342 research outputs found

    Effect of strain on the phase separation and devitrification of the magnetic glass state in thin films of La<SUB>5/8-y</SUB>Pr<SUB>y</SUB>Ca<SUB>3/8</SUB>MnO<SUB>3</SUB> (y= 0.45)

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    We present our study of the effect of substrate induced strain on La5/8 - yPryCa3/8MnO3 (y = 0.45) thin films grown on LaAlO3, NdGaO3 and SrTiO3 substrates that show large scale phase separation. It is observed that unstrained films grown on NdGaO3 behave quite similarly to bulk material but the strained films grown on SrTiO3 show melting of the insulating phase to the metallic phase at low temperatures. However, the large scale phase separation and metastable glass-like state is observed in all the films despite differences in substrate induced strain. The measurements of resistivity as a function of temperature under a cooling and heating in unequal field (CHUF) protocol elucidate the presence of a glass-like metastable phase generated due to kinetic arrest of the first order transformation in all the films. Like structural glasses, these magnetic glass-like phases show evidence of devitrification of the arrested charge order antiferromagnetic insulator (CO-AFI) phase to the equilibrium ferromagnetic metallic (FMM) phase with isothermal increase of magnetic field and/or iso-field warming. These measurements also clearly show the equilibrium ground state of this system to be FMM and the metastable glass-like phase to be AFI phase

    Effect of Maturity and Storage Temperature on Shelf-Life and Quality of Banana Cv. Grand Naine

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    A study was undertaken at Regional Horticulture Research Station, NAU, Navsari, during 2008-2009 to assess the effect of maturity stage and storage temperature on shelf-life and quality of banana cv. Grand Naine. The experiment was evaluated in Completely Randomized Ddesign based on the factorial concept, and comprised of three maturity stages (75, 90 and 100% maturity) and four storage temperatures (12°C, 14°C, 16°C&amp;ambient temperature). Fruits harvested at 75% maturity and stored at 12°C recorded maximum green-life and better overall shelf-life, whereas, yellow-life was highest when fruits at 75% maturity were stored at 14°C. Best colour and texture was seen in fruits harvested at 100% maturity and stored at 16°C

    Understanding the Modus Operandi of Class II KNOX Transcription Factors in Secondary Cell Wall Biosynthesis

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    Lignocellulosic biomass from the secondary cell walls of plants has a veritable potential to provide some of the most appropriate raw materials for producing second-generation biofuels. Therefore, we must first understand how plants synthesize these complex secondary cell walls that consist of cellulose, hemicellulose, and lignin in order to deconstruct them later on into simple sugars to produce bioethanol via fermentation. Knotted-like homeobox (KNOX) genes encode homeodomain-containing transcription factors (TFs) that modulate various important developmental processes in plants. While Class I KNOX TF genes are mainly expressed in the shoot apical meristems of both monocot and eudicot plants and are involved in meristem maintenance and/or formation, Class II KNOX TF genes exhibit diverse expression patterns and their precise functions have mostly remained unknown, until recently. The expression patterns of Class II KNOX TF genes in Arabidopsis, namely KNAT3, KNAT4, KNAT5, and KNAT7, suggest that TFs encoded by at least some of these genes, such as KNAT7 and KNAT3, may play a significant role in secondary cell wall formation. Specifically, the expression of the KNAT7 gene is regulated by upstream TFs, such as SND1 and MYB46, while KNAT7 interacts with other cell wall proteins, such as KNAT3, MYB75, OFPs, and BLHs, to regulate secondary cell wall formation. Moreover, KNAT7 directly regulates the expression of some xylan synthesis genes. In this review, we summarize the current mechanistic understanding of the roles of Class II KNOX TFs in secondary cell wall formation. Recent success with the genetic manipulation of Class II KNOX TFs suggests that this may be one of the biotechnological strategies to improve plant feedstocks for bioethanol production

    Status of exploitation of tuna, mackerel and seerfish in Andaman and Nicobar Islands

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    Annual fish landing of Andaman and Nicobar Islands during 1989-'99 and the contribution of scombroids viz., tuna, mackerel and seerfishes are described. During the period the exploitation of tuna ranged between 321 to 3,8231, the average contribution being about 5% of the total fish landings. Among the tuna species, yellowfin tuna Thunnus albacares is the major contributor followed by skipjack tuna Katsuwonus pelamis and bigeye tuna Thunns obesus all of which are best caught during March to August. The mackerfel fishery is supported by Rastrelliger brachysoma followed by R.kanagurta. The total mackerel landings ranged between 806 to 1,9551, the major fishing season being from March to June and September to October and is best caught in the gill nets and boat seines. Seerfishes are dominantly represented by two genera and three species vjz. Scomberomorus commerson, S. guttatus and Acanthocybium solandri. Their major fishing season is from March to August and November to Febmary, being generally caught by gill nets, troll lines and hand lines. During the period of 1989 -'99, the total exploitation of seerfishes ranged between 293 to 1,172 t and showed a gradual increase in their production

    Effect of Spacing and Crop Duration on Growth, Flowering and Bulb Production in Tuberose (Polianthes tuberosa L.) Cv. Double

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    Field experiments were conducted at Junagadh during 2002-05 to study the response of spacing (45 x 45, 45 x 30, 45 x 15, 30 x 30 and 30 x 15 cm) and crop duration (first year crop, first ratoon and second ratoon) on growth, flowering, cut flower yield and bulb production in tuberose cv. Double. The widest spacing (45 cm x 45 cm) registered the highest values for plant height (46.18 cm), number of leaves per clump (67.25), spike length (89.64 cm), spike diameter (0.95 cm), diameter of open flower (4.6 cm), rachis length (34.8 cm), number of spikes per clump (4.1), number of florets per spike (48.2), number of bulbs per clump (18.40) and number of bulblets per clump (31.60). It also induced early spike emergence and flowering. A planting distance of 30 x 30 cm realized the highest cut flower yield (2.72 lakh ha-1) and that of 30 cm x 15 cm recorded the highest bulb production (22 lakh ha-1). Ratoon crops showed higher plant height, number of leaves, bulbs, bulblets and spikes per clump and cut flower yield as well as bulb production over the first year crop. Early spike emergence and flowering was also noted in ratoon crops compared to the first year crop. However, spike and flower quality was inferior to that of first year crop with regard to spike length and diameter, number of florets per spike, diameter of open flower and rachis length

    Effect of organic manure and sulphur fertilization in pigeonpea (Cajanus cajan) + groundnut (Arachis hypogaea) intercropping system

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    There is large number of sulphur(S) sources available in the country and their efficiency need to be evaluated. In view of the meager information available on sulphur nutrition in a popular intercropping system of pigeonpea + groundnut. A field experiment was conducted during kharif 2003 and 2004 to evaluate the response of pigeonpea [Cajanus cajan (L.) Millsp.] + groundnut (Arachis hypogaea L.) intercropping system to FYM and S fertilization. Application of FYM at 5.0 t/ha significantly increased the yield and yield attributes, nutrient (NPK) uptake in pigeonpea and groundnut, system productivity (1.71 t/ha), net returns (Rs 18,287) and available S in soil after harvest (15.72 kg/ha). However, B: C ratio was higher with crop receiving no FYM. Intercropping failed to influence the yield attributes, yield and nutrient uptake in pigeonpea, however, system productivity, net income and B: C ratio was higher in pigeonpea + groundnut system. The available soil S after harvest of crop(s) was lower in pigeonpea + groundnut system (13.11 kg/ha) when compared with sole pigeonpea (17.06 kg/ha). Application of sulphur at 35 and 70 kg/ha, being on par, recorded significant increase in yield and nutrient uptake in pigeonpea and groundnut, system productivity and total net income over no S. The available soil S after harvest of crop (s) was higher with 70 kg S/ha. The S use efficiency indices were higher at lower i.e. 35 kg S/ha. Among the sources of sulphur, cosavet recorded higher yield and yield attributes, nutrient uptake and S use efficiency. However, the highest soil available S at harvest (19.34 kg/ha) was recorded with elemental S applied at 70 kg/ha, while the highest net income (Rs 20,431) and B: C ratio (2.0) were achieved with gypsum at 35 kg S/ha

    Heterologous expression of Arabidopsis laccase2, laccase4 and peroxidase52 driven under developing xylem specific promoter DX15 improves saccharification in populus

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    Background: Secondary cell wall holds considerable potential as it has gained immense momentum to replace the lignocellulosic feedstock into fuels. Lignin one of the components of secondary cell wall tightly holds the polysaccharides thereby enhancing the recalcitrance and complexity in the biomass. Laccases (LAC) and peroxidases (PRX) are the major phenyl-oxidases playing key functions during the polymerization of monolignols into lignin. Yet, the functions of laccase and peroxidases gene families remained largely unknown. Hence, the objective of this conducted study is to understand the role of specific LAC and PRX in Populus wood formation and to further investigate how the altered Lac and Prx expression affects biomass recalcitrance and plant growth. This study of heterologous expression of Arabidopsis Lac and Prx genes was conducted in poplar to avoid any otherwise occurring co-suppression mechanism during the homologous overexpression of highly expressed native genes. In the pursuit of optimizing lignocellulosic biomass for biofuel production, the present study focuses on harnessing the enzymatic potential of Arabidopsis thaliana Laccase2, Laccase4, and Peroxidase52 through heterologous expression. Results: We overexpressed selected Arabidopsis laccase2 (AtLac2), laccase4 (AtLac4), and peroxidase52 (AtPrx52) genes, based on their high transcript expression respective to the differentiating xylem tissues in the stem, in hybrid poplar (cv. 717) expressed under the developing xylem tissue-specific promoter, DX15 characterized the transgenic populus for the investigation of growth phenotypes and recalcitrance efficiency. Bioinformatics analyses conducted on AtLac2 and AtLac4 and AtPrx52, revealed the evolutionary relationship between the laccase gene and peroxidase gene homologs, respectively. Transgenic poplar plant lines overexpressing the AtLac2 gene (AtLac2-OE) showed an increase in plant height without a change in biomass yield as compared to the controls; whereas, AtLac4-OE and AtPrx52-OE transgenic lines did not show any such observable growth phenotypes compared to their respective controls. The changes in the levels of lignin content and S/G ratios in the transgenic poplar resulted in a significant increase in the saccharification efficiency as compared to the control plants. Conclusions: Overall, saccharification efficiency was increased by 35–50%, 21–42%, and 8–39% in AtLac2-OE, AtLac4-OE, and AtPrx52-OE transgenic poplar lines, respectively, as compared to their controls. Moreover, the bioengineered plants maintained normal growth and development, underscoring the feasibility of this approach for biomass improvement without compromising overall plant fitness. This study also sheds light on the potential of exploiting regulatory elements of DX15 to drive targeted expression of lignin-modifying enzymes, thereby providing a promising avenue for tailoring biomass for improved biofuel production. These findings contribute to the growing body of knowledge in synthetic biology and plant biotechnology, offering a sustainable solution to address the challenges associated with lignocellulosic biomass recalcitrance
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