Effects of climate warming on activity of the soil borne plant pathogens in Polar Regions

植物病原体可以影响自然生态系统中的个体生长和群落结构。气候变暖可能会增强它们的活动，导致极地和阿尔卑斯山的植物死亡。为阐明气候变暖对寒地植物病原菌种群的影响，对寒地植物病原菌的分类学和生态学特性进行了研究。被称为土传植物病原体，分离自斯瓦尔巴特群岛、格陵兰岛和挪威阿尔卑斯山的苔藓。共分离到314株腐霉，经鉴定为未知腐霉1 ~ 4种。在离体接种试验中，大多数菌株对藓类（Sanionia uncinata）和小麦叶片表现出致病性。菌丝在琼脂培养基上生长的最适温度为22 ~ 28℃。这些结果表明，气候变暖可能会增强腐霉的活性。并导致寒地苔藓的死亡。2003年至2006年每年夏季，通过使用腐霉选择性培养基分离病原体，在挪威斯瓦尔巴特群岛的苔藓菌落中进行调查。腐霉种群在2005年和2006年明显高于2003年和2004年。植物表面的温度模式没有变化的年份，并没有影响腐霉种群。土壤水分等环境因子对腐霉种群数量的影响有待进一步研究。挪威斯瓦尔巴特群岛微孢霉（Microbotryum bistortarum）对珠芽蓼存活和生长的影响。结果表明，感染M.bistortarum可以通过降低植物生长和寿命来对高北极地区的珠芽单胞菌种群产生负面影响。

Plant pathogens can effect individual growth and community structure in natural ecosystems. Climate warming may enhance their activity and lead to dying of plants in Polar Regions and Alpines. To clarify effects of climate warming on population of plant pathogens in these cold regions, taxonomical and ecological characteristics of some indigenous plant pathogens were studied.Pythium spp., known as soil borne plant pathogens, were isolated from moss in Svalbard, Greenland and Norwegian Alpine. The total 314 isolates were identified as unknown Pythium species 1 to 4. Most of them showed pathogenicity to a moss (Sanionia uncinata) and wheat leaves in an in vitro inoculation test. Their optimum temperatures for hyphal growth on an agar culture were 22 to 28℃. These results suggest climate warming may enhance activity of Pythium spp. and lead to dying of the moss in the cold regions.Population changes of Pythium spp. was investigated in moss colonies on Svalbard, Norway in every summer from 2003 to 2006 by isolation of pathogens using a Pythium selective medium. Pythium population was significantly higher in 2005 and 2006 than in 2003 and 2004. Plant surface temperature patterns were not varied among the years and had no affect Pythium populations. The other environmental factors such as soil moisture may affect the changes of Pythium population and is remained to be investigated.The effects of the smut fungus Microbotryum bistortarum on survival and growth of Polygonum viviparum in Svalbard, Norway. The results suggested infection by M.bistortarum can negatively impact populations of P.viviparum in the high arctic region by lowering plant growth and longevity.