Studies On The Anatomy And Physiology Of Desmodium Ramosissimum (G. Don) As A Phytoindicator And Phytoremediator On Crude Oil Polluted Soil

desmodium ramosissimum - crude oil-polluted soil
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Studies On The Anatomy And Physiology Of Desmodium Ramosissimum (G. Don) As A Phytoindicator And Phytoremediator On Crude Oil Polluted Soil

 

BY

NJIMOGU, CHARLES UCHENNA

TITLE PAGE

 

 

TABLE OF CONTENT

TITLE PAGE                                                                                                             ii

CERTIFICATION                                                                                                     iii

DEDICATION                                                                                                           iv

DECLARATION                                                                                                       v

ACKNOWLEDGEMENT                                                                                         vi

TABLE OF CONTENT                                                                                             vii

LIST OF TABLES                                                                                                     xi

LIST OF PLATES                                                                                                      xii

LIST OF FIGURES                                                                                                   xiii

ABSTRACT                                                                                                               xiv

CHAPTER 1                                                                                                               1

INTRODUCTION                                                                                                     1

1.1 Background                                                                                                          1

1.2 Justification                                                                                                           3

1.3 Objectives                                                                                                             4

CHAPTER 2                                                                                                               5

LITERATURE REVIEW                                                                                          5

2.1.      Desmodium species- origin.                                                                           5

2.2. Taxonomy of the species D. ramosissimum.                                                        5

2.3. Morphology                                                                                                         6

2.4. Phytochemical constituents of Desmodium species                                            7

2.5. General uses of genus Desmodium                                                                     8

2.5.1. Use in pharmacy                                                                                               8

2.5.2. Use in Africa                                                                                                     9

2.6. Heavy metal: Meaning                                                                                         9

2.7. Properties and occurrence of some heavy metals                                                10

2.7.1 Cadmium                                                                                                           10

2.7.2. Copper                                                                                                              10

2.7.4 Nickel                                                                                                                 11

2.8 Heavy metal phytotoxicity                                                                                   12

2.9    Heavy metal phyto-availability in soils                                                             13

2.10. Harmful effect of heavy metals                                                                         14

2.11. Phytoremediation                                                                                               15

2.12. Types of phytoremediation methods                                                                 17

2.12.1. Phytoextraction                                                                                               17

2.12.2. Phytofiltration                                                                                                 18

2.12.3. Phytostabilization                                                                                           18

2.12.4. Phytovolatilization                                                                                          19

2.12.5. Phytodegradation                                                                                           19

2.13. Effects of crude oil in plants                                                                              19

2.14. Using Plants for biomonitoring (phytomonitoring)                                           20

2.15. Phytochemical composition of D. ramosissimum samples (Leaf and Root)    21

2.15.1. Alkaloids                                                                                                         21

2.15.2. Flavonoids                                                                                                      21

2.15.3. Tannins                                                                                                            22

2.15.4. Saponins                                                                                                          22

CHAPTER 3                                                                                                               24

MATERIALS AND METHODS                                                                               24

3.1. Study area                                                                                                                        24

3.2. Design of the experiment                                                                                     24

3.3. Collection of samples                                                                                           24

3.4. Soil treatment                                                                                                      25

3.5. Germination                                                                                                         25

3.6. Recording of growth parameters                                                                          25

3.7. Anatomical studies                                                                                              25

3.8. Epidermal peels                                                                                                   26

3.9. Photomicrography                                                                                                26

3.10. Determination of heavy metals in soils and plant samples                                26

3.10.1. Soil samples                                                                                                    26

3.10.2. Plant samples                                                                                                  27

3.11. Soil particle size analysis                                                                                   27

3.12. Soil pH                                                                                                               28

3.13. Qualitative phytochemical analysis of D. ramosissimum plant leaf and root   28

3.13.1. Alkaloid tests                                                                                                  28

3.13.2. Test for flavonoid                                                                                           29

3.13.3. Test for tannins (ferric chloride test)                                                              29

3.13.4. Test for saponins                                                                                             29

CHAPTER 4                                                                                                               30

RESULTS AND DISCUSSION                                                                                30

4.1. Effect of crude oil on the growth of D. ramosissimum                                        30

4.2. Anatomical changes in the D. ramosissimum Species and possible use as

Phytoindicators of oil pollution                                                                      32

4.3 Soil physical and chemical properties and heavy metal bioavailability               38

4.4 Percentage reduction of copper, lead, nickel, and cadmium in soil, 16 weeks

after planting (WAP)                                                                                      41

4.5. Preliminary test results                                                                                        43

4.5.1. Alkaloid (qualitative result)                                                                              43

4.5.2. Flavonoid test result                                                                                          44

4.5.3. Tannins test result                                                                                             44

4.5.4. Saponins test result                                                                                           44

CHAPTER 5                                                                                                               45

CONCLUSION AND RECOMMENDATION                                                         45

REFERENCES                                                                                                          46

APPENDICES                                                                                                           51

 

 

 

LIST OF TABLES

Table 4.1         Physical Properties of Soil

Table 4.2         Heavy metal content of different Concentration of Crude Oil contaminated soil

Table 4.3         Heavy metal content of different Concentration of Crude Oil contaminated soil on Leaves of D. ramosissimum

Table 4.4         Heavy metal content of different Concentration of Crude Oil contaminated soil on Root of D. ramosissimum.

Table 4.5         Correlation among the heavy metals in soils, Roots, and Leaves of D. ramosissimum.

Table 4.6         Result on qualitative alkaloid test of D. ramosissimum Root and Leaf samples.

 

 

 

LIST OF PLATES

Plate 3.1          D. ramosissimum experimental layout

Plate 4.1a        Seeds of D. ramosissimum

Plate 4.1b        Seed of D. ramosissimum      

Plate 4.1c        D. ramosissimum Plant

Plate 4.1d        D. ramosissimum twig with inflorescence

Plate 4.2a         Stem tissue of D. ramosissimum (x400) 0%, showing clear cells and straight

hexagonal anticlinal cell walls

Plate 4.2b         Stem tissue of D.ramosissimum (x400)1%, showing oil droplets and irregular

anticlinal cell walls.

Plate 4.2c         Stem tissue of D. ramosissimum (x400)3% ,showing oil droplets and irregular

anticlinal cell walls.

Plate 4.2d         Stem tissue of D. ramosissimum (x400)4%, showing oil droplets and irregular

anticlinal cell walls

Plate 4.3a         Leaf upper epidermis ofD. ramosissimum (x400) 0%, showing lesser level of

epidermal wall sinuosity.

Plate 4.3b         Leaf upper epidermis of D. ramosissimum(x400) 1%, showing irregular of the

anticlinal cell wall.

Plate 4.3c         Leaf upper epidermis of D. ramosissimum (x400) 2%, showing increasing

irregularity of the anticlinal cell wall.

Plate 4.3d         Leaf upper epidermis of D. ramosissimum (x400) 3%, showing increasing

irregularity of the anticlinal cell wall.

Plate 4.3e         Leaf upper epidermis of D. ramosissimum (x400) 4%,showing increasing

irregularity of the anticlinal cell wall.

 

LIST OF FIGURES

Fig. 4.1            Comparison of Growth (Plant Height) between treatments (0% – 4%)

Fig. 4.2            Comparison of Growth (Stem Girth) between treatments (0% – 4%)

Fig. 4.3            Comparison of Growth (Leaf Area) between treatments (0% – 4%)

Fig. 4.4            Comparison of Growth (Number of Leaves) between treatments

(0% – 4%)

Fig. 4.5            Concentration of Heavy Metals in the Soil

Fig. 4.6            Uptake of Heavy Metals by the Root

Fig. 4.7            Uptake of Heavy Metals by the Leaves

 

ABSTRACT

In order to know the capacity of Desmodium ramosissimum species to grow and replenish in crude oil-polluted soil, an experiment was carried out. Two weeks after planting, a number of leaves, plant height, stem girth and leaf area were evaluated bi-weekly. Heavy metals (Copper, Nickel, Lead, and Cadmium) concentrations of crude oil contaminated soils were determined for 16 weeks after planting. Also, phytochemical constituents of the plant and changes in anatomy in the vegetative parts of the plant were examined. The mean values of the growth parameter obtained were higher in control soil (0%) and then progressively decreased in 1 – 4% crude oil-polluted soil. The crude oil pollution had a significant (P£0.05) effect on leaf area, the number of leaves, plant height, and stem girth, but significant (P£0.01) only on leaf area and plant height. The plant accumulated heavy metals in their vegetative parts. Lead accumulated more in the root and leaves followed by Copper, Nickel, and Cadmium, while the higher amounts of copper (48 mg/100 g) and Nickel (26.2 mg/100 g) were left in the soil 16 weeks after planting. Those plants in polluted soils (1 – 4%) exhibited greater sinuosity in their epidermal cell walls compared to those in controls (0 %). Also seen were oil droplets in the ground tissues of the contaminated plants. The presence of phytochemicals like alkaloids, flavonoids, saponins, and tannins mostly observed on the leaves and the uptake of the heavy metals by the vegetative parts of D. ramosissimum and their changes in anatomy in response to oil pollution were discussed in the light of their possible economic value and use in phytoremediation and phytoindication of crude oil polluted soils.

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