Koko Jerry H, Swift Sean O I, Hynson Nicole A
Department of Botany, University of Hawaii at Manoa, 3190 Maile Way, Room 101, Honolulu, HI, 96822, USA.
Pacific Biosciences Research Center, University of Hawaii at Manoa, 1993 East-West Road, Honolulu, HI, 96822, USA.
Am J Bot. 2021 Sep;108(9):1635-1645. doi: 10.1002/ajb2.1731. Epub 2021 Sep 19.
Prior efforts have shown that continents harbor a greater proportion of mycorrhizal hosts than on islands. However, in the Hawaiian Islands, estimates of the proportion of mycorrhizal plant species are higher than on continents (>90%), but there are few studies to support this claim. Concurrently, Hawaii's flora faces some of the greatest global risks of extinction, and significant efforts are aimed at restoring native vegetation. Arbuscular mycorrhizal (AM) fungi have been shown to improve plant restoration success, but little work has been done in Hawaii to understand the extent of mycorrhizal associations among native plant populations.
We surveyed 35 native Hawaiian plant species in the wild, focusing on plant species that are reared for reintroduction. Roots from wild individuals were collected from 10 sites on Oahu to determine degree of mycorrhizal fungal colonization and how this varies across host populations.
Of the species surveyed, 97% had evidence of mycorrhizal colonization, including 25 endemic and nine indigenous species from 23 families. The mycorrhizal status of 22 of the species surveyed was unknown before this study. For four species, the degree of colonization by AM fungi differed among sites, and these differences corresponded with variations in precipitation and temperature.
The high incidence of mycorrhizal colonization provides evidence that island flora can actually harbor more mycorrhizal hosts than species on mainlands and that future reintroduction projects should consider the potentially important roles of AM fungi for success of these hosts in the wild.
先前的研究表明，大陆上菌根宿主的比例高于岛屿。然而，在夏威夷群岛，菌根植物物种比例的估计值高于大陆（>90%），但几乎没有研究支持这一说法。与此同时，夏威夷的植物群面临着一些全球最大的灭绝风险，并且正在做出重大努力来恢复本土植被。丛枝菌根（AM）真菌已被证明能提高植物恢复的成功率，但在夏威夷，对于本土植物种群中菌根共生程度的了解还很少。
我们对35种夏威夷本土野生植物进行了调查，重点关注用于重新引入的植物物种。从瓦胡岛的10个地点采集野生个体的根系，以确定菌根真菌的定殖程度以及其在不同宿主种群中的变化情况。
在所调查的物种中，97%有菌根定殖的证据，包括来自23个科的25种特有物种和9种本土物种。在本研究之前，所调查的22个物种的菌根状况未知。对于4个物种，AM真菌的定殖程度在不同地点存在差异，这些差异与降水和温度的变化相对应。
菌根定殖的高发生率证明，岛屿植物群实际上可能比大陆上的物种拥有更多的菌根宿主，并且未来的重新引入项目应考虑AM真菌对这些宿主在野外成功生长的潜在重要作用。
