Variation in root morphology,enhancement in anti-oxidative enzyme responses and improved arbutin and bergenin levels in Bergenia ciliata (Haw.) Sternb. raised in vitro via EMS and gamma irradiations

Plant Cell, Tissue and Organ Culture (PCTOC) - Plant cells develop defence mechanisms in response to mutagen stress which leads to modulation of certain metabolic and defensive pathways. Owing to...     

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.     

Alteration in nitrogen metabolism and plant growth during different developmental stages of green gram (<Emphasis Type="Italic">Vigna radiata</Emphasis> L.) in response to chlorpyrifos

Chlorpyrifos is a widely used broad-spectrum organophosphate insecticide in the agricultural practice. However, extensive use of this insecticide may lead to its accumulation in ecosystem, thus inducing the toxicity to crops and vegetables. To assess chlorpyrifos-induced toxicity in plants, we performed the experiment focusing on the growth and nitrogen metabolism of green gram plant (Vigna radiata L.). 20-days-old plants were subjected to chlorpyrifos at concentrations ranging from 0 to 1.5 mM through foliar spray in the field condition. Variation in root and shoot length, activities of nitrate reductase (NR) and content of nitrate, sugar, soluble amino acid and soluble protein were studied at preflowering (5 day after treatment, DAT), flowering (10 DAT) and postflowering (20 DAT) stages of plant development. Of the various concentrations of chlorpyrifos, 0.6 and 1.5 mM showed comparatively more severe toxicity to green gram plants by decreasing root and shoot length, nitrate, NR, soluble sugar and protein content where as at low concentration (0.3 mM) of chlorpyrifos proved stimulant for same parameter. Increase in soluble amino acid was observed in age and dose dependent manner. These results reflect strong parallelism between growth and biochemical activities of the model plant. Further lower dose of chlorpyrifos proved as stimulant where as at higher concentration proved detrimental for growth and nitrogen metabolism.     

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.     

Gamma radiation effects on growth and yield attributes of <Emphasis Type="Italic">Psoralea corylifolia</Emphasis> L. with reference to enhanced production of psoralen

The present work describes radiation-induced effects on vegetative, reproductive traits and psoralen content in Psoralea corylifolia L. The effects of gamma radiation on Psoralea seeds were investigated by exposing seeds with doses of 2.5, 5, 10, 15 and 20 kGy at dose rate of 1.65 kGyh⁻¹ and studying the plant growth at three developmental stages: preflowering, flowering and post flowering (seed to seed) after irradiation. Irradiation with lower doses of gamma rays significantly improved vegetative traits while higher doses proved depressing for same parameters. Similar trend was followed in reproductive traits. Psoralen, showed highest concentration in seeds (7.56%) at 20 kGy and lowest in control roots (0.23%). Increment in psoralen was striking for higher gamma doses applied. These long-term changes in plant development may be attributed to alteration in plant genome induced by irradiation. The results show in depth development stimulation and enhancement of secondary metabolite in Psoralea corylifolia L. following low and high dose treatment respectively depicting the potential of gamma rays in plant biotechnology and metabolomics.     

Negative regulation of EGFR/MAPK pathway by Pumilio in Drosophila melanogaster

In Drosophila melanogaster, specification of wing vein cells and sensory organ precursor (SOP) cells, which later give rise to a bristle, requires EGFR signaling. Here, we show that Pumilio (Pum), an RNA-binding translational repressor, negatively regulates EGFR signaling in wing vein and bristle development. We observed that loss of Pum function yielded extra wing veins and additional bristles. Conversely, overexpression of Pum eliminated wing veins and bristles. Heterozygotes for Pum produced no phenotype on their own, but greatly enhanced phenotypes caused by the enhancement of EGFR signaling. Conversely, over-expression of Pum suppressed the effects of ectopic EGFR signaling. Components of the EGFR signaling pathway are encoded by mRNAs that have Nanos Response Element (NRE)-like sequences in their 3'UTRs; NREs are known to bind Pum to confer regulation in other mRNAs. We show that these NRE-like sequences bind Pum and confer repression on a luciferase reporter in heterologous cells. Taken together, our evidence suggests that Pum functions as a negative regulator of EGFR signaling by directly targeting components of the pathway in Drosophila.     

Arbuscular mycorrhizal symbiosis and abiotic stress in plants: A review

Abiotic stresses (such as salinity, drought, cold, heat, mineral deficiency and metals/metalloids) have become major threats to the global agricultural production. These stresses in isolation and/or combination control plant growth, development and productivity by causing physiological disorders, ion toxicity, and hormonal and nutritional imbalances. Some soil microorganisms like arbuscular mycorhizal fungi (AMF) inhabit the rhizosphere and develop a symbiotic relationship with the roots of most plant species. AMF can significantly improve resistance of host plants to varied biotic and abiotic stresses. Taking into account recent literature, this paper: (a) overviews major abiotic stresses and introduces the arbuscular mycorrhizae symbiosis (b) appraises the role and underlying major mechanisms of AMF in plant tolerance to major abiotic stresses including salinity, drought, temperature regimes (cold and heat), nutrient-deficiency, and metal/metalloids; (c) discusses major molecular mechanisms potentially involved in AMF-mediated plant-abiotic stress tolerance; and finally (d) highlights major aspects for future work in the current direction.     

In vitro culture and biochemical and antioxidant potential of the critically endangered medicinal plant Atropa acuminata Royle ex Lindl of Kashmir Himalaya

In Vitro Cellular & Developmental Biology - Plant - Atropa acuminata Royle is a critically endangered annual herb growing in Kashmir Himalaya and is used as a source of medicine for many...     

Current Perspectives on Plant Growth-Promoting Rhizobacteria

The rhizosphere of plant species is an inimitable ecosystem that harbors an extensive range of microbes. Research in the wide areas of rhizosphere biotechnology highlighting new bioinoculants has received ample attention during recent past, and suitable expertises have been developed. However, the global recognition of such technologies by farmers is still overwhelmed with doubts owing to limited shelf-life and efficiency of the products which demonstrate discrepancies. This review illustrates plant growth-promoting rhizobacteria with detailed emphasis on nutrient acquisition and potential roles in conferring tolerance against abiotic stresses. The review demonstrates the recent research in the field of genomic and proteomic analysis, where systematic characterization of potentially effective rhizobacteria is being carried out by screening the extensive bacterial gene pool based on modern molecular tools. The review concludes by emphasizing the efforts made in the proteomics field which could compensate for understanding of prompt evolution in microbe-derived and plant-derived protein and metabolite substitute that activates vulnerability or resistance.

     

24-Epibrassinolide Alleviates the Injurious Effects of Cr(VI) Toxicity in Tomato Plants: Insights into Growth,Physio-Biochemical Attributes,Antioxidant Activity and Regulation of Ascorbate–Glutathione and Glyoxalase Cycles

Journal of Plant Growth Regulation - Brassinosteroids (BRs) are well-ascertained growth regulators that play prime roles in alleviation of a stress in plants. The current investigation determined...