Mung Bean Seedlings Research Articles

Influence of soil water content and soil amendments on trace metal release and seedling growth in serpentine soil

This study was conducted to evaluate the synergistic effects of organic amendments and soil water status on trace metal release from serpentine soil. Two organic amendments, dendro-biochar (BC) and municipal solid waste compost (CM), were added to serpentine soil at four different ratios, specifically 2.5:0.0, 2.5:1.0, 2.5:2.5, and 2.5:5.0% (w/w). Along with the control (with no organic amendments), each soil treatment was incubated separately under saturated point (SP) and field capacity (FC) water content for 10 days. Subsamples were obtained from each treatment to analyze the bioavailable trace metal concentration and related edaphic parameters, namely total organic carbon (TOC), nitrate (NO3−), phosphate (PO43−), and cation exchange capacity (CEC). Then, the soil solution was eluded from each treatment and incubated for 10 days under permanent wilting point (PW). Furthermore, a seed germination test was performed under the different treatments. Significant reductions (p < 0.05) in bioavailable concentration of all four trace metals were observed in all the amendment ratios under all water status treatments (SP, FC, SP-PW, and FC-PW), compared with the control. Furthermore, FC-PW with the highest amendment ratio (2.5% BC:5.0% CM) reduced Ni by 67.6%; FC-PW with 2.5% BC + 2.5% CM immobilized Mn and Co by 92.1 and 96.9%, respectively, and SP water status with all four amendment ratios immobilized 100% of bioavailable Cr. Maximum amendment ratio under all four water status enhanced %TOC and significantly increased PO43− concentration in SP-PW. However, FC showed comparatively high NO3− concentration than other treatments. Germination index (GI) for mung beans and tomato did not show a significant difference in response to amendment ratios or soil water status; however, SP treatment expressed significantly high seedling vigor (SVI) for mung beans. Treatments of BC and CM effectively immobilize the bioavailable fraction of trace metals in serpentine soils. Increasing amendment ratio increases the %TOC regardless of the soil water status, whereas SP-PW is favorable for the availability of PO43−, and FC is favorable for availability of NO3−. The GI for mung beans and tomato seed was not influenced by the soil water status nor by the amendment ratios. However, the SVI of mung bean seedlings was controlled by the soil water status.

Quantification of starch content in germinating mung bean seedlings by terahertz spectroscopy

To investigate the potential of terahertz spectroscopy to monitor and quantify starch in plants, terahertz spectra (3.0–13.5 THz) of mung bean plants 1–7 days after germination were examined and compared to those of starch and its constituent saccharides (standard reagents). Day 1 seedlings showed similar spectral features with standard starch, and absorption peaks gradually disappeared in the subsequent 6 day growth period. To interpret this result and identify useful peaks for starch quantification, standard starch and day 1 seedlings were hydrolyzed by α-amylase in vitro. Since both standard starch and seedlings showed that absorption peak at 9.0 THz disappeared after amylase hydrolysis, this peak is sensitive to changes in starch. Additionally, intensity of this peak was correlated with starch content as quantified by chemical analysis (r = 0.98). Our results indicate terahertz spectra of seedlings can provide an identifiable peak that is attributed to starch and not affected by the constituent saccharides.

Enhanced Antioxidant Activity in Mung Bean Seedlings Grown under Slow Clinorotation

Initial growth studies in space have demonstrated microgravity has the potential to enhance antioxidant activity in fruit and vegetables. To examine whether a slow-rotating clinostat here on Earth can produce functional foods with enhanced antioxidant activity and related compounds, including carotenoids, phenolics and ascorbic acid, we grew mung bean seedlings under clinorotation (2 rpm) and measured the above components. The clinostat seedlings had higher antioxidant activity and accumulation of related compounds, compared to seedlings grown under normal gravity. To further explore the causes for these results, α-amylase activity and amount of starch in cotyledons were measured. Higher α-amylase activity and lower starch levels were observed in the cotyledons under clinorotation, suggesting the higher levels of sugars resulting from starch conversion were promoting the synthesis of antioxidant compounds and higher antioxidant activity in seedlings when grown under clinorotation. Our data indicate that a clinostat can enhance antioxidant activity in vegetables in the early developmental stage.

Graphene quantum dots-induced physiological and biochemical responses in mung bean and tomato seedlings

Different physiological and biochemical responses in mung bean (Vigna radiata L.) and tomato (Solanum lycopersicum L.) seedlings induced by graphene quantum dots (GQDs) (250–1500 mg L−1) were studied. Results showed that both seeds exposed to GQDs can still germinate normally. However, the growth of the seedlings after germination was adversely affected by the GQDs, and mung bean was more sensitive than tomato. In hydroponic experiments, the appropriate concentration of GQDs enhanced the accumulation of chlorophyll in mung bean (250–1250 mg L−1) and tomato (250–500 mg L−1) seedlings after exposure for 2 weeks. High concentrations of GQDs (1000–1500 mg L−1) led to an increase in the H2O2, malondialdehyde (MDA), proline, glutathione (GSH) levels, as well as increased catalase (CAT) and glutathione reductase (GR) activities in seedlings of both species. In addition, the migration of GQDs into plants was observed. Results showed that high concentrations of GQDs had an adverse effect on the growth of both plants, and mung bean seedlings were more sensitive than tomato seedlings. In addition, the problem of nanocontamination was suggested and the resulting food safety problems warrant further investigation.

Promotion of adventitious root formation in root-cut mung bean seedlings by a commercial alkaline hydrolysis product of soy oil and its ingredients, unsaturated long-chain fatty acids

Promotion of adventitious root formation in root-cut mung bean seedlings by a commercial alkaline hydrolysis product of soy oil and its ingredients, unsaturated long-chain fatty acids

Isolation and characterization of plant growth promoting endophytic bacteria isolated from Vigna radiata

A total of 22 endophytic bacteria were isolated from roots and nodules of Vigna radiata (mungbean) obtained from Jind district, Haryana. These were characterized on the basis of plant growth promoting traits. Almost all the endophytic bacteria produced IAA with maximum production of 81.63µg/ml by isolate MJiR8. Among these, 100% root isolates and 84.6% nodule isolates resulted in in vitro root growth promotion of mungbean seedlings. All the isolates produced ammonia; eighteen (all root and nine nodule isolates) produced organic acid while only four root isolates were positive for siderophore production. The four isolates produced hydrogen cyanide and out of these only MJiR9 inhibited the growth of fungal pathogens Fusarium oxysporium and Aspergillus niger. All the endophytes were used to determine molecular diversity by ARDRA (Amplified Ribosomal DNA Restriction Analysis) Results revealed that the nodule isolates were more diverse, being present in separate clusters, in comparison to root isolates which were grouped together in cluster III.

Possible interaction of ROS, antioxidants and ABA to survive osmotic stress upon acclimation in Vigna radiata L. Wilczek seedlings

Acclimation is a process of adjustment to gradual environmental change that enables plants to survive further stress by triggering some tolerance mechanism possibly involving ABA, ROS and oxidative metabolism. Here we have studied acclimation responses in terms of the performances with regard to physiological (growth and relative water content) and biochemical (chlorophyll, carotenoids, protein, malondialdehyde, sugar content) attributes, ABA production and stomatal sensitivity to exogenous ABA, extracellular ROS production and activation of antioxidant system. Our study reveals that repeated exposure to short-term mild water stress simulated by polyethylene glycol (PEG-6000) induces acclimation in mung bean (Vigna radiata L. Wilczek) seedlings. Acclimation induced tolerance was associated with reduced leaf size and enhanced root growth, accumulation of soluble sugar as osmoprotectant, maintenance of water potential, lessening of membrane damage as indicated by lower MDA content. Acclimated mung bean seedlings have shown greater degree of tolerance through increased production of and enhanced sensitivity to ABA (as reflected by faster stomatal closure), enhanced production of extracellular O2.- and H2O2 and the elevated activities of antioxidative enzymes to control the oxidative burst. Taken together, the results convey that acclimated seedlings minimize osmotic stress-induced damage through a possible network of ABA, ROS and antioxidants.

Non-toxicity of nano alumina: A case on mung bean seedlings

Wide use of Al2O3 nanoparticles (NPs) leading to their possible escape into environment and their interaction with living organisms demands immediate attention. We evaluated impact of nanoparticulate (Al2O3-NPs) and ionic (Al3+) forms of aluminium on early seedling growth of Vigna radiata. While Al3+ inhibited growth of seedlings, Al2O3-NPs did not affect it negatively. Unlike enhancement in proline, malondialdehyde and H2O2 levels in roots and shoots induced by Al3+, these stress markers remained unaltered by Al2O3-NPs. No signs of membrane damage were recorded in roots of seedlings raised in presence of Al2O3-NPs; this was witnessed from insignificant electrolyte leakage and Evans blue uptake. Activities of antioxidant enzymes, i.e., superoxide dismustase, catalase, guaiacol peroxidase in root and shoot were enhanced by Al3+. However, they were unaffected by Al2O3-NPs. Al3+ enhanced levels of non-protein thiols, phenolics and ascorbate, with no alterations induced by Al2O3-NPs. These findings revealed that, Al2O3-NPs did not induce oxidative stress in seedlings. Seedlings raised in Al3+ showed higher uptake of Al than those grown in Al2O3-NPs; Al content was higher in roots. Al was not detected in shoots of seedlings grown in Al2O3-NPs. Lower translocation of Al in seedlings raised in Al2O3-NPs was due to adsorption/restriction of Al2O3-NPs on root surface. Al3+ caused ruptures on root epidermis of seedlings and inhibited root-hair formation, whereas no structural damage was caused by Al2O3-NPs. Our findings revealed that while ionic Al is highly toxic, nanoparticulate form of Al is non-toxic to growth of V. radiata.

Indole-3-butyric acid mediates antioxidative defense systems to promote adventitious rooting in mung bean seedlings under cadmium and drought stresses

In vitro experiments were performed to determine whether auxin can mediate the formation of adventitious roots in response to heavy metal and drought stresses using a model rooting plant, mung bean [Vigna radiata (L.) Wilczek]. The treatments with CdCl2 or mannitol alone significantly inhibited the formation and growth of adventitious roots in mung bean seedlings. In contrast, when CdCl2 or mannitol was applied together with indole-3-butyric acid (IBA), IBA considerably cancelled the inhibition of adventitious rooting by stresses. Treatment with CdCl2 or mannitol alone significantly increased the soluble protein and malondialdehyde (MDA) contents. CdCl2 and mannitol stress each induced differentially significant changes in the activities of antioxidative enzyme and antioxidant levels during adventitious rooting. Notably, both CdCl2 and mannitol stress strongly reduced the peroxidase (POD) and ascorbate peroxidase (APX) activities and glutathione (GSH) and phenols levels. Catalase and superoxide dismutase (SOD) activity were enhanced by CdCl2 but reduced by mannitol. CdCl2 increased the ascorbate acid (ASA) level, which was decreased by mannitol. Furthermore, when CdCl2 or mannitol was applied together with IBA, IBA counteracted the CdCl2- or mannitol-induced increase or decrease in certain antioxidants, MDA, and antioxidative enzymes. These results suggest that Cd and mannitol stress inhibition of adventitious rooting is associated with the regulation of antioxidative enzymes and antioxidants in cells to defense the oxidative stress. Moreover, IBA alleviates the effects of Cd and mannitol stress on the rooting process partially through the regulation of antioxidative defense systems.

Effects of different vermicompost extracts of palm oil mill effluent and palm-pressed fiber mixture on seed germination of mung bean and its relative toxicity.

Several treatment technologies are available for the treatment of palm oil mill wastes. Vermicomposting is widely recognized as efficient, eco-friendly methods for converting organic waste materials to valuable products. This study evaluates the effect of different vermicompost extracts obtained from palm oil mill effluent (POME) and palm-pressed fiber (PPF) mixtures on the germination, growth, relative toxicity, and photosynthetic pigments of mung beans (Vigna radiata) plant. POME contains valuable nutrients and can be used as a liquid fertilizer for fertigation. Mung bean seeds were sown in petri dishes irrigated with different dilutions of vermicomposted POME-PPF extracts, namely 50, 60, and 70% at varying dilutions. Results showed that at lower dilutions, the vermicompost extracts showed favorable effects on seed germination, seedling growth, and total chlorophyll content in mung bean seedlings, but at higher dilutions, they showed inhibitory effects. The carotenoid contents also decreased with increased dilutions of POME-PPF. This study recommends that the extracts could serve as a good source of fertilizer for the germination and growth enhancement of mung bean seedlings at the recommended dilutions.

A simple mung bean infection model for studying the virulence of Pseudomonas aeruginosa.

Here we highlight the development of a simple and high-throughput mung bean model to study virulence in the opportunistic pathogen Pseudomonas aeruginosa. The model is easy to set up, and infection and virulence can be monitored for up to 10 days. In a first test of the model, we found that mung bean seedlings infected with PAO1 showed poor development of roots and high mortality rates compared to uninfected controls. We also found that a quorum-sensing (QS) mutant was significantly less virulent when compared with the PAO1 wild-type. Our work introduces a new tool for studying virulence in P. aeruginosa that will allow for high-throughput virulence studies of mutants and testing of the in vivo efficacy of new therapies at a time when new antimicrobial drugs are desperately needed.

English

The study aimed to determine the effects of humic acid (HA) on seedlings of a salt-sensitive plant, mung bean (Vigna radiata (L.) Wilczek), grown on 50 mM (S1) and 100 mM (S2) NaCl concentrations. In controlled room conditions, mung bean seedlings were planted in pots containing torf and perlite mixture and salt effects were observed. The growth parameters were plant height, number of leaves, leaf area, leaf and stem fresh and dry weights in which all parameters significantly decreased at both salt levels. Nutrient analyses of Na, K and Ca were conducted by flame photometry (FP), and Mg, Mn, Zn were tested by inductively coupled plasma atomic emission spectrometry (ICP-AES), for the above and below ground parts of mung bean seedlings. Both salt treatments increased Na content significantly, however 10 ml addition of HA to those samples (S1HA and S2HA; 50 mM NaCl and 100 mM NaCl, respectively) caused reductions in Na contents of the above-ground parts of mung bean compared to plants watered with only Hoagland-Arnon solutions (HO). On the other hand, in the roots of mung bean seedlings, Na content rose significantly in S2 compared with control, but the amount of Na in S2HA significantly increased compared with S2 treated plants. K content was significantly decreased in both salt concentrations, while SHA1 and SHA2 caused slight increases in both above and underground parts of seedlings. In the experiment, SHA2 increased the content of K, Mg, Ca, Mn and Zn in the root of mung bean seedlings compared with both S1 and S2 treatments. Key words: NaCl, mung bean, growth, nutrient Vigna radiata, humic acid.

Chlorophyll, Carotenoid and Anthocyanin Accumulation in Mung Bean Seedling Under Clinorotation

The accumulation of plant pigments in mung bean (Vigna radiata L.) seedlings was measured after clinorotation (2 rpm for 2-4 days), and compared to a stationary control. The pigments measured included chlorophyll and carotenoid in primary leaves, and the anthocyanin in seedlings. While significant changes in chlorophyll and carotenoid accumulation were not observed during the initial 2 to 4 days of cultivation, by day 4 the seedlings grown on the clinostat had lower levels of anthocyanin, compared to those in the control seedlings. To further detail the cause for the observed reduction in anthocyanin accumulation under altered gravity conditions, seedlings were grown in the presence of silver nitrate, a known ethylene inhibitor, for 4 days, since it is known ethylene has a negative impact on anthocyanin accumulation. Silver nitrate promoted anthocyanin accumulation in the clinostat seedlings, and as a result there was no significant difference between the control and clinostat seedlings in anthocyanin accumulation. The results suggest that slow clinorotation negatively impacts anthocyanin pigmentation in mung bean seedlings, with endogenous ethylene suspected to be involved in this.

In situ immobilization of Cd by organic amendments and their effect on antioxidant enzyme defense mechanism in mung bean (Vigna radiata L.) seedlings

In situ immobilization of Cd is desirable due to the damaging effects of ex situ remediation techniques on soil. In this greenhouse study, the role of biochar (BC), chitosan (CH), and green waste (GW) was studied for in-situ Cd immobilization and alleviating Cd toxicity in mung bean seedlings. Amendments were applied at rates of 0.5% and 1% (w/w). The minimum mean value of Cd, in root, shoot, and soil (DTPA-Cd) (12.2, 4.7, and 0.7 mg kg−1, respectively), occurred in the Cd + 1% CH treatment compared to all Cd amended treatments. Shoot dry weight (21%) increased significantly in Cd + 1% BC amended soil compared to the control. Reactive oxygen species were affected significantly, with the lowest increased value of hydrogen peroxide (4%) in the Cd + 1% CH treatment while the minimum increase in the value of superoxide (O2•–) occurred in the Cd + 1% BC soil compared to the control. Malondialdehyde (20%) increased lowest with Cd + 1% CH treatment. Protein, ascorbate (AsA) contents, and catalase (CAT) activity increased the most (3, 2, and 15%, respectively) in the Cd + 1% BC treatment while dehydroascorbate reductase (DHAR) and superoxide dismutase (SOD) activity increased the most (9 and 234%, respectively) in the Cd + 1% CH soil compared to the control. Glutathione reductase (GR), ascorbate peroxidase (APX), and glutathione peroxidase (GPX), activity were reduced the most in the Cd + 1.0% BC treatment while dehydroascorbate (DHA) and glutathione S-transferase (GST) activity decreased the most in the Cd + 1% CH soil. Overall, in situ immobilization by amendments improved growth and antioxidant defense mechanisms of mung bean seedlings and was reflected by tolerance to Cd-toxicity.

Salicylic acid induced antioxidant system enhances the tolerence to aluminium in mung bean (Vigna radiata L. Wilczek) plants

Aluminium (Al) is one of the major constraints reducing the growth and productivity of many crops in acidic soils throughout the world. In order to explore a possible measure to counter Al toxicity in plants salicylic acid (SA) was used as a treatment in this investigation. The seedlings of mung bean were grown in a plant growth chamber under controlled conditions in a sand culture. The seedlings were subjected to Al (0.0, 1.0 or 10.0 mM) stress, at 1 week old stage and were sprayed with 0 or 10−5 M of SA, at 14 day stage. The analysis of the plants at the completion of 3 weeks of growth revealed that the presence of Al in the nutrient medium caused a sharp reduction in growth (length, fresh and dry mass of root and shoot), the activity of carbonic anhydrase (E.C. 4.2.1.1), relative water content, water use efficiency, chlorophyll content and the rate of photosynthesis. However, the activity of antioxidative enzymes [catalase (E.C. 1.11.1.6), peroxidase (E.C. 1.11.1.7) and superoxide dismutase (E.C. 1.15.1.1)] in leaves and the content of proline, both in leaves and roots increased in the Al stressed plants. The spray of SA, in absence of Al strongly favoured the above parameters and also improved them in the plants grown under Al stress. Moreover, SA caused a further stimulation of antioxidative enzymes and proline content, which were already enhanced by Al stress. This implies that the elevated level of proline in association with antioxidant system, at least in part, was responsible for the amelioration of Al stress in mung bean seedlings.

Transcriptomic profiling provides molecular insights into hydrogen peroxide-induced adventitious rooting in mung bean seedlings

BackgroundHydrogen peroxide (H2O2) has been known to function as a signalling molecule involved in the modulation of various physiological processes in plants. H2O2 has been shown to act as a promoter during adventitious root formation in hypocotyl cuttings. In this study, RNA-Seq was performed to reveal the molecular mechanisms underlying H2O2-induced adventitious rooting.ResultsRNA-Seq data revealed that H2O2 treatment greatly increased the numbers of clean reads and expressed genes and abundance of gene expression relative to the water treatment. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated that a profound change in gene function occurred in the 6-h H2O2 treatment and that H2O2 mainly enhanced gene expression levels at the 6-h time point but reduced gene expression levels at the 24-h time point compared with the water treatment. In total, 4579 differentially expressed (2-fold change > 2) unigenes (DEGs), of which 78.3% were up-regulated and 21.7% were down-regulated; 3525 DEGs, of which 64.0% were up-regulated and 36.0% were down-regulated; and 7383 DEGs, of which 40.8% were up-regulated and 59.2% were down-regulated were selected in the 6-h, 24-h, and from 6- to 24-h treatments, respectively. The number of DEGs in the 6-h treatment was 29.9% higher than that in the 24-h treatment. The functions of the most highly regulated genes were associated with stress response, cell redox homeostasis and oxidative stress response, cell wall loosening and modification, metabolic processes, and transcription factors (TFs), as well as plant hormone signalling, including auxin, ethylene, cytokinin, gibberellin, and abscisic acid pathways. Notably, a large number of genes encoding for heat shock proteins (HSPs) and heat shock transcription factors (HSFs) were significantly up-regulated during H2O2 treatments. Furthermore, real-time quantitative PCR (qRT-PCR) results showed that, during H2O2 treatments, the expression levels of ARFs, IAAs, AUXs, NACs, RD22, AHKs, MYBs, PIN1, AUX15A, LBD29, LBD41, ADH1b, and QORL were significantly up-regulated at the 6- and/or 24-h time points. In contrast, PER1 and PER2 were significantly down-regulated by H2O2 treatment. These qRT-PCR results strongly correlated with the RNA-Seq data.ConclusionsUsing RNA-Seq and qRT-PCR techniques, we analysed the global changes in gene expression and functional profiling during H2O2-induced adventitious rooting in mung bean seedlings. These results strengthen the current understanding of H2O2-induced adventitious rooting and the molecular traits of H2O2 priming in plants.

Enhancement Effect of Gibberellic Acid and Kinetin on Sucrose Metabolism in Mungbean Seedlings Under Arsenate Toxicity

Arsenic pollution is at present an emerging global crisis. Arsenic is a naturally occurring metalloid found in water, soil and air from natural and anthropogenic sources. Currently, Arsenic pollution has gained a burning global importance due to its toxic effects. Growth of major pulse crop Mungbean (<i>Vigna radiata</i> (L.)Wilczek) was affected right from seedling stage when treated with Sodium arsenate (Na₂HAsO₄.7H₂O). With the increase in concentration of Sodium arsenate (5μM, 10μM and 20μM) significant decrease in seedling length, water content and primary leaf area was observed. The vital pigments like chlorophyll, caroteniod content as well as Hill activity reduced appreciably in sodium arsenate treated seedlings which indicates poor photosynthetic metabolism. Arsenate exposure also altered metabolism of main photosynthate, sucrose. Arsenate toxicity led to decrease in reducing and non reducing sugar content in the mungbean seedlings whereas starch content was elevated. Pretreatment of mungbean seeds with Phytohormone-GA₃ and Kinetin could ameliorate Arsenate induced toxicity to different extent in terms of growth and sucrose metabolism. Thus, the use of GA₃ and Kinetin may help to resist the arsenic toxicity in seedling stage, to some extent, in arsenic contaminated areas.

A Comparative Study of Three Rhizospheric Bacteria Belonging to Different Genera, Co-Infecting a Leguminous Plant

Nodules obtained from the roots of fenugreek (Trigonella foenum graecum), a leguminous plant yielded three distinct classes of Nitrogen fixing bacteria. Molecular phylogeny based on 16S rRNA gene sequences showed them to be Enterobacter cloacae (R1), Pantoea dispersa (R10) and Enterobacter ludwigii (R12). The biochemical and morphological characterization of the three bacteria showed many similarities. All were gram negative, rod shaped, giving identical biochemical reactions like Catalase test, MR tests, oxidase test etc. However there were differences in their sensitivity to the abiotic stresses like salinity, tolerance to heavy metal ions and temperature. Sensitivity to antibiotics also showed similar responses. Co-infecting the same plant and occurrence in the same nodules by different genera of bacteria, capable of Nitrogen fixation is a novel phenomenon. The commonly held belief that all Nitrogen fixing mucoid bacteria occurring in nodules of legumes are Rhizobial species is not tenable. Plant growth promoting effects of these bacteria were observed by IAA, siderophore production and inhibition of ethylene biosynthesis by plants by producing the enzyme, ACC Deaminase. The host specificity for one of the bacterium, R1 was shown as only Fenugreek showed nodulation but not mung bean or Bengal Gram seedlings. Nitrogen fixation by the isolated bacteria showed all of these could reduce acetylene to ethylene by gas chromatography.

Mix cropping of legume (Vigna Radiata) and non-legume (Zea Mays) crops alleviates water stress as revealed by growth and biochemical parameters

Drought stress is one of the most detrimental factors reducing crops yield throughout the world. The present study was conducted to assess the role of legume and non-legume mix cropping (maize and mung bean) in alleviation of water stress. The experiments were conducted both in Petri plates in the laboratory and in pots in the green house. Laboratory experiment was used for the determination of the effect of mix cropping on germination and growth parameters, while pot experiment was used for the determination of the effect on biochemical characteristics of both the crops. Water stress was induced as mannitol solution. Five treatments, i.e., control (0 M), 0.2, 0.4, 0.6, and 0.8 M mannitol, were used. Germination in both maize and mung bean was completely inhibited at 0.8 M of mannitol in both sole and mixed sown seeds. Germination in maize seeds sown as mix cropping was significantly lower than in maize seeds sown alone. No significance difference was observed in the germination of mung bean seeds sown alone or in mix cropping. The length and fresh and dry biomass of both root and shoot of maize seedlings grown in mix cropping were significantly higher than maize grown alone at various levels of water stress. In mung bean, length and fresh and dry biomass of root and fresh biomass of shoot were significantly higher in seedlings grown in mix cropping than in seedlings grown as sole cropping. Protein and moisture contents of maize grown as mix cropping were significantly higher than seedlings grown as sole cropping. There was a significance difference in protein content between seedlings of mung bean grown alone and mixed with maize at 0.6 M, while there was a significant difference in fat contents at 0.8 M. The moisture and ash contents of mung bean grown as sole and mix cropping showed no significant difference. The overall results showed that mix-cropping alleviated water stress up to 0.6 M of mannitol but did not show any promising effect above this level of water stress. It is concluded that mix cropping can be helpful in alleviation of low-level water stress, but under high water stress, mix cropping may not have any significant role.

Polyamines-induced aluminum tolerance in mung bean: A study on antioxidant defense and methylglyoxal detoxification systems.

We investigated the roles of exogenously applied Spd (0.3 mM spermidine) in alleviating Al (AlCl3, 0.5 mM, 48 and 72 h)- induced injury in mung bean seedlings (Vigna radiata L. cv. BARI Mung-2). Aluminum toxicity induced oxidative damage overproducing reactive oxygen species (ROS; H2O2 and O2•-), increasing lipoxygenase activity and membrane lipid peroxidation. The toxic compound methylglyoxal (MG) also overproduced under Al stress. In order to circumvent Al-induced oxidative stress, enzymatic and non-enzymatic antioxidant defense were activated by the application of exogenous Spd. Exogenous Spd increased ascorbate (AsA) and glutathione (GSH) content, AsA/dehydroascorbate (DHA) ratio, GSH/ glutathione disulfide (GSSG) ratio, activity of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR) and catalase (CAT) which reduced ROS production and oxidative stress under Al stress. Spd-induced improvement of GSH pool and Gly II activity alleviated injurious effects of MG. Exogenous Spd positively modulated the endogenous PAs level. Regulating the osmoprotectant molecule (proline), Spd improved plant water status under Al stress. Exogenous Spd was potent to prevent breakdown of Al-induced photosynthetic pigment and to improve growth performances under Al stress. The mechanism by which Spd enhances antioxidant and glyoxalase components might be studied extensively. Spermidine-induced protection of photosynthetic pigment from damages and growth enhancement were remarkable and recommended for further detailed study to understand the mechanism.