Computational and experimental analysis of foxtail millet under salt stress and selenium supplementation.

Salinity stress is a major threat to crop growth and productivity. Millets are stress-tolerant crops that can withstand the environmental constraints. Foxtail millet is widely recognized as a drought and salinity-tolerant crop owing to its efficient ROS scavenging mechanism. Ascorbate peroxidase (APX) is one of the reactive oxygen species (ROS) scavenging enzymes that leads to hydrogen peroxide (H2O2) detoxification and stabilization of the internal biochemical state of the cell under stress. This inherent capacity of the APX enzyme can further be enhanced by the application of an external mitigant. This study focuses on the impact of salt (NaCl) and selenium (Se) application on the APX enzyme activity of foxtail millet using in silico and in-vitro techniques and mRNA expression studies. The NaCl was applied in the concentrations, i.e., 150 mM and 200 mM, while the Se was applied in 1 µM, 5 µM, and 10 µM concentrations. The in silico studies involved three-dimensional structure modeling and molecular docking. The in vitro studies comprised the morphological and biochemical parameters, alongside mRNA expression studies in foxtail millet under NaCl stress and Se applications. The in silico studies revealed that the APX enzyme showed better interaction with Se as compared to NaCl, thus suggesting the enzyme-modulating role of Se. The morphological and biochemical analysis indicated that Se alleviated the NaCl (150 mM and 200 mM) and induced symptoms at 1 µM as compared to 5 and 10 µM by enhancing the morphological parameters, upregulating the gene expression and enzyme activity of APX, and ultimately reducing the H2O2 content significantly. The transcriptomic studies confirmed the upregulation of chloroplastic APX in response to salt stress and selenium supplementation. Hence, it can be concluded that Se as a mitigant at lower concentrations can alleviate NaCl stress in foxtail millet.

The swansong of petal cell death: insights into the mechanism and regulation of ethylene-mediated flower senescence.

Flower senescence is a fundamental aspect of the developmental trajectory in flowers, occurring after the differentiation of tissues and maturation of petals, and preceding the growth and development of seeds. It is accompanied by various alterations at the cytological, physiological, and molecular levels, similar to other forms of programmed cell death (PCD). It involves an intricate interplay of various plant growth regulators, with ethylene being the key orchestrator in ethylene-dependent petal senescence. Petal senescence mediated by ethylene is marked by various changes such as petal wilting, amplified oxidative stress, degradation of proteins and nucleic acids, and autophagy. Ethylene crosstalks with other growth regulators and triggers genetic and/or epigenetic reprogramming of genes during senescence in flowers. While our understanding of the mechanism and regulation of petal senescence in ethylene-sensitive species has advanced, significant knowledge gaps still exist, which demand critical reappraisal of the available literature on the topic. A deeper understanding of the various mechanisms and regulatory pathways involved in ethylene-dependent senescence has the capacity to facilitate a more precise regulation of the timing and site of senescence, thus leading to optimized crop yields, enhanced product quality, and extended longevity.

Glucose metabolic reprogramming and modulation in glycerol biosynthesis regulates drug resistance in clinical isolates of Candida.

AIMS: The study is aimed at understanding the novel molecular mechanisms governing drug resistance in the opportunistic fungi belonging to the genus Candida. METHODS AND RESULTS: This is a multipronged study wherein different assays like drug susceptibility and whole cell proteome analysis, stress tolerance assay, measurement of total internal glycerol content, western blot analysis, reactive oxygen species (ROS) measurement, glucose uptake, lactate production, ATP generation, and NADPH measurements were made.The study reveals an incidence of different species of Candida in the northern most part of India (Kashmir valley). Resistant isolates, mostly resistant to azoles were reported across all the species. The study revealed a difference in resistance mechanisms between Candida albicans and C. glabrata clinical isolates. Further, such resistance mechanism (in the case of C. albicans) was mostly mediated by Hexokinase 2 (Hxk2) and Glucose-6-phosphate dehydrogenase (G6pd). Increased expression of Hxk2 was associated with increased glucose uptake, more lactate production, and more ATP generation in drug-resistant C. albicans. At the same time, increased G6pd expression was responsible for the increased production of NADPH, which imparts a better ROS scavenging potential. While in C. glabrata the resistance was linked with glycerol metabolism, where the drug-resistant isolate tends to accumulate more glycerol as an osmolyte in response to external stresses. This glycerol accumulation was found to be triggered by the HOG1-MAPK pathway. CONCLUSION: The study concludes that, like various human malignant tumors, there is a strong correlation between drug resistance and aberrant cellular metabolism in the opportunistic fungi belonging to the genus Candida.

Exogenous zinc mitigates salinity stress by stimulating proline metabolism in proso millet (Panicum miliaceum L.).

Salinity is one of the most concerning ecological restrictions influencing plant growth, which poses a devastating threat to global agriculture. Surplus quantities of ROS generated under stress conditions have negative effects on plants' growth and survival by damaging cellular components, including nucleic acids, lipids, proteins and carbohydrates. However, low levels of ROS are also necessary because of their role as signalling molecules in various development-related pathways. Plants possess sophisticated antioxidant systems for scavenging as well as regulating ROS levels to protect cells from damage. Proline is one such crucial non-enzymatic osmolyte of antioxidant machinery that functions in the reduction of stress. There has been extensive research on improving the tolerance, effectiveness, and protection of plants against stress, and to date, various substances have been used to mitigate the adverse effects of salt. In the present study Zinc (Zn) was applied to elucidate its effect on proline metabolism and stress-responsive mechanisms in proso millet. The results of our study indicate the negative impact on growth and development with increasing treatments of NaCl. However, the low doses of exogenous Zn proved beneficial in mitigating the effects of NaCl by improving morphological and biochemical features. In salt-treated plants, the low doses of Zn (1 mg/L, 2 mg/L) rescued the negative impact of salt (150mM) as evidenced by increase in shoot length (SL) by 7.26% and 25.5%, root length (RL) by 21.84% and 39.07% and membrane stability index (MSI) by 132.57% and 151.58% respectively.The proline content improved at all concentrations with maximum increase of 66.65% at 2 mg/L Zn. Similarly, the low doses of Zn also rescued the salt induced stress at 200mM NaCl. The enzymes related to proline biosynthesis were also improved at lower doses of Zn. In salt treated plants (150mM), Zn (1 mg/L, 2 mg/L) increased the activity of P5CS by 19.344% and 21%. The P5CR and OAT activities were also improved with maximum increase of 21.66% and 21.84% at 2 mg/L Zn respectively. Similarly, the low doses of Zn also increased the activities of P5CS, P5CR and OAT at 200mM NaCl. Whereas P5CDH enzyme activity showed a decrease of 82.5% at 2mg/L Zn+150mM NaCl and 56.7% at 2mg/L Zn+200 mM NaCl. These results strongly imply the modulatory role of Zn in maintaining of proline pool during NaCl stress.

Do genotypes ameliorate herbivory stress through silicon amendments differently? A case study of wheat.

Agricultural productivity relies on plant resistance to insect pests, with silicon (Si) being increasingly recognized as an important anti-herbivore defense. However, the processes by which Si works to counteract the effects of insect injury are not completely understood. The role of Si in mitigating the adverse effects of herbivory has been mostly studied at the species level in various crops, ignoring the sensitivity and variability at the genotypic level. Understanding such variation across genotypes is important because Si-derived benefits are associated with the amount of Si accumulated in the plant. Therefore, the present investigation was pursued to study the effect of different Si concentrations (0, 125, and 250 mg L⁻1) on Si accumulation and plant growth using two wheat genotypes (WW-101 and SW-2) under grasshopper herbivory for 48 h. The higher Si absorption increased the concentration of leaf chlorophyll, carotenoids, soluble sugars, and proteins. Silicon application at higher concentrations increased the dry weight, antioxidant enzyme activity, total phenolics, flavonoids and shoot Si concentration, whereas it decreased the electrolyte leakage, hydrogen peroxide (H2O2) and malonaldehyde (MDA) levels, thereby preventing leaf damage. We infer that the higher Si concentration alleviates the adverse effects of herbivory in wheat by improving the accumulation of secondary metabolites and enhancing the antioxidant defense system. The effects were pronounced in the genotype 'WW-101' compared to 'SW-2' for most of the studied traits, indicating overall stress response to be genotype-dependent. Thus, Si acquisition efficiency of genotypes should be considered while developing efficient crop management strategies.

Nitric oxide effectively orchestrates postharvest flower senescence: a case study of Consolida ajacis.

Nitric oxide releasing compound sodium nitroprusside (SNP) is regarded as novel chemical to beat the daunting challenges of postharvest losses in cut flowers. In the recent years, it has yielded propitious results as postharvest vase preservative for cut flowers. Our study explicates the efficacy of SNP in mitigating postharvest senescence in Consolida ajacis (L.) Schur cut spikes. The freshly excised C. ajacis spikes were subjected to different SNP treatments viz , 20µM, 40µM, 60µM and 80µM. The control spikes were held in distilled water. The spikes held in test solutions showed a marked improvement in vase life and flower quality. Our results indicate a profound surge in sugars, phenols and soluble proteins in SNP-treated spikes over control. Moreover, the SNP treatments improved membrane stability as signposted by decreased lipoxygenase activity (LOX). The SNP treatments also upregulated different antioxidant enzymes viz , ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD). The current study recommends 40µM SNP as optimum concentration for preserving floral quality and extending display period of C. ajacis spikes. Together, these findings reveal that SNP at proper dosage can efficiently alleviate deteriorative postharvest changes by modulating physiological and biochemical mechanisms underlying senescence.

Polyamines effectively mitigate senescence in persistent leaves of Berginia ciliata - a novel model system.

Plant leaves provide a unique insight into the changes that occur in organs, tissues and cells as they approach senescence. As part of the parental outlay, plants instigate leaf senescence to reallocate resources from older tissues to new organs towards the termination of the growing season. The aim of crop breeding initiatives is to optimize senescence for specific species. Considering hormonal regulation and their crosstalk during leaf senescence through integration of developmental signals, this work examines the efficacy of polyamines (PAs) in modulating several biochemical and physiological aspects with an ultimate aim to delay leaf senescence in leaf discs of Berginia ciliata (Haw.) sternb. Leaf discs were treated with putrescine (Put), spermidine (Spd) and spermine (Spm) at 20µM, 20µM and 15µM concentration, respectively. A set of leaf discs kept in distilled water served as the control. Leaf discs treated with PAs were green and fresh by about 4 days compared to the control, thus exhibited delayed senescence. This delayed leaf senescence corroborated with the maintenance of high activity of reactive oxygen species (ROS) scavenging antioxidant enzymes viz , superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and higher content of chlorophylls. A marked increase was also observed in membrane stability and soluble proteins in leaf discs treated with PAs. Exogenous PAs reduced oxidative stress in the leaf discs, as revealed by lower malondialdehyde (MDA) level, which is manifested as reduced lipid peroxidation (LPO). Improved membrane stability was proportional to lower LPO, as measured by the membrane stability index (MSI).

Jasmonates and salicylic acid as enigmatic orchestrators of capitula senescence in Cosmos sulphureus Cav.

The fine-tuning of the intricate network of plant growth hormones empowers the balanced responses of plants to environmental and developmental signals. Salicylic acid and jasmonates are emerging as advanced hormones that provide plants with resistance to environmental stresses. Senescence is characterized by coordinated and systematic crosstalk between phytohormones that remodels the biochemical and physiological mechanisms in plants, resulting in cell death. The present investigation examines the role of jasmonates (methyl jasmonate and jasmonic acid) and salicylic acid (SA) in regulating the petal senescence of detached stalks of Cosmos sulphureus. Based on our results, it was revealed that SA and jasmonic acid (JA) at 40 µM and methyl jasmonate (MJ) at 0.75 µM concentration delayed the senescence of detached flowers of C. sulphureus considerably. These growth regulators improved the membrane stability, reinforced the antioxidant enzyme activities and averted the upsurge of hydrogen peroxide (H2O2) content in the petals. Additionally, SA and jasmonates preserved higher content of total phenols, reducing sugars and soluble proteins in the petals, besides impeding the bacterial growth in testing solutions which corroborated with the maximum solution uptake. The elevated soluble protein content was found to be associated with low specific protease activity (SPA) and α-amino acid content in the petal tissues. Our study concluded that SA and jasmonates delayed flower senescence by averting oxidative stress and maintaining the nutritional status of the petals.

Selenate and selenite transporters in proso millet: Genome extensive detection and expression studies under salt stress and selenium.

Crops are susceptible to a variety of stresses and amongst them salinity of soil is a global agronomic challenge that has a detrimental influence on crop yields, thus posing a severe danger to our food security. Therefore, it becomes imperative to examine how plants respond to salt stress, develop a tolerance that allows them to live through higher salt concentrations and choose species that can endure salt stress. From the perspective of food, security millets can be substituted to avoid hardships because of their efficiency in dealing with salt stress. Besides, this problem can also be tackled by using beneficial exogenous elements. Selenium (Se) which exists as selenate or selenite is one such cardinal element that has been reported to alleviate salt stress. The present study aimed for identification of selenate and selenite transporters in proso millet (Panicum miliaceum L.), their expression under NaCl (salt stress) and Na2SeO3 (sodium selenite)treatments. This study identified eight transporters (RLM65282.1, RLN42222.1, RLN18407.1, RLM74477.1, RLN41904.1, RLN17428.1, RLN17268.1, RLM65753.1) that have a potential role in Se uptake in proso millet. We analyzed physicochemical properties, conserved structures, sub-cellular locations, chromosome location, molecular phylogenetic analysis, promoter regions prediction, protein-protein interactions, three-dimensional structure modeling and evaluation of these transporters. The analysis revealed the chromosome location and the number of amino acids present in these transporters as RLM65282.1 (16/646); RLN42222.1 (1/543); RLN18407.1 (2/483); RLM74477.1 (15/474); RLN41904.1 (1/521); RLN17428.1 (2/522); RLN17268.1(2/537);RLM65753.1 (16/539). The sub-cellular locations revealed that all the selenite transporters are located in plasma membrane whereas among selenate transporters RLM65282.1 and RLM74477.1 are located in mitochondria and RLN42222.1 and RLN18407.1 in chloroplast. The transcriptomic studies revealed that NaCl stress decreased the expression of both selenate and selenite transporters in proso millet and the applications of exogenous 1µM Se (Na2SeO3) increased the expression of these Se transporter genes. It was also revealed that selenate shows similar behavior as sulfate, while selenite transport resembles phosphate. Thus, it can be concluded that phosphate and sulphate transporters in millets are responsible for Se uptake.

ß-Nitrostyrene derivatives as broad range potential antifungal agents targeting fungal cell wall.

The prevalence of multidrug resistance has been increasingly witnessed during the past few decades. Resistance of human pathogenic fungi against the currently available antifungal agents has increased the frequency of fungal infections and associated mortality rates. The discovery of novel lead antifungal agents is important to challenge multidrug resistance. The present study examined the antifungal potential of chemically synthesized ß-Nitrostyrene derivatives. Among the eight ß-Nitrostyrene derivatives used in this study, SS45, SS46 and SS47 showed strong antifungal potential. The results show that ß-Nitrostyrene derivatives inhibited the growth of different species of human pathogenic Candida, particularly the highly prevalent C. albicans, C. glabrata and the emerging pathogenic C. auris species. Moreover, ß-Nitrostyrene derivatives also show strong antifungal activities against drug-resistant clinical isolates and drug transporter overexpressing fungal species. The drug susceptibility assays revealed that ß-Nitrostyrene derivatives are fungicidal and show the synergy of action when combined with antifungal drugs caspofungin and fluconazole. The transcriptomic study performed on C. albicans in the presence of ß-Nitrostyrene derivatives revealed the differential expression of genes related to cell wall metabolism. Mechanistically, ß-Nitrostyrene derivatives impact cell wall morphology, enhance ROS generation and modulate drug efflux. Collectively this study reveals that ß-Nitrostyrene derivatives have strong antifungal potential with a particular mode of activity similar to known cell wall perturbing antifungal agents and thus can be exploited as promising potential antifungal agents for further studies.

Development and validation of a reverse phase HPLC-DAD method for separation, detection & quantification of rutin and quercetin in buckwheat (Fagopyrum spp.).

Buckwheat has tremendous nutraceutical potential owing to its rutin and quercetin content. The aim of this study was to optimise and validate an analytical method for separating and quantifying these two flavonoids from it. Factors, such as range, linearity, precision, accuracy, limit of detection and limit of quantification, were evaluated for the two compounds using high performance liquid chromatography. On the basis of resolution and symmetry, mobile phase consisting of methanol and methanol:water:acetic acid in the ratio of (100:150:5), flow rate 1.3 ml/min and column temperature 30 °C were found to be optimal analytical conditions. Calibration curves exhibited good linearity with correlation coefficient of 0.995 & 0.9907 over the range 60-180 µg/ml & 2-10 µg/ml for rutin and quercetin respectively. LOD and LOQ values for rutin and quercetin were 6.36, 0.58 and 19.28, 1.77 µg/ml respectively. Recovery values of 96-100.8% confirmed that the method was accurate for rutin and quercetin analysis. This validated method was successfully used to analyse rutin and quercetin in leaves and seeds of buckwheat plant.

Efficacy of salicylic acid in modulating physiological andbiochemical mechanisms to improve postharvest longevity in cut spikes of Consolida ajacis (L.) Schur.

Postharvest losses of cut flowers is one of the considerable challenges restricting their efficient marketability. Consequently, such challenges have triggered a constant hunt for developing compatible postharvest treatments to mitigate postharvest losses. Interestingly, recent studies entrench extensive role of salicylic acid (SA) in mitigating postharvest losses in various flower systems. The current investigation focusses on role of SA in augmenting physiological and biochemical responses to mitigate postharvest senescence in cut spikes of Consolida ajacis. The cut spikes of C. ajacis were supplemented with various SA treatments viz, 2 mM, 4 mM, 6 mM. The effects of these treatments were evaluated against control set of spikes placed in distilled water. Our study indicates considerable increment in postharvest longevity of cut spikes, besides an increase in solution uptake, sugar and protein content of tepal tissues.SA augmented antioxidant system via upsurge in phenolic content and antioxidant enzymes viz, superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) to forfend reactive oxygen species (ROS) related oxidative damage. SA profoundly reduced lipoxygenase (LOX) activity to preserve the membrane integrity and thus prevented seepage of solutes from tepal tissues. These results authenticate SA particularly 4 mM concentration as effective postharvest treatment to preserve the postharvest quality of C. ajacis cut spikes.

Metabolic flexibility and extensive adaptability governing multiple drug resistance and enhanced virulence in Candida albicans.

Commensal fungus-Candida albicans turn pathogenic during the compromised immunity of the host, causing infections ranging from superficial mucosal to dreadful systemic ones. C. albicans has evolved various adaptive measures which collectively contribute towards its enhanced virulence. Among fitness attributes, metabolic flexibility and vigorous stress response are essential for its pathogenicity and virulence. Metabolic flexibility provides a means for nutrient assimilation and growth in diverse host microenvironments and reduces the vulnerability of the pathogen to various antifungals besides evading host immune response(s). Inside the host micro-environments, C. albicans efficiently utilizes the multiple fermentable and non-fermentable carbon sources to sustain and proliferate in glucose deficit conditions. The utilization of alternative carbon sources further highlights the importance of understanding these pathways as the attractive and potential therapeutic target. A thorough understanding of metabolic flexibility and adaptation to environmental stresses is warranted to decipher in-depth insights into virulence and molecular mechanisms of fungal pathogenicity. In this review, we have attempted to provide a detailed and recent understanding of some key aspects of fungal biology. Particular focus will be placed on processes like nutrient assimilation and utilization, metabolic adaptability, virulence factors, and host immune response in C. albicans leading to its enhanced pathogenicity.

Is proline the quintessential sentinel of plants? A case study of postharvest flower senescence in Dianthus chinensis L.

The present investigation primarily focussed on evaluating the efficacy of exogenous proline on the flower longevity of Dianthus chinensis L. Floral buds were harvested at the paint brush stage (i.e., a day prior to anthesis) and divided into 6 sets, with one set of buds (i.e., control) held in distilled water and rest of the 5 sets were supplemented with various concentrations of proline, viz., 10 mM, 20 mM, 30 mM, 40 mM and 50 mM. The application of proline at 40 mM concentration proved out to be most effective in improving the longevity of the flowers by about 4 days as compared to the control. The ameliorated longevity coincided with enhanced floral diameter, fresh mass, dry mass and water content. The flowers with delayed senescence also maintained higher soluble proteins, sugars and phenols. The results suggest that exogenous proline effectively alleviates oxidative stress in the petal tissue, as evident by a relatively lower maloendialdehyde content, which is manifested in the form of reduced lipid peroxidation (LPO). Reduced LPO was commensurate with increased membrane stability, quantified by membrane stability index. Moreover, the flowers with improved longevity exhibited a decline in lipoxygenase activity and significant augmentation of antioxidant enzymes superoxide dismutase, catalase and ascorbate peroxidase.

Elucidating the role of silicon in drought stress tolerance in plants.

Predicted changes in climate, with more severe droughts and more extreme weather variability, are gaining considerable attention from stakeholders because of the already stressed and seriously challenging agricultural ecosystems of the contemporary world. One of the greatest challenges faced by these unique ecosystems due to climate change is drought stress, which affects plant growth, development and metabolic processes, thus reducing production, yield, and quality of crop plants. Plants counter this stress by employing complex mechanisms through a series of physiological, cellular, and molecular processes. Among the myriad of stress tolerance mechanisms, the positive effects of Si on water status of plants have been widely appreciated. Here, we review the potential of Si supplementation in alleviating drought stress and highlight the imported mechanisms involved in Si mediated reduction of drought stress in plants. Si fertilization not only enhances the photosynthetic pigments, growth, biomass, antioxidant enzymes, gene expression, osmolyte concentrations and nutrient uptake but also improves crop production, yield and grain quality during drought stress. In addition, it provides insights on important mechanisms involved in the modification of gas exchange attributes, gene modification, nutritional homeostasis, control synthesis of compatible solutes, osmotic adjustment and stimulation of phytohormone biosynthesis and antioxidant enzymes under drought stress. We also highlight knowledge gaps and future research prospects to understand Si mediated role in alleviating drought stress.

Nitric oxide effectively curtails neck bending and mitigates senescence in isolated flowers of Calendula officinalis L.

In recent years, there has been a considerable and renewed upsurge in research to ascertain the physiological and biochemical role of Nitric oxide (NO) in plants. The present investigation is focused to study the role of NO on neck bending associated with senescence and postharvest performance in isolated flowers of Calendula officinalis. The flower buds harvested at one day before anthesis stage were supplied with sodium nitroprusside (SNP) as a source of NO at different concentrations viz., 50, 100, 150 and 200 µM. A distinct set of flowers held in distilled water designated the control. The investigation revealed that SNP delayed the senescence in flowers of C. officinalis significantly manifested by prolonged longevity. The maximum longevity of 12 days was recorded in flowers supplemented with 100 µM SNP. The flowers held in distilled water (control) displayed early senescence symptoms and lasted for 6 days only. Our research suggested that improved flower longevity by SNP was commensurate with delayed neck bending, inhibition of bacterial growth in the vase, increased solution uptake, high membrane stability, besides an up-regulated activities of antioxidant enzymes in the tissue samples. In addition, the treated flowers exhibited increased content of  sugar fractions, total phenols and soluble proteins in the petal tissues compared to control. Further, 100 µM SNP was observed as most effective treatment and increased the longevity of flowers by 6 days. The concentration above 150 µM provoked early senescence compared to control, whereas concentration lower than 100 µM was less efficacious in improving the postharvest life and longevity of cut Calendula flowers.

Understanding the Integrated Pathways and Mechanisms of Transporters, Protein Kinases, and Transcription Factors in Plants under Salt Stress.

Abiotic stress is the major threat confronted by modern-day agriculture. Salinity is one of the major abiotic stresses that influence geographical distribution, survival, and productivity of various crops across the globe. Plants perceive salt stress cues and communicate specific signals, which lead to the initiation of defence response against it. Stress signalling involves the transporters, which are critical for water transport and ion homeostasis. Various cytoplasmic components like calcium and kinases are critical for any type of signalling within the cell which elicits molecular responses. Stress signalling instils regulatory proteins and transcription factors (TFs), which induce stress-responsive genes. In this review, we discuss the role of ion transporters, protein kinases, and TFs in plants to overcome the salt stress. Understanding stress responses by components collectively will enhance our ability in understanding the underlying mechanism, which could be utilized for crop improvement strategies for achieving food security.

Aluminium stress modulates the osmolytes and enzyme defense system in Fagopyrum species.

The present investigation describes aluminum-induced changes in the leaves of two buckwheat species using both physiological and biochemical indices. With increasing levels of Al (viz. 100, 200 and 300 µM), the mean length of root, shoot as well as their biomass accumulation decreased linearly with respect to control. Tolerance test of F. kashmirianum revealed that it was more tolerant to Al-stress than F. tataricum as revealed by higher accumulation of Al in its roots without any significant damage. Translocation factor (TF) values of both species were found to be < 1, indicating more Al is restrained in roots. Total chlorophyll showed a non-significant increase in F. tataricum while as decreased in F. kashmirianum at 300 µM concentration besides, the carotenoid content exhibited inclined trend in F. tataricum and showed a concomitant decrease in F. kashmirianum. The anthocyanin level showed a non-significant decline in F. kashmirianum. Exposure to different Al-treatments enhances malondialdehyde (MDA), H2O2 and membrane stability index (MSI) in both species, with increases being greater in F. kashmirianum than F. tataricum as also revealed by DAB-mediated in vivo histo-chemical detection method. The osmolyte level in general were elevated in both buckwheat species however, enhancement was more in F. tataricum than F. kashmirianum. The activities of antioxidant enzymes viz. superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (POD), glutathione reductase (GR), glutathione-S-transferase (GST) were positively correlated with Al-treatment except catalase (CAT) which exhibits a reverse outcome in F. kashmirianum. The present investigation could play an essential role to better understand the detoxification mechanisms of Al in plants.

Epibrassinolide and proline alleviate the photosynthetic and yield inhibition under salt stress by acting on antioxidant system in mustard.

Soil salinity is one of the major abiotic stress factors that hampers plant growth and productivity by limiting photosynthesis and other related metabolic processes. In this study we investigated whether treatment with proline and/or 24-epibrassinolide (EBL) to two contrasting cultivars of Brassica juncea (L.) Czern and Coss viz. Varuna and RH-30 could counteract with the adverse effects of salinity on photosynthesis and seed yield. Plants were treated with proline and/or 24-epibrassinolide (EBL) at 28 and 29d-stages of growth. Salt stress reduced plant growth, photosynthetic attributes, efficiency of PSII (Fv/Fm), leaf water potential and finally seed yield, at harvest but improved the activity of antioxidant enzymes in both the cultivars in a concentration dependent manner. Exogenous application of EBL with proline completely neutralised the adverse effects of salt at 78 mM or 117 mM stress levels whereas the treatment partially neutralised the impact of highest salt concentration of 156 mM, through the upregulation of the antioxidant system.

Adenine type and diphenyl urea derived cytokinins improve the postharvest performance of Iris germanica L. cut scapes.

An experiment was designed to evaluate the effect of various adenine derived cytokinins (kinetin and 6-benzylaminopurine) and diphenyl urea cytokinin (thidiazuron) on the postharvest performance of cut scapes of Iris germanica. Flower scapes were harvested with the oldest bud at '1 day before anthesis stage', brought to laboratory under water, cut to a uniform length of 35 cm, divided into three sets viz., kinetin (KIN), 6-benzyl aminopurine (BAP) and thidiazuron (TDZ). Each set of scapes was treated with a particular cytokinin alone or in combination with 0.1 M sucrose. TDZ was effective than KIN and BAP in improving the postharvest life of the I. germanica scapes by 5.4 days as compared to the control (untreated scapes held in distilled water). This was because of the minimum percentage of bud abortion by TDZ application. Cytokinin application resulted in increased antioxidant activity, higher protein and phenolic content, besides a decrease in specific protease activity and α-amino acids in the tepal tissues. Application of TDZ resulted in the maximum increase in the superoxide dismutase, catalase and ascorbate peroxidase activity in the tepal tissues. The scapes treated with BAP and KIN maintained higher carbohydrate content in the tissue samples as compared to control and TDZ treated scapes. TDZ and BAP application resulted in increased membrane stability because of the decreased lipoxygenase activity which prevented membrane lipid peroxidation. Among the cytokinins tested, TDZ proved to be the promising cytokinin in improving the postharvest performance of beautiful flowers of I. germanica scapes.