种子收获后立即在适当条件下发芽之所以失败,牵涉到种子休眠或其“休眠期”。早熟水稻品种往往不表现种子休眠,而中熟和晚熟品种在收获后需要3—13周的休眠。一个具有较长生育期的品种(播种到开花),它的休眠期也较长。在不同作物中种子休眠的原因各不相同。有人认为,造成种子休眠的原因有六种可能,即种皮不透水性,种皮的机械阻力,种皮不透氧性,不发育胚的存在,胚的休眠和发芽抑制因子的存在。又据帕里加等人的论述,造成水稻种子休眠的唯一原因在于它被颖壳所包藏。他们发现剥去休眠种子外壳可以中断休眠,并使其发芽正常。 Seeds germinated immediately after harvest under appropriate conditions failed, involving seed dormancy or its “dormant period.” Early maturing rice varieties often do not show seed dormancy, while medium and late ripening varieties require 3 to 13 weeks of post-harvest dormancy. A species with a longer growth period (sown to bloom) has a longer dormant period. There are different reasons for seed dormancy in different crops. Some people think that there are six possible causes for seed dormancy, namely, impermeability of seed coat, mechanical resistance of seed coat, impermeability of seed coat, existence of undeveloped embryos, dormancy of embryos and inhibition of germination. According to Pariga and others, the only reason for the dormancy of rice seeds is that they are trapped in glumes. They found that stripping the shell of dormant seeds can interrupt dormancy and allow germination to normal.