THE EFFECTS OF PROPAGATION ENVIRONMENT AND FOLIAR AREA ON THE ROOTINGPHYSIOLOGY OF CORDIA-ALLIODORA (RUIZ-AND-PAVON) OKEN-CUTTINGS

The effects of propagation microclimate and foliar area on the rooting of Cordia alliodora (Ruiz & Pavon) Oken cuttings were investigated us ing non-mist propagators with and without shade. Photosynthetic rates (P-n), stomatal conductance (g(s)) and chlorophyll fluorescence ratio (Fv/Fm) of the cuttings were assessed during propagation. Pronounced d ifferences in microclimate were recorded between treatments, with lowe r temperatures and vapour pressure deficit (VPD) under shade. During t he first 8 days after insertion, P-n varied between 2.21 and 4.96 and 0.47-2.54 mu mol CO2 m(-2)s(-1) in the shaded and unshaded propagators , respectively. In the unshaded propagator, Fv/Fm decreased to a minim um of 0.72 2 days after insertion, recovering thereafter. In two separ ate rooting experiments, rooting percentage was reduced by high irradi ance in the 20 and 30 cm(2) leaf area treatments, but not in the 10 cm (2) treatment. Pn decreased with an increase in leaf area in both shad ed and unshaded propagators. Fv/Fm also declined with increasing leaf area in the high irradiance treatment. PAR and P-n were positively cor related under shade (r(2) = 0.51) but negatively correlated in the uns haded treatment (r(2) = 0.49); maximum P-n values were recorded at a P AR of 400 mu mol m(-2) s(-1). No significant differences in g(s) were found between treatments, values ranging between 130 and 194 mmol H2O m(-2) s(-1). Positive correlations were found between rooting percenta ge and mean Fv/Fm. These results indicate that rooting of C. alliodora cuttings is related to photosynthetic activity during propagation, wh ich is itself influenced both by propagator microclimate and cutting l eaf area.