INFLUENCE OF DIFFERENT LIGHT INTENSITIES ON THE GERMINATION AND EARLY GROWTH OF TRECULIA AFRICANA

INFLUENCE OF DIFFERENT LIGHT INTENSITIES ON THE GERMINATION AND EARLY GROWTH OF Treculia africana

ABSTRACT

This study was carried out to investigate the effect of different lights intensities on the germination and early growth of Treculia africana under different light intensities (100%, 60%, and 40% light intensities) as well as under forest canopy (control I), open nursery condition (control II). The experiment was carried out at the tree nursery site of the Department of Forestry and Wood Technology, Federal University of Technology, Akure and lasted for eighteen weeks. Treculia africana fruits were collected from Forestry Research Institute of Nigeria, Jericho hills, Ibadan. Both germination and early growth characteristics (total height, collar diameter, number of leaves and biomass production) of the seedlings were monitored. Higher value of plant height was recorded under 40% and 60% light intensities while seedlings grown under higher light intensities (open nursery condition and 100% light intensity) showed higher values in both collar diameter and number of leaves. The results also indicated that T. africana seedlings Planted under high light environment (open nursery condition and 100% light intensity) had more biomass accumulated than those recorded under low light environment (40% and 60% light intensities). Faster growth in stem height may be achieved by subjecting T. africana seedlings to low light environment, but will result to spindle and fragile stem, due to their low collar diameter. Collar diameter, number of leaves and biomass accumulation will be higher for T. africana seedlings under higher light intensities (open nursery condition and 100% light intensity), with shorter but more stable and less fragile stem. As a result of this, it has come to light that better T. africana would be produced under high light environment. Domestication and cultivation of T. africana will be enhanced using information from this study.

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Light incident on plant requires the characterization of its intensity, duration, quality, and direction. Light is a source of energy and a source of information for green plants. It is a source of energy for photosynthesis, and a source of information for photoperiodism (night/day length), photomorphogensis (light quantity and quality) and phototropism (light direction). Plants are sensitive to light quality and quantity which play a vital role in their physiological development (Aphalo and Ballaré, 1995). Plants play a vital role in the management of various diseases and have been heavily utilized in the sustainable development of drugs that provide a major focus in global healthcare delivery (Graham et al., 2000).

Kigelia africana (Lam.) Benth belongs to the family Bignoniaceae. It is a multipurpose tree species with many medicinal attributes and potentials. Its common names include sausage tree (Eng); worsboom (Afr); (Coates-Palgrave, 1988) pandoro (West Nigeria) (Aiyelola and Bello, 2006). It is a tree that grows up to 20m tall or more (Roodt, 1992). The tree is evergreen where rainfall occurs throughout the year, but deciduous where there is a long dry season. The leaves are opposite or in whorls of three, 30 – 50 cm long, pinnate, with six to ten oval leaflets up to 20 cm long and 6 cm broad; the terminal leaflet can be either present or absent. The flowers (and later the fruit) hang down from branches on long flexible stems (2-6 m long).

Flowers are bisexual and produced in panicles; they are bell shaped (similar to those of the African tulip tree but darker and waxier), orange to reddish or purplish green and about 10 cm wide. Individual flowers do not hang down but are oriented horizontally (Joffe, 2003) and some birds are attracted to these flowers. Their scent is most notable at night indicating their reliance on pollination by bats, which visit them for pollen and nectar (Hoyo et al., 1997). K. africana is abundant in the tropics and is widely used traditionally in Southern Nigeria as an herb remedy for various ailments such as anticancer, antiulcer, anti-aging, antioxidant, and anti-malarial. It is also widely applied in the treatment of genital infections, gynecological disorders, renal ailments, fainting, epilepsy, sickle-cell anemia, eczema, central nervous system depression, respiratory ailment,