Effects of environmental factors on seed germination of Anthyllis barba-jovis L.

The influence of the main environmental factors on seed germination of Anthyllis barba-jovis L. were analysed. This work is part of a broader investigation aimed at the reintroduction of this species on Mount Conero, Ancona (central Italy), where it is at present extinct. The seeds were collected from the Gargano headland (southern Adriatic coast). Experimental analyses were carried out to determine: (i) dormancy levels of seeds collected in successive years, and also collected from the soil seed bank; (ii) effects of usual pre-treatments for overriding the physical dormancy of the seeds; (iii) optimal temperature range for maximum germination; (iv) effects of fire on seed germination; and (v) effects of NaCl on germination and on early stages of seedling development. Our results confirm that A. barba-jovis seeds have a physical dormancy due to their teguments, which are water-impermeable. This barrier persists in naked seeds that remain in the soil. Regularly waterdrenched seeds show a high germinative ability. The optimal seed germination temperature is 208C, with germination decreasing progressively at lower temperatures, and falling drastically over 208C. Fire and high temperatures positively affected germination. The seeds were shown to be strongly resistant to salt stress, thus enabling the plants to colonize a habitat suitable for halophytes.