The growth of Luffa aegyptiaca in response to various nitrogen sources and concentrations

Abstract

The growth responses of Luffa aegyptiaca to various nitrogen sources and concentrations were investigated. In sand culture at high concentrations of nitrogen, the species showed equally favourable responses to nitrate nitrogen (KNO3 or Ca(NO3)2), ammonium nitrogen ((NH4)2SO4), and the combination of nitrate and ammonium nitrogen (NH4NO3). There was poor growth in response to NaNO3, CO(NH2)2, and a solution lacking nitrogen. In lateritic soil, the species responded better to ammonium nitrogen and the combination of nitrate and ammonium nitrogen than to nitrate nitrogen. Growth was generally poorer in lateritic soil than in sand. Neither the nitrogen sources nor their concentrations had any significant effect on root weight or the leaf weight ratio. There was a significant decrease in growth as nitrogen concentration decreased in KNO3 and Ca(NO3)2 treatments but it was only at the low concentrations of (NH4)2SO4 and NH4NO3 that growth was significantly reduced. The shoot: root mass ratio decreased as nitrogen concentration decreased. The nature of the growth media and the ecological habit of the species are used to partly explain its responses to different nitrogen sources and concentrations. The possible application of these results to increasing the production of L. aegyptiaca is also discussed.