XVI International Botanical Congess
Bromeliads were raised in vitro either with (NH4)2SO4, or urea as the sole nitrogen (N) source, this containing 0, 1, 5, 10, 20 and 50 mM of N. Both N forms stimulated the growth of Ananas comosus up to 20 mM N. However, NH4+ inhibited the growth of Vriesea gigantae in concentrations above 10 mM N. V. gigantae accumulated significantly more free amino acid (AA) in N concentrations above 10 mM N, and A. comosus only in 50 mM N. Bromeliads grown in NH4+ accumulate significantly more AA, mainly in the form of Asn (up to 80% of the AA). With 10 mM N, V. gigantae accumulated more Asn, Arg, Glu, Ile, Leu, Orn and Ser when the nitrogen source was urea and Pro, Trp, and Val when the source of N was NH4+. This did not happen with A. comosus. *Supported by FAPESP.