Water relations of honey mesquite following severing of lateral roots: influence of location and amount of subsurface water
Ansley RJ, Jacoby PW, Cuomo GJ. 1990. Water relations of honey mesquite following severing of lateral roots: influence of location and amount of subsurface water. Journal of Range Management. 43(5):436-442
Location and amount of subsurface water may influence the degree of dependence of honey mesquite (Prosopis glandulosa Torr.) on shallow lateral roots to supply water. The objective of this study was to determine influence of lateral roots on water relations of honey mesquite on 3 sites which differed in location and amount of subsurface water. Lateral roots were severed with barriers placed to 1.5m depth and completely surrounding individual trees in February 1985, during mesquite winter dormancy. Stomatal conductance and predawn leaf water potential were significantly reduced in root-severed trees during the following growing season (May-September) at both sites, but reduction was greater on the site with less subsurface water. Daytime leaf water potential was higher in root-severed than control trees on the site with less subsurface water, but not on the other site. By midsummer 1986, no difference in stomatal conductance between treatments were detected at either site, yet daytime leaf water potential remained higher in root-severed than control trees at the site with less subsurface water. Predawn leaf water potential was greater in root-severed than control trees in 1986, which was a reversal of 1985 trends. Leaf abscission was not observed in either treatment during either growing seasons. These results suggest that: (1) when less subsurface water was available, trees were more dependent on lateral roots to supply water, (2) treatment effects were minimized by the second growing season following root severing, possibly from new root growth within or below the root barrier region, and (3) the lateral root system may play significant role in regulating leaf water relations on sites with limited subsurface water.
- Type
- Journal Article
- Authors
- Ansley, R; Jacoby, P; Cuomo, G
- Units
- SODN
- Keywords
- leaf water potential, Phreatophyte, Prosopis Glandulosa, Soil Moisture, stomatal conductance, Texas, Transpiration