Role of metal resistant plant growth promoting bacteria in ameliorating fly ash to the growth of Brassica juncea.

In this study, we have shown that the plant growth promoting bacterial strain NBRI K24 and strain NBRI K3 from fly ash (FA) contaminated soil reduce the toxicity of Ni and Cr in Brassica juncea (Indian mustard) and promote plant growth under pot culture experiments. Isolated strains NBRI K24 and NBRI K3 were characterized based on the 16S rDNA sequencing and identified as Enterobacter aerogenes and Rahnella aquatilis respectively. Both the strains were siderophore producing and found capable of stimulating plant biomass and enhance phytoextraction of metals (Ni and Cr) from FA by metal accumulating plant i.e. B. juncea. Concurrent production of siderophores, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, indole acetic acid (IAA) and phosphate solubilization revealed their plant growth promotion potential.

Occurrence of aflatoxins in mahua (Madhuca indica Gmel.) seeds: synergistic effect of plant extracts on inhibition of Aspergillus flavus growth and aflatoxin production.

Occurrence of aflatoxin in Madhuca indica Gmel. seeds was determined by competitive ELISA. Eighty percent of mahua seed samples were found to be contaminated with aflatoxin. Total aflatoxin content ranged from 115.35 to 400.54ppb whereas the concentration of AFB(1) was in the range of 86.43 to 382.45ppb. Mahua oil was extracted by cold press expeller and analysed for contamination of aflatoxin in both the oil and cake samples. Total aflatoxin and aflatoxin B(1) were 220.66 and 201.57ppb in oil as compared to that in cake samples where it was 87.55 and 74.35ppb, respectively. Various individual and combined plant extracts were evaluated for their efficacy against growth of Aspergillus flavus and aflatoxin production in vitro. Combination of botanicals were found to be more effective in controlling fungal growth and aflatoxin production than individual extracts. Results of the present study suggests that synergistic effect of plant extracts can be used for control of fungal growth and aflatoxin production. These natural plant products may successfully replace synthetic chemicals and provide an alternative method to protect mahua as well as other agricultural commodities of nutritional significance from toxigenic fungi such as A. flavus and aflatoxin production.

Influence of plant growth promoting bacteria and its mutant on heavy metal toxicity in Brassica juncea grown in fly ash amended soil.

In this study a metal tolerant plant growth promoting bacteria, NBRI K28 Enterobacter sp. was isolated from fly ash (FA) contaminated soils. The strain NBRI K28 and its siderophore overproducing mutant NBRI K28 SD1 were found capable of stimulating plant biomass and enhance phytoextraction of metals (Ni, Zn and Cr) from FA by metal accumulating plant i.e. Brassica juncea (Indian mustard). Concurrent production of siderophores, Indole acetic acid (IAA) and phosphate solubilization revealed its plant growth promotion potential. The strain also exhibited 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. In most of the cases mutant of NBRI K28, exerted more pronounced effect on metal accumulation and growth performance of B. juncea plants than wild type.

Growth and productivity assessment of Casuarina glauca Sieb. ex. Spreng on sodic soil sites.

Casuarina glauca is an introduced tree species to India. It is one the few species that can grow successfully in salt effected sites. C. glauca was investigated for biomass production at highly sodic soil sites (pH 8.6-10.5); it was found to be promising in terms of growth and productivity. Average height of plants in an 8-yr-old trial of Casuarina glauca was 1033.3+/-270 cm, however diameter at breast height (dbh) remained at 8.59+/-2.0 cm with a basal area of 6.68+/-1.6 cm2 per plant. High plant survival and establishment (75%) indicate its potential for afforestation of degraded soil sites. Linear regression equations (Y=a+bx) were developed to predict biomass of standing stocks defining relationships between growth parameters (x) as independent variable and productivity (Y) as dependent variable. Both uni-factor equations based on one independent variable (height or diameter alone), and multifactors involving both height and diameter together (d2h) were derived to predict biomass of different plant components. Coefficient of correlation and regression coefficients were found to be highly significant (p<0.001) in all the equations irrespective of independent variable such as plant height, diameter or both (d2h). There were marginal differences in r2 value (0.78-0.8) among equations derived by using d2 or d2h as independent variables. Height alone had relatively poor functional correlation with yield (r2=0.45). Accordingly, uni-factor linear equations with diameter (d2) were used for computing stand biomass with reasonably good accuracy. At the age of 8 years, stand productivity was 68.2 t ha-1 (oven dry biomass) out of which relatively a very high proportion (80.3%) of biomass was allocated to stem wood (54.8 t ha-1). Both branch wood (8.4 t ha-1) and leaves (5 t ha-1) contributed marginally. Casuarina glauca can be recommended as a promising species for biomass production on sodic soil sites as is evident from its performance.

Biochemical contents, their variation and changes in free amino acids during seed germination in Terminalia arjuna.

The leaves, twigs, stem and bark of T. arjuna were analysed for their protein, phenol, tannin, nitrate, oxalate in addition to vitamin C, anthocyanin and chlorophyll in the leaves. The variation of some of these parameters in the leaves with season and leaf position was also studied. The time course changes in amino acids and protein during seed germination in T. arjuna, showed initial decrease in protein followed by increase at subsequent stages. The seeds contain high level of serine (21.7%) and glutamic acid (22.6%) the later decreased as the germination progressed. After 30 days seeds showed higher amounts of serine (26.0%), valine (2.8%), proline (10.6%), methionine (3.4%), histidine (5.6%) and lysine (7.4%) while threonine, glutamic acid, tyrosine and arginine were in lower amounts than that of initial stage at 0 day.