|Author:||DaMatta, F. M. ; Chaves, A. R. M. ; Pinheiro, H. A. ; Ducatti, C. ; Loureiro, M. E.|
|Book Group Author:||NA|
We compared tolerance to soil drought of two field (Sooretama, Espirito Santo, Brazil)-grown clones of C. canephora cv. Conillon (clone 46, drought-sensitive; and clone 120, drought-tolerant). Under irrigation, there were no significant differences between the clones in water relation parameters, gas exchange and total leaf area. Under rainfed conditions, clone 46 showed osmotic adjustment and increased tissue rigidity. These adjustments, however, were incapable of preventing substantial decreases in xylem pressure potential. By contrast, clone 120 did not exhibit osmotic adjustment, but was able to increase tissue elasticity and to maintain xylem pressure potentials to a greater extent than clone 46 (despite having twice the total leaf area of this clone). Stomatal conductance was lowered by drought in clone 120 but not in clone 46. Carbon assimilation per unit leaf area in both clones remained unaffected under stress. Long-term water use efficiency (WUE), as estimated through carbon isotope discrimination, was consistently greater in clone 120 than in clone 46. Because of these traits, clone 120 was better able to postpone dehydration and also to maintain whole-tree photosynthesis. It is proposed that these features should decisively contribute to buffer its productivity in drought-prone areas.
|Pages:||111 - 117|
clones, coffee, drought, drought resistance, gas exchange,irrigation, leaf area, leaf conductance, osmotic pressure,photosynthesis, plant water relations, stomata, traits, water useefficiency, xylem water potential, Brazil, Espirito Santo, Coffea,Coffea canephora, Coffea, Rubiaceae, Rubiales, Gentianales,dicotyledons, angiosperms, Spermatophyta, plants, eukaryotes, SouthAmerica, America, Developing Countries, Threshold Countries, LatinAmerica, Brazil, carbon assimilation, carbon dioxide fixation, droughttolerance, watering, Horticultural Crops (FF003) (New March 2000), PlantPhysiology and Biochemistry (FF060), Plant Water Relations (FF062),Environmental Tolerance of Plants (FF900), Soil Water Management(Irrigation and Drainage) (JJ800) (Revised June 2002) [formerly SoilWater Management]