Effects of Nutrition on Wheat Photosynthetic Pigment Responses to Arsenic Stress (original) (raw)
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Nitrogenous Nutrition Affects Uptake of Arsenic and Defense Enzyme Responses in Wheat
Polish Journal of Environmental Studies, 2021
Nitrogenous nutrition influences the availability of other plant resources and, consequently, affects plant defense responses. Both a shortage and excess of N impact plants ́ ability to accumulate and survive metals/metalloids, but available data are still fragmented and often contradictory. A series of 8 different NH4NO3 concentrations, ranging from zero to excessive nitrogen (35 mM N), was applied in growth media to hydroponically grown wheat (Triticum aestivum). The plants were grown at a sublethal concentration of arsenic (5 mM As3+) for 10 days and foliar accumulation of As, N and P was determined. In addition, induction of defense-related chitinase and β-1,3-glucanase enzyme isoforms was quantified upon the separation of plant protein extracts in polyacrylamide gels. As3+ interfered with N and P accumulation in shoots and strongly activated several enzyme isoforms. These responses varied with the N supply and indicated a low rate of As accumulation at low N concentrations. On ...
Elevated arsenic content in food crops pose a serious human health risk. Apart from rice wheat being another main food crop is possibly cultivated on contaminated sites. But for wheat uptake mechanisms are not entirely understood especially with regard to nutrient fertilization and different moisture regimes taking into account heavy rainfall events due to climate change. Here we show that especially higher P-fertilization under changing redox conditions may enhance arsenic uptake. This counteracts with higher N-fertilization reducing arsenic transfer and translocation into aboveground plant parts for both higher P-fertilization and reducing soil conditions. Arsenic speciation did not change in grain but for leaves P-fertilization together with reducing conditions increased the As(V) content compared to other arsenic species. Our results indicate important dependencies of nutrient fertilization, moisture conditions and substrate type on As accumulation of wheat as one of the most important crop plants worldwide with implications for agricultural practices.
Negative Impacts of Arsenic on Plants and Mitigation Strategies
Plants
Arsenic (As) is a metalloid prevalent mainly in soil and water. The presence of As above permissible levels becomes toxic and detrimental to living organisms, therefore, making it a significant global concern. Humans can absorb As through drinking polluted water and consuming As-contaminated food material grown in soil having As problems. Since human beings are mobile organisms, they can use clean uncontaminated water and food found through various channels or switch from an As-contaminated area to a clean area; but plants are sessile and obtain As along with essential minerals and water through roots that make them more susceptible to arsenic poisoning and consequent stress. Arsenic and phosphorus have many similarities in terms of their physical and chemical characteristics, and they commonly compete to cause physiological anomalies in biological systems that contribute to further stress. Initial indicators of arsenic’s propensity to induce toxicity in plants are a decrease in yie...
2016
In this study we have examinated the results of two experiments on the uptake and distribution of arsenic (As) in roots, shoots, and grain of wheat grown in As-polluted soils and in an unpolluted soil irrigated with As-contaminated water in absence or presence of phosphorus (P) fertilization. Arsenic concentrations in wheat samples of the two experiments are higher than those in the plants grown on uncontaminated soil. In the experiments showed in this work, it is highlighted the role of P fertilization in preventing As uptake and translocation in wheat plants. These findings could have important implications to reduce the potential risk posed to human health by As entering the food-chain.
Chemosphere, 2007
Arsenic is a well known carcinogenic element, that can harm not only human health but, plant and bacteria as well. Replicated experiments confirmed that, Arsenic accumulates in the different tissues in different parts of the plant and, adversely affects the growth and productivity of the plants. It is a threat for millions of population in terms of health and food security both. Therefore, a pot experiment was designed and conducted to investigate the effect of arsenic on photosynthetic pigments, Chlorophyll-a and-b, growth behavior, and its accumulation in the tissues of different parts of onion plants (Allium cepa). Test plants were subjected to pot experiment under natural conditions. Four pots were prepared to grow onion plants, irrigated with equal volume of different Arsenic solution (NaAs 3), 0.00 mg/l, 0.200mg/l, 0.600mg/l, and 0.800mg/l concentration with one pot for control respectively, throughout the experiments. Both chlorophyll-a and-b contents in onion leaf increased significantly with the increase of water arsenic concentrations. The highest chlorophyll-a (0.004847/g) and chlorophyll-b (0.006528/g) contents were estimated in the onion leaf irrigated with 0.800mg/l of Arsenic whereas, in control plant it was lowest (chl-a 0.002363/ and chl-b 0.004092/g). A high positive correlation was observed between water arsenic (R 2 = 0.897 and 0.963) & soil arsenic (R 2 = 0.926 and 0.919) with chlorophyll-a and chlorophyll-b respectively. High positive correlation was also observed even for onion growth verses soil arsenic and water arsenic (R 2 =0.994 and 0.968) and water Arsenic with leaf biomass (R 2 =0.973) respectively. However, no Arsenic accumulation was detected in the tissues of different parts of the onion plants suggesting that, arsenic (NaAs 3) influenced the 40 K. Singh Sushant and A.K. Ghosh biochemistry of photosynthesis which ultimately resulted in the increase of onion growth and yield. Onion plants can be cultivated in the area where Arsenic containing water is being utilized for irrigating crops but, a chain of in-vitro studies are required to understand the biochemistry and mechanism that influenced growth and productivity of the onion plants.
Consequences of arsenic exposure in Plant-health status: an overview
IntechOpen eBooks, 2023
Arsenic is the biggest threat to all living organisms across the world. It is typically present in very minute amounts in rock, soil, air, and water, but these levels are rising as a result of both natural and man-made activity. Exposure to arsenic increases the risk of developing liver, lung, kidney, and bladder malignancies as well as vascular illnesses such as stroke, ischemic heart disease, and peripheral vascular disease. Arsenic generates oxidative stress, which disrupts the redox balance. In fact, in plants arsenic gets accumulated in different parts of plants upon exposure to either contaminated soil or water, causing hazardous effects on the plant. Therefore, this chapter is aimed to understand the effect of arsenic exposure on the growth and development of the plant as a whole.
Mechanisms of Arsenic Toxicity and Tolerance in Plants
2018
Human activities have changed the global cycle of heavy metals and contributed a lot in heavy metal and metalloid toxicity. The human body is prone to serious harmful effects due to toxic substances like heavy metals and metalloids that are present or released into the environment. Arsenic (As) is found in nature and can enter the human body through a number of pathways including food, water, air, and soil. It also forms an important component of the occupational hazardous agents. The earth crust is the abundant source of As. The main form in which it is present in the earth is arsenopyrite. Human activities contribute nearly 52,000–112,000 tons of As to the soil (Li et al. 2008). The contributing factors include the use of As-rich pesticides and fertilizers in the agricultural sector. As enters the human body directly (through drinking As-contaminated water) or indirectly by consumption of As-contaminated food sources, for instance, the rice grain grown in As-contaminated groundwater and soil. The metalloid alters the physicochemical properties of soil and enters the farming systems through various means like geochemical processes. It, thereafter, elicits a series of reactions leading to inhibition of plant growth. Consequently, the photosynthetic and metabolic processes are disrupted resulting in a decrease in the agricultural output. These plant responses are mainly mediated by the oxidative stress within the plant body. The reactive oxygen species (ROS) produced during the As toxicity cause damage to biological molecules including proteins and lipids. Interaction of arsenic III sulfhydryl groups with the plant enzymes ultimately results in the death of the plants. The adverse effects of As toxicity are not limited to plant body only. In humans, exposure to As causes DNA hypomethylation resulting in carcinogenesis. It also causes activation of proto-oncogene c-myc that can induce chromosome abnormalities by acting synergistically with other toxic substances. Inorganic As also causes skin and lung cancer in a human. A number of other pathological and pathophysiological conditions are also reported. South Asia is the most populous region in the world. The total population of India, Bangladesh, and Pakistan accounts for nearly a quarter of the world’s population. This region is geographically the most diverse region as well. A number of recent cases of As toxicity have been reported in South Asia. The high density of population, poverty, unavailability of As-treated water, adverse socioeconomic conditions, monetary dependence on agriculture, and a number of other factors make the people of this region at the highest risk of As-induced adverse effects (Brammer and Ravenscroft 2009). The chapter introduces the concept of As toxicity followed by its geographical distribution in South Asia. The adverse effects of As toxicity in plants and humans are then presented. Various molecular mechanisms that are disturbed and the manipulation of which can help in addressing As toxicity are then presented. Toward the end of the chapter, various biological, physical, and chemical methods for addressing the As toxicity that can be beneficial for reducing As toxicity in the affected areas have been presented.
EFFECTS OF PHOSPHORUS FERTILIZATION ON ARSENIC UPTAKE BY WHEAT GROWN IN POLLUTED SOILS
Journal of soil science and plant nutrition, 2010
In this study we have examinated the results of two experiments on the uptake and distribution of arsenic (As) in roots, shoots, and grain of wheat grown in As-polluted soils and in an unpolluted soil irrigated with As-contaminated water in absence or presence of phosphorus (P) fertilization. Arsenic concentrations in wheat samples of the two experiments are higher than those in the plants grown on uncontaminated soil. In the experiments showed in this work, it is highlighted the role of P fertilization in preventing As uptake and translocation in wheat plants. These findings could have important implications to reduce the potential risk posed to human health by As entering the food-chain.