| Titre : | Effect of sodium chloride on the germination of carob (Ceratonia siliqua L.) seeds |
| Auteurs : | Moussaoui Hadil, Auteur ; Ouis Soumia, Auteur ; CHALANE. Fatiha, Directeur de thèse |
| Type de document : | texte imprimé |
| Editeur : | Dr. Moulay Tahar Université Saida, Faculté des Sciences Naturelles et de la Vie, 2025/2026 |
| Format : | 79 p / 29 CM |
| Accompagnement : | CD |
| Langues: | Français |
| Langues originales: | Français |
| Catégories : | |
| Mots-clés: | Ceratonia siliqua ; germination ; seed physiology ; drought-adapted species ; dormancy breaking |
| Résumé : |
This study investigates the effect of salinity stress on the germination of Ceratonia siliqua L seeds, a
Mediterranean species known for its ecological and socio-economic importance and its tolerance to harsh environmental conditions. Soil and water salinity represent a major abiotic stress factor limiting plant growth and agricultural productivity, particularly in arid and semi-arid regions such as Algeria. Understanding the response of Ceratonia siliqua L seeds during the germination stage is essential for improving its propagation and use in reforestation and land restoration programs. Temperature is a key environmental factor influencing seed germination by regulating metabolic and enzymatic activities. In this study, exposure to low temperature (5°C) resulted in complete inhibition of germination, confirming the high sensitivity of Ceratonia silique L seeds to cold stress. The experimental work was conducted under controlled laboratory conditions using Ceratonia siliqua seeds subjected to different treatments, including dormancy-breaking methods (mechanical scarification, thermal and cold treatments), disinfection, and exposure to varying concentrations of sodium chloride (NaCl: 0, 100, and 200 mM), as well as a cold stress condition at 5°C. Germination parameters such as germination percentage, germination rate, radicle length, and germination vigor were evaluated over a 21- day period. The results showed that germination was highest under control conditions (0 mM NaCl) and decreased significantly with increasing salinity levels. Moderate salinity (100 mM NaCl) reduced germination and seedling growth, while high salinity (200 mM NaCl) severely inhibited germination and radicle elongation. Complete inhibition of germination was observed under cold stress (5°C). Among the dormancy-breaking treatments, mechanical scarification was the most effective in enhancing germination by improving water uptake through the hard seed coat. Overall, the findings demonstrate that Ceratonia siliqua seeds are highly sensitive to salinity and low temperature during germination, despite the species’ known drought tolerance at later developmental stages. This study contributes to a better understanding of the physiological responses of Ceratonia siliqua seeds under environmental stress and provides useful insights for seed propagation, reforestation strategies, and the management of saline soils in Mediterranean and arid regions. |
| Note de contenu : |
TABLE OF CONTENTS
Acknowledgements - Dedication ....................................................................................................................................................- Dedication ....................................................................................................................................................- Abstract of the Thesis...................................................................................................................................- Résumé.........................................................................................................................................................- ...........................................................................................................................................................- الملخص TABLE OF CONTENTS.............................................................................................................................- List of Abbreviations....................................................................................................................................- LIST OF FIGURES and PHOTOS and TABLE.........................................................................................- General Introduction ...................................................................................................................................1 Chapter I: Germination and Salinity Stress................................................................................................4 I.1 Definition of Germination .....................................................................................................................5 I.2.Germination Stages................................................................................................................................5 I.2.1 Phase I: Imbibition Phase ...................................................................................................................5 I.2.2 Phase II: Germination Phase (Lag Phase)...........................................................................................6 I.2.3Phase III: Growth Phase ......................................................................................................................6 I.3 Factors Affecting Germination ..............................................................................................................7 I.3.1Internal Factors.................................................................................................................................7 a) Maturity.......................................................................................................................................7 b) Longevity.....................................................................................................................................7 I.3.2 External Factors..................................................................................................................................7 a) Oxygen.............................................................................................................................................8 b) Light.................................................................................................................................................8 c) Temperature .....................................................................................................................................8 d) Water..............................................................................................................................................10 I.4 Salinity Stress: .....................................................................................................................................11 I.4.1 Concept of Salinity Stress.................................................................................................................11 I.4.2 Nutritional Imbalance Under Salinity...............................................................................................11 I.5. Role of Sodium Chloride (NaCl) in Seed Germination......................................................................11 I.5.1 Osmotic Effects of NaCl During Germination .................................................................................12 a) Reduction of Water Uptake (Imbibition Constraint) .....................................................................12 b) Effects on Metabolic Activation (Lag Phase)................................................................................12 c) Inhibition of Embryo Growth and Radicle Emergence .................................................................13 I.5.2 Ionic Toxicity at the Seed Level .......................................................................................................13 a) Accumulation of Na+ and Clin Embryonic Tissues.....................................................................13 b) Membrane Destabilization and Cellular Dysfunction ...................................................................13 I.5.3 Nutritional Imbalance in Germinating Seeds...................................................................................14 a)Ionic Competition and Selectivity ..................................................................................................14 b) Potassium (K+ ) Disruption.............................................................................................................14 c) Calcium (Ca²+) Deficiency and Membrane Integrity ....................................................................14 I .5.4 Integration of Osmotic and Ionic Effects.........................................................................................14 a) Initial Osmotic Phase .....................................................................................................................15 b)Secondary Ionic Phase....................................................................................................................15 I.6. Plant Tolerance Mechanisms to Salinity ............................................................................................15 I.6.1 Regulation of Sodium (Na+) and Chloride (Cl-)..............................................................................15 I.6.2 Maintenance of Nutritional Balance .................................................................................................16 a)Potassium (K+) ...............................................................................................................................16 b)Calcium (Ca²+ )................................................................................................................................16 c) Nitrogen (N), Phosphorus (P), Magnesium (Mg²+ ), and Micronutrients.......................................17 I.6.3 Osmotic Adjustment......................................................................................................................17 I.6.4 Growth Modulation and Biomass Allocation ...................................................................................17 Chapter II: General Overview of the(Ceratonia siliqua L.) ....................................................................18 II.1.General description of the Ceratonia siliqua L ..................................................................................19 II.2.Classification of Ceratonia siliqua L .................................................................................................20 II.3.Botanical description ..........................................................................................................................21 II.3.1 The Tree...........................................................................................................................................21 II.3.2 Root System.....................................................................................................................................22 II.3.3 Stem.................................................................................................................................................23 II.3.4 Leaves..............................................................................................................................................23 II.3.5 Flowers............................................................................................................................................24 II.3.6 Fruits................................................................................................................................................25 II.3.7 Seeds................................................................................................................................................25 II.3.8 Wood ...............................................................................................................................................26 II.3.9 Branches..........................................................................................................................................26 II.4.Chemical Composition of Ceratonia siliqua L ..................................................................................27 II.4.1 Mineral composition........................................................................................................................28 II.5.Uses of the Ceratonia siliqua L..........................................................................................................29 II.5.1.1 The Tree........................................................................................................................................29 II.5.1.2 Fruit ..............................................................................................................................................29 II.5.1.3 Leaves and Flowers......................................................................................................................30 II.5.1.4 Bark and Wood.............................................................................................................................30 II.5.2 Uses and Benefits of the Ceratonia siliqua L..................................................................................31 II.5.2.1. Use in the Food Industry .............................................................................................................31 II.6.Biogeographical Distribution .............................................................................................................32 II.6.1 Global Distribution..........................................................................................................................32 II.6.2. Mediterranean Region ....................................................................................................................33 II.6.3 Algeria .............................................................................................................................................33 II.7.Economic and Ecological Importance of the Ceratonia siliqua L Tree.............................................34 Chapter III: Materials and Methods.........................................................................................................35 III.1. Experimental Site .............................................................................................................................36 III.2. Plant Material...................................................................................................................................36 III.3. Laboratory Equipment and Reagents...............................................................................................37 III.4. Seed Preparation...............................................................................................................................37 III.4.1. Seed Selection and Cleaning.........................................................................................................37 III.4.3. Imbibition......................................................................................................................................39 III.5. Preparation of Saline Solutions........................................................................................................39 III.6. Experimental Design ........................................................................................................................41 III.7. Germination Monitoring and Measured Parameters........................................................................42 III.7.1. Germination Percentage (GP) .......................................................................................................42 III.7.2. Germination Precocity ..................................................................................................................43 III.7.3. Germination Rate ..........................................................................................................................43 III.7.4. Germination Energy......................................................................................................................43 III.7.5. Radicle Length ..............................................................................................................................43 III.8. Statistical Analysis...........................................................................................................................43 Chapter IV: results and Discussion ............................................................................................................44 IV.1. Germination Assays.........................................................................................................................45 IV.1.1. Number of Germinated Seeds.......................................................................................................45 IV.1.2. Germination Percentage................................................................................................................46 IV.2. Radicle Length .................................................................................................................................47 IV.2.1. Radicle Length under Different Treatments.................................................................................47 IV.3. Stepwise Analysis According ..........................................................................................................49 Chapter V...................................................................................................................................................50 Interpretation .............................................................................................................................................50 V.1 Physiological Response to Salinity (NaCl)........................................................................................51 V.2 Thermal Constraints and Cold Stress.................................................................................................51 V.3 Comparative Interpretation with Scientific Literature .......................................................................52 V.3.1 Studies Consistent with the Present Results....................................................................................52 V.3.2 Studies Providing Complementary or Contrasting Perspectives.....................................................52 V.4 Implications and Synthesis.................................................................................................................53 General Conclusion ..................................................................................................................................54 Bibliographic References...........................................................................................................................57 |
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