Alok Adholeya

A Review on the Assessment of Stress Conditions for Simultaneous Production of Microalgal Lipids and Carotenoids

Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids) under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C) such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME), and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions.

Effects of the particle size of soil-less substrates upon AM fungus inoculum production.

Glomus intraradices was examined in a locally available sand graded by particle size, planted with Zea mays and fertilized with a nutrient solution. Plants in sand with particle sizes of 0.50–0.78 mm had higher root fresh weights, spore production and percent mycorrhizal colonization than with other particle sizes. Production of spores and infectious propagules was enhanced by a nutrient solution without P. Plants were also inoculated with G. intraradices in pots containing clay-brick granules, charcoal, coalmarl, sand or perlite of the optimal particle size (0.50–0.78 mm). Percent root length colonized by G. intraradices and production of infectious propagules were 40–50 % higher for plants grown in clay-brick granules and sand than in the other media.

An optimized procedure for preconcentration, determination and on-line recovery of palladium using highly selective diphenyldiketone-monothiosemicarbazone modified silica gel

A novel, highly selective, efficient and reusable chelating resin, diphenyldiketone-monothiosemicarbazone modified silica gel, was prepared and applied for the on-line separation and preconcentration of Pd(II) ions in catalytic converter and spiked tap water samples. Several parameters like effect of pH, sample volume, flow rate, type of eluent, and influence of various ionic interferences, etc. were evaluated for effective adsorption of palladium at trace levels. The resin was found to be highly selective for Pd(II) ions in the pH range 4-5 with a very high sorption capacity of 0.73 mmol/g and preconcentration factor of 335. The present environment friendly procedure has also been applied for large-scale extraction by employing the use of newly designed reactor in which on-line separation and preconcentration of Pd can be carried out easily and efficiently in short duration of time.

Growth responses and dependence of Acacia nilotica var. cupriciformis on the indigenous arbuscular mycorrhizal consortium of a marginal wasteland soil

Abstract The responses of Acacia nilotica L. var. cupriciformis to phosphorus application and inoculation with the indigenous consortium of arbuscular mycorrhizal (AM) fungi were evaluated in a nursery experiment using soil from a marginal wasteland. A positive growth response to mycorrhizal inoculation was observed at an Olsen-P level of 20 ppm in the presence of the natural population of AM fungi. There was growth stimulation by either inoculation or additional P at the highest soil P of 40 ppm. Colonization was negatively correlated to soil P but P content of both shoot and root were positively correlated. Inoculation with the indigenous AM consortium significantly increased the uptake of P at all levels of applied P. Acacia is moderately dependent upon the AM symbiosis and exhibited a maximal mycorrhizal dependence (MD) of 18.25% at 20 ppm Olsen-P level under the conditions studied. A sharp and considerable reduction in MD and dry matter yield observed at 40 ppm P suggests that the external P requirement for maximal production of biomass was met at approximately 20 ppm Olsen-P.

Mycorrhiza in Control of Soil Borne Pathogens

Speedy development of agriculture is vital to the progress of a country. For securing maximum crop production, the agricultural practices have evolved into highly technified and sophisticated plant production systems. Until recently, the management of plant diseases in these systems was done exclusively by the use of broad-spectrum chemical pesticides. However, there is reason for concern about the potential damage to ecosystems and pollution of groundwaters resulting from the widespread use of these chemicals on agricultural crops that led scientists to develop disease resistant transgenic plants as an alternative approach for controlling pathogens.

Effect of different organic manures/composts on the herbage and essential oil yield of Cymbopogon winterianus and their influence on the native AM population in a marginal alfisol

Four organic amendments: leaf compost (LC), vegetable compost (VC), poultry manure (PM) and sewage sludge (SSL) applied at four doses (40, 80, 100 and 120 tha(-1)) were evaluated for their effect on the herbage yield, essential oil content and inoculum potential (IP) of native arbuscular mycorrhizal fungi (AMF) on three varieties of Java citronella, Cymbopogon winterianus Jowitt (Manjusha, Mandakini, and Bio-13). PM applied at 100 t ha(-1) followed by SSL increased the herbage, essential oil content and dry matter yield significantly. Bio-13 performed better and produced the highest herbage, essential oil and dry matter yield. The type and dose of the various organic amendments also significantly influenced the indigenous AMF infectious propagules in soil. Highest number of AMF propagules were recorded in the LC amended plots in all the three varieties. Amongst the varieties, highest native mycorrhizal inoculum was recorded in the Bio-13. Least number of AM infectious propagules were recorded in the Mandakini plants grown in 40 t ha(-1) SSL.

Co-composting of physic nut (Jatropha curcas) deoiled cake with rice straw and different animal dung

To address the dispensing of this growing volume, a study on utilization of jatropha (Jatropha curcas) deoiled cake through compost production was carried out. The deoiled cake was composted with rice straw, four different animal dung (cow dung, buffalo dung, horse dung and goat dung) and hen droppings in different proportions followed by assessment, and comparison of biochemical characteristics among finished composts. Nutrient content in finished compost was within the desired level whereas metals such as copper, lead and nickel were much below the maximum allowable concentrations. Although a few finished material contained phorbol ester (0.12 mg/g), but it was far below the original level found in the deoiled cake. Such a study indicates that a huge volume of jatropha deoiled cake can be eliminated through composting.

Growth and flowering in Petunia hybrida, Callistephus chinensis and Impatiens balsamina inoculated with mixed AM inocula or chemical fertilizers in a soil of low P fertility.

Abstract Three seasonal ornamental plants, namely Petunia hybrida, Callistephus chinensis and Impatiens balsamina, were tested for their response to inoculation with mixed indigenous AM culture when grown on a marginal wasteland amended with organic matter. Subsequently, the treatments consisting of AM inoculations were compared with those consisting of recommended chemical fertilizers in terms of growth response and cost economics. In all the three plant species, mycorrhizal inoculation led to marked improvement in both reproductive (number of flowers) and vegetative (dry matter) phase of the plants. P. hybrida showed a threefold increase over uninoculated plants in the reproductive growth as compared to twofold in C. chinensis and I. balsamina. Application of the recommended dose of chemical fertilizers produced a comparable response. The inoculated plants produced greater dry matter, grew taller, flowered at least 15 days earlier and produced more flowers when compared to uninoculated plants. In addition there was a significant increase in P and K uptake in shoots of all the three ornamentals. AM inoculation could be at least 30% cost economic as compared to the chemical fertilizers. Therefore, mycorrhizal inoculation is recommended at the nursery level for nutrient-deficient soil conditions because it is a cost-effective substitute for chemical fertilizers, either partly or fully, which makes the approach particularly suitable to marginal farmers with their low-input farming system.

Diverse Response of Five Ornamental Plant Species to Mixed Indigenous and Single Isolate Arbuscular-Mycorrhizal Inocula in Marginal Soil Amended with Organic Matter

Abstract Five ornamental plant species, Petunia hybrida, Tegetes erecta, Callistephus chinensis, Papaver rhoeas, and Dianthus caryophyllus were inoculated with a consortium of indigenous arbuscular mycorrhizal (AM) fungi (Mi) and a single culture of Glomus intraradices (Gi) in non-sterile, P-deficient sandy loam soil amended with organic matter under field conditions. Mycorrhizal inoculation increased flowering only in C. chinensis, whereas in P. hybrida and T. erecta fewer flowers were recorded in AM-inoculated plants. Total number of flowers in AM-inoculated plants increased by a maximum of 39% in C. chinensis over uninoculated controls. AM colonization and propagule density were found to vary with host and type of AM culture used. Maximum AM colonization was recorded in T. erecta (87.9%) and P. hybrida (85.5%) when inoculated with Mi or 73.6% and 75%, respectively, when inoculated with Gi. The highest AM inoculum production was also recorded in these two hosts with an up to 200-fold increase in the number of infectious propagules at harvest. The smaller number of flowers in P. hybrida and T. erecta was attributed to heavy root colonization coupled with production of large numbers of spores, perhaps indicating the possibility of a fungal carbon drain. This study has the potential to enhance the production of ornamental crops, particularly in nutrient-deficient soils using biologically-based farming systems. Also, a buildup of the mycorrhizal inoculum in soil amended with organic matter during the cropping of these ornamental hosts could be useful in producing AM fungal inoculum for large-scale applications and for decreasing inoculum costs.

Enhanced growth and productivity following inoculation with indigenous AM fungi in four varieties of onion (Allium cepa L.) in an alfisol.

ABSTRACT A field experiment was conducted to evaluate the benefit to growth of Allium cepa L. of inoculation with a mixed culture of indigenous arbuscular mycorrhizal (AM) fungi. Four locally adapted onion cvs., Pusa White Flat (PWF), Pusa White Round (PWR), Early Grano (EG) and Pusa Madhvi (PM) were grown at two phosphorus levels (25 and 50 kg P ha−1) in a P deficient alfisol. Inoculation significantly increased mycorrhiza formation over that caused by the level of native AM fungi present at the site. At harvest, all inoculated onion varieties showed higher values of bulb diameter, fresh weight, shoot dry matter, shoot p content and bulb yield than uninoculated plants. However, the magnitude of AM response for yield in a given onion variety was found to be different at different levels of P. This holds true in all the varieties tested. Inoculated plants tended to have greater bulb yield for varieties PM and PWR grown at 25 kg P ha−1. On the other hand, PWF and EG plants showed similar response at 50 kg P ha−1. The percent root length colonized by AM fungi between both the P levels of inoculated plants did not differ significantly. However, the extent of colonization varied among the varieties. The dependence of plants on mycorrhizal fungi for bulb production varied among the varieties grown at a particular P. EG and PWF plants showed maximum dependence on AM at 50 kg P ha where as PM and PWR plants exhibited a maximum MD at 25 kg P ha−1.