Excavation and Radiocarbon Dating of Ancient Viable Seeds and Permafrost Soils in Arctic Tundra

种子在土壤中保持活力的时间长度 自然植物群落长期以来一直引起生态学家和植物学家的兴趣， 生理学家 拟议中的项目对这一问题进行了抨击 冻土带土壤，最有可能含有 长寿种子 以前的研究表明， 有活力的种子被发现在丰富的soliflection埋 高山冻原环境中的有机土壤。 放射性碳年代 种子和土壤都表明，种子的数量级是 至少有几百年的历史了 初步工作还表明 比这更古老的种子可能会被发现， 额外的实地考察。 本研究将寻求更古老的 种子与广泛挖掘的六个额外的soliflectin- 埋土剖面 这些大规模的挖掘 这可能是由地球观察组织提供的一笔赠款， 研究和提供志愿者。 最大限度地利用 这些剖面的土壤和种子 会被放射性碳测年 放射性碳年代测定法 使用串联加速器质谱法完成， 可以直接测定小型含碳物体的年代。 通过 一个经过验证的程序，种子外壳将被小心地去除， 从新兴的幼苗和日期，而幼苗将是 移植到温室的花盆里。 因此，除了 确定种子在永久冻土中能存活多久 已知年龄组的老年和年轻基因型群体 将确定今后的工作。 土壤将与 传统的放射性碳年代测定法， 运动将被估计为对加速器日期的检查， 种子本身。 加速器方法的其他检查 测年将包括：（1）测量14 C/13 C无线电， 确定是否需要考虑同位素歧视 （2）在约会过程中的帐户，（2）约会的复制 程序上的几个叶片，和（3）定年的幼苗， 在黑暗中出现，还有它们的种皮。

The length of time that seeds remain viable in soils of natural plant communities has long intrigued ecologists and plant physiologists. The proposed project attacks this question directly for tundra soils, which are most likely to contain long-lived seeds. Previous work has demonstrated that isolated viable seeds are found in abundance in solifluction-buried organic soil in alpine tundra environments. Radiocarbon dates of both seeds and soil show that the seeds are on the order of hundreds of years old, at least. Preliminary work also suggests that seeds much older than this are likely to be uncovered by additional fieldwork. The present study will seek still older seeds with extensive excavations of six additional solifluction- buried soil profiles. These extensive excavations are made possible by a grant from Earthwatch, which will support the field research and will supply volunteers. To take maximum advantage of this opportunity both soils and seeds from these profiles will be radiocarbon dated. Radiocarbon dating of the seeds will be accomplished using tandem accelerator mass spectrometry, which allows direct dating of small carbon-containing objects. Through a demonstrated procedure, seed coats will be carefully removed from emerging seedlings and dated, while the seedlings will be transplanted to pots in the greenhouse. Thus, in addition to establishing how long seeds may persist in permafrost soils populations of old and young genotypes of known age classes for future work will be established. Soil will be dated with conventional radiocarbon dating, and rates of solifluction movement will be estimated as a check on the accelerator dates of the seeds themselves. Other checks on the accelerator method of dating will include: (1) measurement of the 14C/13C radio to determine whether isotope discrimination needs to be taken into account in the dating procedure, (2) replication of the dating procedure on several lobes, and (3) dating of seedlings that emerge in the dark, as well as their seed coats.