Gamma amino butyric acid (GABA) application modulated the morpho-physiological and yield traits of fragrant rice under well-watered and drought conditions.

BACKGROUND: Changing climate is causing erratic rainfall and prolonged drought periods, thus posing serious threats to crop productivity. Owing to severity of drought events, it is imperative to take proactive measures to enhance the resilience of drought sensitive crops like rice. Therefore, the present study was carried out to improve the drought stress tolerance in rice through gamma amino butyric acid (GABA) application. METHODS: The experiment was included four GABA concentrations i.e., 0 mM as control, 1 mM, 1.5 mM, and 2 mM, two water levels i.e., 100% and 50% field capacity (referred as FC100 for well-watered and FC50 for drought conditions, respectively), and two fragrant rice cultivars i.e., Super Basmati and Basmati-515. RESULTS: The findings unveiled a comprehensive improvement in various parameters with GABA application in fragrant rice under both well-watered (FC100) and water-limited (FC50) conditions, compared to the control. Specifically, GABA induced enhancements were observed in plant height, root length, fresh weight, dry weight, total soluble protein content, and total free amino acid content across both cultivars. Moreover, GABA application significantly improved peroxidase (POD) and catalase (CAT) enzyme activities, alongside elevating anthocyanin levels, while concurrently reducing H2O2 contents in both FC100 and FC50 treatments. Furthermore, the positive impact of GABA extended to morphological traits, with notable increases in panicle length, total tillers and productive tillers per hill, branch and grain numbers per panicle, and 1000-grain weight for Super Basmati and Basmati 515 cultivars under both water regimes, compared to Ck. Similarly, the grain yield increased by 31.01% and 27.32% under FC100 and 36.85% and 27.71% under FC50 in Super Basmati and Basmati-515, respectively, in response to GABA application, compared to Ck. Additionally, principal component analysis (PCA) revealed significant variances attributed to Dim1 and Dim2, with 86.1% and 4.0% of the variance, respectively, across three bi-plots encompassing rice cultivars, water levels, and GABA treatments. Notably, all tested indices, except for H2O2 and non-productive tillers per hill, exhibited positive correlations amongst themselves and with rice yield, further emphasizing the beneficial effects of GABA application on fragrant rice under well-watered and drought conditions. CONCLUSIONS: GABA significantly improved fragrant rice performance under both well-watered (FC100) and water-limited (FC50) conditions. Moreover, integrating GABA application into rice cultivation practices could not only improve the crop resilience to drought stress but also potentially benefiting the future food and nutritional security globally. However, however; further research is needed to understand the cellular and molecular mechanisms of the functionality of GABA in fragrant rice, particularly under drought conditions.

Alternate wetting and drying modulated physio-biochemical attributes, grain yield, quality, and aroma volatile in fragrant rice.

Alternate wetting and drying (AWD) has been recognized as a water-saving technology in rice production systems; however, pre- and post-flowering AWD could induce changes in yield, quality and aroma biosynthesis in fragrant rice. In the present study, two fragrant rice cultivars (Guixiangzhan and Nongxiang-18) were subjected to AWD till soil water potential reached -25 to -30 kPa during vegetative stage (VS), reproductive stage (RS), and both stages (VS + RS). The AWD did not affect net photosynthesis and gas exchange significantly, while malondialdehyde (MDA), H2 O2 and electrolyte leakage (EL) were higher than in control plants. The AWD treatments variably affected soluble sugars, proline and protein accumulation as well as the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and reduced glutathione (GSH) contents. Moreover, filled grain percentage and 1000-grain weight in AWD treatments were found to be statistically similar (p > 0.05) to control, except grains panicle-1 under AWD-VS + RS that was reduced by 11% and 14% for Guixiangzhan and Nongxiang-18, respectively. On average, yield and related attributes in Guixiangzhan remained higher than in Nongxiang-18. In addition, the grain aroma volatile (2-acetyl-1-pyrroline, 2-AP) content increased by 8.79%, 14.45%, and 6.87% and 7.95%, 14.02%, and 5.04% under AWD-VS, AWD-RS, and AWD-VS + RS treatments, for Guixiangzhan and Nongxiang-18, respectively. Overall, AWD treatments, either at VS or RS, could promote rice aroma in terms of accumulation of 2AP, which might be linked with enhanced endogenous proline contents (a precursor for 2AP biosynthesis) without any severe consequences on rice yield and quality.

Exogenous Gamma-Aminobutyric Acid Application Induced Modulations in the Performance of Aromatic Rice Under Lead Toxicity.

Gamma-aminobutyric acid (GABA) is a non-protein amino acid and has a multi-functional role in abiotic stress tolerance. A pot experiment was conducted to assess the role of exogenous gamma-aminobutyric acid (GABA) application to modulate the growth, yield, and related physio-biochemical mechanisms in two aromatic rice cultivars, that is, Guixiangzhan (GXZ) and Nongxiang 18 (NX-18), under Pb toxic and normal conditions. The experimental treatments were comprised of Ck: without Pb and GABA (control), GABA: 1 mM GABA is applied under normal conditions (without Pb), Pb + GABA: 1 mM GABA is applied under Pb toxicity (800 mg kg-1 of soil), and Pb= only Pb (800 mg kg-1 of soil) is applied (no GABA). The required concentrations of GABA were applied as a foliar spray. Results revealed that Pb stress induced oxidative damage in terms of enhanced malondialdehyde (MDA), electrolyte leakage (EL), and H2O2 contents, while exogenous GABA application improved leaf chlorophyll, proline, protein and GABA contents, photosynthesis and gas exchange, and antioxidant defense under Pb toxicity in both rice cultivars. Moreover, glutamine synthetase (GS) and nitrate reductase (NR) activities were variably affected due to GABA application under Pb stress. The yield and related traits, that is, productive tillers/pot, grains/panicle, filled grain %, 1,000-grain weight, and grain yield were 13.64 and 10.29, 0.37% and 2.26%, 3.89 and 19.06%, 7.35 and 12.84%, and 17.92 and 40.56 lower under Pb treatment than Pb + GABA for GXZ and NX-18, respectively. Furthermore, exogenous GABA application in rice reduced Pb contents in shoot, leaves, panicle, and grains compared with Pb-exposed plants without GABA. Overall, GXZ performed better than NX-18 under Pb toxic conditions.

Maize Tolerance against Drought and Chilling Stresses Varied with Root Morphology and Antioxidative Defense System.

Maize belongs to a tropical environment and is extremely sensitive to drought and chilling stress, particularly at early developmental stages. The present study investigated the individual and combined effects of drought (15% PEG-Solution) and chilling stress (15/12 °C) on morpho-physiological growth, osmolyte accumulation, production of reactive oxygen species (ROS), and activities/levels of enzymatic and non-enzymatic antioxidants in two maize hybrids (i.e., "XD889" and "XD319") and two inbred cultivars (i.e., "Yu13" and "Yu37"). Results revealed that individual and combined exposure of drought and chilling stresses hampered the morpho-physiological growth and oxidative status of maize cultivars, nevertheless, the interactive damage caused by drought + chilling was found to be more severe for all the studied traits. Between two individual stress factors, chilling-induced reductions in seedling length and biomass of maize cultivars were more compared with drought stress alone. Greater decrease in root length and biomass under chilling stress ultimately decreased the volume and surface area of the root system, and restricted the shoot growth. All the stress treatments, particularly chilling and drought + chilling, triggered the oxidative stress by higher accumulation of superoxide anion, hydrogen peroxide, hydroxyl ion, and malondialdehyde contents compared with the control. Variations in response of maize cultivars were also apparent against different stress treatments, and XD889 performed comparatively better than the rest of the cultivars. The better growth and greater stress tolerance of this cultivar was attributed to the vigorous root system architecture, as indicated by higher root biomass, root surface area, and root volume under drought and chilling stresses. Moreover, efficient antioxidant defense system in terms of higher total antioxidant capability, superoxide dismutase, peroxidase, catalase, and glutathione reductase activities also contributed in greater stress tolerance of XD889 over other cultivars.

Lead (Pb) distribution and accumulation in different plant parts and its associations with grain Pb contents in fragrant rice.

Lead (Pb) affects the growth and productivity of rice negatively through soil-Pb-plant interactions. A pot experiment was conducted to assess the Pb uptake and its distributive pattern in different fragrant rice cultivars i.e., Meixiangzhan-2 (MXZ-2), Xiangyaxiangzhan (XYXZ), Guixiangzhan (GXZ), Basmati-385 (B-385), and Nongxiang-18 (NX-18) and relationship of Pb uptake with grain Pb-contents and rice yield and related traits i.e., productive tillers hill-1, spikelets panicle-1, filled grain percentage, and 1000-grain weight. Lead as Pb(NO3)2 was applied at 0 (control), 400 (Pb1), 800 (Pb2) and 1200 mg kg-1 (Pb3) of soil in solution form. Results showed that all rice cultivars accumulated different concentration of Pb, with the highest in roots and the lowest in grains. The translocation factors (TF) from stems to leaves were higher than root to stems and leaves to ears/grains. The grain Pb contents have significant positive associations with ear Pb contents and TF of Pb from leaves to ear at reproductive stage. Moreover, relative changes (RC) in grain yields have significant correlations with the RC in some yield attributes i.e., productive tillers per hill, spikelets per panicle, and filled grain percentage under Pb toxicity. Overall, grain Pb contents are affected mainly by the transference of leaves Pb contents to ears/grains (an index to determine final grain Pb contents) whereas RC in rice yields suggested its relationships with some agronomic attributes of fragrant rice under Pb stress.

Author Correction: Effect of Plant Density, Boron Nutrition and Growth Regulation on Seed Mass, Emergence and Offspring Growth Plasticity in Cotton.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Effect of Plant Density, Boron Nutrition and Growth Regulation on Seed Mass, Emergence and Offspring Growth Plasticity in Cotton.

Seed nutrients reserves have direct relationship with seed functional traits and influence offspring performance. Effects of plant density, foliage boron (B) nutrition and mepiquat chloride (MC) growth regulation on seed nutrients reserves, seed mass and production, and emergence and offspring growth traits of cotton were studied in two years field experiment. Seed nutrients reserves and seed mass were decreased at higher maternal plant density relative to lower plant density with concomitant decrease in emergence and offspring seedling growth. However, maternal foliage B nutrition and MC growth regulation enhanced seed nutrients reserves, seed mass, emergence and offspring seedling growth performance. There was a significant positive relationship between seed mass and seed nutrients reserves indicating that changes in nutrient availability/uptake in response to maternal ecological factors determine variation in seed functional traits. Nonetheless, seed mass was positively correlated with emergence percentage and negatively with emergence timing. Furthermore, variation in offspring seedling growth traits with seed mass indicated the significance of initial seed nutrients reserves for early seedling vigour and establishment. In conclusion, lower maternal plant density, B nutrition and MC growth regulation ensued in higher emergence and offspring seedling growth of cotton because of higher seed nutrient reserves and seed mass.

Chilling and Drought Stresses in Crop Plants: Implications, Cross Talk, and Potential Management Opportunities.

Plants face a combination of different abiotic stresses under field conditions which are lethal to plant growth and production. Simultaneous occurrence of chilling and drought stresses in plants due to the drastic and rapid global climate changes, can alter the morphological, physiological and molecular responses. Both these stresses adversely affect the plant growth and yields due to physical damages, physiological and biochemical disruptions, and molecular changes. In general, the co-occurrence of chilling and drought combination is even worse for crop production rather than an individual stress condition. Plants attain various common and different physiological and molecular protective approaches for tolerance under chilling and drought stresses. Nevertheless, plant responses to a combination of chilling and drought stresses are unique from those to individual stress. In the present review, we summarized the recent evidence on plant responses to chilling and drought stresses on shared as well as unique basis and tried to find a common thread potentially underlying these responses. We addressed the possible cross talk between plant responses to these stresses and discussed the potential management strategies for regulating the mechanisms of plant tolerance to drought and/or chilling stresses. To date, various novel approaches have been tested in minimizing the negative effects of combine stresses. Despite of the main improvements there is still a big room for improvement in combination of drought and chilling tolerance. Thus, future researches particularly using biotechnological and molecular approaches should be carried out to develop genetically engineered plants with enhanced tolerance against these stress factors.

Water management regimes alter Pb uptake and translocation in fragrant rice.

Rice cultivation in lead (Pb) polluted soils often leads to high Pb contents in rice grains. The present study investigated the dynamics of Pb uptake under different water regimes in two fragrant rice cultivars i.e., Guixiangzhan and Nongxiang-18. Results revealed that water dynamics regulated the antioxidant activities in both rice cultivars under Pb toxicity. Compared to continuous ponding (CP), taken as control, alternate wetting and drying (AWD) reduced the Pb contents in roots, stems, leaves, and grains up to 17%, 41%, 22%, and 52% in Guixiangzhan and 23%, 19%, 17%, and 37% in Nongxiang-18, respectively. Furthermore, AWD-treatments reduced paddy yield from 11% to 21% in Guixiangzhan and 11-33% in Nongxiang-18 under Pb toxicity. In conclusion, Pb loadings in fragrant rice can be regulated by effective water management and/or by controlling irrigation water at different growth stages. Special control measures or management is required to cultivate the rice in metal(loid)s polluted soils.

Relay cropping of wheat (Triticum aestivum L.) in cotton (Gossypium hirsutum L.) improves the profitability of cotton-wheat cropping system in Punjab, Pakistan.

Delayed sowing of wheat (Triticum aestivum L.) in cotton-based system reduces the productivity and profitability of the cotton-wheat cropping system. In this scenario, relay cropping of wheat in standing cotton might be a viable option to ensure the timely wheat sowing with simultaneous improvement in wheat yields and system profitability. This 2-year study (2012-2013 and 2013-2014) aimed to evaluate the influence of sowing dates and relay cropping combined with different management techniques of cotton sticks on the wheat yield, soil physical properties, and the profitability of the cotton-wheat system. The experiment consisted of five treatments viz. (S1) sowing of wheat at the 7th of November by conventional tillage (two disc harrows + one rotavator + two plankings) after the removal of cotton sticks, (S2) sowing of wheat at the 7th of November by conventional tillage (two disc harrows + two plankings) after the incorporation of cotton sticks in the field with a rotavator, (S3) sowing of wheat at the 7th of November as relay crop in standing cotton with broadcast method, (S4) sowing of wheat at the 15th of December by conventional tillage (two disc harrows + one rotavator + two plankings) after the removal of cotton sticks, and (S5) sowing of wheat at the 15th of December by conventional tillage (two disc harrows + two plankings) after the incorporation of cotton sticks in the field with a rotavator. The highest seed cotton yield was observed in the S5 treatment which was statistically similar with the S3 and S4 treatments; seed cotton yield in the S1 and S2 treatments has been the lowest in both years of experimentation. However, the S2 treatment produced substantially higher root length, biological yield, and grain yield of wheat than the other treatments. The lower soil bulk density at 0-10-cm depth was recorded in the S2 treatment which was statistically similar with the S5 treatment during both years of experimentation. The volumetric water contents, net benefit, and benefit-cost ratio were the highest in the S3 treatment during both years of experimentation. Thus, relay cropping of wheat in standing cotton might be a viable option to improve the soil physical environment and profitability of the cotton-wheat cropping system.

Crop Production under Drought and Heat Stress: Plant Responses and Management Options.

Abiotic stresses are one of the major constraints to crop production and food security worldwide. The situation has aggravated due to the drastic and rapid changes in global climate. Heat and drought are undoubtedly the two most important stresses having huge impact on growth and productivity of the crops. It is very important to understand the physiological, biochemical, and ecological interventions related to these stresses for better management. A wide range of plant responses to these stresses could be generalized into morphological, physiological, and biochemical responses. Interestingly, this review provides a detailed account of plant responses to heat and drought stresses with special focus on highlighting the commonalities and differences. Crop growth and yields are negatively affected by sub-optimal water supply and abnormal temperatures due to physical damages, physiological disruptions, and biochemical changes. Both these stresses have multi-lateral impacts and therefore, complex in mechanistic action. A better understanding of plant responses to these stresses has pragmatic implication for remedies and management. A comprehensive account of conventional as well as modern approaches to deal with heat and drought stresses have also been presented here. A side-by-side critical discussion on salient responses and management strategies for these two important abiotic stresses provides a unique insight into the phenomena. A holistic approach taking into account the different management options to deal with heat and drought stress simultaneously could be a win-win approach in future.

Alterations in growth, oxidative damage, and metal uptake of five aromatic rice cultivars under lead toxicity.

Lead (Pb) affects plant growth and its related physio-biochemical functions negatively. The present study investigated the responses of five different fragrant rice cultivars viz., Meixiangzhan (MXZ-2), Xiangyaxiangzhan (XYXZ), Guixiangzhan (GXZ), Basmati-385 (B-385), and Nongxiang-18 (NX-18) to four different Pb concentrations viz., 0, 400, 800 and 1200 µM. Results depicted that Pb toxicity significantly (P < 0.05) reduced the plant height, tillering ability and biomass accumulation by causing oxidative damage to rice plants; nonetheless, a significant variation was found in the sensitivity of rice cultivars to Pb toxicity. Soluble sugars increased significantly only at 1200 µM in GXZ and 800 µM in B-385, whilst the maximum reductions in protein contents were observed at 1200 µM Pb for all rice cultivars. Proline contents were reduced for XYXZ and NX-18 at Pb1200 µM. Activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) as well as reduced glutathione (GSH) and oxidized glutathione (GSSG) showed differential behavior among Pb treatments and rice cultivars. Among rice cultivars, GXZ showed better antioxidative defense system under Pb toxicity compared with all other cultivars. For all rice cultivars, the trend for Pb accumulation was recorded as: roots > stems > leaves. Furthermore, significant but negative correlations among Pb uptake and plant height (r = -0.79), tillers per plant (r = -0.91) and plant dry biomass (r = -0.81) were recorded for all rice cultivars whereas the values of translocation factor (TF) from stems to leaves were higher than roots to stems. In sum, Pb reduced the early growth and caused physio-biochemical changes in all rice cultivars, nonetheless, GXZ proved better able to tolerate Pb stress than all other rice cultivars under study.

Drought Induced Changes in Growth, Osmolyte Accumulation and Antioxidant Metabolism of Three Maize Hybrids.

Consequences of drought stress in crop production systems are perhaps more deleterious than other abiotic stresses under changing climatic scenarios. Regulations of physio-biochemical responses of plants under drought stress can be used as markers for drought stress tolerance in selection and breeding. The present study was conducted to appraise the performance of three different maize hybrids (Dong Dan 80, Wan Dan 13, and Run Nong 35) under well-watered, low, moderate and SD conditions maintained at 100, 80, 60, and 40% of field capacity, respectively. Compared with well-watered conditions, drought stress caused oxidative stress by excessive production of reactive oxygen species (ROS) which led to reduced growth and yield formation in all maize hybrids; nevertheless, negative effects of drought stress were more prominent in Run Nong 35. Drought-induced osmolyte accumulation and strong enzymatic and non-enzymatic defense systems prevented the severe damage in Dong Dan 80. Overall performance of all maize hybrids under drought stress was recorded as: Dong Dan 80 > Wan Dan 13 > Run Nong 35 with 6.39, 7.35, and 16.55% yield reductions. Consequently, these biochemical traits and differential physiological responses might be helpful to develop drought tolerance genotypes that can withstand water-deficit conditions with minimum yield losses.

Relay cropping as a sustainable approach: problems and opportunities for sustainable crop production.

Climate change, soil degradation, and depletion of natural resources are becoming the most prominent challenges for crop productivity and environmental sustainability in modern agriculture. In the scenario of conventional farming system, limited chances are available to cope with these issues. Relay cropping is a method of multiple cropping where one crop is seeded into standing second crop well before harvesting of second crop. Relay cropping may solve a number of conflicts such as inefficient use of available resources, controversies in sowing time, fertilizer application, and soil degradation. Relay cropping is a complex suite of different resource-efficient technologies, which possesses the capability to improve soil quality, to increase net return, to increase land equivalent ratio, and to control the weeds and pest infestation. The current review emphasized relay cropping as a tool for crop diversification and environmental sustainability with special focus on soil. Briefly, benefits, constraints, and opportunities of relay cropping keeping the goals of higher crop productivity and sustainability have also been discussed in this review. The research and knowledge gap in relay cropping was also highlighted in order to guide the further studies in future.

Early- and late-stage morphea subtypes with deep tissue involvement is treatable with Abatacept (Orencia).

OBJECTIVES: This case series explores the potential efficacy of Abatacept in patients presenting with morphea subtypes and deep tissue involvement. METHODS: Three patients with established morphea subtypes and deep tissue involvement and with no contraindication to Abatacept were included in this prospective open-label study. The index patient was exceptionally severely affected with a mean Modified Rodnan Skin Score (MRSS) of 38/51. At baseline, whole-body MRI and skin biopsy were performed which confirmed classical deposition of dense fibrous tissue in the appropriate layer of the skin. MRSS was performed independently by three clinicians and VAS scores (10cm) were measured at baseline for Patient Global Disease Activity (PGDA), Patient Global Pain (PGP), Patient Day Pain (PDP), Patient Night Pain (PNP), and Physician Global Disease Activity (PhGDA). Patients 2 and 3 were similarly screened at baseline except for MRI. Patients were commenced on Abatacept as per body weight (10mg/kg) given intravenously with concomitant tapering dose of oral prednisolone. All three were re-assessed at 6 months and the index case was further re-assessed at 18 months. RESULTS: All patients tolerated the Abatacept well and showed dramatic improvement. The index patient's clinical signs and symptoms, whole-body MRI, and mean Modified Rodnan Skin Score improved dramatically from baseline by 37% at 6 months and by 74% at 18 months. There were no clinically significant adverse outcomes noted. CONCLUSION: We present three cases, one with exceptionally severe disease, which demonstrated excellent clinical response to Abatacept. Abatacept is a promising option for the treatment of severe or resistant morphea, especially in those with deep tissue involvement.

Lodging stress in cereal-effects and management: an overview.

Uncertainty in climatic and weather conditions may result in lodging. Lodging is a most chronic constraint, which is causing tremendous yield reduction in crop plants; therefore, better understanding to control lodging-induced adversities or to enhance lodging resistance in cereals is imperative. In this review, we presented a contemporary synthesis of the existing data regarding the effects of lodging on growth and yield of cereals. Moreover, we highlighted key factors which trigger the detrimental effects of lodging in cereals. Numerous morphological, anatomical, and biochemical traits in plants that can influence lodging risk have also been discussed. These traits showed significant correlation with lodging resistance in cereals. At end, we tried to link our hypothetical concepts with previous evidences and provided a comprehensive summary of all the possible management approaches that can be used to further control lodging effects on cereals. The selection of a management option though is based on cereal type and genotype; nonetheless, different agronomic approaches including seeding rate, sowing time, tillage system, crop rotation, and fertilizer application help in reducing lodging risk in cereals.

Is There Any Impact Of The Gutkha Ban on Users and Vendors in Rangareddy District? A Cross Sectional Study

Introduction: Gutkha contains harmful and carcinogenic chemicals and oral cancer caused by tobacco usage has been reported as a major preventable cause of death worldwide by the World Health Organization. The Telangana state government implemented a ban on gutkha usage starting in 2013 but how effective this ban has been remains unclear. Objectives: The objective of this study was to determine the actual impact of the gutkha ban on users and vendors. Methodology: A cross-sectional study was conducted among gutkha users and tobacco vendors in Ranga Reddy district, Telangana. Based on a pilot study the sample size was determined as 368 and 384 for users and vendors respectively. Two separate questionnaires were administered to these groups. The parameters studied mainly included knowledge regarding the ban, and its impact. Results: About 49.1% of the users were aware of the ban on gutkha. Newspapers were the main source of information regarding the ban as reported by 45.3% of users. After the ban, 29.8% of gutkha users switched to other tobacco products. Awareness of health hazards and non-availability of gutkha was the most important reason stated for quitting or reducing consumption. Conclusion: The perspective of ban when visualized from the users point of view depicted a negative impact while the vendors portrayed a positive impact. Considering the addictive potential of the ingredients of gutkha, recording the effects of the ban on regular consumers and determining whether they can still obtain the products by illicit trade, would be noteworthy for implementation of strict rules.

Lithium toxicity in plants: Reasons, mechanisms and remediation possibilities - A review.

Lithium (Li) is a naturally occurring element; however, it is one of the non-essential metals for life. Lithium is becoming a serious matter of discussion for the people who do research on trace metals and environmental toxicity in plants. Due to limited information available regarding its mobility from soil to plants, the adverse effects of Li toxicity to plants are still unclear. This article briefly discusses issues around Li, its role and its essentiality in plants and research directions that may assist in inter-disciplinary studies to evaluate the importance of Li's toxicity. Further, potential remediation approaches will also be highlighted in this review. Briefly, Li influenced the growth of plants in both stimulation and reduction ways, depending on the concentration of Li in growth medium. On the negative side, Li reduces the plant growth by interrupting numerous physiological processes and altering metabolism in plant. The contamination of soil by Li is becoming a serious problem, which might be a threat for crop production in the near future. Additionally, lack of considerable information about the tolerance mechanisms of plants further intensifies the situation. Therefore, future research should emphasize in finding prominent and approachable solutions to minimize the entry of Li from its sources (especially from Li batteries) into the soil and food chain.

Effect of progressive drought stress on growth, leaf gas exchange, and antioxidant production in two maize cultivars.

Drought stress is one of the major environmental factors responsible for reduction in crop productivity. In the present study, responses of two maize cultivars (Rung Nong 35 and Dong Dan 80) were examined to explicate the growth, yield, leaf gas exchange, leaf water contents, osmolyte accumulation, membrane lipid peroxidation, and antioxidant activity under progressive drought stress. Maize cultivars were subjected to varying field capacities (FC) viz., well-watered (80 % FC) and drought-stressed (35 % FC) at 45 days after sowing. The effects of drought stress were analyzed at 5, 10, 15, 20, ad 25 days after drought stress (DAS) imposition. Under prolonged drought stress, Rung Nong 35 exhibited higher reduction in growth and yield as compared to Dong Dan 80. Maize cultivar Dong Dan 80 showed higher leaf relative water content (RWC), free proline, and total carbohydrate accumulation than Run Nong 35. Malondialdehyde (MDA) and superoxide anion were increased with prolongation of drought stress, with higher rates in cultivar Run Nong 35 than cultivar Dong Dan 80. Higher production of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and glutathione reductase (GR) resulted in improved growth and yield in Dong Dan 80. Overall, the cultivar Dong Dan 80 was better able to resist the detrimental effects of progressive drought stress as indicated by better growth and yield due to higher antioxidant enzymes, reduced lipid peroxidation, better accumulation of osmolytes, and maintenance of tissue water contents.

Osmoregulation and antioxidant production in maize under combined cadmium and arsenic stress.

An investigation was carried out to examine the combined and individual effects of cadmium (Cd) and arsenic (As) stress on osmolyte accumulation, antioxidant activities, and reactive oxygen species (ROS) production at different growth stages (45, 60, 75, 90 days after sowing (DAS)) of two maize cultivars viz., Dong Dan 80 and Run Nong 35. The Cd (100 µM) and As (200 µM) were applied separately as well as in combination (Cd + As) at 30 DAS. Results revealed pronounced variations in the behavior of antioxidants, osmolytes, and ROS in both maize cultivars under the influence of Cd and As stress. Activities of enzymatic (SOD, POD, CAT and APX, GPX, GR) and non-enzymatic (GSH and AsA) antioxidants, generation of ROS, and accumulation of osmolytes were enhanced with the passage of time; therefore, the maximum values for these attributes were observed at 90 DAS for both cultivars. Exposure of plants to Cd or As stress considerably enhanced the antioxidant activities, ROS, and osmolyte accumulation compared with control, while combined application of Cd + As was more devastating in reducing plant biomass of both maize cultivars. Among cultivars, Dong Dan 80 was better able to negate the heavy metal-induced oxidative damage, which was associated with higher antioxidant activities, greater osmolytes accumulation, and lower ROS production in this cultivar.