Study of seed dormancy origins in three atlas pistachio ecotypes (Pistacia atlantica desf.)
Résumé
The Atlas pistachio (Pistacia atlantica Desf.), a rustic tree distributed in different bioclimatic areas, is rapidly declining, particularly in Algeria. Among the actions to be undertaken is the launch of a restocking program. Nevertheless, Atlas pistachio seed dormancy is an obstacle limiting its germination and obtaining seedlings. The aims of the present study are to define the nature of seed germination inhibitors and to propose pretreatments that would limit their effects. Seeds were collected from three locations in Algeria. Quantitative and qualitative traits of phenolic compounds and total antioxidant activity were determined at three levels, namely, seed, epicarp and kernel. Germination was investigated in seeds with epicarp, epicarp removed, and with or without H2O2 treatment. Results showed that whole seed germination is not effective. Scarification by removing epicarp did not improve the germination rate. Chemical analyses indicated that seeds, kernel and epicarp were rich in total phenolic compounds. These compounds are known to limit seed germination in several species. Application of hydrogen peroxide induced a significant increase in seed germination rate in the three ecotypes. H2O2 caused inhibition of polyphenol compounds effects on germination The results indicated that the inhibitory effect of phenolic compounds can be found at the kernel level instead of the epicarp. However, studied genotypes indicated that only one ecotype was distinguished by seed dormancy that originated in the epicarp and kernel.