, Volume 70, Issue 3, pp 475–480

Water use by the desert cucurbit Citrullus colocynthis (L.) Schrad.

  • Ali Mubarak Althawadi
  • John Grace
Original Papers

DOI: 10.1007/BF00379514

Cite this article as:
Althawadi, A.M. & Grace, J. Oecologia (1986) 70: 475. doi:10.1007/BF00379514


The rates of water use and leaf surface conductance of Citrullus colocynthis (Cucurbitacea) were evaluated from measurements of the surface temperature and microenvironment of leaves. At desert sites in Saudi Arabia the transpiration rates reached 0.13–0.17 g m-2 s-1 and the leaf temperatures were always close to air temperature. Leaf models (dry) placed in the canopy were considerably warmer than the air. To investigate responses over a wider range of conditions, plants were grown in a controlled environment room. It was found that when conditions were made hotter than those that occurred in the desert, the stomatal conductance increased greatly. Transpiration rate attained 0.6 g m-2 s-1 and the leaves were up to seven degrees cooler than the air. The results suggest a finely-tuned control mechanism working like a switch when the leaves experience extreme conditions, and enabling the plant to avoid lethal temperatures.

Key words

Leaf temperatureTranspirationEnergy balanceCitrullus

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • Ali Mubarak Althawadi
    • 1
  • John Grace
    • 1
  1. 1.Department of Forestry and Natural ResourcesUniversity of EdinburghEdinburghScotland
  2. 2.Centre for Science and MathematicsDammanSaudi Arabia