpiration rate, and relative growth rate in all studied plants. OC, BG, and LL showed higher adaptability than AB and EB. Wastewater concentrations < 30% resulted in less affected growth of OC, BG, and LL; However, AB and EB were suppressed when coking wastewater concentrations were > 15%. High concentrations of coking wastewater generated oxidative stress which resulted in increased malondialdehyde and proline contents and inhibition of superoxide dismutase. OC, BG, and LL were considered tolerable species in purifying coking wastewater (concentrations < 30%). [ABSTRACT FROM AUTHOR]

The objective of the present work was to investigate the antioxidant enzyme activities and the occurrence of lipid peroxidation during storage of J. curcas seeds obtained from fruits at different maturity stages. Seeds extracted from fruits collected at three stages of maturity were used, i.e., yellow, brownish-yellow, and brown (dry fruits). The seeds were subsequently stored for 18 months in Kraft paper bags in a laboratory environment. Initially as well as every three months, the seeds were evaluated for germination and electrical conductivity, and the seed embryos were evaluated for lipid peroxidation; protein content; and superoxide dismutase, peroxidase, and ascorbate peroxidase enzyme activity at the same time points. In general, the seeds from the three stages of fruit maturity did not differ regarding germination throughout the entire period of storage, although a reduction in viability was observed after nine months of storage. The electrical conductivity increased during storage and was greater for the seeds obtained from brown fruits. There was a reduction in protein content and in enzyme activities in the seed embryo, except for superoxide dismutase. No relationship was observed between reduction in seed viability and lipid peroxidation. Thus, J. curcas seeds with high initial quality can be stored under environmental conditions for up to 9, 15 and 15 months for brown (dry), yellow and brownish-yellow fruits, respectively, without a significant reduction in germination but with a reduction in seed vigour. [ABSTRACT FROM AUTHOR]

In this study experiment was conducted to evaluated the effect of accelerated aging on germination characteristics, seed reserve utilization and malondialdehyde of two wheat cultivars. The experiment was conducted in factorial with a randomized complete block design with 3 replications. Results of variance analysis showed that, seed aging had significant effects on germination percentage, germination index, normal seedling percentage, mean time to germination, malondialdehyde content, seedling dry weight, weight of utilized (mobilized) seed reserve and electrical conductivity. The highest germination percentage, germination index, normal seedling percentage, seedling dry weight and weight of utilized (mobilized) seed reserve and the minimum mean time to germination, electrical conductivity and malondialdehyde content were attained from Verinak cultivar under control conditions (0 day aging). Results indicates that germination percentage, germination index, normal seedling percentage, seedling dry weight, and weight of utilized (mobilized) seed reserve decreased significantly as seed aging progressed. But, mean time to germination, electrical conductivity and malondialdehyde content increased significantly as seed aging progressed. Also, the decrease in seed reserve mobilization rate was the cause of decreased other traits.

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To increase the thermotolerance of improved White Ponni (IWP), two quantitative trait loci (QTLs), qHTSF1.1 and qHTSF4.1 , controlling spikelet fertility under high-temperature stress, were introgressed from Nagina 22 into IWP through marker-assisted breeding. The progenies were subjected to foreground selection of target QTLs using simple sequence repent markers RM431 and RM5757 linked to qHTSF1.1 and qHTSF4.1 , respectively. At each generation, foreground selection with single target QTL or both QTLs was done together. The QTL-positive plants were forwarded to next generation by selfing. The F 2:3 progenies were subjected to phenotypic analyses under high-temperature stress at the flowering stage. Chlorophyll stability index, malondialdehyde content, grain yield, and yield-related components of the F 2:3 progenies were measured. The progenies IWP-295, IWP-277 and IWP-246 harboring both qHTSF1.1 and qHTSF4.1 showed higher fertility percentages under high-temperature stress at the flowering stage. These QTLs were responsible for maintaining membrane integrity and yield under elevated temperature conditions. [ABSTRACT FROM AUTHOR]

Six mulberry varieties in Sichuan were used to study the chlorophyll content, water saturation deficit and malondialdehyde content changes under drought stress. The results showed that, under drought stress, the change of chlorophyll content and water saturation deficit was negatively correlated with malondialdehyde and the difference was very significant. Under mild drought stress, the chlorophyll content rose and reached the maximum value and the saturation deficit and malondialdehyde content had no obvious change. Under moderate drought stress, The chlorophyll content showed a decrease trend and the water saturation deficit and malondialdehyde content showed a rising trend, but the change ranges were slow. Under severe drought stress, the change ranges were big. Accordingly, with drought stress aggravated, the physiological functions of mulberry varieties were destroyed in different degree and the leaf morphology appeared differences. [ABSTRACT FROM AUTHOR]

In order to find out the mechanism of cold resistance of Rhododendron and promote the development and utilization of new varieties，the activities of antioxidant enzymes，the content of osmotic adjustment substance，soluble protein and MDA of three Rhododendron species were measured through artificial temperature control. Results: with decreasing temperature，SOD activity of Rhododendron descend first， then ascend，and descend at last. At 10 °C，SOD activity of R. agastum was 87. 7 % of the control. POD activity of R. decorum raised constantly ，POD activity was 1. 58 times of the control at 0 °C. But POD activity of R. agastum and R. irroratum increased first and then decreased. The content of soluble sugar and proline increased，the soluble protein content of R. decorum and R. agastum ascend first，then descend last. However，the soluble protein of R. irroratum increased constantly. The relative membrane permeablility of them were enhanced constantly，and MDA content continually increased. MDA content and relative membrane permeability of R. decorum were higher than that of the other two species，MDA content of R. decorum was 18. 97 nmol/mg at 0 °C，MDA content of R. agastum and R. irroratum were 12. 5 nmol/mg and 9. 97 nmol/mg respectively. The cold resistance of R. irroratum and R. delavayi were stronger than R. decorum. [ABSTRACT FROM AUTHOR]

Methyl salicylate (MeSA) is a signal molecule in plant responses to biotic and abiotic stress and elicits plant resistance against chilling injury. An experiment was conducted to determine whether MeSA applied at 0, 0.25, 0.5, and 0.75 mM as a seed soak or foliar application would protect cucumber (Cucumis sativus L.) seedlings subjected to chilling at 3°C for 5 days. The MeSA improved growth rate of cucumber seedlings and increased relative leaf chlorophyll and relative water contents by inhibiting malondialdehyde and H2O2 accumulation and increasing proline and antioxidant capacity. MeSA was most effective when applied using the seed soak method at 0.5 and 0.75 mM. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Members of the P4 subfamily of P-type ATPases are implicated in generating lipid asymmetry between the two lipid leaflets of the plasma membrane in Arabidopsis and are important for resistance to low temperatures, but the function of P4-ATPases in cotton remains unclear. In this study, we found using quantitative reverse transcription- PCR analysis that the expression of the P4-ATPase gene GbPATP in cotton was induced at low temperatures. In addition, GbPATP-silenced cotton plants were more sensitive to low temperatures and exhibited greater malondialdehyde (MDA) content and lower catalase (CAT) activity than the control plants. GbPATP transgenic tobacco plants showed better chilling tolerance, had a lower MDA content and had higher CAT activity than wild-type plants under low-temperature treatment. The green fluorescent protein (GFP)-GbPATP fusion protein was found to be localized to the cell plasma membrane. Collectively, the results suggest that GbPATP functions as a P4-ATPase and plays an important role in improving chilling tolerance in plant. [ABSTRACT FROM AUTHOR]

Abstract: Effects of shading at the flowering and grain filling stages on osmotic regulation substance content and protective enzyme activities in the leaves of different rice genotypes (e.g., IIyou 498, Gangyou 188, Dexiang 4103, Gangyou 527 and Chuanxiang 9838) were investigated. The results showed that the malondialdehyde content of Gangyou 188 significantly increased under shading, whereas those of IIyou 498, Dexiang 4103, Gangyou 527 and Chuanxiang 9838 showed no significant differences compared to the control. The soluble sugar content significantly decreased in IIyou 498, Gangyou 188, Dexiang 4103 and Chuanxiang 9838, whereas it did not significantly increase in Gangyou 527 under the weak light conditions (shading). Moreover, the soluble protein content in the leaves of different genotypes tended to decrease under shading. Further, the protective enzyme activities in the leaves varied in different rice genotypes under the shading treatment. Based on the osmotic regulation substance content and the protective enzyme activities in the leaves of different rice genotypes, it was concluded that Gangyou 188 and Gangyou 527 had strong abilities to adapt to the low light conditions. In addition, the mechanism of damage to rice leaves in different genotypes under shading was discussed. [Copyright &y& Elsevier]

The main objective of this investigation was to evaluate the effects of nitrogen on waterlogging resistance in terms of changes in dry-matter accumulation, root antioxidant enzyme activities, root vigor, and photosynthesis under waterlogging during the flowering and boll-development stage. Cotton plants grown in pots with three N levels (0, 4.5, and 9.0 g N pot-1, equivalent to 0, 240, and 480 kg N ha-1, respectively) were subjected to waterlogging for eight days and then permitted to recover for fifteen days. The dry weights of root and shoot were decreased by waterlogging, and were highest at 240 kg N ha-1. In waterlogged root, the activities of superoxide dismutase and catalase decreased and that of peroxidase increased in comparison with the control. The application of N increased the activities of catalase and peroxidase of both waterlogged root and the control, but decreased superoxide dismutase activity. Malondialdehyde content, an indicator of membrane lipid peroxidation, was significantly increased, and was lowest in the 240 kg N ha-1 N treatment during waterlogging. Both root vigor and canopy apparent photosynthesis rate, which were weakened by waterlogging, reached a peak at 240 kg N ha-1. At the 15th day after termination of waterlogging, N application promoted root vigor and canopy apparent photosynthesis rate of waterlogged cotton plants. These results indicated that an appropriate N supply (240 kg N ha-1) may contribute to waterlogging resistance of cotton by adjusting the antioxidant enzyme activities of root, reducing lipid peroxidation and boosting root vigor; however, excessive N supply (480 kg N ha-1) may lead to an adverse impact on waterlogging resistance of cotton. Therefore, the application of N should be reduced to decrease stress when waterlogging occurs, and additional N fertilizer may be used to promote cotton growth after waterlogging. [ABSTRACT FROM AUTHOR]

Production of Jatropha curcas as a biodiesel feedstock on marginal lands is growing rapidly. Biomass production on these lands is limited. Hence, the objective of this study was to evaluate the effect of arbuscular mycorrhiza (AM) fungi and salinity (0.1, 0.2, 0.3, 0.4, and 0.5% NaCl) on (1) seedling growth, leaf relative water content (RWC), lipid peroxidation, solute accumulation (proline and sugars), and photosynthetic pigments (Chl a and b) of Jatropha; (2) mycorrhizal colonization (%) and mycorrhizal dependency (MD) of Jatropha; and (3) glomalin content (Bradford reactive soil protein) in soil. Increased soil salinity significantly ( P < 0.05) decreased AM root colonization ( r2 = 0.98) of AM-inoculated plants and decreased survival ( r2 = 0.93) and growth (shoot length, r2 = 0.89; tap root length, r2 = 0.93; shoot diameter, r2 = 0.99; shoot dry weight, r2 = 0.92; and root dry weight, r2 = 0.92) of non-AM-inoculated Jatropha. Under salt stress, AM-inoculated Jatropha plants had greater dry weight of shoots and roots, better leaf water status, less leaf membrane damage (low lipid peroxidation activity), higher solute (proline and sugars), and higher leaf chlorophyll concentrations than non-AM-inoculated plants. The mycorrhizal dependency (MD) of Jatropha increased from 12.13 to 20.84% with salinity (0–0.4% NaCl). Root AM colonization (%) and glomalin content in soil were negatively correlated with salinity ( P < 0.05, r = −0.95). We conclude that inoculation with AM fungi lessens the deleterious effect of salt stress on seedling growth parameters under salt levels up to 0.5% NaCl (electrical conductivity of 7.2 dS m−1). Inoculation of Jatropha seedlings with AM fungi can promote the establishment of Jatropha under NaCl-induced stress. [ABSTRACT FROM AUTHOR]

Abstract: The effects of CO2 levels (0.03, 0.5, 1, 2 and 5%) on growth and antioxidant responses in 5l bioreactor (working volume 4l) root suspension cultures of Echinacea angustifolia were studied. CO2 caused reduction in growth, malondialdehyde content (MDA), lipoxygenase (LOX, EC 1.13.11.13) activity and superoxide anion (O2 −) accumulation along with high total phenols accumulation and pH levels. Maximal increases (37%) in total phenols were obtained at 1% CO2 compared to the control. An increase in total glutathione and total ascorbate (ASC+DHA), accompanied with enhanced ascorbate–glutathione cycle enzymes were observed in CO2-treated roots, which played an important role for the detoxification of harmful substances. CO2 also induced an increase in glutathione peroxidase (GPx, EC 1.11.1.9) and glutathione-S-transferase (GST, EC 2.5.18) activities. After native polyacrylamide gel electrophoresis (PAGE) analysis, three superoxide dismutase (SOD, EC 1.15.1.1) isoenzymes were detected. Increase in SOD and CAT (EC 1.11.16) activities observed at 0.5% CO2-treated roots and induced SOD activity seemed to be mainly due to Mn-SOD. However, both SOD and CAT activities were inhibited at 2 and 5% CO2 but reached similar to control value. Three APX (EC 1.11.1.11) and three guaiacol peroxidase (G-POD, EC 1.11.1.7) isoenzymes were strongly detected, an increase in APX and G-POD activities suggests increased scavenging of ROS, indicating the tolerance to CO2. These results indicated that limited oxidative damage as shown by lower MDA level, low LOX activity and low O2 − accumulation may be due to the induced activities of antioxidant enzymes and non-enzymatic antioxidant. It is therefore, suggested that roots cultured in a bioreactor could protect themselves from CO2 by altering the defense systems. [Copyright &y& Elsevier]

The present study was carried out with the aim of (i) evaluating the effect of chitosan (CTS) on the growth of durum wheat under salinity and (ii) examining CTS-regulated mechanisms of salinity tolerance associated with the antioxidant defense system. To achieve these goals, durum wheat seedlings were treated with CTS at different molecular weight, low (L-CTS, 50–190 kDa), medium (M-CTS, 190–310 kDa) and high (H-CTS, 310–375 kDa). The results obtained show that exposure to 200 mM NaCl reduced the shoot and the root dried biomass by 38% and 59%, respectively. The growth impairment induced by salinity was strongly correlated with an increase in the superoxide anion production (5-fold), hydrogen peroxide content (2-fold) and malondialdehyde (MDA) content (4-fold). Seedlings responded to the oxidative stress triggered by salinity with an increase in the total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant activity (TAA) by 67%, 51% and 32%, respectively. A salt-induced increase in the activity of the antioxidant enzymes superoxide dismutase and catalase (CAT) of 89% and 86%, respectively, was also observed. Treatment of salt-stressed seedlings with exogenous CTS significantly promoted seedling growth, with the strongest effects observed for L-CTS and M-CTS, which increased the shoot biomass of stressed seedlings by 32% and 44%, respectively, whereas the root dried biomass increased by 87% and 64%, respectively. L-CTS and M-CTS treatments also decreased the superoxide anion production (57% and 59%, respectively), the hydrogen peroxide content (35% and 38%, respectively) and the MDA content (48% and 56%, respectively) and increased the TPC (23% and 14%, respectively), the TFC (19% and 10%, respectively), the TAA (up to 10% and 7%, respectively) and the CAT activity (29% and 20%, respectively). Overall, our findings indicate that CTS exerts its protective role against the oxidative damages induced by salinity by enhancing the antioxidant defense system. L-CTS and M-CTS were the most effective in alleviating the adverse effect of NaCl, thus demonstrating that the CTS action is strictly related to its molecular weight. [ABSTRACT FROM AUTHOR]

Cell division cycle 37 (Cdc 37) is an important cytoplasmic phosphoprotein, which usually functions as a complex with heat shock protein 90 (Hsp90), to effectively reduce the damage caused by heavy metals, such as cadmium (Cd), in aquatic animals. The high toxicity of Cd in aquatic systems generally has a deleterious effect on healthy farming of shrimps. In the present study, a novel Cdc 37 gene from Penaeus monodon was identified and designated as PmCdc 37. Following exposure to Cd stress, the expression levels of PmCdc 37 were upregulated at the transcriptional level in both the hepatopancreas and hemolymph. RNA interference and recombinant protein injection experiments were carried out to determine the function of PmCdc37 in P. monodon following Cd exposure. To clarify the correlations between PmCdc 37 and PmHsp 90, the respective recombinant proteins were expressed in vitro, and the ATPase activity of PmHsp 90, with or without PmCdc 37, was assessed. Moreover, a pull-down assay was conducted to detect the correlation between PmCdc 37 and PmHsp 90. After analyzing the expression patterns of PmHsp 90 following Cd challenge, whether PmHsp 90 can promote the ability of PmCdc 37 to resist Cd stress or not was investigated. The results showed that formation of a PmHsp 90/ PmCdc 37 complex protected shrimp against Cd stress-induced damage. Moreover, we also confirmed that PmSOD is involved in Cd stress, and that the PmHsp 90/ PmCdc 37 complex can regulate SOD enzymatic activity. PmSOD was involved in decreasing the MDA content in shrimp hemolymph caused by Cd stress. We concluded that during exposure to Cd, the PmHsp 90/ PmCdc 37 complex increases SOD enzyme activity, and in turn decreases the MDA content, thereby protecting shrimp against the damage caused by Cd stress. The present studies contribute to understanding the molecular mechanism underlying resistance to Cd stress in shrimp. • The full-length cDNA sequence of a novel Cdc37 gene (PmCdc 37) was firstly cloned from Penaeus monodon. • PmCdc 37 can interact directly with PmHsp90 to inhibit the ATPase activity of PmHsp90. • Hsp 90/ Cdc 37 can decrease the MDA content caused by Cd stimulation by regulating SOD enzyme activity. [ABSTRACT FROM AUTHOR]

Excessive industrialization and the usage of pesticides plague the farming soils with heavy metals, reducing the quality of arable land. Assessing phytoavailability of cadmium (Cd) from growth medium to plant system is crucial and necessitates precise and timely monitoring of Cd to ensure food safety. Zinc (Zn) and silicon (Si) have singularly demonstrated the potential to ameliorate Cd toxicity and are important for agricultural production, human health, and environment in general. However, Zn-Si interaction on Cd toxicity alleviation, their effects and underlying mechanisms are still fragmentarily understood. Seven treatments were devised besides control to evaluate the single and combined effects of Zn and Si on the physio-biochemical attributes and ultrastructural fingerprints of Cd-treated rice genotypes, i.e., Cd tolerant "Xiushui-110" and Cd sensitive "HIPJ-1". Supplementation of both Zn and Si promoted plant biomass, photosynthetic parameters, ionic balance, and improved chloroplast ultrastructure with minimized Cd uptake and malondialdehyde (MDA) content due to the activation of antioxidant enzymes in Cd stressed plants. The combined effects of 10 μM Zn and 15 μM Si on 15 μM Cd displayed a greater reduction in Cd uptake and root-leaf MDA content, while enhancing photosynthetic activity, superoxide dismutase (SOD) activity and root-leaf ultrastructure particularly in HIPJ-1, whilst Xiushui-110 had an overall higher leaf catalase (CAT) activity and a higher root length and shoot height was observed in both genotypes compared to the Cd 15 µM treatment. Alone and combined Zn and Si alleviation treatments reduced Cd translocation from the root to the stem for HIPJ-1 but not for Xiushui-110. Our results confer that Zn and Si singularly and in combination are highly effective in reducing tissue Cd content in both genotypes, the mechanism behind which could be the dilution effect of Cd due to improved biomass and competitive nature of Zn and Si, culminating in Cd toxicity alleviation. This study could open new avenues for characterizing interactive effects of simultaneously augmented nutrients in crops and provide a bench mark for crop scientists and farmers to improve Cd tolerance in rice. [ABSTRACT FROM AUTHOR]

Abstract: Malondialdehyde (MDA) is the final product of lipid peroxidation, and MDA content can reflect the stress tolerance of plants. To map QTLs conditioning the MDA content in rice leaves, a recombinant inbred line (RIL) population with 247 lines derived from an indica-indica cross Zhenshan 97B×Milyang 46, and a linkage map consisting of 207 DNA markers were used. The RIL population showed a transgressive segregation in the MDA content of rice leaves. Two QTLs for the MDA content in rice leaves were detected in the intervals RG532–RG811 and RG381–RG236 on chromosome 1, with the additive effects from maternal and paternal parents, accounting for 4.33% and 4.62% of phenotype variations, respectively. [Copyright &y& Elsevier]

In plants, lipoxygenases (LOXs) are involved in various processes, such as growth, development, and response to stress cues. In the present study, the expression pattern of six durum wheat LOX-encoding genes (TdLpx-B1.1, TdLpx-B1.2, TdLpx-A2, TdLpx-B2, TdLpx-A3 and TdLpx-B3) under hyperosmotic stress was investigated. With osmotic (0.42 M mannitol) and salt (0.21 M NaCl) stress imposed at the early stages of seedling growth, a strong induction of the TdLpx-A2 gene expression in the shoots paralleled an equally strong increase in the LOX activity. Enhanced levels of malondialdehyde (MDA) and increased rates of superoxide anion generation were also observed as a result of the stress imposition. Sequence analysis of the TdLOX2 encoded by the TdLpx-A2 gene revealed that it belonged to the type-1 9-LOX group. When overexpressed in E. coli, TdLOX2 exhibited normal enzyme activity, high sensitivity to specific LOX inhibitors, with 76% and 99% inhibition by salicylhydroxamic and propyl gallate, respectively, and a preference for linoleic acid as substrate, which was converted exclusively to its corresponding 13-hydroperoxide. This unexpected positional specificity could be related to the unusual TV/K motif that in TdLOX2 replaces the canonical TV/R motif of 9-LOXs. Treatment of seedlings with propyl gallate strongly suppressed the increase in LOX activity induced by the hyperosmotic stress; the MDA accumulation was also reduced but less markedly, whereas the rate of superoxide anion generation was even more increased. Overall, our findings suggest that the up-regulation of the TdLpx-A2 gene is a component of the durum wheat response to hyperosmotic stress and that TdLOX2 may act by counteracting the excessive generation of harmful reactive oxygen species responsible for the oxidative damages that occur in plants under stress. [ABSTRACT FROM AUTHOR]