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Adya P. Singh

Bio: Adya P. Singh is an academic researcher from Scion. The author has contributed to research in topics: Middle lamella & Tracheid. The author has an hindex of 26, co-authored 101 publications receiving 2429 citations. Previous affiliations of Adya P. Singh include Commonwealth Scientific and Industrial Research Organisation & Forest Research Institute.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the degradation patterns of various types of microbial wood decay are briefly described, and examples of decay type(s) in wood exposed in various wet environments presented, in order to find appropriate ways to prolong woodʼs service life and properly restore wooden artefacts.
Abstract: SUMMARY Wood in wet environments is attacked and degraded by soft rot fungi and erosion and tunnelling bacteria, which are more tolerant to high moisture and reduced oxygen conditions than basidiomycetes, such as white and brown rot fungi. Since wood decaying basidiomycete fungi are normally more aggressive and can degrade wood faster than soft rot fungi and bacteria, wood in wet environments can survive for a relatively long time. Archaeological investigations show that wood buried deep in ocean sediments can survive for hundreds and even thousands of years. In this review degradation patterns of various types of microbial wood decay are briefly described, and examples of decay type(s) in wood exposed in various wet environments presented. It is important to understand biological wood decay in wet environments in order to find appropriate ways to prolong woodʼs service life and properly restore wooden artefacts.

174 citations

Journal ArticleDOI
Tripti Singh1, Adya P. Singh1
TL;DR: In this paper, the authors present information on the natural compounds that have shown promise for wood protection, and the information is presented under defined interactive categories, and some thoughts are presented on potential use of rapidly evolving technologies such as nano-and gene-technologies that can lead to significant advances, particularly from the consideration of specificity of natural products and their economic value.
Abstract: Traditional wood protection methods employ chemicals that are considered toxic and can adversely affect human health and the environment. Fortunately, serious efforts are being made globally to develop alternative protection methods based on natural products with little or no toxicity, but the progress in implementation of the technologies has been slow because of certain limitations, including discrepancies between laboratory and field performance of natural products, variability in their efficacy related to exposure/environmental conditions, and legislation difficulties due to disagreements globally on setting standards defining the quality of their performance and use. The focus of this review is to present information on the natural compounds that have shown promise for wood protection, and the information is presented under defined interactive categories. In closing, some thoughts are presented on potential use of rapidly evolving technologies, such as nano- and gene-technologies that can lead to significant advances, particularly from the consideration of specificity of natural products and their economic value.

158 citations

Book ChapterDOI
01 Jan 1988
TL;DR: A subculturable meristematic tissue system capable of plantlet regeneration has been developed for Pinus radiata and genetic stability and automation, two prerequisites for commercial use, are discussed as well as the potential for gene transfer.
Abstract: A subculturable meristematic tissue system capable of plantlet regeneration has been developed for Pinus radiata. Multiplication was achieved by the continuous production of meristematic tissue on a modified Lepoivre medium containing 5 mg/1 BAP (LP5). This tissue has been maintained for 2.5 years to date. Meristematic nodules multiplied for one year consisted of three zones: the outer meristematic layer, a bulky layer of vacuolated cells, and friable cells containing tannins and degrading cell walls. Cavities (hollows) were often present near the center of meristematic nodules. Natural separation of meristematic nodules contributed to the multiplication process. Factors affecting the success of the system were studied because there was a large variation in response. Embryos formed shoots and multipliable meristematic tissue in similar percentages. Seedlot was not a major factor in multiplication of meristematic tissue. Half-strength LP5 medium proved best for the first 12 weeks in culture, whereas LP5 medium proved best after six months in culture. Both gelrite and liquid induced vitrification, and habituation on LP5 medium had not occurred after 20 months in culture. One of the best embryos produced 5,480 pieces of meristematic tissue in 13.5 months. In a separate experiment with the same clone, an average of 68.4 shoots elongated from each piece of tissue. It was estimated that 260,000 trees could be produced from a single, good reacting seed in 2.5 years. Genetic stability and automation, two prerequisites for commercial use, are also discussed as well as the potential for gene transfer.

135 citations

Journal ArticleDOI
01 Jun 1999-Botany
TL;DR: Two anatomically different samples of mild compression wood were compared with a sample of normal wood using quantitative interference microscopy and microdensitometry combined with confocal fluorescence microscopy to estimate the quantitative or semiquantitative lignin distribution in the S2 and S2L regions of the secondary cell wall and of the cell corner middle lamella (CCML).
Abstract: Lignin distribution in the tracheid cell wall of mild compression wood in Pinus radiata D. Don was examined by interference microscopy, confocal fluorescence microscopy, and ultraviolet (UV) micros...

99 citations

Journal ArticleDOI
TL;DR: Observations suggest that the accumulation of hydrogen peroxide appears to mediate decreases in water transport in cucumber roots under low temperature.
Abstract: Water transport across root systems of young cucumber (Cucumis sativus L.) seedlings was measured following exposure to low temperature (LT, 8–13 8C) for varying periods of time. In addition, the amount of water transported through the stems was evaluated using a heat-balance sap-flow gauge. Following LT treatment, hydrogen peroxide was localized cytochemically in root tissue by the oxidation of cerium (III) chloride. The effects of hydrogen peroxide on the hydraulic conductivity of single cells (Lp) in root tissues, and on the H 1 -ATPase activity of isolated root plasma membrane, have been worked out. Cytochemical evidence suggested that exposure of roots to LT stress caused a release of hydrogen peroxide in the millimolar range in the vicinity of plasma membranes. In response to a low root temperature (8 8C), the hydraulic conductivity of the root (Lpr) decreased by a factor of 4, and the half-times of water exchange increased by a factor of 5–6. Decreasing root temperatures from 25–13 8C increased the half-times of water exchange in a cell by a factor of 6–9. The measurement of axial water transport with a heat-balance sap-flow gauge showed that only a small amount of water was transported when 8 8C was imposed on cucumber roots. Lp and the H 1 -ATPase activity of the isolated root plasma membrane were very sensitive to externally applied hydrogen peroxide at a concentration of 1–16 mM. These observations suggest that the accumulation of hydrogen peroxide appears to mediate decreases in water transport in cucumber roots under low temperature.

99 citations


Cited by
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Journal ArticleDOI
Tamar Frankel1
TL;DR: The Essay concludes that practitioners theorize, and theorists practice, use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ.
Abstract: Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

2,077 citations

Journal ArticleDOI
TL;DR: This review provides a “beginning‐to‐end” analysis of the recent advances reported in lignin valorisation, with particular emphasis on the improved understanding of lign in's biosynthesis and structure.
Abstract: Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple "upstream" (i.e., lignin bioengineering, lignin isolation and "early-stage catalytic conversion of lignin") and "downstream" (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a "beginning-to-end" analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

1,390 citations

Journal ArticleDOI
TL;DR: How a wide range of selectivity profiles and regulation properties allows aquaporins to be integrated in numerous functions, throughout plant development, and during adaptations to variable living conditions is examined.
Abstract: Aquaporins are channel proteins present in the plasma and intracellular membranes of plant cells, where they facilitate the transport of water and/or small neutral solutes (urea, boric acid, silicic acid) or gases (ammonia, carbon dioxide). Recent progress was made in understanding the molecular bases of aquaporin transport selectivity and gating. The present review examines how a wide range of selectivity profiles and regulation properties allows aquaporins to be integrated in numerous functions, throughout plant development, and during adaptations to variable living conditions. Although they play a central role in water relations of roots, leaves, seeds, and flowers, aquaporins have also been linked to plant mineral nutrition and carbon and nitrogen fixation.

1,121 citations

Journal ArticleDOI
TL;DR: A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques, so this review focuses on the application of Spectroscopic methods for the structural analysis of these compounds.
Abstract: Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.

848 citations

Journal ArticleDOI
01 Jun 2018-Nature
TL;DR: This work focuses on the current understanding of tree hydraulic performance under drought, the identification of physiological thresholds that precipitate mortality and the mechanisms of recovery after drought, and the potential application of hydraulic thresholds to process-based models that predict mortality.
Abstract: Severe droughts have caused widespread tree mortality across many forest biomes with profound effects on the function of ecosystems and carbon balance. Climate change is expected to intensify regional-scale droughts, focusing attention on the physiological basis of drought-induced tree mortality. Recent work has shown that catastrophic failure of the plant hydraulic system is a principal mechanism involved in extensive crown death and tree mortality during drought, but the multi-dimensional response of trees to desiccation is complex. Here we focus on the current understanding of tree hydraulic performance under drought, the identification of physiological thresholds that precipitate mortality and the mechanisms of recovery after drought. Building on this, we discuss the potential application of hydraulic thresholds to process-based models that predict mortality.

811 citations