Photomorphogenetic effects of lamp type on growth of some species of tropical grain legumes in controlled environment growth cabinets

Abstract

The effects on vegetative growth and flowering of selected cultivars of four species of potentially tropic-adapted grain legumes were investigated in controlled environment growth cabinets using three commercially available fluorescent lamp types, either alone or supplemented with tungsten lamps. Although the practical aspects of producing tropical grain legumes in controlled environments which closely resemble plants grown in the field were the main concern of this investigation, the results clearly show the need to consider the responses not just of different species but of different cultivars. Mean specific leaf area, number of main stem nodes and mean internode length were recorded within 2 days of the onset of flowering in respective cultivars and were used as indices of leaf expansion and plant stature, respectively. Accordingly, photomorphogenetic effects due to the various lamp types were assessed and the most suitable light regime for respective cultivars — of those so far investigated — was determined. It is clearly possible to extend further the range of cultivars and species of tropical grain legumes which can be studied in controlled environments.