Xylem water potentials of native shrubs from northeastern Mexico
2011
González-Rodríguez, H. | Cantú-Silva, I. | Ramírez-Lozano, R.G. | Gómez-Meza, M.V. | Sarquis-Ramírez, J. | Coria-Gil, N. | Cervantes-Montoya, J.R. | Maiti, R.K.
Xylem water potentials (Ψ) were evaluated in browse plants such as Forestiera angustifolia (Oleaceae), Celtis pallida (Ulmaceae), Zanthoxylum fagara (Rutaceae), and Eysenhardtiatexana (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.
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