Papers by P Pardha Saradhi
International Journal of Biological and Chemical Sciences, 2007
The synthetic characters of different plant communities are analysed. Community-coefficient for t... more The synthetic characters of different plant communities are analysed. Community-coefficient for tree and shrub layer were 89.99 and 88.49%, respectively in NorthWest aspect of Cedrus deodara forest, probably due to maximum number of species common to both sites. Among the twelve tree species, only two viz., Cedrus deodara and Cupressus torulosa showed 100% presence amongst all the sites. The maximum equitability (10.47) value was computed in site five, because of similar type of species found in this site. Cedrus deodara (6.34) and Cupressus torulosa (5.54) had broader niches due to their presence at all the sites. Species diversity was highest (3.22) on the North West (NW) aspect of the V site and was directly related to the high density of tree species in this site. Dominance-diversity curve (d-d curve) for the tree layer and shrub layer, based on Importance Value Index (IVI) exhibited a geometric series for all forest sites except site IV, where it reflected Preston's log normal models. The log normal distribution of this site indicated the mixed nature of vegetation. These species are gradually loosing their niche width, density, dominance and diversity in different sites because of over exploitation and over grazing pressure on these species. In view of the great anthropogenic pressure on the plant community, conservation and management measures are required for sustainable use of these important ethnobotanical plant species and plant biodiversity protection.
Biomass & Bioenergy, May 1, 2011
Agrobiodiversity and agroecosystem management have changed in central Himalaya due to increasing ... more Agrobiodiversity and agroecosystem management have changed in central Himalaya due to increasing emphasis on market economy and the motive 'maximization of profit'. Such changes have benefited local people in economic terms, but at the same time increased their vulnerability to environmental and economic risks. The present study addressed the issue of how the ecological functions that are provided by agrobiodiversity translate into tangible benefits for the society. Important characteristics of agrodiversity management are the use of bullocks for draught power, human energy as labour, crop residues as animal feed and animal waste mixed with forest litter as organic input to restore soil fertility levels. The present analysis of resource inputeoutput energy currency in traditional crop production indicated that inputs into different crop systems were significantly higher during kharif season compared to rabi season both under rainfed and irrigated conditions. The maximum input for crop during rabi season (second crop season) was about 31% of that of kharif season (first crop season after fallow) under rainfed conditions. Under irrigated conditions the rabi season input was about 63% of kharif season input. Under rainfed conditions, paddy sole cropping required maximum inputs (231.31 GJ/ha) as compared to mustard sole cropping (11.79 GJ/ha). The present investigation revealed that the total energy inputs and outputs are higher for irrigated agriculture as compared to rainfed system, the difference in inputs is about 5 fold and outputs is about 2 fold. The outputeinput ratio showed that irrigated systems have higher values as compared to rainfed systems.
Plant Science, Nov 1, 2000
Brassica juncea cv. Pusa Jaikisan was transformed with the codA gene for choline oxidase from Art... more Brassica juncea cv. Pusa Jaikisan was transformed with the codA gene for choline oxidase from Arthrobacter globiformis with an aim to introduce glycine betaine biosynthetic pathway, as it lacks any means to synthesize glycine betaine. Western blot analysis revealed the presence of choline oxidase in the protein extract from the codA transgenic lines, demonstrating that the bacterial codA gene had been successfully transcribed and translated in transgenic lines. Good activity of choline oxidase indicated its presence in fully functional form in the transformed lines. This was further confirmed by the presence of glycine betaine only in the transformed lines of B. juncea. The shoots of both wild type and transformed lines were exposed to various concentrations of choline in order to evaluate if the introduction of the codA gene in any way enhances the potential of B. juncea to tolerate high levels of choline. The growth (in terms of fresh weight and dry weight) of the shoots of transformed lines exposed to high levels of choline was significantly superior to those of wild type. Moreover, the loss in chlorophyll content and the activity of photosystem II in shoots of the transformed lines exposed to high concentration of choline were significantly lower than that observed in wild type. These results showed that shoots of B. juncea transformed with the codA gene, most probably had the potential to readily convert choline to glycine betaine. Therefore, choline tolerance can be used as an efficient marker for the identification of the lines transformed with the codA gene.
Biologia Plantarum, Dec 1, 2002
Functional Plant Biology, 1995
Four-day-old Vigna radiata (L.) Wilczek seedlings were exposed to water stress (5% mannitol), sal... more Four-day-old Vigna radiata (L.) Wilczek seedlings were exposed to water stress (5% mannitol), salt stress (200 mM sodium chloride) and heavy metal stress (2.5 mM cadmium nitrate), in continuous light and darkness. The seedlings exposed to any of these stresses accumulated higher levels of proline in their shoots compared with control seedlings. Irrespective of the type of stress, accumulation of proline was higher in light than in the dark, which suggests that the photosynthetic activity of the seedlings might be responsible for light-induced enhancement of proline levels. In a second set of experiments, seeds were germinated under water stress, salt stress and heavy metal stress in continuous light and darkness. The plumule did not emerge from seeds germinated under stress, even after day 7. However, a 1.0-1.5 cm long radicle did emerge in light and in darkness. In spite of the lack of photosynthetic organs, seedlings raised under stress in light accumulated more proline than those raised in continuous darkness. In a third set of experiments, roots excised from 7-day-old light-grown seedlings were exposed to salt stress in light and in continuous darkness. The roots exposed to stress accumulated considerably more proline in light than in darkness. The results obtained in the last two sets of experiments suggest, for the first time, that some factoris) or process(es) other than photosynthesis plays an important role in light-induced enhancement of proline accumulation.
A synthetic fusion gene of Bacillus thuringiensis encoding a translational fusion product of Cry1... more A synthetic fusion gene of Bacillus thuringiensis encoding a translational fusion product of Cry1B and Cry1Ab δendotoxins was transferred to a tropical cabbage breeding line by Agrobacterium-mediated transformation. Selection of transformants was carried out on media containing kanamycin. Polymerase chain reaction (PCR) analysis revealed that twelve of the putative transformants contained the transgene. Insect bioassays carried out with the leaves of PCR-positive plants and neonate larvae of Diamondback moth (DBM) showed that one of the transgenic plants was completely resistant to repeated infestation by the larvae. Southern hybridization confirmed gene integration in the DBM-resistant plant. Doubleantibody sandwich Enzyme-Linked Immunosorbant Assay (ELISA) analysis revealed accumulation of fusion protein up to 0.16% of total soluble protein in the leaves of the transgenic plants. Progeny (T 1 generation) of the selfed transgenic plants were analyzed for the transgene segregation and insect protection. These studies clearly demonstrated the efficacy of Cry1B-Cry1Ab fusion protein to confer protection to cabbage against DBM infestation. The transgenic cabbage plants will serve as a good system to study the role of gene pyramiding in resistance management strategies intended to prevent evolution of resistance in DBM.
Ecotoxicology and Environmental Safety, Sep 1, 2011
Salvinia possess inherent capacity to accumulate high levels of various heavy metals. Accumulatio... more Salvinia possess inherent capacity to accumulate high levels of various heavy metals. Accumulation of Cr, Fe, Ni, Cu, Pb and Cd ranged between 6 and 9 mg g À 1 dry wt., while accumulation of Co, Zn and Mn was $ 4 mg g À 1 dry wt. Heavy metal accumulation affected the physiological status of plants. Photosystem II activity noted to decline in Ni, Co, Cd, Pb, Zn and Cu exposed plants, while Photosystem I activity showed enhancement under heavy metal stress in comparison to control. The increase in PS I activity supported build up of transthylakoidal proton gradient (DpH), which subsequently helped in maintaining the photophosphorylation potential. Ribulose 1,5 dicarboxylase/oxygenase (Rubisco) activity noted a decline. Alterations in photosynthetic potential of Salvinia result primarily from changes in carbon assimilation efficiency with slight variations in primary photochemical activities and photophosphorylation potential. Studies suggest that Salvinia possess efficient photosynthetic machinery to withstand heavy metal stress.
Biochemical and Biophysical Research Communications, Apr 1, 1995
Springer eBooks, 1998
Considerable amount of research has been carried out to study the photosynthetic contribution of ... more Considerable amount of research has been carried out to study the photosynthetic contribution of fruiting structures to yield of seeds (1,2). However, to the best of our knowledge so far no direct attempts have been made to evaluate the contribution of the cotyledons of developing embryos in harvesting the light energy during seed development. Developing seed is a strong sink for various metabolites such as sugars (especially sucrose), amino acids etc, which are later converted into polymers, which acts as reserve food material to be used in initial stages of next generation, plantlet establishment (3). In general the concentration of various solutes in the sap surrounding the developing embryo is very high and this high osmoticum is necessary for the normal development of embryos (4). The present investigations were carried out with an aim to compare photosynthesis in green cotyledons from maturing embryos of developing seeds under different levels of NaCl.
African Journal of Biotechnology, Feb 8, 2010
Chickpea production is limited worldwide because of abiotic and biotic stresses. Efforts to overc... more Chickpea production is limited worldwide because of abiotic and biotic stresses. Efforts to overcome these production constraints through traditional breeding are difficult due to limited genetic variation. Novel regeneration is prerequisite for genetic transformation offers the opportunity to overcome hybridization barriers and introduce novel genes for resistance. Although direct gene transfer via direct DNA transfer has been reported, Agrobacterium mediated transformation is the preferred method and standard protocols have been established for the production of transgenic plantlets derived from cocultivation of embryonic axes. This was soon adopted due to difficulties associated with regeneration of whole plants from callus. Only few reports have been reported using genetic transformation/ transgene(s) against abiotic stress tolerance transgenic chickpea plants. Transgenic chickpea using bacterial codA gene tolerance against abiotic stresses have been developed. Chickpea improvement and application of genomics tools to the study of the chickpea genome will be enhanced through the use of genetic transformation.
Agriculture, Ecosystems & Environment, 2011
Diploid, tetraploid and hexaploid species of wheat were grown at ambient (375 l l −1) or elevated... more Diploid, tetraploid and hexaploid species of wheat were grown at ambient (375 l l −1) or elevated (550 l l −1) CO 2 concentration [CO 2 ] in a mid Free-Air CO 2 Enrichment (FACE) facility, to study their differential response to CO 2 enrichment. It was observed that elevated [CO 2 ] consistently reduced the activity of Photosystem I (PS I) and PS II in all three wheat species investigated. Down regulation of photosynthesis may be attributed to feed back inhibition due to significantly higher accumulation of starch and total soluble sugars in grains and leaves. In spite of photosynthetic acclimation, dry weight of plants at harvest significantly increased in all the three species. CO 2 enrichment also delayed the date of ear emergence and anthesis. Highest reduction in activity of PS I, and maximum accumulation of carbohydrates along with increase in biomass, was observed in Triticum dicoccoides. Maximum delay in ear emergence and anthesis was also observed in this species. Minimum reduction in the activity of PS I and PS II, and least increase in biomass, were observed in T. aestivum. The study reports, for the first time, a correlation between the altered carbohydrate composition and activity of the two photosystems and flowering time in wild and cultivated species of wheat grown in FACE facility.
Process Biochemistry, 2013
While evaluating the potential of microorganisms to generate Au nanoparticles, we found that incl... more While evaluating the potential of microorganisms to generate Au nanoparticles, we found that inclusion of HAuCl 4 in Yeast Extract Mannitol (YEM) medium turns it wine red on autoclaving. UV-Vis spectra and TEM investigations confirmed that alteration in color of medium was due to formation of Au nanoparticles. Yeast extract and mannitol were key components of YEM medium responsible for formation of Au nanoparticles. In general, nanoparticles formed by YEM medium, yeast extract and mannitol were nearly spherical and in the size range of ~4-20, ~4-12 and ~10-20 nm, respectively. PXRD analysis suggested fcc geometry of Au nanoparticles in all cases. These findings caution autoclaving of metal salts along with microbial culture medium for authentic impact assessment studies of trace/toxic metals. Our findings also furnish ideal protocol for green synthesis of Au nanoparticles using yeast extract or mannitol under sterile aqueous conditions, which may find potential application in medicine, cosmetics and engineering.
Indian Journal of Crop Science, 2007
Rice is grown in over 100 countries and is the primary food for half the people in the world. Wor... more Rice is grown in over 100 countries and is the primary food for half the people in the world. World population is expected to increase to 8.5 billion by 2025. Invariably, many agricultural solis of the world are deficient in one or more of the essential nutrients. The atmospheric CO2 could increase from current levels of about 370 ppm to between 540 and 970 ppm by end of the 21 st century. The likely effect of global climate change due to predicted doubling of CO2 was studied in a randomized complete block design. Four popular Indian rice varieties viz Pusa Sugandh-2, Pusa Sugandh-3, Pusa Hybrid-10, and Pusa Basmati-1 were exposed to two CO2 levels (Ambient 350±20 ppm & Elevated 570±50 ppm) in triplicates in Open Top Chambers (OTC) at IARI-New Delhi in the year 2004. Elevated CO2 increased the levels of phosphorus, potassium, iron, zinc and manganese in ail the rice varieties. Pusa Hybrld-10 and Pusa Basmati-1 showed increase in phosphorus levels under elevated CO2 in comparison to ...
Vegetos, 2021
Crops, livestock and forests are interlinked components of Central Himalayan agro-ecosystems. Tra... more Crops, livestock and forests are interlinked components of Central Himalayan agro-ecosystems. Traditionally, farm yard manure is produced from forest leaf litter and excreta of livestock obtaining > 50% feed from forests. Chemical fertilizers are not used in rainfed farms on slopes. Experiments were conducted to test whether increase in FYM input rates results improvement in economic and environmental functions of agro-ecosystems. Increase in FYM input rate from 30 t/ha/crop-season currently practiced by farmers to 60 t/ha/crop-season showed substantial increase in crop yield and soil quality. Rice and wheat were more responsive to FYM input than the legume black gram. Harvest index is maximum for 60 t/ha/crop-season FYM treatment for rice and wheat. In blackgram maximum harvest index was obtained when no FYM was provided. During the 3 years of study, soil pH decreased (becoming more acidic) as compared to that recorded at the start of the study. Soil organic carbon generally declined upto second kharif season and then improved during second rabi (fallow) under no input treatment, and 16t/ha/crop-season FYM treatment and levels of N, P and Mg too showed patterns similar to soil organic carbon, but the trends varied for Ca, Na and K. Soils of fields put to 0 and 16 t/ha/crop-season FYM treatments showed a net decrease in concentration of these elements and those put to 30 and 60 t/ha/crop-season FYM treatments showed increase in their level.
Algal Research, 2016
Investigations were initiated with an aim to develop an apt method for long-term preservation/con... more Investigations were initiated with an aim to develop an apt method for long-term preservation/conservation of microalgae. Cells of Chlorella minutissima and Chlamydomonas sp. were immobilized on cotton cloth pieces. Scanning electron microscopic investigations revealed presence of immobilized cells on/between fibers of cloth pieces. Chlorophyll (Chl) a fluorescence transients revealed that immobilized cells were photosynthetically active. Cotton cloth pieces with immobilized microalgae were stored in Eppendorf tubes under (i) ambient conditions with light (14 h)/dark (10 h) cycle; (ii) ambient conditions in dark; and (iii) at 4°C in dark. After storage for 18 months, immobilized microalgal cells on cotton cloth pieces lost their photosynthetic potential. However, on incubation in BG 11 medium, these 18-month stored cotton cloth pieces with immobilized microalgal cells turned dark green. Simultaneously, this BG 11 medium showed increase in (a) number of cells; (b) Chl content; and (c) absorbance, with time. These findings revealed the viability of immobilized microalgal cells on cotton cloth pieces even after 18-month storage. These cotton cloth pieces which turned green, displayed perfect Chl a fluorescence transients revealing good photosystem (PS) II efficiency of revived microalgal cells. Polarographic investigations revealed the potential of microalgal cells in the medium to evolve oxygen in presence of light, further confirming prevalence of functional light harnessing photosynthetic machinery. These findings authentically revealed for the first time that algal cells immobilized on cotton cloth pieces can be stored with ease for long duration. We believe that this new protocol would help not only in apt maintenance/conservation but also for easy transport of algae across the globe.
PloS one, 2014
Potential of root system of plants from wide range of families to effectively reduce membrane imp... more Potential of root system of plants from wide range of families to effectively reduce membrane impermeable ferricyanide to ferrocyanide and blue coloured 2,6-dichlorophenol indophenol (DCPIP) to colourless DCPIPH2 both under non-sterile and sterile conditions, revealed prevalence of immense reducing strength at root surface. As generation of silver nanoparticles (NPs) from Ag+ involves reduction, present investigations were carried to evaluate if reducing strength prevailing at surface of root system can be exploited for reduction of Ag+ and exogenous generation of silver-NPs. Root system of intact plants of 16 species from 11 diverse families of angiosperms turned clear colorless AgNO3 solutions, turbid brown. Absorption spectra of these turbid brown solutions showed silver-NPs specific surface plasmon resonance peak. Transmission electron microscope coupled with energy dispersive X-ray confirmed the presence of distinct NPs in the range of 5-50 nm containing Ag. Selected area elect...
PLoS ONE, 2014
While evaluating impact of Au nanoparticles on seed germination and early seedling growth of cowp... more While evaluating impact of Au nanoparticles on seed germination and early seedling growth of cowpea, HAuCl 4 was used as control. Seedlings of cowpea raised in HAuCl 4 , even at concentration as high as 1 mM, did not show any suppression in growth. Accordingly, Au 3+ , despite being a heavy metal, did not alter levels of stress markers (viz. proline and malondialdehyde) in cowpea. Interestingly, cowpea turned clear pale yellow HAuCl 4 solutions colloidal purple during the course of seed germination and seedling growth. These purple colloidal suspensions showed Au-nanoparticle specific surface plasmon resonance band in absorption spectra. Transmission electron microscopic and powder X-ray diffraction investigations confirmed presence of crystalline Au-nanoparticles in these purple suspensions. Each germinating seed of cowpea released ,35 nmoles of GAE of phenolics and since phenolics promote generation of Au-nanoparticles, which are less/non toxic compared to Au 3+ , it was contemplated that potential of cowpea to withstand Au 3+ is linked to phenolics. Of the different components of germinating seed of cowpea tested, seed coat possessed immense power to generate Aunanoparticles, as it was the key source of phenolics. To establish role of phenolics in generation of Au-nanoparticles (i) seed coat and (ii) the incubation medium in which phenolics were released by germinating seeds, were tested for their efficacy to generate Au-nanoparticles. Interestingly, incubation of either of these components with Au 3+ triggered increase in generation of Au-nanoparticles with concomitant decrease in phenolics. Accordingly, with increase in concentration of Au 3+ , a proportionate increase in generation of Au-nanoparticles and decrease in phenolics was recorded. In summary, our findings clearly established that cowpea possessed potential to withstand Au 3+-stress as the phenolics released by seed coat of germinating seeds possess potential to reduce toxic Au 3+ to form non/less toxic Au-nanoparticles. Our investigations also pave a novel, simple, green and economically viable protocol for generation of Au-nanoparticles.
Environmental Monitoring and Assessment, 2014
This paper addresses the phenotypic variation among Ricinus communis L. populations in four urban... more This paper addresses the phenotypic variation among Ricinus communis L. populations in four urban habitat types (road verges, garbage dumps, construction debris, and natural area) in Delhi, India, by evaluating important traits such as plant height, basal circumference, seeds per plant, seed size, seed weight, specific leaf area, and reproductive index. An important biochemical marker, proline, considered as a good plant performance indicator under stress was also quantified in leaves of R. communis to evaluate its response in different habitats. Interestingly, the species showed significant variation in plant height, specific leaf area, seed size, seed weight, and leaf proline content in different habitat types. Leaf proline content was positively related to plant height, specific leaf area, and seed size while negatively related to the total number of seeds/plant. Interestingly, reproductive index, calculated as a ratio of the total number of seeds to the plant height also showed a negative relation with leaf proline content. Results indicated that R. communis exhibits adaptive modulation of growth, reproductive traits, and leaf proline content in various urban habitats which contributes to invasiveness, range expansion, and establishment of the species. The study also gives evidence of how morphological and physiological traits could directly affect invasiveness of R. communis.
African Journal of Biotechnology, 2010
Chickpea production is limited worldwide because of abiotic and biotic stresses. Efforts to overc... more Chickpea production is limited worldwide because of abiotic and biotic stresses. Efforts to overcome these production constraints through traditional breeding are difficult due to limited genetic variation. Novel regeneration is pre-requisite for genetic transformation offers the opportunity to overcome hybridization barriers and introduce novel genes for resistance. Although direct gene transfer via direct DNA transfer has been reported, Agrobacterium mediated transformation is the preferred method and standard protocols have been established for the production of transgenic plantlets derived from cocultivation of embryonic axes. This was soon adopted due to difficulties associated with regeneration of whole plants from callus. Only few reports have been reported using genetic transformation/transgene(s) against abiotic stress tolerance transgenic chickpea plants. Transgenic chickpea using bacterial codA gene tolerance against abiotic stresses have been developed. Chickpea improvem...
Frontiers in plant science, 2017
In this study, we have investigated variations in the potential of floating and submerged leaves ... more In this study, we have investigated variations in the potential of floating and submerged leaves of longleaf pondweed (Potamogeton nodosus) to withstand silver ion (Ag(+))-toxicity. Both floating and submerged leaves changed clear colorless AgNO3 solutions to colloidal brown in the presence of light. Transmission electron microscopy revealed the presence of distinct crystalline Ag-nanoparticles (Ag-NPs) in these brown solutions. Powder X-ray diffraction pattern showed that Ag-NPs were composed of Ag(0) and Ag2O. Photosystem (PS) II efficiency of leaves declined upon exposure to Ag(+) with a significantly higher decline in the submerged leaves than in the floating leaves. Similarly, Ag(+) treatment caused a significant reduction in the carboxylase activity of the ribulose bisphosphate carboxylase/oxygenase in leaves. The reduction in this carboxylase activity was significantly higher in the submerged than in the floating leaves. Ag(+) treatment also resulted in a significant decline ...
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Papers by P Pardha Saradhi