Showing papers by "Madhoolika Agrawal published in 2015"
TL;DR: Ethylene diurea (EDU) has been the most effective protectant used and has also served as a monitoring agent for assessing plant yield losses from 0 3 exposure, and indicates that EDU should be more widely used on 0 3 sensitive plants as a tool for biomonitoring of 0 3 concentrations.
Abstract: Rapid economic growth, industrialization, urbanization, and improper implementation of environmental regulations have contributed to increased tropospheric O3 levels since preindustrial times, and this increase has produced a serious air pollution problem Apart from being a hazardous air pollutant, O3 has also been recognized as the third major (carbon dioxide and methane) green house gas in terms of additional radiative forcing and climate change (Forster et al 2007) Because of its oxidative capacity, high O3 levels in the atmosphere are detrimental to living organisms, including plants Ozone is among the most damaging air pollutants to which plants are exposed, and produces substantive plant biomass and yield (seed weight) reductions (Thompson 1992; Agrawal et al 2005; Manning 2005; Hassan 2006; Hassan and Tewfik 2006; Singh et al 2009a, 2014; Wahid 2006 a, b; Sarkar and Agrawal 2010a, b; Tripathi and Agrawal 2013) The economic loss for 23 horticultural and agricultural crops from O3 exposure was estimated to be approximately $67 billion for the year 2000 in Europe (Holland et al 2006) Wang and Mauzerall (2004) anticipated economic losses of upto 9 % for four important cereal crops (viz, wheat, rice, maize and soybean) grown in China, South Korea and Japan To minimize such crop losses many potential antioxidants (eg, fungicides, insecticides, growth regulators and plant extracts) have been evaluated Among these, the systemic antioxidant, ethylene diurea, –N-[2-(2-oxo-1-imidazolidinyl) ethyl]-N′ phenylurea (popularly known as EDU) was found to be the most effective
48 citations
TL;DR: The study suggests that elevated CO2 has positively affected plants by increasing growth and alkaloids production and reducing the level of oxidative stress, however, the positive effects were comparatively lesser in plants grown under limited N availability than in moderate and higher N availability.
Abstract: Catharanthus roseus L. plants were grown under ambient (375 ± 30 ppm) and elevated (560 ± 25 ppm) concentrations of atmospheric CO2 at different rates of N supply (without supplemental N, 0 kg N ha−1; recommended N, 50 kg N ha−1; and double recommended N, 100 kg N ha−1) in open top chambers under field condition. Elevated CO2 significantly increased photosynthetic pigments, photosynthetic efficiency, and organic carbon content in leaves at recommended (RN) and double recommended N (DRN), while significantly decreased total nitrogen content in without supplemental N (WSN). Activities of superoxide dismutase, catalase, and ascorbate peroxidase were declined, while glutathione reductase, peroxidase, and phenylalanine-ammonia lyase were stimulated under elevated CO2. However, the responses of the above enzymes were modified with different rates of N supply. Elevated CO2 significantly reduced superoxide production rate, hydrogen peroxide, and malondialdehyde contents in RN and DRN. Compared with ambient, total alkaloids content increased maximally at recommended level of N, while total phenolics in WSN under elevated CO2. Elevated CO2 stimulated growth of plants by increasing plant height and numbers of branches and leaves, and the magnitude of increment were maximum in DRN. The study suggests that elevated CO2 has positively affected plants by increasing growth and alkaloids production and reducing the level of oxidative stress. However, the positive effects of elevated CO2 were comparatively lesser in plants grown under limited N availability than in moderate and higher N availability. Furthermore, the excess N supply in DRN has stimulated the growth but not the alkaloids production under elevated CO2.
42 citations
TL;DR: Chandramukhi et al. as discussed by the authors evaluated the effects of different levels of carbon dioxide (ambient (382ppm) and elevated (570ppm)) and O 3 (50ppb) on physiological and biochemical characteristics of potato using open top chambers.
37 citations
TL;DR: EDU alleviated the negative effects of O3 by enhancing the first line of defense against ROS and protecting N assimilation enzymes at flowering and maintaining adequate supply of photosynthates to developing pods during pod filling stage.
36 citations
TL;DR: In this article, the effects of ambient ozone (O 3 ) on wheat (Triticum aestivum L.) varieties HUW 510 and LOK-1 were studied at recommended and 1.5 times recommended NPK under natural field conditions using open top chambers under varying NPK levels.
23 citations
TL;DR: In this article, the authors assess the heavy metal accumulation and the potential human health risks associated with consumption of contaminated vegetables irrigated with waste (WWT) and mixed wastewater (MWWT), grown in an agricultural area of Bhagwanpur, near Banaras Hindu University, Varanasi, India.
Abstract: Consumption of wastewater-irrigated vegetables is a common practice in developing countries including India. The wastewater irrigation gradually raises the contents of heavy metals in soils and vegetables. The consumption of heavy metal-rich vegetables may cause serious risk to the human health. Therefore, quantification of heavy metals in vegetables collected from wastewater-irrigated field is needed as proportion of farmers using wastewater for irrigation is increasing due to scarcity of water. The aim of the present study was to assess the heavy metal accumulation and the potential human health risks associated with consumption of contaminated vegetables irrigated with waste (WWT) and mixed wastewater (MWWT), grown in an agricultural area of Bhagwanpur, near Banaras Hindu University, Varanasi, India. Seven common vegetables growing at two differentially irrigated areas (WWT and MWWT) were considered for the study. At each site, three samples, each from water, soil and different vegetables, were taken. The samples after digestion were analysed for heavy metal contents using atomic absorption spectrophotometer. Heavy metal contents in soils, vegetables, transfer factor (TF) from soil to vegetables, metal pollution index (MPI) and their health risk in form of target hazard quotients (THQs) were calculated. Results showed significantly higher contents of heavy metals in water, soil and vegetable at WWT than MWWT. The TF value of Cd was notably greater in WWT compared to the MWWT. The values of THQ in children and adults were >1 for Pb and Cd in case of all vegetables at both WWT and MWWT. Among the vegetables, MPI was highest for B. vulgaris followed by B. botrytis, B. capitata, R. sativus, B. nigra, A. sativum and S. tuberosum. THQ for both categories were mostly higher for WWT compared at MWWT, suggesting a greater health risk to local residents from vegetable of the former than latter site. The present study suggests regular monitoring of water quality prior to discharge for irrigation uses and also points out to adopt better wastewater management strategies for proper utilization and disposal of wastewater.
19 citations
TL;DR: Application of recommended level of NPK caused least changes in N metabolism leading to minimum yield losses due to elevated UV-B stress, which suggests competition between sucrose synthesis and nitrate reduction under additional P level.
Abstract: The effects of elevated UV-B (280–315 nm) were assessed on nitrogen metabolism, carbohydrate pool, total phenolics, photosynthetic pigments, UV-B absorbing compounds, variables related to oxidative stress, biomass and yield of pea plants grown under various levels of NPK. The NPK levels assayed were: background NPK level (F0); recommended NPK (F1) and recommended NK + 1.5 × recommended P (F2) and the UV-B levels were: control (C) and elevated (T). The responses of T plants varied with different combinations of NPK. Yield reduced under elevated UV-B at all NPK levels with maximum reduction in F0T and minimum reduction in F1T. Leghaemoglobin content was reduced under elevated UV-B at all NPK levels. Maximum increase in malondialdehyde content recorded in F0T plants corresponded with higher superoxide and hydrogen peroxide contents. Nitrite reductase activity decreased significantly under UV-B at all NPK levels, but nitrate reductase activity increased significantly in F1T and F2T. Maximum reduction in C : N ratio of leaves in F2T plants suggests competition between sucrose synthesis and nitrate reduction under additional P level. The study concludes that application of recommended level of NPK caused least changes in N metabolism leading to minimum yield losses due to elevated UV-B stress.
14 citations
TL;DR: The study showed that extracellular soil enzymes respond sensitively to tillage practices as well as environmental variables, particularly soil temperature and moisture and hence can serve as a sensitive indicator of changes in soil processes.
Abstract: Microbial processes, particularly enzyme activities, play crucial functional roles in soil ecology, hence serving as sensitive indicators of soil quality. We assessed the temporal dynamics of microbial biomass and selected soil enzymes (β-d-glucosidase, cellobiohydrolase, polyphenol oxidase, urease, glycine-aminopeptidase and alkaline phosphatase) during wheat cultivation, under four different tillage practices in the rice–wheat system. The four practices involved conventional tilling of soil before cultivating each crop (CTR-CTW); no tilling before cultivating rice but conventional tillage before wheat (NTR-CTW); conventional tilling before cultivating rice but no tilling before wheat (CTR-NTW) and no tilling before cultivation of each crop (NTR-NTW). Microbial biomass and activities of hydrolytic enzymes increased under NTR-NTW followed by CTR-NTW and NTR-CTW with respect to the conventional practice CTR-CTW, thus reflecting improvement in microbial activities with reduced tillage frequency. Enzyme acti...
13 citations
TL;DR: The differential response of the test plant under varying CO 2 and N levels concluded that C-allocation toward biomass and metabolites synthesis under future projected level of CO 2 will be greatly modified by soil nitrogen availability.
7 citations
TL;DR: In this paper, the authors measured the fluxes of CH4, N2O and CO2 during the cultivation of two important crops; sugarcane and pigeon pea following the closed chamber technique.
Abstract: Quantification of greenhouse gas (GHG) emissions from agricultural lands is essential for strategic planning towards GHG efficient development in India. We measured the fluxes of CH4, N2O and CO2 during cultivation of two important crops; sugarcane and pigeon pea following the closed chamber technique. Both the soils acted as net CH4 sinks, but sources of N2O and CO2. Pigeon pea soil acted as a weak sink, removing 0.054 ± 0.002 kg CH4 ha−1 from the atmosphere, while sugarcane soil removed 11.061 ± 0.093 kg CH4 ha−1. Urea application in sugarcane field increased the fluxes of N2O, but the total N2O emission over growth period of sugarcane (355 days) was similar to the total emissions during pigeon pea cultivation (245 days); 2.69 ± 0.09 and 2.07 ± 0.17 kg N2O ha−1, respectively. CO2 fluxes from pigeon pea cultivation were higher than sugarcane cultivation. Pigeon pea cultivation was a low input farming, but its global warming potential was higher than that of sugarcane cultivation. This study presents the GHG estimates from cultivation of the two important crops in India for which GHG estimates are lacking.
5 citations
23 Dec 2015
TL;DR: To optimize both the roles of light, plants evolved complex system and the most established higher plants photoautotrophic mode of nutrition is responsible for establishing and sustaining the human civilization.
Abstract: During the course of evolution, plants developed the capability of capturing and utilizing the solar radiation. These plants gained an evolutionary advantage over those that have not developed these traits. Light besides being an important source of energy also controls many developmental processes like photoperiodism, phototropism and photomorphogenesis of plant growth. Oxygen in the atmosphere is generally believed to come from light induced water-splitting that occurs in oxyphotosynthetic organisms catalysed by the oxygen evolving centre of photosystem II. To optimize both the roles of light, plants evolved complex system and the most established higher plants photoautotrophic mode of nutrition is responsible for establishing and sustaining the human civilization.
01 Jan 2015
TL;DR: In higher plants, UV-B is known to have two very diverse effects: evoked damage and the other in response to the perception of UV by postulated receptor, leading to UV-b-induced photomorphogenesis and thus acclimation.
Abstract: In higher plants, UV-B is known to have two very diverse effects: one in response to the evoked damage and the other in response to the perception of UV-B by postulated receptor, leading to UV-B-induced photomorphogenesis and thus acclimation. The UV-B-specific pathway involves the UVR8-COP1-HY5 pathway. The response depends on wavelength, fluence rate, and duration of the UV-B radiation as well as the extent of adaptation. On the other hand, the damage response pathway includes activation of more general stress responses.
01 Jan 2015
TL;DR: In this paper, the authors present an integrated analysis of all inputs-outputs to estimate the actual impact of GHG emissions in the agricultural system, which plays dominating role in the global fluxes of CH4 and N2O, as their biggest emitter.
Abstract: Continually rising concentration of greenhouse gases (GHGs) in the atmosphere is increasing concerns over how to manage global warming. Quantification of sources and sinks of these gases have been carried out, but there remains incoherence among the estimates due to different nature of sources and processes related therewith. This renders inter-comparison and further utilization of available assessments quite incomparable. Except major point sources like thermal power plants, cement manufacturing, etc. which have been quantified confidently (Matthews et al., 2008), fugitive and sensitive sources/sinks still need proper quantification. Agriculture is one such system which plays dominating role in the global fluxes of CH4 and N2O, as their biggest emitter. Substantial inputs of energy, machinery, synthetic fertilizers and pesticides in the modern agriculture bear embodied emissions in addition to much focused direct emissions from soil (Lal, 2004a). At the same time, agricultural soils may reportedly act as considerable carbon sink (Lal, 2004b). Therefore it becomes essential to integrate all inputs-outputs to estimate the actual impact.