Germination and revegetation of coastal sand dune plants

本研究旨在为山菖蒲和山菖蒲的保护积累有用的资料，并作为海岸沙丘景观材料。对它们的萌发生态学进行了研究。这两个物种的种子都是在北海道石kari海滩收集的，用硫酸处理以释放坚硬的种子休眠。在秋天和第二年夏天，在不同埋深的沙丘上播种。秋播时，在埋深5cm处出苗率最高，达89%，出苗率随埋深的增加而降低，甚至在埋深1cm处出苗率也有所下降。夏播和秋播的出苗率在埋深5cm处最高，但各埋深出苗率下降幅度均小于秋播。秋播时，埋深1cm ~ 15cm处的出苗率为60 ~ 76%，埋深1cm处出苗率最低。夏播期出苗率最高，为11%。干砂层在夏季或埋深1cm处的出苗率下降的原因是由于干砂层的高温和干燥。埋深5cm及以上对两种植物出苗的影响不同。这似乎是两种幼苗穿透力不同的原因。

We aimed to accumulate the useful information of Calystegia soldanella and Lathyrus japonicus for the conservation of them and as the landscape material in coastal sand dune. The germination ecology of them was investigated. Seeds of both species, which collected in the Hokkaido Ishikari beach, were treated with sulfuric acid to release the hard seed dormancy. Seeds were sown in sand dune with various burial depths in the autumn and next summer. In the sowing in autumn, seedling of C.soldanella emerged at the highest 89% from the burial depth 5cm, and the emergence rate was decreased with the burial depth and even at 1cm of depth. In the sowing in summer, highest emergence rate was shown from the burial depth 5cm as well as the sowing in autumn, though emergence rates decreased less than sowing in autumn at the each burial depth. In the sowing in autumn, L.japonicus showed good emergence rate of 60-76% from 1cm to 15cm of burial depth, and it was the lowest at burial depth 1cm. The highest emergence rate in the sowing in summer was 11%. The dry sand layer, which became extreme high temperature and dry, was considered as the cause of decreasing in emergence rates of both species in summer or at the burial depth of 1cm. The influence of the burial depth of 5cm or more on the emergence was different in both species. It seemed that this reason was a difference of the soil penetration power of both seedling.