Salil Tewari

Biomass production and carbon sequestration in different tree-based systems of Central Himalayan Tarai region

Biomass, carbon storage and carbon dioxide mitigation potential of plantations of Populus deltoides, Eucalyptus tereticornis, Dalbergia sissoo, Mangifera indica, Litchi chinensis and Prunus salicina were assessed. Being economically viable, such tree plantations are grown by farmers on a large scale in north India. The maximum total biomass (94.8 Mg ha− 1) was observed in a 10-year-old D. sissoo monoculture plantation, followed by an 8-year-old P. deltoides block plantation (63.0 Mg ha− 1). Carbon stocks ranged from 4.51 Mg ha− 1 in an 8-year-old P. deltoides boundary plantation to 43.39 Mg ha− 1 in D. sissoo plantation. The carbon sequestration rate for P. deltoides block and boundary plantations was estimated to be 2.75 and 0.43 Mg C ha− 1 year− 1, respectively. Eucalyptus boundary plantation sequestered 0.84 Mg C ha− 1 year− 1 while D. sissoo plantation sequestered 2.73 Mg C ha− 1 year− 1. Among fruit trees, the highest sequestration rate was recorded in M. indica (mango) plantation, with 1.43 Mg C ha− 1 year− 1.

Seasonal effect on rooting behaviour of important bamboo species by culm cuttings

We investigated the influence of season on the rooting behaviour of eight important bamboo species viz., Bambusa balcooa, B. bambos, B. nutans, B. tulda, B. vulgaris, Dendrocalamus giganteus, D. hamiltonii and D. strictus. We collected 2–3 node culm cuttings in three growing seasons viz. spring (March), summer (June) and rainy (August) from superior candidate plus clumps (CPCs) centralized in the germplasm garden. Cuttings were placed horizontally in sand and were provided with intermittent misting at regular intervals. Bamboo species exhibited differential rhizogenesis behavior in different seasons. The study reveals significant variation in sprouting and rooting behaviour in different bamboo species. B. bambos had maximum rooting (78.89%), followed by B. vulgaris (74.44%). In general, the potential of different bamboo species for rooting was found to be in the order: B. bambos > B. vulgaris > B. balcooa > D. hamiltonii > B. tulda > D. strictus > D. giganteus >B. nutans. The maximum rooting was recorded in spring (56.67%), which was closely followed by summer (54.58%). In winter season, minimum rooting (36.67%) was observed. The interaction effect of species × season was also significant on sprouting and rooting parameters. In B. balcooa, B. nutans, B. vulgaris, D. hamiltonii and D. strictus, cuttings collected in summer season showed maximum sprouting and rooting, whereas, B. bambos, B. tulda and D. giganteus had maximum rooting in spring. The maximum number of roots developed per cutting was observed in B. tulda (43.8) during spring season.

Lignolytic mushroom Lenzites elegans WDP2: Laccase production, characterization, and bioremediation of synthetic dyes

A mycoremedial study was undertaken for decolourization of synthetic dyes using wood rot fungal culture Lenzites elegans WDP2. The culture was isolated from decaying wood as fruiting body, and identified on the basis of 5.8S ITS rRNA gene sequence analysis. Qualitative plate screening of culture showed extracellular laccase and lignin peroxidase production, while only laccase enzyme was produced in higher amount (156.793 Uml-1) in minimal salt broth medium containing glucose and veratryl alcohol. Laccase activity was increased up to 189.25 Uml-1 after optimization of laccase production by optimization of one variable at a time approach. Molecular characterization of laccase enzyme was done using SDS PAGE and Native PAGE based isozyme analyses. The culture was able to decolorize three synthetic dying compounds (congo red, Malachite green and brilliant green) in broth media, while showed very less decolourization in plate assay. The fungal culture varied in their dye decolourizing potential in broth culture, showing 92.77%, 21.27% and 98.8% maximum decolourization of brilliant green, malachite green and congo red respectively. The congo red dye was completely bio-absorbed by fungal culture within one month. The fungal decolourized broth also revealed the extracellular laccase activity; varied from 10 Uml-1 to 68.5 Uml-1 in all the three cases, supports the involvement of laccase enzyme in decolorization. Phase contrast microscopy clearly revealed bio-sorption of the dyes by fungal culture into the mycelium/spores in the photomicrographs.

Phytostimulating Mechanisms and Bioactive Molecules of Trichoderma Species: Current Status and Future Prospects

Ever-increasing pressure on the agricultural land due to various biotic and abiotic stresses made agriculture a nonprofitable venture. In order to bring back the lost glory to agriculture, there is an urgent need to reclaim this eroded agriculture with sustainable practices, one among them is the use of plant growth-promoting microorganisms such as rhizosphere-competent Trichoderma sp. In this chapter, the major mechanisms and bioactive molecules involved in plant growth promotory activity of Trichoderma sp. are described in detail. Trichoderma sp. is also known to produce growth-regulating phytohormones and other bioactive molecules which are known to protect them against antimicrobial compounds secreted by plant, but they also help the plants in overcoming various stresses. Various hydrolytic enzymes such as chitinases, glucanases, and proteinases are produced by Trichoderma which aid in its mycoparasitic response. The fungus is also able to enhance plant growth through nutrient solubilization and its uptake. It mobilizes phosphates from fixed organic/inorganic phosphorus sources through both enzymatic (phosphatases, phytases) and nonenzymatic mechanisms (production of organic acids and siderophores). Trichoderma produces a wide array of secondary metabolites and volatile compounds which are mainly responsible for its biocontrol action. Suppression of fungal plant pathogens through mycoparasitism involves signal transduction and G protein signaling in Trichoderma. Secondary metabolites and volatile compounds produced by this fungus are very diverse in their occurrence and mode of action against phytopathogens. Recent developments in molecular biology, metabolomics, and proteomics have opened an insight for the use of secondary metabolites as biopesticides rather than the application of whole organisms.

Quantitative Estimation of Genetic Variability in Morphological Characteristics of Eastern Cottonwood (Populus deltoides Bartr.) Clones

The study was carried out to analyze the genetic variability for different growth parameters in poplar clones at the age of 2 and 3 yr in the nursery. Forty-nine exotic and indigenous clones of poplar were evaluated for eight morphological traits. Clones were planted in randomized block design (RBD) with three replications with four clones in a block in each treatment. Observations for different characters were recorded on six selected competitive clones per genotype. Results showed a high interclonal variability for most parameters. Statistically significant differences among clones indicated that the majority of study characters are controlled by genetic factors, specific to each clone. Highly significant genotypic difference supported by wide range of variation of mean and range values were observed for the characters under study. Significant and positive correlation was observed between diameter at breast height (DBH) and plant height. Leaf lamina length showed positive and significant correlation with petiole length, total leaf length, leaf width, and L/B ratio. Total leaf length showed positive and significant correlation with leaf width and L/B ratio. High estimates of heritability (in a broad sense) were observed for almost all characters in the study. High genetic advance expressed as percent of mean was recorded for petiole length (60.90), followed by plant height (60.78) and collar diameter (44.19) at 2 yr. At the age of 3 yr, genetic advance was found maximum for petiole length (60.05), followed by collar diameter (47.62) and plant height (45.29). The efforts for selecting new clones and their field-testing must continue under a long-term improvement plan so that the best clones can be recommended for plantations and hybridization programs.