Proporções de amônio e nitrato no crescimento de plantas de Lippia alba (Mill) N. E. Br. cultivadas sob ambientes de luz

Abstract

The objective of this work was to evaluate the growth of Lippia alba under different proportions of ammonium (NH4+) and nitrate (NO3-) and light environments. The plants were subjected to five ratios of NH4+:NO3 – in nutritive solutions, and four light environments. The cuttings of L. alba were transplanted to plastic pots containing 6 dm3 of a substrate containing a mixture of washed sand + vermiculite in a 2:1 ratio. At 120 days after application of the treatments, the following parameters were evaluated: the index of chlorophyll ‘a’, ‘b’, total, ratio a/b, dry weight of leaves, stem, roots, plant, aerial part, volume of roots, leaf area, ratio of leaf area, leaf area and specific mass ratio of leaf. The meshes have significantly influenced the indices of chlorophyll. There was significant interaction between proportions of ammonium and nitrate with the environments of light for the volume of roots. The plants grown in nutritive solution with 100% of N-NO3 - as well as under the mesh aluminet had values of leaf area higher than the others.