Effect of water stress on germination of some palm species seeds

In this study, germination reactions of seeds under water stress in different origins of Washingtonia filifera, Phoenix theophrasti and Phoenix dactylifera were investigated. For this purpose, first of all, some morphological characteristics (diameter, length, and the thousand grain weight) and moisture percentages of the seeds were determined. Then, germination tests were performed at different water stress levels (Control, -0, 2, -0, 4, -0, 6, -0, 8 MPa) using PEG-6000 solution. Germination tests were completed in an incubator at 25°C in 48 days. Before the tests, the surface sterilization was used on seeds. After the germination tests, the germination percentages (GP) and mean germination times (MGT) of the seeds were calculated. At the end of the study, as the water stress level increased, a decrease in (GP) values and an increase in (MGT) values were observed. It has also been statistically proven that there are significant differences between species in terms of these values. Accordingly, the Nabi sultan and Harissa origins of Phoenix dactylifera species were found to be more drought resistant than Washingtonia filifera species, showing 92,5% and 89.5% GP at -0,4MPa water stress level. The -0, 6 MPa water stress level was found as the breaking point for the species (GP) values, and at the -0, 8 MPa water stress level, very low germination values were obtained in all species. In the study, according to the stress levels, the (MGT) in palm species ranged from 22, 9 to 41, 1 days. In addition, no germination values were obtained in Phoenix theophrasti at all water stress levels. This situation can be explained by the fact that the seed is exposed to a biotic and abiotic factor or is not stored under appropriate conditions. According to the results of this study, the use of the species that were found to be more resistant to drought in planting studies in arid and semi-arid areas may increase the success.