Shri Krishna Tewari

Stimulatory Effects of Arsenic-Tolerant Soil Fungi on Plant Growth Promotion and Soil Properties

Fifteen fungi were obtained from arsenic-contaminated agricultural fields in West Bengal, India and examined for their arsenic tolerance and removal ability in our previous study. Of these, the four best arsenic-remediating isolates were tested for plant growth promotion effects on rice and pea in the present study. A greenhouse-based pot experiment was conducted using soil inocula of individual fungi. The results indicated a significant (P<0.05) increase in plant growth and improvement of soil properties in inoculated soils compared to the control. A significant increase in plant growth was recorded in treated soils and varied from 16–293%. Soil chemical and enzymatic properties varied from 20–222% and 34–760%, respectively, in inoculated soil. Plants inoculated with inocula of Westerdykella and Trichoderma showed better stimulatory effects on plant growth and soil nutrient availability than Rhizopus and Lasiodiplodia. These fungi improved soil nutrient content and enhanced plant growth. These fungi may be used as bioinoculants for plant growth promotion and improved soil properties in arsenic-contaminated agricultural soils.

Biochemical Composition of Curcuma longa L. Accessions

The essential oil composition and total phenolic content (TPC) of curcuminoids were studied in rhizomes of nine Curcuma longa L. accessions. Curcuminoids, present in commercially available turmeric rhizomes, play vital roles in various pharmacological activities. A simple, rapid, and sensitive high performance liquid chromatography photodiode array (HPLC-PDA) method was optimized for simultaneous determination of curcuminoids, namely, a mixture of curcumin, demethoxy curcumin (DMC), and bisdemethoxy curcumin (BDMC) in rhizomes of C. longa. Chromatographic separation was performed on an RP C18 column within 13 minutes (11.4 to 12.95 minutes). Elution was accomplished by the application of acetonitrile and 1.5% acetic acid in water in a gradient system with flow rate of 2.0 mL min−1. PDA was employed for qualitative and quantitative analysis. The calibration curves were found linear (0.99) for all cucuminoids; the limit of detection and quantification ranged between 1.01 µ g mL−1 to 1.16 µ g mL−1 and 2.30 µ g mL−1 to 3.05 µ g mL−1, respectively, while recovery values ranged between 97.97% to 98.32%. The amount of curcumin varied from 0.46% to 2.17%, DMC from 0.13% to 0.92% and BDMC from 0.06% to 0.52%. The validated method was successively used to determine the above compounds in C. longa rhizomes. The TPC in rhizomes ranged from 14.12 mg g−1 to 27.72 mg g−1. The chemical composition of rhizome essential oil, analyzed by gas chromatography mass spectrometry (GCMS,) showed large variations in major compounds like ar-tumerone (7.31–38.66%), β-curcumene (1.58–24.53%), and curlone (1.55–15.97%).

Use of a Bioaugmented Organic Soil Amendment in Combination with Gypsum for Withania somnifera Growth on Sodic Soil

Limited availability of organic matter is a problem to sustain crop growth on sodic soil. Organic soil amendments are a cost-effective source of nutrients to enhance crop growth. A field study was conducted to evaluate the effect of an organic soil amendment bioaugmented with plant growth-promoting fungi (SFOA) in combination with gypsum on soil properties and growth and yield attributes of Withania somnifera, one of the most valuable crops of the traditional medicinal system in the world, on a sodic soil at the Aurawan Research Farm of CSIR-National Botanical Research Institute, Lucknow, India. The SFOA used was prepared by pre-enriching farm waste vermicompost with plant growth-promoting fungi before mixing with pressmud and Azadirachta indica seed cake. The application of SFOA at 10 Mg ha−1 after gypsum (25.0 Mg ha−1) treatment significantly (P < 0.05) increased root length (by 96%) and biomass (by 125%) of Withania plants compared to the control without SFOA and gypsum. Similarly, the highest withanolide contents were observed in leaves and roots of Withania plants under 10 Mg ha−1 SFOA and gypsum. Combined application of SFOA and gypsum also improved physical, chemical and enzymatic properties of the soil, with the soil bulk density decreasing by 25%, water-holding capacity increasing by 121%, total organic C increasing by 90%, pH decreasing by 17% and alkaline phosphatase, β-glucosidase, dehydrogenase and cellulase activities increasing by 54%, 128%, 81% and 96%, respectively, compared to those of the control. These showed that application of the SFOA tested in this study might reclaim sodic soil and further support Withania cultivation and results were better when the SFOA was applied after gypsum treatment.

Variations in Yield, Quality, and Antioxidant Potential of Kalmegh (Andrographis paniculata Nees) with Soil Alkalinity and Season

The edaphoclimatic conditions that affect the yield and qualities of Andrographis paniculata Nees, (Kalmegh) were studied. Under seasonal and soil pH variations, andrographolide content ranged between 2.25–3.85% in aerial parts of the plant. Total phenolic content, antioxidant activity and reducing power were 20.3 mg g−1 GAE, 66.8% and 2.8 ASE mL−1. FRSA measured by DPPH showed an IC50 of 0.34 mg mL−1, EC50 of 14.7 mg mg−1 DPPH, and anti-radical power of 6.76. AOA in different assays expressed as IC50 ranged from 0.31 to 1.29 mg mL−1. The extract showed significant protective effect against Fentons reaction on supercoiled pUC18 DNA.

Isotopic Ratio Mass Spectrometry Study for Differentiation Between Natural and Adulterated Essential Oils of Lemongrass (Cymbopogon flexuosus) and Palmarosa (Cymbopogon martinii)

Abstract: Adulteration in aromatic oils with natural isolates and identical synthetic compounds is common practice in flavour and fragrance industry. Blending of synthetic materials is done in such a way that the chemical profile by gas chromatography of product (adulterated) oil remains nearly identical to original one. This practice makes complex issue for detection of adulterants in aromatic oil. In the present study, natural and adulterated essential oils of lemongrass (Cymbopogon flexuosus) and palmarosa (Cymbopogon martinii) were differentiated and identified on the basis of their carbon isotope composition (13C/12C) using isotopic-ratio mass spectrometry (IRMS) technique. This technique differentiates the natural oils (lemongrass and palmarosa oils) with adulterated oils by showing decrease in their carbon isotopic composition as blending of synthetic compounds viz. geraniol, citral, polyethylene glycol (PEG), dioctyl phthalate (DOP) and diethyl phthalate (DEP) of these adulterants with increasing order (5 % to 50 %).

A New Agro-technology for Increasing Oil Yield and Yield Contributing Characters of Menthol Mint (Mentha arvensis L.)

Abstract A pot experiment were conducted at the research farm of Central Institute of Medicinal and Aromatic Plant, Research Centre, Pantnagar (Udham Singh Nagar) Uttarakhand, India, during 2013 to ascertain the response of nipping (cutting of apical portion in each branch of mint) on yield and yield contributing characters of mint (Mentha arvensis). The results revealed that, nipping of mint (Mentha arvensis L.) at 35 day after transplanting (T) recorded the highest plant height (89.3 cm), no. of branches/plant (99), leaf: stem ratio (1.31:1), fresh herb yield of mint (272.67 q/ha), oil content (1.20%) and oil yield (326.27  kg/ha) as compared to others and the lowest was found in T - control (no nipping).

Organic Amendments with Plant-Growth-Promoting Fungi Support Paddy Cultivation in Sodic Soil

Excessive sodium content in sodic soils is an important limiting factor for cultivation of agricultural crops. The present study was conducted to explore the influence of a novel organic amendment (SFOA) along with use of plant-growth-promoting fungi (PGPF) on soil properties and growth/yield of Oryza sativa L. The combined application of PGPF and SFOA increased total organic carbon (TOC) (0.62%) and decreased the exchangeable sodium percentage (ESP) (15.6%) of soil more significantly from 0.56% (TOC) and 30.1% (ESP), respectively compared to SFOA alone treatment. The combined application reduced soil bulk density, pH, and electrical conductivity (EC) and improved soil enzymatic activities. A significant negative correlation was observed between grain yield with soil ESP and bulk density (r = –0.728, and –0.789, respectively). This study showed that the combined treatment of PGPF and SFOA could enhance the potential of organic amendments for alleviating salt stress in rice.