Seed germination of wild caper (Capparis spinosa L., var. parviflora) as affected by dormancy breaking treatments and salinity levels

Caper (Capparis spinosa L.) is an adaptable plant to rangelands which is also planted for use as a condiment, for forage and for prevention of soil erosion. Seeds of this species have poor germination in natural conditions. We subjected the seeds to different dormancy breaking treatments (sulfuric acid for 20, 30 and 40 min., soaking in warm water, scarification (injury the seed coat), unscarified seeds (control), gibberellic acid (GA) at five concentrations (0, 100, 200, 300 and 400 mg/l), and to various salinity levels. The highest seed germination (60%) and time to germination (18.2 days for 50% seed germination) were obtained under sulfuric acid application for 30 min. followed by 200 to 400 mg l⁻¹ of GA soaking. It is more likely that hard seed coat was not the only barrier to germination and the dormancy was partly due to physiological limitation as well. Increased salinity decreased seed germination percentage, and plumule and radicle lengths and seedling dry weight and increased 50% seed germination time. Radicle growth of caper seedling was less sensitive to salinity than plumule growth. It is recommended to germinate the caper seeds in pots under specified treatment and transfer the seedlings into the wild.