SEASONAL WATER RELATIONS OF SAVANNA SHRUBS AND GRASSES IN KENYA, EAST-AFRICA Academic Article uri icon

abstract

  • Measurements of leaf conductance to water vapor and leaf water potential were taken at 2 grasslands where highly predictable rainfall patterns cause seasonal droughts. Diurnal and seasonal patterns of these 2 leaf parameters were investigated for 2 grass species and 2 shrub species at each site. During the wet seasons both growth forms showed similar patterns of diurnal water relations behaviour. However, shrub stomatal conductances and water potentials were always higher than the corresponding grass values. During the dry seasons dawn leaf water potentials for the grasses ranged from -1.3 MPa to -4.0 MPa, while wet season values were all near -0.3 MPa. Similar seasonal differences were observed for stomatal conductances and estimated transpiration rates of these grasses. The shrub leaves showed small or no differences between the wet and dry seasons, implying that their access to a suitable water supply was not strongly affected by the seasonal precipitation patterns. Three of the 4 shrub species showed progressive stomatal closure throughout the day, resulting in a curbing of estimated transpiration rates at high air saturation deficits, especially in the dry season. Significant correlations were found between air saturation deficit and leaf water potential (all species), surface soil moisture and leaf water potential (grasses only), and stomatal conductance and leaf water potential (grasses only). -Authors

published proceedings

  • JOURNAL OF ARID ENVIRONMENTS

author list (cited authors)

  • HESLA, B. I., TIESZEN, H. L., & BOUTTON, T. W.

citation count

  • 28

complete list of authors

  • HESLA, BI||TIESZEN, HL||BOUTTON, TW

publication date

  • January 1985