ABSTRACT

Ectomycorrhizal fungi (EMF) are critical to the establishment of many plant species and an important consideration in ecological restoration of southern beech (Nothofagaceae) forest. However, information on spore viability and storage is lacking for EMF taxa associated with southern beech. This study tested the viability and germination of spores from fruiting bodies collected during autumn and spring from mountain beech forest, Otago, New Zealand. Nuclear ribosomal ITS sequences matched autumn collections to the EMF genera Cortinarius, Inocybe and Russula, but all spring collections were an undescribed hypogeous taxon resembling the native EMF genus Hysterangium, referred to here as Hysterangiaceae ‘Motatapu’. We investigated propidium iodide as a spore viability test, and compared spore germination in water vs glucose, in different temperature and light regimes, and between freshly collected spores and spores from fruiting bodies dried at 30°C or frozen at −20°C. Propidium iodide did not stain all devitalised spores, so may be unreliable for quantifying viability of fresh spores. Spore germination in water was <6% for all genera and <2% for most taxon × treatment combinations. Fresh spores of Hysterangiaceae ‘Motatapu’ suspended in 4°C water showed higher germination than at 20°C; excluding light had no significant effect. Spores of the same taxon suspended in 10% and 20% glucose showed lower germination in comparison to water and showed deformations. Germination percentages of all taxa decreased with storage, but spores of some taxa retained viability for 120 days in 4°C water suspensions. Spores of Hysterangiaceae ‘Motatapu’ showed the least loss of viability with storage of all taxa investigated. For the purposes of storing EMF material for use as inoculum, we recommend drying fruiting bodies at 30°C for storage, then preparing fresh spore suspensions in water when inoculum is required.

摘要

外生菌根真菌（EMF）对于许多植物物种的建立至关重要，也是南部山毛榉（Nothofagaceae）森林生态恢复的重要考虑因素。但是，缺乏与南部山毛榉相关的EMF分类群的孢子生存能力和储存信息。这项研究测试了秋天和春季从新西兰奥塔哥山毛榉森林中收集的子实体孢子的存活力和发芽率。核糖体ITS序列与EMF属Cortinarius，Inocybe和Russula的EMF秋季收藏相匹配，但所有春季收藏都是未描述的伪劣分类群，类似于原生EMF属Hysterangium，在这里称为Hysterangiaceae'Motatapu'。我们调查了碘化丙锭作为孢子的活力测试，并比较了在不同温度和光照条件下，以及新鲜收集的孢子和在30°C下干燥或在-20°C下冷冻的子实体的孢子之间，水与葡萄糖中的孢子萌发情况。碘化丙锭并未染色所有灭活的孢子，因此可能对定量新鲜孢子的活力并不可靠。对于所有属，水中的孢子萌发率<6％，而大多数分类群×处理组合的<2％。悬浮在4°C水中的Hysterangiaceae'Motatapu'的新鲜孢子的发芽率高于20°C。排除光没有明显影响。与水相比，悬浮在10％和20％葡萄糖中的同一分类群的孢子显示出较低的萌发并出现变形。所有分类单元的萌发百分率随贮藏而降低，但某些分类单元的孢子在4°C水悬浮液中可存活120天。所研究的所有分类单元的贮藏性都表明，杂合子科“ Motatapu”的孢子活力丧失最小。为了存储用作接种物的EMF材料，我们建议将子实体在30°C下干燥以进行存储，然后在需要接种物时在水中制备新鲜的孢子悬浮液。