Cytokinin and indole-3-acetic acid crosstalk is indispensable for silicon mediated chromium stress tolerance in roots of wheat seedlings.

The rising heavy metal contamination of soils imposes toxic impacts on plants as well as other life forms. One such highly toxic and carcinogenic heavy metal is hexavalent chromium [Cr(VI)] that has been reported to prominently retard the plant growth. The present study investigated the potential of silicon (Si, 10 µM) to alleviate the toxicity of Cr(VI) (25 µM) on roots of wheat (Triticum aestivum L.) seedlings. Application of Si to Cr(VI)-stressed wheat seedlings improved their overall growth parameters. This study also reveals the involvement of two phytohormones, namely auxin and cytokinin and their crosstalk in Si-mediated mitigation of the toxic impacts of Cr(VI) in wheat seedlings. The application of cytokinin alone to wheat seedlings under Cr(VI) stress reduced the intensity of toxic effects of Cr(VI). In combination with Si, cytokinin application to Cr(VI)-stressed wheat seedlings significantly minimized the decrease induced by Cr(VI) in different parameters such as root-shoot length (10.8% and 13%, respectively), root-shoot fresh mass (11.3% and 10.1%, respectively), and total chlorophyll and carotenoids content (13.4% and 6.8%, respectively) with respect to the control. This treatment also maintained the regulation of proline metabolism (proline content, and P5CS and PDH activities), ascorbate-glutathione (AsA-GSH) cycle and nutrient homeostasis. The protective effect of Si and cytokinin against Cr(VI) stress was minimized upon supplementation of an inhibitor of polar auxin transport- 2,3,5-triiodobenzoic acid (TIBA) which suggested a potential involvement of auxin in Si and cytokinin-mediated mitigation of Cr(VI) toxicity. The exogenous addition of a natural auxin - indole-3-acetic acid (IAA) confirmed auxin is an active member of a signaling cascade along with cytokinin that aids in Si-mediated Cr(VI) toxicity alleviation as IAA application reversed the negative impacts of TIBA on wheat roots treated with Cr(VI), cytokinin and Si. The results of this research are also confirmed by the gene expression analysis conducted for nutrient transporters (Lsi1, CCaMK, MHX, SULT1 and ZIP1) and enzymes involved in the AsA-GSH cycle (APX, GR, DHAR and MDHAR). The overall results of this research indicate towards possible induction of a crosstalk between cytokinin and IAA upon Si supplementation which in turn stimulates physiological, biochemical and molecular changes to exhibit protective effects against Cr(VI) stress. Further, the information obtained suggests probable employment of Si, cytokinin and IAA alone or combined in agriculture to maintain plant productivity under Cr(VI) stress and data regarding expression of key genes can be used to develop new crop varieties with enhanced resistance against Cr(VI) stress together with its reduced load in seedlings.

Unlocking a 'lock-key' mechanism governing pollen-pistil interactions.

Pollen-pistil interactions ensure genetic diversity and shape the reproductive success of plants. Lan et al. recently revealed that the interaction among various receptor-like kinases, cell-wall proteins, and stigmatic RALF peptides (sRALFs) or pollen RALF peptides (pRALFs) on the stigma surface govern the penetration of pollen tubes in members of the Brassicaceae.

Silicon nanoforms in crop improvement and stress management.

Although, silicon - the second most abundant element in the earth crust could not supersede carbon (C) in the competition of being the building block of life during evolution, yet its presence has been reported in some life forms. In case of the plants, silicon has been reported widely to promote the plant growth under normal as well as stressful situations. Nanoform of silicon is now being explored for its potential to improve plant productivity and its tolerance against various stresses. Silicon nanoparticles (SiNPs) in the form of nanofertilizers, nanoherbicides, nanopesticides, nanosensors and targeted delivery systems, find great utilization in the field of agriculture. However, the mechanisms underlying their uptake by plants need to be deciphered in detail. Silicon nanoformss are reported to enhance plant growth, majorly by improving photosynthesis rate, elevating nutrient uptake and mitigating reactive oxygen species (ROS)-induced oxidative stress. Various studies have reported their ability to provide tolerance against a range of stresses by upregulating plant defense responses. Moreover, they are proclaimed not to have any detrimental impacts on environment yet. This review includes the up-to-date information in context of the eminent role of silicon nanoforms in crop improvement and stress management, supplemented with suggestions for future research in this field.

Application of zinc oxide nanoparticles as fertilizer boosts growth in rice plant and alleviates chromium stress by regulating genes involved in oxidative stress.

Chromium toxicity impairs the productivity of rice crops and raises a major concern worldwide and thus, it calls for unconventional and sustainable means of crop production. In this study, we identified the implication of zinc oxide nanoparticles (ZnO NPs) in promoting plant growth and ameliorating chromium-induced stress in seedlings of rice (Oryza sativa). This investigation demonstrates that the exogenous supplementation of ZnO NPs at 25 µM activates defense mechanisms conferring rice seedlings significant tolerance against stress imposed by the exposure of 100 µM Cr(VI). Further, supplementation of this nanofertilizer reversed the inhibitory effects of Cr(VI) on growth and photosynthetic efficiency. The growth promotion was primarily associated with the function of ZnO NPs in inducing activity of antioxidative enzymes i.e. APX, DHAR, MDHAR and GR belonging to the ascorbate-glutathione cycle in the Cr-exposed seedlings, exceeding the levels in control. The overexpression of these antioxidative genes correlated concomitantly with the decrease of oxidants including SOR and H2O2 and the increase in the levels of non-enzymatic antioxidants: AsA and GSH.

Synergistic action of silicon nanoparticles and indole acetic acid in alleviation of chromium (CrVI) toxicity in Oryza sativa seedlings.

The present study investigates ameliorative effect of silicon nanoparticles (SiNPs) and indole acetic acid (IAA) alone and in combination against hexavalent chromium (CrVI) toxicity in rice seedlings. The results of the study revealed protective effects of SiNPs and IAA against CrVI toxicity. The 100 µM of CrVI imposed toxic effects in rice seedlings at morphological, physiological and biochemical levels which coincided with increased level of intracellular CrVI and declined level of endogenous nitric oxide (NO). The CrVI enhanced levels of superoxide radicals (SOR) (59.51% and 50.1% in shoot and root, respectively) and H2O2 (19.5% and 23.69% in shoot and root, respectively). However, when SiNPs and IAA were applied to plants under CrVI stress, they enhanced tolerance and defence mechanisms as manifested in terms of increased biomass, endogenous NO, photosynthetic pigments, and antioxidants level. It was also noticed that CrVI arrested cell cycle at G2/M phase whereas growth was restored as compared to control when SiNPs and IAA were supplemented. Thus, the hypothesis that combined application of SiNPs and IAA will be effective in alleviating CrVI toxicity is validated from the results of this study. Moreover, in SiNPs and IAA-mediated mitigation of CrVI toxicity, endogenous NO has a positive role. The importance of the study will be that the combination of SiNPs and IAA can be utilized against heavy metal stress and even when supplied alone, they will enhance the crop productivity parameters with and without stress conditions.

Ethylene needs endogenous hydrogen sulfide for alleviating hexavalent chromium stress in Vigna mungo L. and Vigna radiata L.

Chromium toxicity to crops is a big scientific issue of the present time. Thus, continuous scientific attempts have been taken for reducing chromium toxicity in crop plants. In this study, we have tested potential of ethylene (ET) and hydrogen sulfide (H2S) in alleviating hexavalent chromium [(Cr(VI)] stress in two pulse crops i.e. black bean and mung bean. Cr(VI) declined growth (by 21 % and 27 % in black and mung bean, respectively) and also negatively affected photosynthesis in both pulse crops due to accumulation of Cr(VI) and cell death in roots. Under similar conditions, levels of reactive oxygen species (ROS) were enhanced but antioxidant defense system showed differential responses. The addition of AVG (an inhibitor of ethylene biosynthesis) and PAG (an inhibitor of H2S biosynthesis) with Cr(VI) further increased toxicity of Cr(VI) suggesting that endogenous H2S and ET are important for tolerating Cr(VI) toxicity. But supplementation of either ET or H2S alleviated Cr(VI) toxicity. Interestingly, ET did not rescue negative effects of PAG under Cr(VI) stress but NaHS rescued negative effect of AVG. Overall, results indicate that though both ET and H2S are able in alleviating Cr(VI) stress but endogenous H2S is crucial in ET-mediated mitigation of Cr(VI) stress. Furthermore, H2S appears to be a downstream signal of ET in alleviating Cr(VI) stress in two pulse crops.

Endogenous indole-3-acetic acid and nitric oxide are required for calcium-mediated alleviation of copper oxide nanoparticles toxicity in wheat seedlings.

The action of nanoparticles is increasingly being studied in recent years to minimize their toxic impacts. Besides this, efforts are also being made to minimize their toxicity in crop plants by using various chemicals, i.e. nutrients, donors of signaling molecules, plant hormones, and so on. However, associated alleviatory mechanisms are still not well known. Therefore, in the present study, we have investigated the toxicity of CuONPs and its mitigation by exogenously applied calcium (Ca). The focus was on whether indole-3-acetic acid (IAA) or endogenous nitric oxide (NO) has any role in accomplishing this task. CuONPs declined wheat growth due to increased accumulation of Cu and oxidative stress markers such as superoxide radicals, hydrogen peroxide, and lipid peroxidation (malondialdehyde) and it was also accompanied by a decline in endogenous NO. CuONPs also altered the redox status of ascorbate and glutathione by inhibiting the activity of their regenerating enzymes. This collectively leads to cell death in wheat seedlings. However, exogenous supplementation of Ca mitigated toxic effects of CuONPs by reducing the excess accumulation of Cu, which caused remarkable enhancement in growth, protein contents, photosynthetic pigments, and endogenous NO; altogether protecting wheat roots from cell death. Interestingly, addition of 2,3,5-triiodobenzoic acid (TIBA) further increased CuONPs toxicity even in the presence of Ca, but the addition of IAA rescued this effect of TIBA. These results clearly show that Ca mitigates CuONPs toxicity in wheat seedlings by involving IAA. Further, the results also showed that endogenous NO has a positive and indispensable role in Ca-mediated mitigation of CuONPs toxicity in wheat seedlings.

Effect of Yoga on Blood Pressure in Prehypertension: A Systematic Review and Meta-Analysis.

INTRODUCTION: Prehypertension is a precursor for developing hypertension and is a risk factor for cardiovascular diseases. Yoga therapy may have a role in lowering the blood pressures in prehypertension and hypertension. This systematic review aims to synthesize the available literature for the same. Methodology. Databases such as PubMed, Embase, Scopus, and Web of Science were searched for randomised control trials only in the time duration of 2010-2021. The main outcome of interest was systolic and diastolic blood pressures. Articles were screened based on the inclusion criteria, and 8 articles were recruited for the review. Meta-analysis was done for suitable articles. RevMan 5.4 by Cochrane was used for meta-analysis and forest plot construction. Risk of bias was determined using the Downs and Black checklist by three independent authors. RESULTS: The meta-analysis of the articles favoured yoga intervention over the control intervention. Yoga therapy had significantly reduced the systolic pressure (-0.62 standard mean difference, at IV fixed 95% CI: -0.83, -0.41) and diastolic pressure (-0.81 standard mean difference, at IV random 95% CI: -1.39, -0.22). Secondary outcome measures studied were heart rate, weight, BMI, waist circumference, and lipid profile. The main protocol of yoga therapy included postures, breathing exercises, and different meditation techniques. A significant reduction in secondary outcomes was observed, except for HDL values in lipid profile which showed a gradual increase in yoga group in comparison with alternative therapy. CONCLUSION: Yoga therapy has shown to be significant in the reduction of systolic and diastolic pressure in prehypertensive population. Supporting evidence lacks in providing a proper structured dosage of yoga asanas and breathing techniques. Considering the existing literature and evidence, Yoga therapy can be used and recommended in prehypertensive population and can be beneficial in reducing the chances of developing hypertension or cardiovascular diseases.

Histochemical Techniques in Plant Science: More Than Meets the Eye.

Histochemistry is an essential analytical tool interfacing extensively with plant science. The literature is indeed constellated with examples showing its use to decipher specific physiological and developmental processes, as well as to study plant cell structures. Plant cell structures are translucent unless they are stained. Histochemistry allows the identification and localization, at the cellular level, of biomolecules and organelles in different types of cells and tissues, based on the use of specific staining reactions and imaging. Histochemical techniques are also widely used for the in vivo localization of promoters in specific tissues, as well as to identify specific cell wall components such as lignin and polysaccharides. Histochemistry also enables the study of plant reactions to environmental constraints, e.g. the production of reactive oxygen species (ROS) can be traced by applying histochemical staining techniques. The possibility of detecting ROS and localizing them at the cellular level is vital in establishing the mechanisms involved in the sensitivity and tolerance to different stress conditions in plants. This review comprehensively highlights the additional value of histochemistry as a complementary technique to high-throughput approaches for the study of the plant response to environmental constraints. Moreover, here we have provided an extensive survey of the available plant histochemical staining methods used for the localization of metals, minerals, secondary metabolites, cell wall components, and the detection of ROS production in plant cells. The use of recent technological advances like CRISPR/Cas9-based genome-editing for histological application is also addressed. This review also surveys the available literature data on histochemical techniques used to study the response of plants to abiotic stresses and to identify the effects at the tissue and cell levels.

Auxin metabolic network regulates the plant response to metalloids stress.

Metalloids are among the major pollutants posing a risk to the environment and global food security. Plant roots uptake these toxic metalloids from the soil along with other essential minerals. Plants respond to metalloid stress by regulating the distribution and levels of various endogenous phytohormones. Recent research showed that auxin is instrumental in mediating resilience to metalloid-induced stress in plants. Exogenous supplementation of the auxin or plant growth-promoting micro-organisms (PGPMs) alleviates metalloid uptake, localization, and accumulation in the plant tissues, thereby improving plant growth under metalloid stress. Moreover, auxin triggers various biological responses such as the production of enzymatic and non-enzymatic antioxidants to combat nitro-oxidative stress induced by the metalloids. However, an in-depth understanding of the auxin stimulated molecular and physiological responses to the metalloid toxicity needs to be investigated in future studies. The current review attempts to provide an update on the recent advances and the current state-of-the-art associated with auxin and metalloid interaction, which could be used as a start point to develop biotechnological tools and create an eco-friendly environment.

Dose dependent differential effects of toxic metal cadmium in tomato roots: Role of endogenous hydrogen sulfide.

In this study, hydroponic experiments were conducted to elucidate mechanism(s) that are associated with differential effects of low (5 µM) and high (25 µM) dose of cadmium (Cd) stress in tomato. Furthermore, emphasis has also been focused on any involvement of endogenous hydrogen sulfide (H2S) in differential behaviour of low and high doses of Cd stress. At low dose of Cd, root growth i.e. root fresh weight, length and fitness did not significantly alter when compared to the control seedlings. Though at low dose of Cd, cellular accumulation of Cd was slightly increased but this was accompanied by higher endogenous H2S and phytochelatins, L-cysteine desulfhydrase (DES) activity, activities of glutathione biosynthetic and AsA-GSH cycle enzymes, and maintained redox status of ascorbate and glutathione. However, addition of hypotaurine (HT, a scavenger of H2S) resulted in greater toxicity, even at low dose of Cd, and these responses resembled with higher dose of Cd stress such as greater decline in root growth, endogenous H2S and phytochelatins, activities of DES, glutathione biosynthesis and AsA-GSH cycle enzymes, disturbed redox status of ascorbate and glutathione which collectively led to higher oxidative stress in tomato roots. Moreover, addition of HT with higher dose of Cd also further enhanced its toxicity. Collectively, the results showed that differential behaviour of low and high dose of Cd stress is mediated by differential regulation of biochemical attributes in which endogenous H2S has a crucial role.

Glutathione and hydrogen sulfide are required for sulfur-mediated mitigation of Cr(VI) toxicity in tomato, pea and brinjal seedlings.

In plants, investigation on heavy metal toxicity and its mitigation by nutrient elements have gained much attention. However, mechanism(s) associated with nutrients-mediated mitigation of metal toxicity remain elusive. In this study, we have investigated the role and interrelation of glutathione (GSH) and hydrogen sulfide (H2 S) in the regulation of hexavalent chromium [Cr(VI)] toxicity in tomato (Solanum lycopersicum), pea (Pisum sativum) and brinjal (Solanum melongena) seedlings, supplemented with additional sulfur (S). The results show that Cr(VI) significantly reduced growth, total chlorophyll and photosynthetic quantum yield of tomato, pea and brinjal seedlings which was accompanied by enhanced intracellular accumulation of Cr(VI) in roots. Moreover, Cr(VI) enhanced the generation of reactive oxygen species in the studied vegetables, while antioxidant defense system exhibited differential responses. However, additional supply of S alleviated Cr(VI) toxicity. Interestingly, addition of l-buthionine sulfoximine (BSO, a glutathione biosynthesis inhibitor) further increased Cr(VI) toxicity even in the presence of additional S but GSH addition reverses the effect of BSO. Under similar condition, endogenous H2 S, l-cysteine desulfhydrase (DES) activity and cysteine content did not significantly differ when compared to controls. Hydroxylamine (HA, an inhibitor of DES) also increased Cr(VI) toxicity even in the presence of additional S but sodium hydrosulfide (NaHS, an H2 S donor) reverses the effect of HA. Moreover, Cr(VI) toxicity amelioration by NaHS was reversed by the addition of hypotaurine (HT, an H2 S scavenger). Taken together, the results show that GSH which might be derived from supplied S is involved in the mitigation of Cr(VI) toxicity in which H2 S signaling preceded GSH biosynthesis.

Nitrogen alleviates salinity toxicity in Solanum lycopersicum seedlings by regulating ROS homeostasis.

The present study was aimed to investigate adaptation in physiology and biochemistry of Solanum lycopersicum seedlings under NaCl (NaCl0; 0.0 g NaCl kg-1 sand, NaCl1; 0.3 g NaCl/kg sand and NaCl2; 0.5 g NaCl/kg sand) stress, simultaneously supplemented with different (deprived; 0 mg/kg sand, LN; 105 mg/kg sand, MN; 210 mg/kg sand and HN; 270 mg/kg sand) levels of nitrogen (N). NaCl at both doses caused significant loss in growth, K+ content, K+/Na+ ratio, total chlorophyll and photosynthetic oxygen evolution. Further, N supplementation influences growth of test seedlings, that attained maximum growth in HN followed by MN, LN and deprived N conditions. N at HN level significantly declined Na+ accumulation in the cell and enhanced level of K+. NaCl treatment enhanced level of oxidative stress biomarkers: superoxide radical (O2•-), hydrogen peroxide (H2O2), MDA equivalents contents and electrolyte leakage in leaf as well as root despite enhanced activity of SOD, POD, CAT and GST, and enzymes participating in the ascorbate-glutathione cycle (AsA-GSH cycle) viz. APX, DHAR and GR. At the same time, higher contents of total AsA (AsA + DHA) and total GSH (GSH + GSSG), and maintained ratios of AsA/DHA and GSH/GSSG in HN fed seedlings were observed. Overall, the results suggest that HN supplementation was able in alleviating NaCl induced toxicity in test seedlings which was mainly due to the up-regulation of the AsA-GSH cycle, K+ and K+/Na+ ratio, which resulted into better growth performance of HN fed seedlings under NaCl stress while reverse was noticed for LN and deprive N conditions.

Responses of photosynthesis, nitrogen and proline metabolism to salinity stress in Solanum lycopersicum under different levels of nitrogen supplementation.

In the present study, effect of different levels of nitrogen (N0, deprived; N25, sub-optimum; N75, optimum and N150, supra-optimum) in Solanum lycopersicum L. seedlings under NaCl (NaCl1, 0.3 g kg-1 sand and NaCl2, 0.5 g kg-1sand) stress was investigated. Biomass accumulation, pigments, K+ concentration, nitrate and nitrite contents were declined by NaCl in dose dependent manner. As compared to control (N75 without NaCl), fresh weight declined by 4% and 11%, and dry weight by 7 and 13% when seedlings were grown under N75+NaCl1 and N75+NaCl2 combinations, respectively. Furthermore, fluorescence parameters (JIP-test): the size and number of active reaction centres of photosynthetic apparatus (Fv/F0), efficiency of water splitting complex (F0/Fv), quantum yield of primary photochemistry (φP0 or Phi_P0), yield of electron transport per trapped excitation (Ψ0 or Psi_0), the quantum yield of electron transport (φE0), and performance index of PS II (PIABS) and parameters related to energy fluxes per reaction centre (ABS/RC, TR0/RC, ET0/RC and DI0/RC) were also affected by NaCl. However, toxic effect of NaCl on photosystem II photochemistry was ameliorated by N. The lower dose (NaCl1) of NaCl exerts damaging effect on oxidation side of PS II, while higher dose (NaCl2) damages PS II reaction centre and its reduction side. Moreover, control seedlings (N75 without NaCl) when exposed to NaCl1 and NaCl2 exhibited a significant enhancement in respiration rate by 6 and 16%, Na+ accumulation by 111 and 169% in shoot, and 141 and 223% in root and ammonium contents by 19 and 34% respectively. Nitrate and ammonium assimilating enzymes such as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS) and glutamate synthase (GOGAT) were adversely affected by NaCl stress while glutamate dehydrogenase (GDH) showed reverse trend. N addition caused further enhancement in free proline, and activity of Δ1-pyrroline-5-carboxylate synthetase (P5CS), while activity of proline dehydrogenase (ProDH) decreased. The results indicate that different levels of N significantly modulated NaCl-induced damaging effects in tomato seedlings. Furthermore, the results suggest that after N addition Na+, nitrite, nitrate, ammonium contents, nitrogen metabolic enzymes, proline content, and activity of P5CS are favourably regulated, which might be associated with mitigation of NaCl stress and effect was more pronounced with supra-optimum level of N (N150).

LIB spectroscopic and biochemical analysis to characterize lead toxicity alleviative nature of silicon in wheat (Triticum aestivum L.) seedlings.

The responses of wheat seedling treated with silicon (Si; 10 µM) and lead (Pb; 100 µM) for 7 days have been investigated by analyzing growth, Pb uptake, chlorophyll fluorescence, oxidative stress, antioxidants and nutrients regulation. Results indicated that, Pb significantly (P<0.05) declined growth of seedlings which was accompanied by uptake of Pb. Under Pb stress, fluorescence parameters: Fv/Fm ratio and qP were significantly (P<0.05) decreased while NPQ was increased. Si addition alleviated Pb-induced decrease in growth and alterations in photosynthesis, and also significantly (P<0.05) lowered Pb uptake. Under Pb treatment, oxidative stress markers: hydrogen peroxide and lipid peroxidation were enhanced while DPPH(•) scavenging capacity and total phenolic compounds (TPCs) were decreased significantly, however, Si addition improved the status of antioxidants. The non-protein thiols (NP-SH) showed enhanced level under Pb stress. Pb stress considerably disturbed status of the nutrients as decrease in Ca, P, Mg, Zn and Ni contents while an increase in K, S, B, Cu, Fe, Mn and Na contents were noticed. Si addition maintained status of all the nutrients remarkably. The quickest method of element analysis: LIBS spectra revealed significantly lower uptake of Pb in seedlings grown under Si and Pb combination and same was correlated with the data of AAS. Overall results pointed out that excess Pb uptake disturbed status of nutrients, photosynthetic performance, antioxidant capacity, hence severe oxidative damage to lipids occurred. Further, Si supplementation successfully regulated these parameters by inhibiting Pb uptake hence maintained growth of wheat seedlings. Similar pattern of data recorded by the LIBS, AAS and ICAP-AES confirmed that LIBS may be one of the promising and authentic tools to monitor the mineral and metal distribution in the plants without hampering or disturbing the environment due to its eco-friendly and non-invasive nature.

Dimethoate modifies enhanced UV-B effects on growth, photosynthesis and oxidative stress in mung bean (Vigna radiata L.) seedlings: implication of salicylic acid.

The present study is aimed to investigate implication of salicylic acid (SA) in regulation of dimethoate (30 and 150 ppm designated as D1 and D2, respectively) and enhanced UV-B radiation (ambient + supplemental; ambient + 4.0 kJ m(-2) and ambient + 8.0 kJ m(-2), designated as UV-B1 and UV-B2, respectively) induced responses in mung bean seedlings. Seeds of Vigna radiata L. cv. Narendra 1 were surface sterilized, washed thoroughly and soaked for 24 h in sterilized distilled water. Soaked seeds were sown in acid washed sterilized sand filled in plastic trays, and incubated in dark at 26 ± 2 °C for 2 days. The seedlings were grown in growth chamber at 26 ± 2 °C with 12 h photoperiod (350 µmol photons m(-2 )s(-1), PAR) and watered regularly. Six day old seedlings of equal size were gently transferred in 0.2 strength Rorison nutrient medium (pH 6.8) for acclimatization. Thereafter, dimethoate (30 and 150 ppm designated as D1 and D2, respectively) and enhanced UV-B radiation treatments were given. On the 12th day, seedlings of each set were harvested and various parameters related to growth, pigments, photosynthesis, oxidative stress and antioxidant system were analyzed. The D2 dose of dimethoate and UV-B1 and UV-B2 alone and together significantly (P < 0.05) declined growth, photosynthetic pigments and photosynthesis (Fv/Fm and qP except NPQ) which were accompanied by significant decrease in SA level. Similarly, D2 and UV-B also enhanced (P < 0.05) accumulation of reactive oxygen species and concomitantly damaging effects on lipids, proteins and membrane stability were observed. In contrast, in SA-pretreated seedlings damaging impacts of D2, UV-B1 and UV-B2 alone and together were significantly (P < 0.05) alleviated. Besides this, interestingly D1 dose of dimethoate alone had stimulatory effect on growth and it also ameliorated damaging effects of both the doses of UV-B. The activity of superoxide dismutase was stimulated by all the combinations. However, catalase, glutathione reductase and dehydroascorbate reductase activities were significantly (P < 0.05) inhibited by D2, UV-B1 and UV-B2 while SA-pretreatment ameliorated D2 and UV-B-induced inhibitions in activities of these enzymes. Total ascorbate and glutathione pools also decreased by D2 and both doses of UV-B; however, in SA-pretreated seedlings their amounts were significantly (P < 0.05) higher than D2, UV-B1 and UV-B2 alone. Interestingly, D1 also alleviated damaging impact of UV-B1 and UV-B2 on total ascorbate and glutathione pools. Results revealed that D2, UV-B1 and UV-B2 might alter SA biosynthesis that results into declined SA level which might be related with their toxicity. However, SA-pretreatment might act as a signal that reduces oxidative stress by triggering up-regulation of antioxidants hence improved growth and photosynthesis noticed. Alleviation of UV-B toxicity by D1 suggests about hormesis that triggers SA biosynthesis and hence protection against both doses of UV-B was observed.

Kinetin supplementation modifies chromium (VI) induced alterations in growth and ammonium assimilation in pea seedlings.

In the present study, impact of kinetin (KN; 10 and 100 µM) supplementation on growth, ammonium (NH(4)(+)) assimilation and antioxidant system in pea under hexavalent chromium toxicity (Cr VI; 50, 100 and 250 µM) was investigated. Chromium decreased growth, protein, and nitrogen, and activity of glutamine synthetase (GS) and glutamate synthase (GOGAT) while it increased NH(4)(+) content and activity of glutamate dehydrogenase (GDH). Kinetin at 100 µM decreased growth and NH(4)(+) assimilation, and together with Cr, it increased Cr toxicity. Chromium and 100 µM KN increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities while decreasing activities of catalase (CAT), glutathione reductase (GR) and dehydroascorbate reductase (DHAR). Ascorbate and glutathione levels were decreased by Cr and 100 µM KN. In contrast, supplementation of 10 µM KN under Cr (VI) toxicity, protected NH(4)(+) assimilation and promoted growth of pea by increasing levels of some of the antioxidants i.e., CAT, GR, DHAR, ascorbate and glutathione. Results showed that 10 µM KN increases Cr tolerance while 100 µM KN exhibited opposite responses. These results could contribute to an understanding of the mechanisms of KN-mediated dual influence on metal tolerance in crop plants.

Comparison of the effectiveness of music and progressive muscle relaxation for anxiety in COPD--A randomized controlled pilot study.

Acute effects of music and relaxation have not been evaluated in hospitalized subjects with chronic obstructive pulmonary disease (COPD). This study aims to evaluate the acute effects of music and progressive muscle relaxation (PMR) in hospitalized COPD subjects after a recent episode of exacerbation. A Randomized controlled study was performed of pre-test post-test design after recruiting 82 COPD subjects from K.M.C hospitals. All patients were admitted for acute exacerbation and were medically stabilized. After being screened for the inclusion and exclusion criteria, 72 subjects were selected for the study. Demographic and baseline data was taken on the day subjects were screened. Music group listened to a self selected music of 60-80 beats per minute for 30 minutes. PMR group practiced relaxation through a pre-recorded audio of instructions of 16 muscle groups. Outcome variables were Spielberger's state anxiety inventory (SSAI), Spielberger's trait anxiety inventory (STAI), dyspnea, systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse rate (PR) and respiratory rate (RR). There was statistically significant main effect across the sessions for state anxiety (F = 62.621, p = 0.000), trait anxiety (F = 19.528, p = 0.000), dyspnea (F = 122.227, p = 0.000), SBP (F = 63.885, p = 0.000), PR (F = 115.780, p = 0.000) and RR (F = 202.977, p = 0.000). There was statistically significant interaction effect between the two groups for state anxiety (F = 6.024, p = 0.003), trait anxiety (F = 8.222, p = 0.000), dyspnea (F = 10.659, p = 0.000), SBP (F = 12.889, p = 0.000), PR (F = 4.746, p = 0.008) and RR (F = 12.078, p = 0.000). There were greater changes observed after the second session in both groups however, change in DBP was not significant in either group. Music and PMR are effective in reducing anxiety and dyspnoea along with physiologic measures such as SBP, PR and RR in two sessions in COPD patients hospitalized with exacerbation. However, reductions in the music group were greater compared to the PMR group.