Resumo

PINEDA-PINEDA, J. et al. Chrysanthemum response to foliar methanol application and nitrogen source in nutrient solution. Terra Latinoam [online]. 2010, vol.28, n.2, pp.129-137. ISSN 2395-8030.

This work was conducted to evaluate the effect of nitrogen sources (NO₃^-, NH₄⁺, NH₂-CO-NH₂) in combination with three levels (0, 5, and 10% v/v) of foliar methanol application as a source of C on the growth of chrysanthemum (Dendranthema x grandiflorum) cv. Indianapolis under conditions of high temperature (30-35 °C), radiation > 550 watt m^-2 and low relative humidity (< 60%). The variables measured were plant height, stem and flower diameter; leaf, stem and flower fresh weight; leaf, stem and flower dry weight; flower shelf-life and leaf nutrient concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn). Of the tested variables, only P concentrations in leaves showed interaction between N sources and foliar methanol application. P in leaves did not respond to methanol when nutrient solution contained urea, but NH₄⁺ and NO₃^- or both in combination with 5% methanol reduced P concentration (10-15%) and with 10% methanol increased it (20-25%). The combination 50% NO₃^- + 50% NH₄⁺ (ammonium nitrate) increased the concentration of P (35%), K (5%), Ca (24%), Zn (86%), Cu (36%), and Mn (332%) in leaves, while foliar methanol application (5 or 10% v/v) increased N (54%), P (13%) and K (6%), but reduced Ca (54%), Mg (7%), and Cu (27%) concentration. In plant growth, negative effects were observed only with foliar solution of 5% methanol which affected leaf, stem and total fresh weight (leaf + stem + flower) and leaf dry weight.

Palavras-chave : nutrition; hydroponics; nitrate; ammonium; urea; alcohol.

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