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Onion (Allium cepa L.) is one of the most important vegetables in family Alliaceae, which is cultivated worldwide. In onion, weeds are among one of the major concerns which cause its yield reduction. The present study was designed to assess the effectiveness of different methods for weed control in onion. In this study, five treatments were selected including control, black polythene mulch sheet, white polythene mulch sheet, Dual Gold spray @ 9.0 mL L-1 and Preact spray @ 7.5 mL L-1 to control weeds. The weedicides were applied as pre-emergence sprays before transplanting the seedlings. The experiment was laid out in Randomized Complete Block Design with three replications. From the results, it was concluded that there were significant differences among the studied weed control treatments. Among the five treatments, greater plant height (33.0 cm), number of leaves per plant (8), bulb diameter (4.7 cm) and bulb weight (73 g) were observed in the ridges covered with black mulch sheet. However, the minimum weed biomass (fresh and dry) was recorded in black mulch sheet and Preact pre-emergence weedicide spray (140 and 80 g in both). Thus, black polythene sheet as mulching material was found better option for weed management in onion fields.

Globally, soil salinity is a serious threat to horticultural crop productivity. Chili (Capsicum annum L.) is a major spice horticultural crop. Its growth and production is severely affected by salt stress. To address this problem, a sand culture experiment was conducted in which two contrasting chili genotypes ‘Plahi’ (salt tolerant) and ‘A-120’ (salt sensitive) were grown under salt stress (50 mM NaCl) with foliar application of proline (0.8 mM). Proline application enhanced salt tolerance in both genotypes by osmoregulation of sodium and potassium. It enhanced chili growth and fruit yield by improving plant water relations and gas exchange attributes under salt stress. Antioxidants were increased with proline application under salt stress. There was also a significant positive correlation found among glycinebetaine and proline contents. In conclusion, protein-treated chili plants performed better than untreated plants as evidenced by normal function of photosynthetic machinery and antioxidant mechanisms under salt stress.

Nickel (Ni) element is strongly phytotoxic at high concentrations for several plants, but due to its dual behavior and complicated chemistry, it has received little attention in plant nutrition and relevant experimental data are limited. The current research was carried out to study the effect of Ni on maize (Zea mays L.) growth and phytoextraction potential with EDTA assistance, a process termed as chemical assisted phytoremediation. Treatments included two levels of EDTA (0 and 0.5 mM), two levels of Ni (0 and 40 µM) and their combination (EDTA+Ni) that were applied to maize plants grown in a pot experiment. Application of Ni alone or in combination with EDTA reduced maize root and shoot length by 7.8% to 13.3% and by 15.6% to 21.1%, respectively, compared with control, as well as root and shoot dry weight by 42.0% to 60.0% and by 29.8% to 46.6%, respectively. A similar declining trend was observed also for the content of photosynthetic pigments (chl-a, chl-b, total chlorophyll, and carotenoids) as well as total proteins. However, proline, total soluble sugars, and free amino acids showed an increasing trend with application of Ni and EDTA alone or in combination. These treatments significantly decreased P and Na content in maize roots, stems, leaves, and grains, while increased K content compared with control. Application of EDTA with Ni was the most effective treatment to enhance Ni accumulation in maize (50.23 mg per plant) compared with Ni alone (40.62 mg per plant), EDTA alone (27.75 mg per plant), and control (15.51 mg per plant). Application of EDTA in combination with Ni enhanced Ni accumulation by 4.9 folds in maize shoots and by 2.6 folds in roots over control. In conclusion, application of EDTA in suitable concentrations may enhance Ni uptake by maize providing an effective and economic phytoremediation method of Ni-contaminated soils.

Salt stress is the major risk to the seed germination and plant growth via affecting physiological and biochemical activities in plants. Zinc nanoparticles (ZnNPs) are emerged as a key agent in regulating the tolerance mechanism in plants under environmental stresses. However, the tolerance mechanisms which are regulated by ZnNPs in plants are still not fully understood. Therefore, the observation was planned to explore the role of ZnNPs (applied as priming and foliar) in reducing the harmful influence of sodium chloride (NaCl) stress on the development of spinach (Spinacia oleracea L.) plants. Varying concentrations of ZnNPs (0.1%, 0.2% & 0.3%) were employed to the spinach as seed priming and foliar, under control as well as salt stress environment. The alleviation of stress was observed in ZnNPs-applied spinach plants grown under salt stress, with a reduced rise in the concentration hydrogen peroxide, melondialdehyde and anthocyanin contents. A clear decline in soluble proteins, chlorophyll contents, ascorbic acid, sugars, and total phenolic contents was observed in stressed conditions. Exogenous ZnNPs suppressed the NaCl generated reduction in biochemical traits, and progress of spinach plants. However, ZnNPs spray at 0.3% followed by priming was the most prominent treatment in the accumulation of osmolytes and the production of antioxidant molecules in plants.

Heat stress is one of the major issues that are curtailing yield and productivity of the crops. This situation is to aggravate further under the global warming scenario. Keeping in consideration the prevailing problem, the present study was designed to investigate the role of exogenously applied salicylic acid in enhancing heat tolerance of tomato. Tomato genotypes (two heat tolerant and two heat sensitive) were exposed to controlled conditions of high temperature (40/32°C day and night) and were sprayed with salicylic acid at various concentrations. The data regarding growth related attributes, gas exchange related attributes and chlorophyll contents were recorded and analyzed statistically. The study proved that exogenously applied salicylic acid induced heat tolerance in tomato genotypes as enhanced tolerance was noted as compared to control. The results revealed that the foliar application of salicylic acid with a concentration of 1.5 mM was found appropriate in alleviating the drastic effects of high temperature as compared to other concentrations tested. It can be concluded that heat tolerance potential of the tomato can be enhanced by applying salicylic acid exogenously. The findings of this study will not only help in boosting yield but will also expand the growing period of tomato in the summer months.

Keeping in view the yield losses instigated by heat stress in several crops, we carried out an experiment to explore the curative effect of exogenous applications of proline on the morpho-physiological, biochemical, and water-related attributes of okra genotypes under high-temperature stress (controlled conditions). Four contrasting genotypes C1, C2, C3, and C4 heat tolerant and heat sensitive genotypes were selected from a diverse panel of okra genotypes (n = 100) to examine plant responses to high-temperature stress and exogenous application of proline. Four-week-old seedlings were subjected to heat stress by gradually increasing the temperature of a growth chamber from 28/22 °C to 45/35 °C (day/night) and sprayed with an optimized proline concentration 2.5 mM. The experiment consisted of a factorial arrangement of treatments in a completely randomized design. The results showed that there were maximum increases in shoot length (32.7%), root length (58.9%), and shoot fresh (85.7%). The quantities of leaves per plant were increased by 52.9%, 123.6%, 82.5%, and 62.2% in C1, C2, C3, and C4 after proline application. On the other hand, only root fresh weight decreased in all genotypes after proline application by 23.1%, 20%, 266.7%, and 280.8% (C1, C2, C3, C4). A lower leaf temperature of 27.72 °C, minimum transpiration of 3.29 mmol m−2 s−1, maximum photosynthesis of 3.91 μmol m−2 s−1, and a maximum water use efficiency of 1.20 μmol CO2 mmol H2O were recorded in the genotypes C2, C1, C3, and C4, respectively. The highest enzymatic activity of superoxide dismutase, peroxidase and catalase were 14.88, 0.31, and 0.15 U mg-protein in C2, C1, and C3, respectively. Maximum leaf proline, glycinebetaine, total free amino acids, and chlorophyll content 3.46 mg g−1, 4.02 mg g−1, 3.46 mg g−1, and 46.89 (in C2), respectively, due to foliar applications of proline. Another important finding was that heat tolerance in okra was highly linked highly linked to genotypes’ genetic potential, having more water use efficiency, enzymatic activities, and physio-biochemical attributes under the foliar applications of proline.

Drought stress is considered one of the most severe stresses, which can result in devastating yield reduction in agriculture crops. There are many approaches recommended by the researchers and adopted by the farmers to minimize the devastating effect of drought. However, exogenous application of growth regulators in combination to plant nutrients is the innovative attitude to ameliorate the shocking effects of drought stress. So we planned a study to investigate the ameliorative effect of exogenously applied potassium silicate wheat (Triticum aestivum L.) crop under water deficit conditions. The current study was conducted at the Agronomic Research Farm area, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur. RCBD-Split plot design with four repeats was used. The treatments consist on “T0” (Control), “T1” (exogenous application of potassium silicate @ 1% solution), “T2” (exogenous application of potassium silicate @ 2% solution), “T3” (exogenous application of potassium silicate @ 3% solution). The results of our study revealed that drought stress can significantly affect crop yield as a result of the reduction in chlorophyll-a (1.07), chlorophyll-b (0.49), total chlorophyll contents (1.62), flag leaf area (38.33 cm2), plant height (100.17cm), number of nodes per plant (3.91), tiller height (92.42), number of tillers m− 2 (191.17), spike length (7.58 cm), number of spikes per plant (10.25), number of grains per spike (25.08), 1000-grain weight (36.66g), total dry weight per plant (309.75g), biomass yield (23424kg/ha) and grain yield (4564.2 kg/ha). On the other hand, the exogenous application of potassium silicate at 2% solution showed promising results in terms of ameliorating the drought effect by significantly enhancing chlorophyll-a (1.21), chlorophyll-b (0.64), total chlorophyll contents (1.92), flag leaf area(45.25 cm2), plant height (123.50cm), number of nodes per plant (5.25), tiller height (99.42), number of tillers m− 2 (276.26), spike length (12.92cm), number of spikes per plant (14.25), number of grains per spike (38.33), 1000-grain weight (44.33g), total dry weight per plant (385.00g), biomass yield (24000 kg/ha) and grain yield (5074.8kg/ha). These findings led us to conclude that the exogenous application of potassium silicate has a great ability to compensate for the detrimental effects of drought in wheat crops.

Series of experiments have been conducted to find the optimized dose and efficacy of nitrogen to fulfill the requirements of plant at each level by making split doses. Being most important macro nutrient, afield trial was conducted to study the effect of without applying nitrogen (control) single nitrogen (N) application at planting time on yield and nitrogen uptake of potato in comparison to various split applications. Data were collected about plants vegetative growth, total yield and qualitative factors (TSS, nitrogen, phosphorus, potassium and protein percentage in tuber). Experimental design used was Randomized Complete Block Design (RCBD) having seven treatments with three replications. Data were analyzed by using standard statistical techniques. Overall, qualitative characters of tubers and yield enhanced with split nitrogen application as compared to all nitrogen applied once at planting time whereas, there was no significant difference between tuber nitrogen, potassium, phosphorus and protein contents.

Gene silencing is the epigenetic regulation of any gene in order to prevent gene expression at the transcription or translation levels. Among various gene silencing techniques, RNA silencing (RNAi) is notable gene regulation technique that involves sequence-specific targeting and RNA degradation. However, the effectiveness of transgene-induced RNAi in F1 generation of chrysanthemum has not been studied yet. In the current study, we used RNAi-constructed CmTFL1 (white-flowered) and CmSVP overexpressed (yellow flowered) transgenic plants of previously conducted two studies for our experiment. Cross hybridization was performed between these intergeneric transgenic and non-transgenic plants of the winter-growing chrysanthemum selection “37” (light pink flowered). The transgene CmSVP was confirmed in F1 hybrids by RT-PCR analysis, whereas hybrids of CmTFL1 parental plants were non-transgenic. Besides this, quantitative real-time PCR (qPCR) was used to explain the molecular mechanism of flower development using reference genes. Intergeneric and interspecific hybrids produced different colored flowers unlike their respective parents. These results suggest that generic traits of CmSVP overexpressed plants can be transferred into F1 generations when crossed with mutant plants. This study will aid in understanding the breeding phenomenon among intergeneric hybrids of chrysanthemum plants at an in vivo level, and such transgenics will also be more suitable for sustainable flower yield under a low-light production system.

Background: Potato is an important vegetable; however, salt stress drastically affects its growth and yield. A pot experiment was therefore conducted to assess salicylic acid efficacy in improving performance of potato cultivars, grown under salt stress (50 mmol L-1 ). Salicylic acid at 0.5 mmol L-1 was sprayed on to potato plants after 1 week of salinity application.; Results: Salt stress effects were ameliorated by salicylic acid effectively in both the studied cultivars. N-Y LARA proved more responsive to salicylic acid application than 720-110 NARC, which confirmed genetic variation between cultivars. Salicylic acid scavenged reactive oxygen species by improving antioxidant enzyme activities (superoxide dismutase, catalase, peroxidases) and regulating osmotic adjustment (proline, phenolic contents), which led to enhanced water relation and gaseous exchange attributes, and thereby increased potassium availability and reduced sodium content in potato leaves. Moreover, potato tuber yield showed a positive correlation with potassium content, photosynthesis and antioxidant enzyme activities.; Conclusion: Salt tolerance efficacy of salicylic acid is authenticated in improving potato crop performance under salt stress. Salicylic acid effect was more pronounced in N-Y LARA, reflecting greater tolerance than 720-110 NARC, which was confirmed as a susceptible cultivar. Hence salicylic acid at 0.5 mmol L-1 and cultivation of N-Y LARA may be recommended in saline soil. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

An effective and simple screening technique for identification of salt tolerant and salt sensitive radish genotypes was observed. Sand is used as potting media. Six genotypes of radish were used for screening against four salinity levels (0, 1, 3, 5 and 7 dS/m-1). Twenty days old seedlings of radish were salinized with salt solution (NaCl). Morphological, physiological and ionic parameters were studied. Radish genotypes Laal-Pari and 40 Days executed the best performance in all the measured attributes and categorized as salt tolerant genotype while Green Neck was the poorest in retaining normal functioning at higher salinity levels thus grouped under salt sensitive cultivar.

Increasing concentration of Cd in soil is of great concern due to risk of its entry into food chain. Zinc (Zn) being antagonist to Cd is an important micronutrient to ameliorate its toxic effects on plants and to limit its entry into food chain. A pot experiment was conducted using Cd contaminated soil (30 mg Cd kg(-1) soil as 3CdSO4 · 8H2O) to investigate the effect of soil and foliar applied Zn on physiological response and Cd concentration in wheat. In soil, Zn was applied at 15 and 30 mg Zn kg(-1) soil as zinc sulfate (ZnSO4 · 7H2O). For foliar applications, 3 and 6 g L(-1) ZnSO4 solution was sprayed on completing eight weeks of growth. Results indicated that Zn application could effectively improve physiological performance and mineral content of wheat grown on Cd contaminated soils. Among different Zn fertilization treatments, foliar application of 3 g L(-1) ZnSO4 solution recorded the maximum soluble proteins and the minimum grain-Cd concentration. Soil application of ZnSO4 or foliar application at 6 g L(-1) did not affect Cd concentration in grains. Zinc application through both the methods significantly increased phosphorus (P), potassium (K) and Zn concentrations in shoots. Concentration of P and K in grains showed positive relationship with that of Zn. In crux, present study suggests that foliar application of Zn at booting stage in a suitable concentration (3 g L(-1) ZnSO4 solution) can effectively ameliorate the adverse effects of Cd and decrease grain-Cd of wheat grown in Cd contaminated soil.

BACKGROUND Tomato (Solanum lycopersicum L.) is an important but heat-sensitive vegetable crop. The losses in tomato production associated with heat stress are aggravating further under a global warming scenario. The present study was designed to investigate the comparative performance of tomato genotypes under high temperature stress. Tomato genotypes (191) were exposed to the controlled conditions of high temperature (40/32 °C day/night temperature). Different morphological (shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight and number of leaves), physiological (photosynthetic rate, transpiration rate, water use efficiency, stomatal conductance to water, sub-stomatal CO2 and leaf temperature) and SPAD value (chlorophyll content) were recorded to check the diversity among genotypes against heat stress. RESULTS All the genotypes showed a significantly variable response in almost all the attributes under high-temperature conditions. Correlation among the variables provided a clear understanding of the phenomena involved. Based on all the attributes studied, genotypes L00090 and L00091 were found to be the most heat tolerant compared to other genotypes, whereas CLN1462A and CLN 1466E were found to be comparatively sensitive. CONCLUSION It was concluded that the studied attributes were genotype dependent, and significant diverse performance was noted. The findings of this study pave the way towards the selection of tolerant genotypes, not only for use under high-temperature conditions but also to employ them in breeding programs to produce heat-tolerant hybrids. © 2015 Society of Chemical Industry

For horticultural crops and especially for vegetables, salinity is dilemma. It is the most limiting factor for plant growth and development by producing reactive oxygen species and ultimately oxidative stress. In the present study, the screening of watermelon (Citrullus lanatus Thanb. Mavs.) Cultivars was observed for salt tolerance. Four salinity levels (1.5, 3, 4.5, and 6 dS·m-1 NaCl) and six cultivars (Crimson, Charleston Gray, Anarkali, Chairman, Sugar Baby and Champion) tested for screening. It was observed that all morphological attributes and ionic contents were severely affected. But it was revealed by statistical analysis that Charleston Gray was affected least while Champion was most salt sensitive cultivar due to oxidative stress and ionic toxicity. It is concluded that different genotypes under consideration vary in their ability to tolerate salt stress.

Salicylic acid (SA) is a vital plant growth regulator providing promising role in plant development and adopts defense mechanism to abiotic stresses. Salinity is the most limiting abiotic factor for plant development and growth changes in watermelon by producing reactive oxygen species and ultimately oxidative stress. The present study was aimed to investigate the mechanism involved in salt stress alleviation in watermelon (Citrullus lanatus Thanb. Mavs.) through the foliar application of salicylic acid. Watermelon cv. Charleston Gray was grown under moderate saline regime of 3 ds·m-1 NaCl and sprayed with salicylic acid with four level (0.5, 1.0, 2.5 and 5.0 mmol/L) compared along with control. SA @ 5.0 mmol/L was found to be very effective in mitigation of salt stress. SA was found to be very effective in alleviation of salinity stress by produced antioxidants and acted as osmo-regulator.

Presence of heavy metals in agricultural soils is of major environmental concern and a great threat to life on the earth. A number of human health risks are associated with heavy metals regarding their entry into food chain. Various physical, chemical and biological techniques are being used to remove heavy metals and metalloids from soils. Among them, phytoremediation is a good strategy to harvest heavy metals from soils and have been proven as an effective and economical technique. In present review, we discussed various sources and harmful effects of some important heavy metals and metalloids, traditional phytoremediation strategies, mechanisms involved in phytoremediation of these metals, limitations and some recent advances in phytoremediation approaches. Since traditional phytoremediation approach poses some limitations regarding their applications at large scale, so there is a dire need to modify this strategy using modern chemical, biological and genetic engineering tools. In view of above, the present manuscript brings both traditional and advanced phytoremediation techniques together in order to compare, understand and apply these strategies effectively to exclude heavy metals from soil keeping in view the economics and effectiveness of phytoremediation strategies.

Potato is an important vegetable; however, salt stress drastically affects its growth and yield. A pot experiment was therefore conducted to assess salicylic acid efficacy in improving performance of potato cultivars, grown under salt stress (50 mmol LSalt stress effects were ameliorated by salicylic acid effectively in both the studied cultivars. N-Y LARA proved more responsive to salicylic acid application than 720-110 NARC, which confirmed genetic variation between cultivars. Salicylic acid scavenged reactive oxygen species by improving antioxidant enzyme activities (superoxide dismutase, catalase, peroxidases) and regulating osmotic adjustment (proline, phenolic contents), which led to enhanced water relation and gaseous exchange attributes, and thereby increased potassium availability and reduced sodium content in potato leaves. Moreover, potato tuber yield showed a positive correlation with potassium content, photosynthesis and antioxidant enzyme activities.Salt tolerance efficacy of salicylic acid is authenticated in improving potato crop performance under salt stress. Salicylic acid effect was more pronounced in N-Y LARA, reflecting greater tolerance than 720-110 NARC, which was confirmed as a susceptible cultivar. Hence salicylic acid at 0.5 mmol L