Bean trefoil (Anagyris foetida L.), the only species within the Anagyris genus (L.) of the Fabaceae family in Algeria, demonstrates considerable promise for reforestation actions in arid and semi-arid areas throughout the Mediterranean basin. Nevertheless, a prominent obstacle impeding the successful establishment of the species is the hardness of its seeds, resulting in reduced germination rates and inconsistent seedling emergence. The objective of this research is to improve seed germination and seedling development in A. foetida. A total of 750 pods were randomly collected from a population including 13 individuals. From this sample, 100 intact pods and 100 seeds were chosen for measurement and weight assessment. Three different scarification techniques were utilized as pretreatments: chemical scarification, involving varying durations of immersion in 98% concentrated sulphuric acid; thermal scarification, involving 24 hours of exposure to a water bath set at 35°C; and mechanical scarification, achieved through the use of abrasive paper. Each treatment comprised four replicates of 50 seeds, while untreated seeds were utilized as controls. Germination and initial seedling development were assessed after 30 days of cultivation. Statistical analysis revealed significant differences (p<0.001) among pretreatments concerning germination and seedling emergence. The highest germination percentages were observed following 120 minutes and 150 minutes of sulphuric acid soaking, with 86% and 91.5% of germination, respectively. The chemical pretreatments demonstrated correlations with shoot and root growth, as well as collar diameter. In contrast, the control group exhibited notably low germination (5.5%), while mechanical scarification resulted in a 55% germination rate. Seedling survival rates ranged from 93.7% to 99.4%. The seeds of A. foetida predominantly exhibit physical dormancy attributed to their hard and impermeable seed coat. These findings could be valuable for the generative reproduction of the species, especially for producing plants for afforestation/reforestation programs.

The woody fodder species Myrtus communis (L.) is commonly found in the forested areas of northeastern Algeria, thus helping to alleviate the goat husbandry shortage during the summer. This study aims to conserve the species and counteract its declining populations due to various biotic and abiotic factors. A specific objective of this study is to assess the correlation between seed size and germination vigor in M. communis, as well as emergence of seedlings. A sample of 15 M. communis individuals was selected, and 500 fruits were randomly collected in the vegetation of Jijel National Park (Jijel, northeast Algeria). One month after post-ripening, when fruit moisture content reached 25.2%, seeds were manually extracted from the fruits and categorized into three sizes (large, medium, and small). Then, 100 leaves, 100 intact fruits, and 100 seeds from each size category were measured and weighed. Various morphological characteristics were recorded, including leaf and fruit length and width, pulp weight, seed number, pulp-to-seed ratio, seed size, and moisture content. Seed germination and initial seedling growth were monitored weekly.  Seeds of M. communis ranged in weight from 0.03 to 0.18 grams. In comparison with medium (1.5%) and small (0%) seeds, large seeds showed significantly higher germination rates (93%) after three weeks of sowing. Moreover, seedlings originating from large seeds grew vigorously, reaching a length of 10.9 cm. According to our findings, seed size in M. communis can affect seed germination and high-quality seedling establishment.

The carob tree (Ceratonia siliqua L.) is an important component of the Mediterranean vegetation and its cultivation is important environmentally and economically.  It is also an interesting leguminous species for afforestation-reforestation. In this study, carob seeds collected in a representative area of the Mediterranean basin at the national park of Gouraya (Béjaïa, Algeria), were subjected to germination tests under Mediterranean seawater (SW) irrigation of different concentrations (0, 10, 30, 50 and 100% SW) for 15-day period. Before germination tests, a 20 min pre-treatment with 96% sulphuric acid was necessary to overcome seed coat dormancy which does not permit germination. Results showed that the seeds of C. siliqua were able to germinate at different seawater concentration, except for 50% SW and 100% SW which resulted in total inhibition of germination. The maximum number of C. siliqua seed germination of 100% FGP (final germination percentage) appeared at 0% SW and 10% SW. Only 35.5% of the seeds have germinated in 30% SW. Ungerminated seeds of C. siliqua from different SW treatments showed medium germination recovery (FGPRecov) of 39.9% at 50% SW and low recovery of 18.2% at 100% SW when transferred to distilled water after 15 day-period. Seedlings length and seedling fresh and dry weight were significantly (P < 0.001) decreased with increasing SW concentrations. Seedling water content remained constant in 10% SW in comparison with the control, while it decreased very slightly in 30% SW. These findings may serve as useful information for C. siliqua habitat establishment and afforestation-reforestation programs in coastal sites and for exploiting seawater in the area.

The tree of heaven Ailanthus altissima (Mill.) Swingle is a multipurpose tree in forestry. However, it is considered an invasive and dangerous plant for native species, and in particular for national parks, where many studies have recorded their involvement in the disturbance of the already developed floral diversity. Assessing the impact of certain abiotic conditions on this species may identify the expected areas to be colonized by its seed propagation. Germination of tree of heaven were tested for germination at constant temperatures of 25, 30, 40°C, and at room temperature varying from 25-30°C coupled with total darkness. Seeds were sown in Petri dishes (0.8% agar water) for 6 days of incubation. The kinetic of germination was determined according to five closely related parameters viz. final germination percentage (FGP), mean germination time (MGT), coefficient of velocity of germination (CVG), time to 50% germination (T50) and seedling length (SL). For the saline condition, the seeds underwent various NaCl concentrations from 0, 50, 100 or 200 mM. For each treatment, there were four replicates with 50 seeds incubated in a plastic container between two layers of moist sand at 15% of the appropriate treatment and then placed in a culture chamber at 27°C (± 2°C) for 30-day period. The effect of temperature was not significant on the MGT, CVG and T50. However, it was significant (p< 0.0001) on FGP and SL. The maximum germination of 94% was obtained at a temperature of 30°C and the lowest FGP of 40% was obtained at 25°C. For the salinity effect, the FGP of 75% in the control was much higher compared to the seeds treated at 50 mM NaCl with only 17.2% of FGP.  Germination was completely inhibited from 100 mM NaCl. A. altissima can be classified as sensitive to salt stress during seed germination and seedling emergence. The salinity effect then joined the temperature to monitor nature's A. altissima seed propagation.

Seeds of many tree-species possess a hard seed coat which is impervious to water. These seeds often take a long time to germinate, resulting in heterogeneity and a delay in seedlings development which is an inconvenience for reforestation success. The aim of the present work was to determine the possibilities to improve the germination of five leguminous trees of the genus Acacia that have been recorded in the arid and the desert region of Algeria using sulphuric acid. A duration of 30 min of immersion in sulphuric acid improved the seed germination up to 97.5% and 99% for A. albida and A. laeta, respectively. Increasing the time of immersion (from 30 to 90 min) improved the germination percentages for A. ehrenbergiana and A. seyal seeds to 92.5% and 93.7%, respectively. Increasing this duration to 120 min had a positive effect on A. tortilis seed germination, improving the final germination rate up to 97%. Understanding of seed Germination Requirements is very important for regeneration and successful tree establishment in forest nurseries as well as for direct plantation in arid and semi-arid lands.

Drought and salinity act simultaneously in tolerance and acclimatization under saline conditions. Therefore, plants subjected to these types of stress should have developed specific structural adaptations at the early stages of development. The solution to these environmental problems is to look for species that are relatively water-efficient and resistant to recurrent episodes of various abiotic stresses such as salt stress. In this study, the salinity tolerance index, ionic homeostasis and osmoprotection were evaluated in A. karroo and A. saligna plants of 90 days old and cultured at various concentrations of NaCl for 21 days. Results showed that salt caused remarkable changes in some growth-related parameters (dry biomass) represented by the salinity tolerance index (STI). Na+, Ca2+, and RatioNa+/K+ content in the leaves increased with salinity levels, while K+ contents were significantly reduced compared to the control in both acacia species. Levels of proline, total free amino acids and reducing sugars have been accumulated considerably in the leaves. A. karroo was more salt-tolerant than A. saligna. Our results showed that the adaptability of a species to salinity is closely related to ion selectivity and biomass production. The seedlings also accumulated significantly a set of important osmolytes in leaves under salt stress, showing a marked increase in secondary metabolite accumulation. This adaptation proved very specific to each species for better survival in saline environments.  

The present work demonstrates the effects of moist cold stratification on seed dormancy breaking in Hawthorn (Crataegus monogyna Jacq.). We also examined the fruit and seed morphology. Mature and ripe fruits were collected, the pulp removed and the seeds (stones) left in the sun to dry for three days. Four temperature regimes viz. 4°C, 6.5°C (natural conditions where the fruits were harvested), 10°C and 20°C were used for stimulating seed germination under total darkness. For each treatment, there were four replicates with 50 seeds incubated in a plastic container between two layers of moist sand at 15%. At the end of the experiment, non-germinating seeds were tested for viability using Tetrazolium chloride (TZ).  After 4 months, the final germination (FGP) was expressed as a percentage of the total number of seeds in each treatment. The fruits of Hawthorn were 14.9 ± 0.73 mm long and 15.1 ± 0.84 mm in diameter and weigh 2.05 ± 0.28 g. The seeds were 8.29 ± 0.43 mm long and 6.75 ± 0.39 mm in diameter and weigh (0.25 ± 0.04) g. The thousand-fruit weight was 2,000 g and of the thousand-seeds weight was 280 g. The statistical analysis indicated significant effect (p < 0.0001) of treatment on seed germination. Dormancy in this species was broken most effectively by cold stratification at 4°C and under natural conditions with 76% and 67.5% of FGP, respectively. Most of the nongerminated seeds of C. monogyna were viable (dormant) as judged by TZ.

The experiments were led to study the effect of pretreatments and their duration on germination behavior of three Acacia species A. cyanophylla Lindl., A. farnesiana L. and A. decurrens Willd. by analyzing three parameters (GP: germination percentage; MGT: germination mean time (days) and GRI: germination rate index) for various times of incubation (5, 10 and 15 days) in Petri dishes. Pre-sowing treatment included immersion in concentrated sulphuric acid for 60, 90 and 120 minutes. The sowing in distilled water (Control) had no positive effect on the germination induction. Generally, the seed pretreatments were very useful to improve germination. Time of immersion significantly (P < 0.0001) affected GP, MGT and GRI in all species. Increasing the duration of sulphuric acid immersion (from 60 to 120 min) improved the germination percentages for A. cyanophylla and A. farnesiana seeds to (98% and 99%), respectively. However, increasing this duration had a negative effect on A. decurrens seed germination, reducing the final germination percentage from 97% at 60 minutes of immersion to 43% at 120 minutes.