Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Field studies of leaf gas exchanges (Elaeis guineensis Jacq.). | 439s Ann. Sci. For. 1989 46 suppl. 439s-442s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Field studies of leaf gas exchanges in oil palm tree Elaeis guineensis Jacq. E. Dufrene and B. Saugier Laboratoire d Ecologie Végétale Université Paris-Sud 91405 Orsay Cedex France Introduction This study is part of a larger research program on climatic and biological factors affecting oil palm yield. Our purpose was to characterize under conditions of good water supply variations in leaf photosynthesis with internal and external factors. Several authors have been working on the co2 assimilation rate A in oil palm. Most of them have used young plants under laboratory conditions to study effects of photosynthetically active radiation Corley et al. 1973 Hirsch 1975 foliar temperature Hong and Corley 1976 or leaf water potential and stomatai conductance Adjahossou 1983 . Only 2 experiments were conducted in the field Bolle-Jones 1968 determined the amount of soluble sugars in 9 yr old leaflets and Corley 1983 observed the effects of leaf senescence on photosynthesis using the 14CO2 method. In this study we evaluated variations in leaf photosynthesis in 8 trees of the same progeny and the effect of vapor pressure deficit VPD es Ta - ea and leaf temperature Tf on stornatal conductance and leaf gas exchanges. Materials and Methods The study site was located at the 2 3 experimental station of La Mé JỊeạr Abidjan Ivory Coast 5 26 N Lat. 3 50 W Long. . The studied trees belong to one single line L2T D10D used as a reference in many trials of the production area and characterized by a moderate vegetative development associated with good bunch production. The net co2 assimilation rate A was measured using a leaf chamber PLC and a portable co2 analyzer LỌA2 . connected in an open system. Leaf temperature transpiration rate boundary layer and stomatai conductances were calculated using the energy balance equation Parkinson 1985 combined with .
