The effect of sodium hypochlorite, gibberellic acid, and light on seed dormancy and germination of wild buckwheat (Polygonum convolvulus) and cow cockle (Saponaria vaccaria)

Abstract

Seed germination of wild buckwheat (Polygonum convolvulus L.) and cow cockle (Saponaria vaccaria L.) increased with increasing time of immersion in 6% sodium hypochlorite (NaOCl). Maximum germination was obtained at 6 to 8 h for wild buckwheat and at 2 h for cow cockle. The effect of NaOCl treatment of wild buckwheat seeds mimics the effect of acid scarification. Wild buckwheat germination was not influenced by light and (or) gibberellic acid (GA3). To induce 50% germination (t½) of cow cockle NaOCl treatments of 0.5 and 1 h were required for seeds incubating in the dark and light, respectively. Once the seed coat was made more permeable by NaOCl, both the promoting effect of GA3 and the inhibitory effect of light were increased. When the optimum effect of NaOCl occurred, all the seeds germinated. However, prolonged NaOCl treatment resulted in either poor germination or seed disintegration.The hard coat seems to be the main factor in regulating wild buckwheat seed germination. Cow cockle, however, is regulated by at least two other factors, light and hormones, in addition to seed coat.