Talat Parween

Effects of presowing gamma irradiation on the photosynthetic pigments, sugar content and carbon gain of Cullen corylifolium (L.) Medik.

To determine the effects of gamma radiation on the photosynthetic pigments, sugar content and total carbon gain, seeds of Cullen corylifolium (L.) Medik. were irradiated with variable doses (0, 2.5, 5, 10, 15, and 20 kGy) at the rate of 1.65 kGy h-1 from 60Co gamma source. Cullen corylifolium represents an important Chinese medicine with adequate levels of secondary metabolites, thus we hypothesized that gamma irradiation could modulate primary metabolites which could supplement secondary metabolite levels. The seeds were then transferred to field for biochemical analysis at different developmental stages; pre-flowering, flowering and post-flowering. Gamma dosage at 10 kGy resulted in a significant increase in concentration of chlorophyll a (61.17%), chlorophyll b (93.18%) and total chlorophyll (71.66%), suggesting that low doses of radiation could activate photosynthetic pigment system while at 15 and 20 kGy dose resulted in depletion of such parameters. Sugar and total C analysis of plants irradiated at 10 kGy demonstrated significantly maximum (216.01%) sugar content in leaves at all developmental stages and significantly minimum (46.13%) and (57.81%) in plants raised from seeds irradiated at 15 and 20 kGy respectively. Effective stimulatory dose for C. corylifolium ‘11062’ is 10 kGy. In contrast, the carotenoid content of the plants exposed to 15 and 20 kGy was maximum than control. Significance of such stimulation correlated with increasing C mass of the plant concerned is discussed in the light of newer aspects in research.

Interaction Between Pesticide and Soil Microorganisms and Their Degradation: A Molecular Approach

The use of pesticide in crops is meant to protect plants against harmful insects and increases crop yields. Pesticides are biologically active compounds, and an unintended consequence of its application may influence physicochemical proprieties of soil and lead to significant changes in microbial populations and activities influencing microbial ecological balance affecting soil fertility and metabolic activity of soil microbial communities. Inactivation of nitrogen-fixing and phosphorus-solubilizing microorganisms is observed in pesticide-contaminated soils. Recent studies show that some pesticides disturb molecular interactions between plants and N-fixing rhizobacteria and consequently inhibit the vital process of biological nitrogen fixation. Similarly, many studies show that pesticides reduce activities of soil enzymes that are key indicators of soil health. The applied pesticides may also influence many biochemical reactions such as mineralization of organic matter, nitrification, denitrification, ammonification, redox reactions, methanogenesis, etc. The fate of pesticides applied in agricultural ecosystems is governed by the transfer and degradation processes and their interaction with soil microorganisms. The increasing reliance of sustainable agriculture on pesticide has led to concern about their ecotoxicological effects influencing microbial populations and enzyme activities, which may serve as indicators of soil quality. In this chapter, we attempt to analyze the impacts of pesticides on soil microbial communities, soil biochemical reactions, and molecular approach of degradation of pesticide by soil microorganisms.

Pesticide Contamination and Human Health Risk Factor

The use of pesticide has become an integral part of modern agricultural practices. Majority of pesticides applied in agriculture are not target specific and during their application they also affect non-target organisms. Repetitive use of pesticide leads to loss of biodiversity. Continuous and non-judicious use of pesticide has leads to increase pesticide contamination in the environment. It is associated with various ecological and health problems. It leads to over three million poisoning cases annually and up to 220,000 deaths, primarily in emerging countries. Pesticides may present instantaneous danger to the user if applied inadequately or without appropriate knowledge of their toxic effects. Occupational exposure to pesticides repeatedly occurs in the case of agricultural workers in open fields and greenhouses, workers in the pesticide industry, and exterminators of house pests. Some are highly toxic and may cause serious illness and even death if spilled on the skin, inhaled, or otherwise used imprecisely. Potential future hazards to human health can be created by pesticide residues that may cause accumulation in the food chain and widespread contamination of the environment. Acute and chronic effect of pesticide contamination cause various carcinogenic, oncogenic, genotoxic and teratogenic effect on the human being. This chapter explores the different types of pesticide, their mode of action, various ways through which pesticide enters our environment (soil, air and water) lead to pesticide contamination. We also learn about the way that how pesticides enters the human body and causes various health effects and also discuss about their future perspectives.

Bioremediation: A Sustainable Tool to Prevent Pesticide Pollution

The revolution in manufacturing of different types of agrochemical has no doubt enhanced yield in our agricultural products and protect crops from diseases and pests. Pesticides at present play an important role in enhancing the yield and provide an economical benefit to our farmers. Environmental contamination is a potential threat to human health.With the advent of agrochemicals there has been enhancement in crop productivity and improved resistance against diseases. To combat economic losses in agriculture sector pesticides plays crucial role in sustaining agro-productivity. Due to indiscriminate use of chemical pesticides together amplified industrialization and urbanization; there has been a parallel increase in environmental pollution. To counterfeit environmental contamination, we need to implement bioremediation. Bioremediation is most effective technology wherein we utilize microbes as a potential contrivance for degradation of environmental pollutants. Bioremediation is eco-friendly, inexpensive, competent and proficient technology for pesticide detoxification. Bioremediation encompasses numerous in-situ initiatives for instance bioventing, biosparging, bioaugmentation and ex-situ contrivances namely land farming, biopiling, bioreactors etc. Detoxification of pesticides via phytoremediation methods like phytodegradation (Phytotransformation), phytovolatilization, rhizoremediation etc., has also been employed. The central theme of this chapter will be summarizing limitations and challenges linked with some widely employed bioremediation techniques and consequently evaluating the impending relevance of these remedial tools to eliminate pesticides from the environment.

Use of Plant Secondary Metabolites as Nutraceuticals for Treatment and Management of Cancer: Approaches and Challenges

Nowadays cancer has become a common and life-threatening disease, claiming millions of lives and adding many more millions of new cases every year globally. Due to increasing incidences of cancer, a new trend is emerging globally due to accessibility of information on the internet; a lot of cancer patients’ claimed to be “cancer survivor” by use of dietary supplements or nutraceuticals. Nutraceuticals are rich source of nutrients or part of a food that has a medical or health benefit, including the prevention and treatment of diseases. In this chapter, we will discuss the most important nutraceuticals as a source of anticancer agents, such as green tea, chili, pepper, saffron, turmeric, soy, black pepper, fenugreek, cloves, and ginger. These agents are the source of phytomolecules, such as curcumin, crocin, crocetin, capsaicin, diosgenin, isoflavones, resveratrol, epigallocatechin gallate, piperine, eugenol, and gingerol. It has been reported that these phytomolecules are able to prevent, reverse, or delay the carcinogenic process. Over the decades, attention over these nutraceuticals has been increased due to their promising effects on tumor cells. These nutraceuticals exhibit anticancer properties by induction of apoptosis, DNA damage, causing G2/M arrest, inhibition of proliferation, migration and invasion of cancer cells, and sensitizing cancer cells to chemotherapy and radiotherapy. The aim of this chapter is to focus on the sources of nutraceutical compounds and their importance in the management of cancer. Moreover, the mechanism of action is also highlighted.

Role of Bioinoculants as Plant Growth-Promoting Microbes for Sustainable Agriculture

The green revolution bought amazing consequences in food grain production but with insufficient concern for agriculture and environmental sustainability. The efficient biofertilizers are gaining importance in sustaining agriculture. Various complementing combinations of microbial inoculants for management of major nutrients are necessary for agriculture sustainability. In such case, microorganisms are useful for biomineralization of bound soil and make nutrients available to their host and/or its surroundings. Nitrogen and phosphorus are major plant nutrients which occupy a key place in the balanced use of fertilizer. Leguminous crop fixes the atmospheric nitrogen by Rhizobium which requires optimum level of phosphorus in plant tissue. Mineral solubilizers play an important role in seedling setting because more of the tropical soils are phosphate fixing and make it unavailable to the plants. Phosphate-solubilizing microorganisms (PSMs) that solubilize bound form of phosphorus and AM fungi act as uptaker of phosphorus and make it available to the host plants. Microorganisms facilitate plant mineral nutrition by changing the amounts, concentrations and properties of minerals available to plants. Because of the various challenges faced in screening, formulation and application, PGPB have yet to fulfil their promise and potential as commercial inoculants. This chapter focuses on some important information regarding the various types of biofertilizing potential of some important group of microbes, their formulations, their application for the development of sustainable technology, their scope of improvement by promising new technique and commercially available biofertilizer and its application in India.

Biofilm: A Next-Generation Biofertilizer

Microbial communities attached to surfaces are found in many environments including the soil. This chapter deals with the applications of developed biofilms as biofertilizers in crop production and their contribution to battle against microbial pathogens involved in plant diseases. It describes the formation of biofilm involving various processes including surface conditioning, microbial cell adsorption to conditioned surface, growth of bacteria, and formation of EPS that resulted in growth of biofilm. There are various factors responsible for the formation and growth of biofilm. It includes topography of surface, physicochemical properties of medium, hydrodynamics, horizontal gene transfer, and quorum sensing. Here are a summary of factors involved in the different stages of biofilm development: (i) initiation of biofilm formation, (ii) maturation of the biofilm, and (iii) regulation of the biofilm architectural structure. Some ecological advantage and relevance of biofilm can be listed, viz., defense, nutrient availability and metabolic cooperation, colonization, acquisition of new genetic traits, etc. At last, this chapter describes the molecular mechanism of biofilm formation and biocontrol.

Pesticide Tolerance and Crop Production

In the early twentieth century, various plant pathologists demonstrated the capability of plants to treat diverse contaminants from soil and water without any obvious mechanism. Conversely, the treatments of recalcitrant organic compounds generate incoherent consequences for biotreatment by plants because of varied recalcitrant compound structures from naturally occurring molecules. Several pesticides generally attack the target enzymes, which are normally inhibited; this may be due to overexpression or overstimulation of the target proteins. The enzymes of nontarget organisms and microbial enzymes can also be inhibited by a few pesticides. This makes the herbicide/pesticide tolerance a more intricate process connecting the profuse machinery of a plant. These include phytochromes, antioxidant machinery, glycoproteins, and the metabolic interface of various processes. Genetic heterogeneity of wild populations and weedy species growing on pesticide-contaminated soil provides a source of plant species tolerant to these conditions. In this section, we deal with various aspects of herbicide/pesticide resistance mechanisms found in plants. The herbicide resistance pathway in plants is affected by various components such as enzymes and heredity. In fact, some genes conferring tolerance to inconsequential effect might be amplified under herbicide selection, which exerts a corresponding effect on survival of HR plant species. This chapter provides insights into the main hurdles that could be raised as a result of increased pesticide tolerance to achieve increased crop production.

Elemental, biochemical and essential oil modulation in developing seedlings of Psoralea corylifolia L. exposed to different presowing gamma irradiation treatment

Seeds of Psoralea corylifolia L. were irradiated with different doses of gamma rays; 2.5, 5, 10, 15 and 20 kGy from a cobalt source a at dose rate of 1.65 kGy/hour. The stimulatory effects of gamma irradiation at 10 kGy were evident for biochemical and elemental parameters at the flowering stage and thereafter declined. Nitrogen was found to be maximum in leaves and sulfur in roots at the flowering stage of seedlings grown from seeds exposed to 10 kGy. Sulfur content was found to be most sensitive to gamma irradiation doses resulting in a maximum decline in stems (89.10%), leaves (65.79%) and roots (57.07%) with 20 kGy, respectively. Amino acids exhibited a similar percent decline (52.79%) at the pre-flowering stage in plants raised from seeds irradiated with 20 kGy. Using gas chromatography–mass spectrometry (GC–MS) and solid-phase particle microextraction (SPME) analysis, a remarkable percent increment was confirmed in tricyclene, α-pinene, β-myrcene, camphene, caryophyllene, β-gurgenene, n-nonanal, β-(E)-ocimene, (Z)-3-hexene-ol and germacrene D in plants raised from seeds exposed to 20 kGy. Maximum oil content (1.60%) was found in seeds irradiated with 20 kGy and minimum oil content was found in control seeds (0.89%). The study demonstrates the inverse response between primary and secondary metabolites in terms of enhancement in essential oil yield, as well as concentration of antioxidant components at 15 and 20 kGy.