Sudha Gupta

Abstract: Two rice varieties, viz. Nonabokra and Pokkali, have been evaluated for their responses to salinity in terms of some physiological and biochemical attributes. During the exposure to salinity (200 mM concentration of sodium chloride for 24, 48, and 72 h), a significant increase in sodium was recorded which was also concomitant with the changes of other metabolic profiles like proline, phenol, polyamine, etc. The protein oxidation was significantly increased and also varied between the two cultivars. The changes in activities of anti-oxidative enzymes under stress were significantly different to the control. The detrimental effects of salinity were also evident in terms of lipid peroxidation, chlorophyll content, protein profiles, and generation of free radicals; and these were more pronounced in Pokkali than in Nonabokra. The assessment and analysis of these physiological characters under salinity could unravel the mechanism of salt responses revealed in this present study and thus might be useful for selection of tolerant plant types under the above conditions of salinity.

Abstract: Antioxidative stress response of free-floating aquatic fern (Salvinia natans Linn.) was studied under increasing toxic amount of aluminium (Al) and its modulation by exogenous application of polymaine. Increased levels of superoxide (O2−) and hydrogen peroxide (H2O2) species from affected tissues suggested that plants were undergoing oxidative stress and it was concominant with increased accumulation of Al in a dose dependent manner. Application of polyamine like putrescine (Put) led to a decrease in oxidative stress as revealed by reduced level of O2− and H2O2. Al toxicity resulted into decreased biomass that was ameliorated by the application of Put. The changes observed in lipid peroxidation (MDA) and protein oxidation also indicated that plats are undergoing Al induced oxidative stress. In order to circumvent the oxidative stress resulting from Al toxicity, plants enzymatic and nonenzymatic antioxidant pathways were active. The ratio of both oxidized and reduced cellular glutathione exhibited significant variation in response to Al stress and was improved upon Put treatment. Peroxidase and glutathione were upregulated whereas catalse was downregulated under varying doses of Al. Isozyme profile of above enzymes also showed a trend with increasing amount of Al. The nuclear disintegration study using comet assay was indicative of Al induced oxidative stress. In the present study, we have explored the antioxidative response of aquatic fern Salvinia natans Linn in response to Al toxicity. The application of polyamine Put improved the overall antioxidative response and thus would make it a better candidate to be used as hyper accumulator of Al and other toxic metals.

Abstract: Diverse palynomorphs and phytoliths recovered from coprolites of ovi-caprids (sheep, goat) collected from Yang-Hai Tomb at Xinjiang Province, China, have been used to elucidate the dietary pattern of ancient livestock and to reconstruct the paleovegetation and paleoclimate of this part of northwest China ca. 2500 14C yr BP. Palynological and phytolith data suggest that a rich dry temperate vegetation prevailed in the area during the said period. Climatic conditions and grassland vegetation type of the area are explored using phytolith indices.

Abstract: Cytomixis is reported to be a uniform phenomenon in the context of fertilization during spermatogenesis of animals and in some lower groups of plants where oogamous reproduction prevails. However, the phenomenon is versatile in flowering taxa as it lacks uniformity in occurrences, causes, formation of intercellular bridges, involvement of number of cells in a cluster, evolutionary significance among others. A review on cytomixis is conducted with an objective that it may offer a scope to unravel some of the ambiguities associated with it and provide further information on cell, reproductive, structural and evolutionary biology.

Abstract: The rice varieties viz. Nonabokra and Swarna were evaluated on the basis of their responses for oxidative stress induced by sodium chloride (NaCl) and the effects of exogenously applied polyamine thereon. Rice seedlings were treated with 200 mM of NaCl supplemented with two dosages: 1 mM and 2 mM putrescine. Following treatments, plants were evaluated for accumulation of reactive oxygen species (ROS) like O 2 − , H2O2 etc. in tissues, lipid peroxidation, protein carbonylation, accumulation of flavonoids and anthocyanin, activities of different oxidative enzymes like guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR). Preliminary, oxidative stress out of salinity was ensured by plants from significantly higher accumulation of O 2 − and H2O2 in the tissues of the NaCl treated varieties. Irrespective of varieties, there recorded a significant variation of the endogenous polyamine profiles under NaCl stress. Interestingly, exogenous application of putrescine had a close relationship on O 2 − and H2O2 content for both the varieties. However, Nonabokra was evident as more respondent than Swarna to applied putrescine. The other effects of oxidative stress was impacted on plants as higher values of MDA content, enhanced rate of protein oxidation and putrescine recorded as an alleviating agent regardless of varieties with dose dependant manner. The generation of ROS and cellular disintegration was accompanied by up regulation of non-enzymatic and enzymatic antioxidation pathways with exogenous application of putrescine. For non-enzymatic antioxidant, it revealed that putrescine was highly effective for sustaining the anthocyanin and flavonoid content in both the varieties under salinity. Whereas, antioxidative enzyme, CAT showed its diminished activity; but activity of GPX and GR were significantly induced under salinity and it was according to the concentration of applied putrescine.

Abstract: Rather than enjoying a fine ebook as soon as a mug of coffee in the afternoon, instead they juggled when some harmful virus inside their computer. Methods Of Enzymatic Analysis is clear in our digital library an online admission to it is set as public appropriately you can download it instantly. Our digital library saves in complex countries, allowing you to get the most less latency period to download any of our books considering this one. Merely said, the Methods Of Enzymatic Analysis is universally compatible behind any devices to read.

Abstract: Life history biology sits on the interface between genetics and ecology, and both have made important theoretical and empirical contributions to our understanding. However, the connections between the disciplines have not always been as close as they might have been and this book takes some useful steps towards remedying this. It gives an excellent review of life history theory, and integrates this well with results from the empirical literature. After an 11-page introduction, Roff sets out ‘a framework for analysis’ in which he covers the necessary elements of quantitative and population genetics. This includes clear definitions of fitness in a range of circumstances, from density independent populations in constant environments through to the more complex situations of density and frequency dependence and environments that are spatially or temporally stochastic. Trade-offs are then examined, including a valuable analysis of potential pitfalls in studying them and ways that these can be avoided. The author then deals in turn with evolution in constant environments; stochastic environments and ‘predictable environments’. The last of these covers situations where there is environmental variation, but at least some information is available to allow individuals to make an adaptive response. The final chapter identifies 20 topics for future study. Some will find the book too dominated by theory. Others (but probably not readers of Heredity!) will find it contains too much genetics. But Roff does an excellent job of making the theory accessible, covering the essential issues and pointing to original sources for the details. Theory is related to a significant number of empirical studies, although there is room for another book reviewing the empirical literature on life histories in detail, and Roff’s book would provide a robust skeleton on which to hang this. To make my own assessment, I examined in detail Roff’s discussion of the question of fitness measures for density dependent populations in stochastic environments – an area in which I have been involved. I could not fault him – all the key references were there and the issues were made very clear without the more esoteric mathematics. I also examined some areas that I was less familiar with, and again the text was clear and easy to read. My only real criticism of the book would be that its very long chapters (more than 130 pages in one case) makes it difficult to find things. It would have been simple to address this by including the section headings on the contents pages. A minor personal quibble would be that the book usually expresses problems in terms of the intrinsic rate of increase, r, and the characteristic (Lotka) equation. A matrix formulation is often more tractable and is easier to generalise to density dependent populations and stochastic environments, so expanding on the relationship between the two would have been useful. But overall this is an excellent book. It brings together the key theory in a single place. It gives an invaluable route into the literature, with a bibliography of 1600 or so items. These features, and its identification of topics that need further study should make an important contribution to moving the field forward.

Abstract: ‘‘Gentlemen don’t need mistletoe’’ said the Christmas whiskey billboard I saw recently in Florida, a garish reminder of how much mistletoe lore is embedded in western society. Mistletoe The Genus Viscum, one in the series of medicinal and aromatic plants for industry and academic researchers, centers on the mistletoe in this advertisement, the common European mistletoe,Viscum album. There are helpful discussions on African, Asian, and Argentine mistletoes and their uses but the corpus of the book deals with V. album. Viscum album, considered sacred by the Druids, is no doubt the most widely used parasitic angiosperm for various health concoctions. As a result, much has been learned about its biochemistry and pharmaceutical potential. A great deal of the work on the culture and utilization ofV. album has been done by investigators at Institute Hiscia Center for Cancer Research in Switzerland where votaries of Rudolf Steiner’s distinct form of homeopathy have used mistletoe extracts (‘‘Iscador’’) for many years in cancer treatment. Mistletoe collected from less common hosts are considered to have greater efficacy in preparation of Iscador. As a result, there is a helpful chapter on culturing V. album which is not as difficult as might be imagined for an obligate parasite. Most of the chapters deal with the medicinal aspects of mistletoe including toxicology, clinical aspects, chemistry, and biochemistry emphasizing the lectins which are one of the more desirable compounds produced by the parasite. I found the treatment by Bu ̈ssing (Biological and pharmacological properties of Viscum album L.) helpful because it reviews the link between folk and modern medicine. However, several relevant papers were omitted which are included in a recent excellent review of mistletoes (Watson 2001). Like many books with a diversity of authors, the quality of chapters varies. Obviously produced as a reference volume, Mistletoe lacks an extensive index. Especially aggravating is the lack of an author’s index, limiting the value of the book for anyone looking for specific papers. These days, $70 for a hardbound monograph is reasonable. Color images are well-produced but some of the black and white figures are blurry in my copy. This volume will be of value to ethnobotanists, anyone interested in alternative medicines, and students of mistletoes and parasitic plants. LITERATURE CITED

Abstract: In a persistently changing environment, plants are constantly challenged by various abiotic stresses such as salinity, drought, temperature extremes, heavy metal toxicity, high-light intensity, nutrient deficiency, UV-B radiation, ozone, etc. which cause substantial losses in the yield and quality of a crop. A key sign of such stresses at the molecular level is the accelerated production of reactive oxygen species (ROS) such as singlet oxygen (1O2), superoxide (O2•−), hydrogen peroxide (H2O2) and hydroxyl radicals (OH•). ROS are extremely reactive in nature because they can interact with a number of cellular molecules and metabolites, thereby leading to irreparable metabolic dysfunction and death. Plants have well-developed enzymatic and non-enzymatic scavenging pathways or detoxification systems to counter the deleterious effects of ROS that include the enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST), glutathione peroxidase (GPX) and peroxidases (POX) as well as non-enzymatic compounds such as ascorbate (AsA), glutathione (GSH), carotenoids and tocopherols. In plant cells, specific ROS-producing and scavenging systems are found in different organelles and the ROS-scavenging pathways from different cellular compartments are coordinated. Recent studies in plants have shown that relatively low levels of ROS act as signaling molecules that induce abiotic stress tolerance by regulating the expression of defense genes. Additionally, numerous results have shown that plants with higher levels of antioxidants, whether constitutive or induced, showed greater resistance to different types of environmental stresses. In this chapter we attempt to summarize recent researches on the mechanisms and possible regulatory roles of ROS in abiotic stress tolerance. Further, we discuss the progress made during the last few decades in improving the oxidative stress tolerance of plants through genetic engineering by different components of ROS detoxification systems in plants.

Abstract: The physiological relationship between abiotic stress in plants and polyamines was reported more than 40 years ago. Ever since there has been a debate as to whether increased polyamines protect plants against abiotic stress (e.g., due to their ability to deal with oxidative radicals) or cause damage to them (perhaps due to hydrogen peroxide produced by their catabolism). The observation that cellular polyamines are typically elevated in plants under both short-term as well as long-term abiotic stress conditions is consistent with the possibility of their dual effects, i.e., being protectors from as well as perpetrators of stress damage to the cells. The observed increase in tolerance of plants to abiotic stress when their cellular contents are elevated by either exogenous treatment with polyamines or through genetic engineering with genes encoding polyamine biosynthetic enzymes is indicative of a protective role for them. However, through their catabolic production of hydrogen peroxide and acrolein, both strong oxidizers, they can potentially be the cause of cellular harm during stress. In fact, somewhat enigmatic but strong positive relationship between abiotic stress and foliar polyamines has been proposed as a potential biochemical marker of persistent environmental stress in forest trees in which phenotypic symptoms of stress are not yet visible. Such markers may help forewarn forest managers to undertake amelioration strategies before the appearance of visual symptoms of stress and damage at which stage it is often too late for implementing strategies for stress remediation and reversal of damage. This review provides a comprehensive and critical evaluation of the published literature on interactions between abiotic stress and polyamines in plants, and examines the experimental strategies used to understand the functional significance of this relationship with the aim of improving plant productivity, especially under conditions of abiotic stress.