Seed Dormancy in C ereal Weed Adonis flammea Jacq. (Ranunculaceae)

Abstract

In some European countries, Adonis flammea is very rare and endangered primarily due to increasing fertilizer and herbicide use, more efficient seed cleaning, and s trong 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 GA 3 ) and to evaluate the effects of light on germination a bility. Germination responses of A. flammea were tested in light and dark conditions at three alternating temperatures ( 15/ 5°C, 20/10°C, 25/15°C) after stratification. Embryo growth was determined by measuring its lengths. Fresh seeds did not germinate dur ing 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 0.2 to 1.5 mm in length before radicle emergence (germination); thus they had Morphological Dorma ncy (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 brok en, but PD prevented germination. Therefore, the seeds have morpho - physiological dormancy. Germination was promoted by 12 weeks of warm stratification followed by 12 weeks of cold stratification. In conclusion, good conservation management in arable land f or A. flammea involves annual cultivation, ideally in mid - summer (warm stratification) without subsequent disturbance until the following summer. Keywords: E mbryo length, Gibberellic acid, Morpho - physiological seed dormancy.