Effects of Pre-Germination Treatments, Salt and Water Stresses on Germination of Acacia Ehrenbergiana Hayne and Acacia Seyal Del. (Mimosoideae): Two Algerian Native Species

Abstract

Ben Zetta et al.: Effects of pre-germination treatments, salt and water stresses on germination of two Acacia species - Abstract. Acacia ehrenbergiana Hayne and Acacia seyal Del. are two desert trees of the Algerian Sahara that for a long time were confused. These two species present high potentials for desert areas rehabilitation therefore for successful seed germination and establishment three pre-germination treatments (manual scarification, boiling water and concentrated sulphuric acid) were used to overcome seeds dormancy. Once the optimal conditions are determined, we examined the effects of two abiotic stresses (salinity and water deficiency) on their seeds germination using eight levels of salinity (0,50, 100, 150, 200, 250, 300 and 350mM of NaCl) and six concentrations of PEG 6000 (0, -2, -4, -6, -8 and -10 bars) on Acacia ehrenbergiana Hayne and Acacia seyal Del. Germination rate and mean germination time were calculated and data were subjected to analysis of variance (ANOVA) followed by Newman-Keuls test. Our results show that manual scarification and sulphuric acid had significant effects on the seeds germination of Acacia ehrenbergiana Hayne meanwhile, only sulphuric acid enhanced Acacia seyal Del. seeds germination. Under salt and water stresses, the germination rate and mean germination time of Acacia ehrenbergiana Hayne were less affected than those of Acacia seyal Del. Therefore manual scarification and sulphuric acid treatments could be applied and adopted at laboratory level or even at nurseries to raise plants germination and plantations establishment for desert areas rehabilitation. Thus, Acacia ehrenbergiana Hayne seems to be more suitable for massive propagation as it demonstrates resilience when facing harsh abiotic stresses (salt and water stresses).

Effet des traitements sur la germination de <i>Acacia tortilis</i> subsp. <i>raddiana</i> (Savi) Brenan au Niger, sahel

“…Il n'y a pas une différence significative entre les taux de germination des graines extraites dans les fèces des animaux et ceux des graines témoins (sans traitement). Les résultats obtenus avec le traitement avec l'acide sulfurique sont similaires à ceux observés par Benbada (2013), Moulay (2012), Jaouadi et al (2010). Ces résultats ne corroborent pas ceux des travaux de Kheloufi et al (2017) qui ont montré que les trempages des graines de A. nilotica dans de l'acide sulfurique pendant 60 et 120 minutes donnent des taux de germination inférieurs à 50%.…”

“…Elles ont 2 à 6 paires de pétioles secondaires. Chaque pétiole porte 5 à 12 paires de folioles (Jaouadi et al, 2010). Les fleurs sont blanches et jaunes pâles, odorantes, groupées en glomérules sphériques.…”

“…En effet, les contraintes majeures au renouvellement de ces populations en condition naturelle résident principalement dans la germination de leurs graines. La structure anatomique du tégumentaire de la graine de A. tortilis est typique des légumineuses qui se traduit par une forte inhibition tégumentaire de la germination (Jaouadi et al, 2010). Elle est composée de l'extérieur vers l'intérieur de la graine d'une cuticule cireuse fine, d'une couche de cellules palissadiques, des cellules des Malpigi disposées radialement et dont l'épaisseur est comprise entre 80 et 90 µm, d'une couche de cellules en forme de sablier, des ostéosclérides, nettement séparées les unes des autres et d'un tissu parenchymateux interne composé de cellules à parois cellulosiques d'une épaisseur comprise entre 130 et 180 µm.…”

Water Use Efficiency of Acacia seyal (Del.) in extreme arid environment prevails in South-Western Desert, Egypt

“…Seed collection from Desert Garden, Aswan University Campus, Aswan, Egypt in May 2015, seed dormancy of impermeable seed coat of Acacia seyal was breaked through a pregermination treatment by immersing seeds in concentrated sulphuric acid (95%) for 10 minutes to weaken seed coat (Danthu et al, 1992;Ndour, 1997;Zetta et al, 2017) then washed with tap water. Seeds were sown directly into plastic pots of 30 cm in diameter and 20 cm deep with four 1.5 mm-holes at the bottom.…”

Ecophysiological Responses of Acacia raddiana savi and Acacia nilotica (L.) During Seedling Establishment in Extreme Arid Conditions

“…Seed collection from Desert Garden, Aswan University Campus, Aswan, Egypt in 2015. Seed dormancy of impermeable seed coat of A. raddiana and A. nilotica was breaked through a pre-germination treatment by immersing seeds in concentrated sulphuric acid (95%) for 10min to weaken seed coat (Danthu et al, 1992;Ndour, 1997;Zetta et al, 2017) then washed with tap water. Seeds were sown directly into plastic pots of 30cm in diameter and 20cm deep with four 1.5mm-holes at the bottom.…”