PERTANIKA JOURNAL OF SOCIAL SCIENCES AND HUMANITIES

 

e-ISSN 2231-8534
ISSN 0128-7702

Home / Regular Issue / JSSH Vol. 15 (2) Aug. 1992 / PERT-0721-1992

 

Growth, Plant Water Relation and Photosynthesis Rate of Young Theobroma cacao as Influenced by Water Stress

Mohd Razi L, Abd Halim H, Kamariah D. And Mohd Noh, J Mohd. Razi Ismail and Muhamad AwaNG

Pertanika Journal of Social Science and Humanities, Volume 15, Issue 2, August 1992

Keywords: Theobroma cacao; water availability; growth; leaf water potential; diffusive resistance; photosynthesis rate.

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The effects of duration of water stress on the growth and physiological changes of young Theobroma cacao plants were investigated. Water xoas withheld, for 4y 8, and 12 days before rewatering for a period of 20 weeks. Leaf area, leaf area index, leaf root and stem dry weights zvere significantly reduced with duration of withholding water. There was a close relationship betiueen photosynthesis rate and changes in leaf water potential. Leaf photosynthesis rate was reduced when leaf xoater potential dropped below -2.0 MPa. Determinations of plant processes showed a clear variation between three local clonal plants i.e. KKM 4, KKM 5 and KKM 25 with KKM25 recording the highest leaf water potential, stomatal conductance and leaf photosynthesis rate.