Mycorrhizal Ecology of Plant Colonization of Glacier Forefronts

植物对根共生（菌根）真菌的相对依赖性可能对新土壤上植物演替至关重要，但这一生态学领域很少受到重视。华盛顿北喀斯喀特山脉的冰川适合这个目的。在后退的过程中，它们沉积的碎石最初没有共生真菌，随着距离冰川终点的距离增加，暴露的时间也会增加。随着时间的推移，在这些冰川前沿定居的植物将与相邻的、未受干扰的群落中的相同物种进行菌根形成的比较。这三大类植物是：(1)在没有共生真菌的情况下生存，(2)依靠通过空气传播的菌根真菌生存，(3)依靠通过移动土壤传播的菌根真菌生存。第一组植物被预测为第一批殖民者，其次是第二组和第三组。田间取样、温室和生长室接种试验将验证这一假设。如果这是真的，它将解释为什么冰川附近的许多种子生产植物中只有少数是最初的殖民者。这对生态学理论的贡献在解释演替现象和恢复受干扰或退化的生态系统方面有许多应用。

The importance of relative dependency of plants on root- symbiotic (mycorrhizal) fungi may be critical to plant succession on new soils, but this area of ecology has received little attention. Glaciers of the North Cascade Mountains of Washington suit this purpose. In receding, they deposit rubble initially devoid of symbiotic fungi, which increase in time of exposure with distance from the glacier terminus. Plants that colonize these glacier forefronts over time will be compared with the same species in adjacent, undisturbed communities for mycorrhiza formation. The three major groups are plants that (1) survive without the symbiotic fungi, (2) depend on mycorrhizal fungi dispersed by air, and (3) depend on mycorrhizal fungi dispersed with moving soil. Plants in group 1 are predicted to be first colonizers, followed in turn by groups 2 and 3. Field sampling and greenhouse and growth chamber inoculation experiments will test the hypothesis. If true, it will explain why only a few of the many seed-producing plants adjacent to glaciers are initial colonizers. This contribution to ecological theory has many applications in interpreting successional phenomena and in rehabilitating disturbed or degraded ecosystems.