ABSTRACT
The morphology, phenology and seed germination of the multipurpose African oil bean tree, Pentaclethra macrophylla Benth. belonging to the family Fabaceae were studied. The study area covered the entire Nsukka zone of Enugu State, Nigeria, and the ten towns randomly selected included: Adani, Amalla Egazi, Ede Oballa, Eha Alumona, Eha Amufu, Ibagwa,
Imilike, Nsukka, Ogrute and Orba. Morphological aspects of the study included: the bole type, branching pattern, leaf types, leaf arrangement and crown shape; height of the trees and girth of the bole at breast height; size of the leaves, raches and leaflets; thickness of the bark, length of some of the buttress roots and diameter of the roots 20 cm away from the stem; type of inflorescence and flower, and morphology of pollen. The morphology of the seedling of P. macrophylla was studied and photographed from the onset of seed germination up to 40 days after germination. The phenological aspects of the species studied were period of flowering, fruiting, leaf fall (defoliation) and replacement (refoliation), fruit maturity and ripening. The phenological observations were made every month for three years (2009, 2010 and 2011). There were two flowering periods of the species within a season (May to June and October to February). Fruiting took place between December and the following August. Defoliation of P. macrophylla trees occurred mainly between the months of April and September, with very negligible percentage in the rest of the months. Refoliation was observed from the month of October to March. Fruit maturation and seed dispersal in the locations sampled started in April and ended in November in the three years of sampling. Seed germination was carried out to determine the effects of different types of media on seed germination and seedling growth of P. macrophylla. The media used were Garden soil (which served as control), saw dust (SD), 1:1 mixture of Saw dust and Garden soil (SD+GS),
1:1:1 mixture of Saw dust, Garden soil and Poultry droppings (SD+GS+PD), 1:1 mixture of Garden soil and Poultry droppings (GS+PD), 1:1 mixture of Saw dust and Poultry droppings (SD+PD). The highest percentage germination response was obtained using SD+GS+PD and GS+PD respectively which differed significantly (P<0.05) from SD+PD, SD and SD+GS. The results of the effects of mechanical scarification on the germination of oil bean seeds showed that there was remarkable improvement in the germination rate of the seeds scarified mechanically with sand paper and on rough cement floor at both the micropylar and stylar ends. The seeds scarified at the stylar end on rough cement floor began germinating 11 days after sowing while the control started germinating on the 16th day after sowing with a peak on the 19th day. The association between tree phenology, temperature and rainfall reinforces the evidence for potential effects of changes in climate on P. macrophylla and probably other species of the Tropical Rainforest.
Chapter one
1.0 Introduction
1.1 Background to the study
The earth’s vegetation is very rich in diverse phytobiota that sustains man and his livestock. Man’s dependence on plants dates back to man’s origin. Of all the vegetations, tropical rainforests have been reported to contain the greatest number of various types of plant species (Nzekwe et al.,1993; Singh, 2004; Gurevitch et al., 2002). Singh (2004) reported that tropical rainforests occupy about 8% of the earth’s surface. Of all the tropical rainforests, those in the developing countries have been reported to be the reservoir of plant bioresources, and contain about 60-90% of the total number of plants on earth (Isichei, 2005). Man depends on plants for his diverse food requirements either directly or indirectly. Okafor (1983) reported that man obtains food from plants in the form of grains, stem and root tubers, seeds, nuts, fruits and leafy vegetables among others.
Numerous authors have reported that plants constitute the major sources of man’s industrial raw material (Okafor, 1981; Okafor, 1983; Isichei, 2005; Okojie,1993). Apart from food and industrial raw materials, several reports have revealed that man obtains herbal drugs, dyes, spices and other numerous resources from plants for his well being as well as other socio- economic reasons ( Okafor, 1981; Sofowora,1982; Mendelson and Black, 1995; Okafor and Ham, 1999; Anon, 2005). Despite the indispensable roles plants play in man’s socio- economy, reports have shown that the forests that habour the plants are being rapidly depleted (Nzekwe et al.,1993). Depletion of the forests, particularly, tropical rainforests has been globally associated with various factors of which increase in population and advancement in technology are prominent.
Several ecologists have given insight on the rate of depletion of the world’s tropical rainforest and its endangered status. Nzekwe et al.(1993) reported that about twenty million hectares of land are lost annually in the world as a result of anthropogenic activities. Anyiam (1995) reported that in the 1950’s, about 40% of the earth’s surface was occupied by the tropical rainforests, and by 1975, the forested area was reduced to about 15%. Wilson (1992) pointed out that progressive depletion of the tropical rainforests has reduced it to 10%. Many environmentalists have shown that Africa alone has lost about 65% of her original rainforests, while Central America and Asia have lost about 66% of theirs (Wilson, 1992; Nzekwe et al.,1993; Mendelson and Black, 1995). Wilson (1992) pointed out that if the rate of the depletion of the rainforests continues, it could result in their disappearance in about 25-30 years time.
Similar alarm was also raised by Sayer and Whitemore (1991) about the depletion of the tropical rainforests. The authors pointed out that if the depletion of the tropical rainforests is not put on check, most plant species as well as animals would be driven into extinction in about 30 years time. The authors further pointed out that the disappearance of the tropical rainforest would be a great global setback in the availability of biodiversity. According to them, Nigeria is among the twelve nations whose deforestation rate accounts for about 80% of the global total. With the recent climate change and its effects on the vegetation and the ongoing deforestation, it is likely that more hectares of the tropical rainforest would disappear.
1.2 Deforestation of Nigeria’s tropical rainforests
Okafor and Ham (1999), Okali (2004) and Isichei (2005) observed that depletion/deforestation of Nigeria’s tropical rainforest mainly located in the southern states of the country was caused by human activities. The authors reported that lumbering is one of the factors responsible for the depletion of the tropical rainforests in Nigeria. They posited that most people cut down trees for timber indiscriminately without replanting and without regard to the age of the trees. According to the authors (Okafor and Ham, 1999; Okali, 2004; and Isichei, 2005),when the trees are felled, other non-timber species are destroyed in the process of logging especially during felling of the trees and clearing of the area for the sawing of the logs into sizes.
Nzekwe (2002) reported that slash and burn agricultural practices; indiscriminate establishment of industries, tertiary institutions, filling stations, state and local government area headquarters hospitals, railway, airports and other business centres exert pressure on the tropical rainforest of Nigeria. Okafor (1983) reported that forest fires strongly attack tropical rainforests as such fires spread to other places not targeted for burning. The author noted that forest fire kills off plants, especially shrubs that stand well above the ground. He also noted that forest burning exposes the soil to erosion which is acknowledged nationwide to be common in the tropical rainforest zones of Nigeria. Forest fire has been identified to destroy seed bank, delay regeneration and reproduction in plants, as well as kill off non fire resistant plant species (Okojie, 1995; Okali 2004). Keay (1989) and Nzekwe (2002) reported that constant fire outbreak in the tropical rainforest which always occurs in the dry season, results in retrogressive succession, hence converting tropical rainforests to savanna woodland or
derived savanna forest as exemplified by most vegetations of Enugu and Anambra States of
Nigeria.
1.3 Statement of the Problem
There is no doubt that forest is vital to man’s socio-economic survival. Emphasizing the contribution of the forests and their resources to man’s economy, Wilson (1992) described the forest as a vital source of new wealth and knowledge. Several other authors (Okafor,1983; Achinewhu et al., 1995) reported that the forest provides man with timber, food, shelter and different types of industrial raw materials. Most of the current orthodox drugs used in treating different types of ailments are directly or indirectly derived from plants (Anon 2005; Kannaiyan, 2005; Sofowora, 2008). Okorie et al. (2006) reported that more than one third of the modern drugs are derived from plant species of the Tropical Rainforest.
Okafor and Ham (1999) in a summary of the importance of tropical rainforests to man reported that “by losing plants, we are losing our natural economic packages”. Conservation management and biotechnological exploitation of the resources of phytobiota in developed countries have led to revolutionalised agricultural, industrial and enterpreneural activities that consequently caused a decrease in unemployment, increase in wealth and convergence of intellectual giants (Singh, 2004). Presently, biotechnologically processed products of these industrial countries now flood the developing countries in different forms of herbal drugs, tea, soap, toothpaste etc. making the latter dumping grounds.
Following the current events in the developing countries; increased population; mass unemployment; retrenchment/disengagement of healthy, able bodied personnel; hunger, poverty, diverse crime waves, climate change- influenced vegetation etc., it becomes necessary that national income resources be diversified. In Nigeria, dependence on petroleum
products as the main source of income generation should not be relied upon since such reliance could create more problem than it could solve. Non-oil and non-timber resources should be given priority attention. Nigeria, being the largest country in sub-Saharan Africa, has humid tropical rainforest zones that are richly endowed with a lot of different plant species of economic value. Though detailed account of the economic plants in Nigerian tropical rainforest zone is inadequate, it is necessary that those of ethnobotanical economic values be conserved for fuller biotechnological exploitation especially the indigenous species whose economic importance was not appreciated early (Okafor,1983). One of the indigenous plant species of Nigeria’s Rainforest zone that requires urgent attention for conservation is the multipotential African oil bean tree, Pentaclethra macrophylla Benth.(“Ukpaka”-
‘1bo’),which has been chosen as the main species for the present study. The species cannot be conserved without the full knowledge of its ecological requirements for establishment and survival. The plant is highly felled for fuel wood because of its hardwood yet the seeds are major sources of protein and other food nutrients. Unfortunately, conscious efforts are not made to replant it as it should probably because of its long gestation period. It is therefore necessary to understudy the plant and contribute to the conservation of the otherwise currently endangered species for future biotechnological exploitation.
Although African oil bean seed is a popular indigenous plant in many countries in the tropics, it is referred to as underutilized species because of its small total economic value in commercial production and trade compared with other crops and agricultural commodities (Akindahunsi, 2004; Enujiugha and Akanbi,2005). It is listed among other crops as an underutilized plant (IPGRI, 2002; Jaenicke and Hoschle-Zeledon, 2006).
Underutilised crops are those that were once grown more widely or intensively but are falling into disuse for a variety of agronomic, genetic, economic and cultural reasons.
Farmers and consumers are using these crops less because they are in some way not competitive with other species in the same agricultural environment. The decline of these crops may erode the genetic base and prevent distinctive and valuable traits being used in crop adaptation and improvement (IPGRI, 2002).
1. 4 Aim and Objectives of the Study
The aim of the study was to investigate the morphology, phenology and seed germination of
P. macrophylla.
The specific objectives of this work were:
(i) to ascertain the morphology of the seedling and the mature tree, (ii) to determine the phenology of the plant, (iii) to evaluate the effects of different media on its seed germination.
This material content is developed to serve as a GUIDE for students to conduct academic research
STUDIES ON THE MORPHOLOGY PHENOLOGY AND SEED GERMINATION OF PENTACLETHRA MACROPHYLLA BENTH
A1Project Hub Support Team Are Always (24/7) Online To Help You With Your Project
Chat Us on WhatsApp » 09063590000
DO YOU NEED CLARIFICATION? CALL OUR HELP DESK:
09063590000 (Country Code: +234)
YOU CAN REACH OUR SUPPORT TEAM VIA MAIL: [email protected]
09063590000 (Country Code: +234)
