Ratikanta Maiti

Xylem water potentials of native shrubs from northeastern Mexico

Abstract Xylem water potentials (Ψ) were evaluated in browse plants such as Forestiera angustifolia (Oleaceae), Celtis pallida (Ulmaceae), Zanthoxylum fagara (Rutaceae), and Eysenhardtia texana (Fabaceae). Collections were carried out at Linares County, a semi-arid region of northeastern Mexico. Ψ (MPa) were estimated at 10-day intervals between July 10 and September 30, 2008 by using a Scholander pressure bomb, and were monitored in five different plants per species at 06:00 h (predawn) and 14:00 h (midday). Air temperature, relative humidity, precipitation, and soil water content were registered throughout. Data were subjected to one-way ANOVA and linear correlation analysis. At the wettest period, Ψ at predawn varied from − 0.29 (C. pallida and E. texana) to − 0.37 (F. angustifolia and Z. fagara); in contrast, at the driest period, predawn Ψ ranged from − 3.28 (F. angustifolia) to − 4.50 (Z. fagara). At midday E. texana achieved the highest (−1.14) and lowest (−4.20) values at wettest and driest sampling dates, respectively. It seems that air temperature and vapor pressure deficit negatively influenced Ψ values in all species; conversely, Ψ values augmented as relative humidity increased. Since F. angustifolia and C. pallida maintained higher predawn and midday Ψ values under water stress, these species may be considered as drought-adapted species while, Z. fagara and E. texana that acquired lower values, may be less adapted to drought and in physiological disadvantage under limited water conditions.

Phenology of woody species: a review

An attempt has been made to synthesize a brief account on research advances on various phases of phenology. Climate has positive impact on the timing of phenology; cold-air drainage may influence the start of leaf growth, however leaf phenology in tropical evergreen forests is not determined by the seasonality of precipitation. Climate warming in late winter and spring may enhance sensitivity of the growing season’s spatial response due to the relationship of beginning date to temperature. Elevated temperature strongly influences greater in C3 plants than in C4 plants but the disadvantages of warming may be considerably attenuated by elevated CO2, especially for C3 grasses. Species with high wood densities can able to store only limited quantities of water in their trunks; leaf fall in these species occurred during the dry season. Flowering phenology may be changing faster and precipitation may play a more important role in semi-arid grasslands than in humid-temperate systems. Peak flowering and fruiting are dependent on seasons for both endemic and non-endemic species. Population sensitivity to global warming might be stable for a given species, in spite of its possible local adaptation. It might be possible for ecologists to establish comprehensive networks for long-term monitoring of potential photosynthetic capacity from regional to global scales by linking satellite-based programme. Use of satellite-derived metrics,such as VARI, may be used for evaluating the spatial patterns and temporal dynamics of species composition across broad geographic regions.

Autoecology and ecophysiology of woody shrubs and trees: Concepts and applications

Forest trees and shrubs play vital ecological roles, reducing the carbon load from the atmosphere by using carbon dioxide in photosynthesis and by the storage of carbon in biomass and wood as a source of energy. Autoecology deals with all aspects of woody plants; the dynamism of populations, physiological traits of trees, light requirements, life history patterns, and physiological and morphological characters. Ecophysiology is defined by various plant growth parameters such as leaf traits, xylem water potential, plant height, basal diameter, and crown architecture which are, in turn, influenced by physiological traits and environmental conditions in the forest ecosystem. In short, this book details research advances in various aspects of woody plants to help forest scientists and foresters manage and protect forest trees and plan their future research.

Variability in leaf Traits of 14 Native Woody Species in Semiarid Regions of Northeastern Mexico

The present study was undertaken with the goal of analyzing the morphology and variability of leaf length, width, petiole length, and total leaf length, fresh and dry weight of individual leaves of 14 species native to Northern Mexico. The native species Cordia boissieri, Condalia hookeri, Sargentia greggii, Diospyros texana, Zanthoxylum fagara, Sideroxylon celastrinum, Karwinskia humboldtiana, Celtispallida, Guaiacum angustifolium, Prosopis laevigata, Celtis laevigata, Parkinsoniatexana, Forestiera angustifolia and Havardia pallens where chosen due to their ecological and economic importance to the rural villages as well as large variability in morphological characteristics between them. Descriptive statistical analyses showed that there was large variability in these leaf traits between the different species. Principal component analysis (PCA) revealed that it was possible to produce two axes that can explain more than 83% of the observed variation and could therefore be used in the future for separating tree species in ecological guilds and to study. Species and vegetation community level response to perturbations or individual performance in the field or under experimental conditions between the different species of this study. This suggests that similar advances are possible for other species for the same traits both in the region of study but also elsewhere.

Low Cost Technology Developed and Used for Screening and Selecting Few Field and Vegetable Crops for Tolerance to Few Abiotic Stresses

Stress is a global threat in achieving potential crop yield. Abiotic stresses like drought, salinity, heat stress and other abiotic stresses associated several associated with ever increasing human populations affect crop productivity drastically under sustainable agriculture in the farmers fields. Though significant research activities have been taken place to address these problems with respect to the mechanism of resistance and crop improvement but little progress has been achieved. Here, several low cost technologies have been developed for screening crop cultivars for few abiotic stresses viz. screening for tolerance to salinity, drought, heat stress, flooding and cold stress. Seedling Emergence percentage, tap root length and number of lateral roots was considered important parameters for selection of salinity tolerant hybrids in cotton. Salinity tolerant genotypes showed high emergence percentage under saline concentration compared to remaining genotypes. These hybrids produced more number of profuse lateral roots and long tap roots in saline concentration compared to control for osmotic adjustment and increase in tap root length. 90% of seeding survival may be selected for heat tolerant at seedling stage. These hybrids may be recommended for growing under heat and drought stress prone areas for better adaptation. Hybrids with thick leaves, stout petiole, good survival under drought & recovery from stress are considered for selecting drought resistant hybrids in castor