Collaborative Research: Patch Formation and Mycorrhizal Colonization During Succession on Glacial Till

植物演替可以通过先锋植物斑块的形成来启动。这项研究将包括一系列实验，以确定这些斑块的形成是否与菌根在最近融化的冰川上的定植有关。单个植物最初的定殖可能受非生物因素的控制，如种子沉积和集水的微区，而后期斑块的形成可能受非生物因素和生物因素的共同调控。这些生物因素是本研究的重点。最初定植的植物既可以改善微环境，也可以为后来的定殖者提供菌根接种来源，从而起到“看护”植物的作用。研究人员推测，阿拉斯加北部的最初定居者是兼职的菌根，他们可以在冰川中生存，直到没有菌根，直到接种物自然分散。下一波植物移居者可能是兼职的或必然的菌根，如果他们的种子存放在保育植物附近，他们可能会更快地建立起来。因此，阿拉斯加冰川演替初期斑块的形成可能依赖于菌根真菌。实验包括在冰川耕作上种植VA和外生菌根接种和未接种的苗木，在苗木周围种植未接种的苗木，观察自然植物和菌根的定植情况。通过比较接种和未接种的苗木附近和远处的植物生长，可以区分接种和菌根接种对微环境改善的影响。单株植物对菌根的生理反应将在受控条件下进行测量。许多早中期植物在冰川耕作演替过程中既是VA真菌又是外生菌根真菌，这两种类型的真菌都将被操纵和观察。

Plant succession may be initiated by patch formation by the pioneer plants. This research will consist of a series of experiments to determine whether the formation of these patches is related to mycorrhizal colonization on recently deglaciated till. Initial colonization by individual plants may be controlled by abiotic factors such as microsites for seed deposition and water catchment, while later patch formation may be regulated by both abiotic and biotic factors. These biotic factors are the focus of this study. The initial colonizing plant may act as a "nurse " plant both by ameliorating the microenvironment and by providing a source of mycorrhizal inoculum for later colonists. The investigators hypothesize that the initial colonizers in boreal Alaska are facultatively mycorrhizal, and that they can survive in glacial till without mycorrhizae until inoculum is naturally dispersed. The next wave of plant colonists may be facultatively or obligately mycorrhizal, and they may establish more rapidly if their seeds are deposited near a nurse plant. Thus patch formation in the initial stages of glacial succession in Alaska may depend on mycorrhizal fungi. Experiments will consist of planting both vesicular- arbuscular (VA) and ectomycorrhizal inoculated and uninoculated nurse plants on glacial till, planting uninoculated seedlings around the nurse plant, and observing natural plant and mycorrhizal colonization. The effects of microenvironmental amelioration by the nurse plants versus mycorrhizal inoculation can be separated by comparing plant growth near and at a distance from inoculated versus uninoculated nurse plants. The physiological response of the individual plants to mycorrhizae will be measured under controlled conditions. Many early to mid- seral plants have been reported to be both VA and ectomycorrhizal during succession on glacial till, and both types of fungi will be manipulated and observed.