Vijaylata Pathania

Organic acid production and plant growth promotion as a function of phosphate solubilization by Acinetobacter rhizosphaerae strain BIHB 723 isolated from the cold deserts of the trans-Himalayas

An efficient phosphate-solubilizing plant growth–promoting Acinetobacter rhizosphaerae strain BIHB 723 exhibited significantly higher solubilization of tricalcium phosphate (TCP) than Udaipur rock phosphate (URP), Mussoorie rock phosphate (MRP) and North Carolina rock phosphate (NCRP). Qualitative and quantitative differences were discerned in the gluconic, oxalic, 2-keto gluconic, lactic, malic and formic acids during the solubilization of various inorganic phosphates by the strain. Gluconic acid was the main organic acid produced during phosphate solubilization. Formic acid production was restricted to TCP solubilization and oxalic acid production to the solubilization of MRP, URP and NCRP. A significant increase in plant height, shoot fresh weight, shoot dry weight, root length, root dry weight, and root, shoot and soil phosphorus (P) contents was recorded with the inoculated treatments over the uninoculated NP0K or NPTCPK treatments. Plant growth promotion as a function of phosphate solubilization suggested that the use of bacterial strain would be a beneficial addition to the agriculture practices in TCP-rich soils in reducing the application of phosphatic fertilizers.

Effect of decapitation and nutrient applications on shoot branching, yield, and accumulation of secondary metabolites in leaves of Stevia rebaudiana Bertoni

The axillary buds of stevia (Stevia rebaudiana Bertoni) often remain dormant for a long time and sometimes remain dormant permanently until the plants enter into the reproductive stage. The present study was conducted to ascertain whether decapitation and foliar fertilization enhance the productivity and quality of stevia through breaking the apical dominance and increasing physiological activities. Ten treatment combinations comprising two cultural operations (non-decapitation and decapitation) and five foliar spray treatments (water spray control, KNO3 @ 5.0gL(-1), Ca(NO3)2 @ 4.06gL(-1), CuSO4·5H2O 2.0gL(-1) and (NH4)6Mo7O24 @ 1.0gL(-1)) were applied. The decapitation of apical buds of stevia increased the branches and increased dry leaf yield by 13 and 17% compared with non-decapitation during 2010 and 2011, respectively, without affecting quality. Foliar application of nutrient solutions also exerted a considerable effect on growth parameters, yield attributes and chlorophyll content, and significantly (P=0.05) higher dry leaf yield ranging from 8 to 26% over the control. Among the foliar spray treatments, KNO3 @ 5.0gL(-1) and Ca (NO3)2 4.06gL(-1) were found most effective in dry leaf yield. Thus, the decapitation of apical buds and foliar application of KNO3 and Ca (NO3)2 could enhance the productivity of stevia through improving the growth of axillary buds and physiological activities.

Evaluation of antioxidant activity of Picrorhiza kurroa (leaves) extracts

Picrorhiza kurroa is a well-known herb in Ayurvedic medicine. Although it shows antioxidant, antiinflammatory and immunomodulatory activities, it is most valued for its hepatoprotective effect. The rhizomes are widely used against indigestion problems since ancient times due to improper digestive secretions. Aim of this study was to explore antioxidant study of P. kurroa leaves for a new source of naturally occurring antioxidants. Two pure compounds, luteolin-5-O-glucopyranoside (1) and picein (2) were isolated from butanol extract through column chromatography. Different extracts of P. kurroa leaves (ethanol, ethyl acetate, butanol) were quantified for isolated compound (2) by high-performance liquid chromatography. All the extracts and isolated compounds were evaluated for its antioxidant activity using two assays, 2,2-diphenyl-1-picrylhydrazyl radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay. The linear detection range was 1.56-200 μg/ml for picein. The limit of detection and limit of quantification for picein were 2.34 and 7.81 μg/ml, respectively. Butanol and ethyl acetate extract showed greater antioxidant activity as compare to ethanol extract. Compound 1 and ascorbic acid showed nearly similar antioxidant activity where as 2 showed no activity at standard concentration. The IC50 values for 2,2-diphenyl-1-picrylhydrazyl radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay for ascorbic acid, compound 1, ethanol extract and its different fractions (ethyl acetate and butanol) were found to be 0.81, 1.04, 67.48, 39.58, 37.12 and 2.59, 4.02, 48.36, 33.24, 29.48 μg, respectively.

Selective Th2 Upregulation by Crocus sativus: A Neutraceutical Spice

The immunomodulatory activity of an Indian neutraceutical spice, saffron (Crocus sativus) was studied on Th1 and Th2 limbs of the immune system. Oral administration of alcoholic extract of Crocus sativus (ACS) at graded dose levels from 1.56–50 mg/kg p.o. potentiated the Th2 response of humoral immunity causing the significant increases in agglutinating antibody titre in mice at a dose of 6.25 mg/kg and an elevation of CD19+ B cells and IL-4 cytokine, a signature cytokine of Th2 pathway. Appreciable elevation in levels of IgG-1 and IgM antibodies of the primary and secondary immune response was observed. However, ACS showed no appreciable expression of the Th1 cytokines IL-2 (growth factor for CD4+ T cells) and IFN-γ (signature cytokine of Th1 response). A significant modulation of immune reactivity was observed in all the animal models used. This paper represents the selective upregulation of the Th2 response of the test material and suggests its use for subsequent selective Th2 immunomodulation.

Irradiance stress and plant spacing effect on growth, biomass and quality of wild marigold (Tagetes minuta L.) – an industrial crop in western Himalaya

A study was carried out over 2 years (2009 and 2010) at the CSIR–Institute of Himalayan Bioresource Technology, Palampur, India, to investigate the effect of irradiance stress and plant spacing on growth, biomass yield, essential oil content and composition in wild marigold (Tagetes minuta L.). Four shade levels (0%, 25%, 50% and 75%) and three plant spacing (45 × 30, 45 × 45 and 60 × 45 cm) were tested as per split plot design. Heavy shading (50% and 75%) strongly reduced the total essential oil content in fresh leaves and flowers. The essential oil content of leaves, flowers and the total oil increased up to the 25% shade level and declined thereafter, with a decrease in irradiance level. Ocimene and dihydrotagetones concentration in leaf oil decreased with decrease in irradiance level; however, tagetone and ocimenone showed the reverse trend. In flower oil, ocimene decreased with an increase in shade levels. Fresh leaf, stem, flower, leaf + flower biomass, and total biomass was significantly higher in the 45 × 30 cm spacing level. Essential oil content in flowers of T. minuta grown in 25% shade at 45 × 45 and 45 × 30 cm spacing recorded significantly higher essential oil content than other treatments.

Effect of shading and plant density on growth, yield and oil composition of clary sage (Salvia sclarea L.) in north western Himalaya

The experiments were commenced in January 2009 and repeated in 2010 at the CSIR-Institute of Himalayan Bioresource Technology (Council of Scientific and Industrial Research), Palampur, India to investigate the effect of shading and plant density on plant growth, yield, volatile oil content and composition in clary sage. Four levels of shade (0, 25%, 50%, 75% shade) and three planting geometry levels (30 × 30 cm, 45 × 30 cm, 45 × 45 cm) were tested as per split plot design. Plants grown in full sunlight (control) produced significantly higher number of leaves than heavy shading (75% shade). Plant spread, root length, number of roots/plant, flower weight/plant, total biomass/plant, oil content and oil yield significantly reduced with increase in shade levels. Flower yield (q/ha) was significantly higher when the crop was planted under narrow spacing 30 × 30 cm compared with 45 × 30 cm and 45 × 45 cm spacing levels. Oil content and oil yield were not affected by different spacing levels. Linalyl acetate and sclareol were higher under 25% shade, germacrene D required 50% shade, but linalool was better in open environment.

Intraspecific variability of main phytochemical compounds in Picrorhiza kurroa Royle ex Benth. from North Indian higher altitude Himalayas using reversed- phase high-performance liquid chromatography

Picrorhiza kurroa Royle ex Benth. is an important medicinal plant belonging to family Scrophulariaceae. It is known to contain iridoid glycosides, picroside I and II as major bioactive compounds. The present study provides an analytical HPLC method with well-resolved and symmetrical peaks for the two reference compounds picroside-I and picroside-II. Separation was achieved on RP-18e, Merck made column. The mobile phase consisted of methanol:water (60:40, v/v) in isocratic elution with flow rate 1 ml/min. Injection volume of standard and samples was 10 µl and run time was 30 min. The detection of analyte was carried out using photodiode array detector with wavelength of 270 nm. Calibration curves were constructed for each analyte. The HPLC method was developed and applied to determine the picroside-I and picroside-II in rhizome of all the seven accessions [Rohtang-3978 m (PKR-1); Marhi-3300 m (PKM-2); Manali-2050 m (PKM-3); Keylong-3350 m (PKK-4); Khoksar-3160 m (PKK-5); Manikaran-1737 m (PKM-6) and Chamba-996 m (PKC-7)] from higher altitude North Indian Himalayas of Himachal Pradesh. Both of these reference compounds have been detected in the rhizome samples of all these seven accessions of P. kurroa. After detailed comparison, it was concluded that the percentage of both analytes were found to be maximum, that is, picroside-I (3.5%) and picroside-II (2.0%) in rhizome parts of P. kurroa collected from Rohtang area (3978 m).

A New Dihomosesquiterpene, Termioic Acid A, from Curcuma aromatica

The naturally occurring C17 compound dihomosesquiterpene (1), along with two known compounds (2, 3), was isolated from the ethanolic extract of Curcuma aromatica rhizomes. Compound 1 was identified as a new compound using 1D and 2D NMR (1H, 13C, DEPT, 1H–1H-COSY, HMQC, HMBC, and NOESY) spectroscopic techniques and called termioic acid A ((1S,4S,5R,6S,8E,10Z)-1,13-dihydroxy-4-epoxy-8(12),9(10)-diene-termi-11-oic acid). With the help of HPLC, the content of compound 1 in the extract was also determined.

Comparative efficiency of phosphate-solubilizing bacteria under greenhouse conditions for promoting growth and aloin-A content of Aloe barbadensis

This study was conducted with Aloe barbadensis in order to investigate the efficacy of four phosphate-solubilizing bacteria (PSB), Pseudomonas synxantha 10223, Burkholderia gladioli 10242, Enterobacter hormaechei 10240 and Serratia marcescens 10241 to solubilize Mussorie rock phosphate (MRP) and to evaluate its effects on growth, soluble P content and P uptake compared with control, i.e. uninoculated plants. Pot experiments were conducted in a greenhouse, in soil supplemented with MRP. Each PSB treatment showed different effects on different plant growth parameters. The maximum increase in leaf length (23.7%), total number of leaves (33.33%) and dry rind weight (69.10%) was observed in plants treated with P. synxantha 10223 compared with control. Whereas, maximum increase in root length (23.43%), fresh leaves weight (79.03%), dry gel weight (113.08%) and total gel volume (112.10%), was observed in plants treated with S. marcescens 10241 compared with uninoculated plants. Maximum increase in aloin-A content [114.92% (per g dry gel weight) and 322.32% (per plant dry gel weight)] was observed in plants treated with P. synxantha 10223 compared with control plants. Root colonization by inoculated PSB as estimated by RAPD technique showed that all PSB were able to survive in the rhizosphere of Aloe plants.

Essential Oil Analysis and Antimicrobial Activity of Artemisia parviflora from Losar

Abstract The essential oil composition of Artemisia parviflora Buch.-Ham. ex D. Don has been done for the first time from Losar- a Cold Desert of North Indian Higher Altitude Himalayas (4079 m) in July, 2007. Essential oil was isolated by hydro distillation from the aerial parts of the plants collected from the wild sources. The extraction yield for the essential oil of A. parviflora was 0.27 %. The oil was analyzed by GC-MS, the components of the essential oil were identified by comparing their retention indices and mass spectra fragmentation patterns with those stored on the MS-computer library and also from the published literatures. The essential oil analysis led to the identification of 27 constituents representing 80.93 % of the composition of oil. The major constituents of the oil were as following: ß-eudesmol (15.58%), spathulenol (8.50%), ß-selinene (6.0%), citronellol (5.68%), y-cadinene (4.95%), phytol (4.95%), guaiol (4.68%), germacrene-D (3.81%), 10-epi-y-eudesmol (3.51%) and Ot-cadinol (4.51%). The present study describes the phytochemical profile and antimicrobial activity of essential oil of A parviflora. Furthermore, antimicrobial activity of oil was evaluated using agar well diffusion method. The antimicrobial test results showed that the oil had a great potential antimicrobial activity against all 7 bacterial strains. Among all gram positive bacterial growths, the maximum zone of inhibition was recorded against Bacillus subtilis (MTCC-2451), followed by gram negative bacterial strain Salmonella typhimurium (MTCC-1251). The minimum zone of inhibition was recorded against the Escherichia coli (MTCC-443) strain. Among all tested microorganisms, the minimal inhibition concentration (MIC) was recorded in gram negative strain Salmonella typhimurium (MTCC-1251).