Effect of the NO3-/NH4+ ratio in nutrient solution on Pelargonium stock plants: yield and quality of cuttings
1990
Ganmore-Neumann, R. | Hagiladi, A.
The objective of this study was to evaluate the effect of the NO3-/NH4+ ratio in the nutrient solution, combined with seasonal ambient temperature and irradiation level provided to Pelargonium zonale cvs. 'Empress' and 'Rubin' stock plants, on production and their cuttings' qualities. Plants were grown for 7 months on tuff:peat medium with three NO3-/NH4+ ratios, in a greenhouse with high natural irradiance conditions or at reduced irradiance level (30% shading simulated the marginal production season). Cutting production was negatively affected by the low irradiance level and low ambient temperature. The NO3-/NH4+ ratio did not affect cutting yields in natural and reduced irradiance except for a very high NH4+ proportion (70%) in the solution. Rooting ability and quality were affected reciprocally by the irradiance level, compared with yield. The NO3-/NH4+ ratio applied in the two irradiance regimes affected the rooting significantly; a low ratio was preferable at low irradiance level and low temperature. Carbohydrate content could serve to predict the propagation capability of the cuttings.
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