Seed Dormancy in Cereal Weed Adonis flammea Jacq. (Ranunculaceae)

In some European countries, Adonis flammea is very rare and endangered primarily due to increasing fertilizer and herbicide use, more efficient seed cleaning, and strong soil acidification. The aims of this study were to determine the requirements for embryo growth, dormancy break, and seed germination to characterize the type of seed dormancy (via effects of GA۳) and to evaluate the effects of light on germination ability. Germination responses of A. flammea were tested in light and dark conditions at three alternating temperatures (۱۵/۵°C, ۲۰/۱۰°C, ۲۵/۱۵°C) after stratification. Embryo growth was determined by measuring its lengths. Fresh seeds did not germinate during one month of incubation in either light or darkness over a range of temperatures. Seeds of A. flammea had underdeveloped embryos that must grow from about ۰.۲ to ۱.۵ mm in length before radicle emergence (germination); thus they had Morphological Dormancy (MD). In addition to MD, the seeds also had Physiological Dormancy (PD) at maturity in mid-July; moreover, the embryos grew during warm stratification, and the seeds needed a subsequent period of cold stratification to germinate. Thus, MD had been broken, but PD prevented germination. Therefore, the seeds have morpho-physiological dormancy. Germination was promoted by ۱۲ weeks of warm stratification followed by ۱۲ weeks of cold stratification. In conclusion, good conservation management in arable land for A. flammea involves annual cultivation, ideally in mid-summer (warm stratification) without subsequent disturbance until the following summer.

Keywords:

Embryo length , Gibberellic acid , Morpho-physiological seed dormancy