Initial growth of <I>Colubrina glandulosa</I> Perkins var. <I>Reitzii</I> (M.C. Johnston) M.C. Johnston in field and greenhouse under different light intensity

Abstract

In view of the uses of Colubrina glandulosa Perkins var. reitizi (M.C. Johnson) M.C. Johnson, sobraji, in forest regeneration and commercial exploration, this work studied aspects of the development of seedlings in field (Lowland Dense Ombrophilous and Submontane Dense Ombrophilous Forest) and in greenhouse. This was done by direct sowing, in greenhouse, under three different light intensities and using two substrata types. Plants grown under direct sunlight showed lower total biomass, root biomass and stem biomass when compared to plants grown under 20% of full sunlight. In forest soil, plants grown under full sunlight showed lower stem, root and leaf biomass when compared to plants grown under 20% and 50% of sunlight. The RGR (relative growth rate), leaf number, diameter of the root collar and leaf area were also lower under full sunlight. The comparison between plants grown under the same light intensity, but on different substrata, indicates that forest soil was less favorable for biomass accumulation and leaf and stem growth. Plants grown under full sunlight showed a much lower RGR on forest soil. There was no plant emergence after direct seed sowing on Low Land Forest, possibly because of frequent floods. In Submontane Forest, the species show higher development under higher sunlight levels. Plants grown under lower light intensity showed lower height and root collar diameter than plants grown under higher light intensity.