Seed dormancy of northern landscaping plants requiring two winters from seed dispersal to shoot emergence above ground.

通过室内和室外试验，研究了日本北部极具园林绿化潜力的两种植物——惠兰（Convallaria keiskei）和张菊（Maianthemum dilatatum）种子的萌发特性。两种植物的种子均于10月在室外传播，次年6月或7月种子出根，2年后5月萌发新芽。这意味着种子从传播到发芽需要大约20个月，其中包括两个冬天。种子扩散后立即发育的胚胎很小，几乎与种子出根同时发育，起吸收胚乳营养的吸器作用。两种种子的胚根出苗率均因冷分层而增加，但交变温度和光照对其有抑制作用。

We revealed the germination characteristics of seeds of Convallaria keiskei and Maianthemum dilatatum, which are promising species as landscape materials in northern Japan, by laboratory and outdoor experiments. In both species, seeds were dispersed in October outdoors, roots emerged from seeds in next June or July, and shoot emerged in May two years later of seed dispersal. This means seeds require about 20 months including two winter from seed dispersal to shoot emergence. Embryos in seeds immediately after dispersal were small and developed at the almost coincidentally with root emergence from seeds functioning as haustorium absorbing nutrition from endosperm. In both seeds, percentages of radicle emergence increased by cold stratification but alternating temperatures and light inhibit them.