The Effect of Mechanical Scarification on Seed Germination of Helianthemum lippii (L.) Dum. Cours.

Abstract

Improving germination of Helianthemum lippii is important for conservation efforts regarding the regeneration of the desert flora and for truffle cultivation. As with other members of Cistaceae, the species is characterized by hard-coated seeds that causes long seed dormancy. In this experiment, the effect of mechanical scarification of seeds using sandpaper, shaker or household mixer on seed germination of Helianthemum lippii was investigated. The results showed that manual rubbing of seeds of H. lippii between two pieces of sandpaper grid size 400μm 4, 8, 16, or 32 times enhanced germination rates from 19% for the control to 92-99%. Using a Shaker for 5, 10 or 15 minutes improved the germination rates upto 74- 79%. Significant differences between the control and the treated seeds appeared very early and lasted throughout the experiment. The number of rubbing times or the time of exposure of the seeds to shaker had no significant effect. Using a household mixer for 1, 2, or 4 minutes increased the germination rates to 41, 99 and 90% respectively. However, stretching the time of exposure to 6 minutes gave nil germination. Mechanical scarification using sandpaper, mixer or shaker was found very effective for seed germination in H. lippii, but the first method was especially practical and easy to apply.