INFLUENCE OF MYCORRHIZA ON SELECTED TREE SPECIES: Gliricidia sepium, Acacia auriculiformis, Leucaena leucocephala
ABSTRACT
The influence of mycorrhiza fungi inoculation on the growth performance of Gliricidia sepium, Acacia auriculiformis, and Leucaena leucocephala was studied in a nursery experiment. The results obtained indicated the dependence of Gliricidia sepium, Acacia auriculiformis, and Leucaena leucocephala on mycorhizal symbiosis. Inoculation with mycorrhiza significantly improved the growth performance of Gliricidia sepium, Acacia auriculiformis, and Leucaena leucocephala. The height growth increased significantly by 65% after only three months while the nodulation and root ability increased by 70% and 50% respectively. Inoculation with mycorrhiza did not however cause an increase in nitrogen concentration in the plant tissues (stem, root, and leaves).
TABLE OF CONTENTS
ABSTRACT ............................................................................................................................... ii
CERTIFICATION ................................................................................................................... iii
DEDICATION .......................................................................................................................... iv
ACKNOWLEDGEMENTS ....................................................................................................... v
TABLE OF CONTENTS .......................................................................................................... vi
LIST OF TABLES .................................................................................................................... ix
LIST OF PLATES ..................................................................................................................... x
TABLES IN APPENDICES ..................................................................................................... xi
CHAPTER ONE ........................................................................................................................ 1
1.0 INTRODUCTION .......................................................................................................... 1
1.1Background of the study ................................................................................................... 1
1.2 Statement of the problem ................................................................................................. 2
1.3 Objectives of the study ..................................................................................................... 2
1.4 Justification ...................................................................................................................... 3
1.5 Scope of work................................................................................................................... 3
CHAPTER TWO ....................................................................................................................... 4
2.0 LITERATURE REVIEW ............................................................................................... 4
vi
2.1 The test species and their importance ......................................................................... 4
2.1.1 Acacia auriculiformis........................................................................................... 4
2.1.2 Gliricidia sepium ................................................................................................. 5
2.1.3 Leucaena leucocephala ........................................................................................ 6
2.2 Meaning of Mycorrhiza ............................................................................................... 7
2.3 Types of Mycorrhiza ................................................................................................... 8
2.4 Effects of Mycorrhiza on the growth of trees ........................................................... 9
2.5 Mycorrhiza and Tree Physiology .............................................................................. 10
2.5.1 Leaf function ...................................................................................................... 11
2.5.2 Stem Function .................................................................................................... 12
CHAPTER THREE ................................................................................................................. 15
3.0 MATERIALS AND METHODS ....................................................................................... 15
3.1 The Study Site ................................................................................................................ 15
3.2 Procedure for Experimentation ....................................................................................... 15
3.2.1 Materials for experimentation .................................................................................. 15
3.2.2 Seed collection, Pre-treatment, and Sowing ............................................................. 16
3.2.3 Procedure for Mycorrhiza inoculation .................................................................... 16
3.3 Statistical Analysis of Data ............................................................................................. 17
CHAPTER FOUR .................................................................................................................... 22
vii
4.0 RESULTS AND DISCUSSION ................................................................................... 22
4.1 RESULTS.................................................................................................................. 22
4.2 DISCUSSION ........................................................................................................... 28
4.2.1 Effects of Mycorrhiza application on the Growth characteristics of selected tree
legumes 28
4.2.2 Effects of Mycorrhiza application on the nodulation and root ability of selected
tree legumes. ..................................................................................................................... 29
4.2.3 Effects of Mycorrhiza application on the nitrogen concentration in the leaf,
stem and roots of selected tree legumes. .......................................................................... 30
5.0 CONCLUSION ............................................................................................................. 31
REFERENCES ........................................................................................................................ 32
APPENDICES ......................................................................................................................... 38
LIST OF TABLES
Table 1: Growth characteristics of selected tree legumes as influenced by mycorrhiza
application ................................................................................................................................ 22
Table 2: Nodulation and rootability of selected tree legumes as influenced by mycorrhiza
application. ............................................................................................................................... 24
Table 3: Nitrogen concentration in the leaf, stem and root in selected tree legume as
influenced by mycorrhiza application. ..................................................................................... 26
LIST OF PLATES
Plate 1: Experimental layout .................................................................................................... 18
Plate 2: Readings taking........................................................................................................... 19
Plate 3: The plants six weeks after planting............................................................................. 20
Plate 4: Wetting of the test species .......................................................................................... 21
TABLES IN APPENDICES
Appendices Table 1: Analysis of Variance (ANOVA) for plant Height .............................................. 38
Appendices Table 2: Analysis of variation (ANOVA) for Number of Leaves ..................................... 38
Appendices Table 3: Analysis of variation (ANOVA) for Nodulation ................................................ 39
Appendices Table 4: Analysis of variance (ANOVA) for Root Number ............................................. 39
CHAPTER ONE
1.0 INTRODUCTION
1.1Background of the study
Successful establishment of most tropical woody legumes depends on their ability to form
symbiotic associations between their roots and beneficial micro organisms rhizobia and
Mycorrhiza (Stahl Hal., 1988; Barea et al., 1990; ). Different types of mycorrhizal fungi
form associations with plant roots, but arbuscular Mycorrhiza are by far the most widespread
type of Mycorrhiza in nature (Harley and Smith, 1983) and are also the most commonly
occurring on modulated nitrogen fixing plants (Barea et al., 1992; Hayman, 1986; Roskoski
et al., 1986)
Over 2 billion ha of degraded land soils occur worldwide (Grainger 1988,) Approximately
30% of the world's land areas are deserts (Hellden 1992) Inoculation of tree seedlings with
mycrorihiza fungi, both vesicular-arbuscular mycrorihiza (VAM) and ecto-mycorrhiza,
significantly improve survival and juvenile growth (Hayman 1983,). Preliminary assessments
also reveal that inoculation of tropical trees, particularly fast-growing nitrogen-fixing species,
with VAM fungi will improve survival and juvenile growth (Osonubi et al. 1991)The choice
of hedgerow trees for alley cropping has always been site, intercrop and situation specific
(Nair, 1993). Among the long list of multipurpose tree species that had been found useful in
alley cropping, especially in the humid to sub-humid lowland tropics of West Africa three
have been used consistently by both scientists and farmers in on-farm, on-station and
adopting farmer’s plots. They are Leucaena leucocephala (Lam) de Witt, Gliricidia sepium
(Jacq) Lam. Irwin and Barneby. However, this study will focus on three selected agro-
forestry species; Leucaena leucocephala, Gliricidia sepium and Acacia auriculiformis.
Little information is available about the role of VAM in the water relations of fast-growing
nitrogen-fixing tree species (Michelsen & Rosendahl 1990, Osonubi et al. 1991). Drought,
which leads to wilting of leaf tissue, reduces biomass production in Acacia, Leucaena and
Prosopis (Felker et al. 1983, Michelsen & Rosendahl 1990). Assessments in irrigated, fertile
soil suggest that the water relations of Acacia, Leucaena and Prosopis species are altered
following inoculation with selected VAM (Huanget al. 1985, Osonubi et al. 1991). Acacia
seedlings exhibit drought tolerance characteristics such as osmotic adjustment (Michelsen &
Rosendahl 1990), whereas Leucaena species appear to avoid drought (Samson &Pacardo
1983, Huang et al 1985).
1.2 Statement of the problem
Mycorrhiza is considered such a fundamental part of the plant that most species could not
survive in nature without it. Shinkafi, 2000 reported that most soil in semiarid zones are
marginal and deficient in nitrogen and phosphorus which are principal element required in
plant growth and development. Adequate supply of mycorrhiza fungi that has been found to
increase the drought tolerance of host plants (Pandy, 2000; Osunubi and Mulongy, 1991).
This also promotes root health, store carbon in soil and glue soil particles together into a
healthful porous structure. It is not yet understood how Leucaena leucocephala, Gliricidia
sepium and Acacia auriculiformis will respond to mycorrhiza inoculation during the early
growth stages.
1.3 Objectives of the study
The general objective is to determine the effect of Mycorrhiza on three selected tree species.
The specific objectives are to
1. To evaluate the influence of Mycorrhiza application on the rootability (number of
root, root length) and growth of the selected tree legumes.
2. To investigate the effect of mycorrhizae on the nodulation of the selected tree
legumes.
3. To determine nitrogen storage in the leaf, stem and roots of the selected tree legumes
after mycorrhizae application.
1.4 Justification
The use of Mycorrhiza as a biological, ecologically safe alternative to chemical treatments
has been gaining popularity. Studies have indicated plants inoculated to develop a
Mycorrhiza association and are healthier than plants that are not. The use of Mycorrhiza
allows plants to become more efficient in water and nutrient absorption, drought resistant,
healthier, and less stressed The problem that occurs with soil is that as plants use up nutrients,
synthetic fertilizers are used, or new ground is used for growing that is less than desirable,
that soil or grow medium needs to be re-stimulated. Mycorrhiza lives for just this purpose.
The better the plant grows, the better they grow; Mycorrhiza fungi increase the root system
several hundred to several thousand times.
1.5 Scope of work
The study investigated the influence of mycorrhiza inoculation of the early growth, root
development, nodulation and nutrient storage of Gliricidia sepium, Acacia auriculiformis and
Leucena leucocephala seedlings.
.