Main environmental factors affecting flowering of Anthurium andreanum Lind. Soillesss cultivation in tropical conditions

Correspondance: fax +33 4 9961 3034 ; email: dufourl@supagro.inra.frInternational audienceAnthurium is the main cultivated tropical cut flower all over the world. The yield elaboration in tropical environment and soilless cultivation is poorly known. The use of empirical cultivation systems can restrict production optimization and increase inputs costs and environmental risks. The plant morphogenesis and mineral and light requirements are essential elements of yield elaboration in sheltered cultivation under tropical conditions. Growth and development of tissue cultured plants have been followed with different nitrogen and calcium fertilization levels or under different shade levels. Plants, solutions and substrate mineral analyses, and photosynthesis measurements in our studies allow us to assess plant growth potential. Finally, recycling of the drainage solution was tested in order to seriously reduce pollution. Anthurium plantlets first have a monopodial growth without flower production; fertilization affects only this phase duration. Thereafter growth is sympodial. The plant produces successive articles, each including one leaf and one inflorescence. The leaves and flower size, the biomass, and plant composition depend on fertilization. The best results regarding flowers number and size were obtained for higher ammonium, total nitrogen and potassium concentrations, but not for high levels of calcium. Anthurium is a shade plant and its photosynthetic activity is enhanced by a lowered PAR level (3.6 mol photons × m-2 × day-1). At 10.5 mol photons × m-2 × day-1 PAR level, flower production increases but there is an obvious decrease in their size. In our tropical conditions, growing management requires a high shade level (85%), with the fertilization balance: 1-0.1-1.4-0.9-0.3 (N-P-K-Ca-Mg) during flower productio