Mycorrhizosphere responsiveness to atmospheric ozone and inoculation with Phytophthora citricola in a phytotron experiment with spruce/beech mixed cultures.
Mycorrhizosphere responsiveness to atmospheric ozone and inoculation with Phytophthora citricola in a phytotron experiment with spruce/beech mixed cultures.
复制标题
在云杉/山毛榉混合培养物的 phytotron 实验中，菌根圈对大气臭氧的响应和柠檬疫霉的接种。
作者：
K. Pritsch;G. Luedemann;R. Matyssek;Anton Hartmann;M. Schloter;Hagen Scherb;T. Grams
研究了幼龄云杉和山毛榉接种柑橘疫霉根际病原菌后，在常温和两次常温臭氧条件下生长的幼龄云杉和山毛榉的菌根圈功能变化。人工气候室试验分两个植被期进行，在第一个生长季结束时加入病原菌。根生物量数据表明，复合处理对云杉的影响大于山毛榉，臭氧对云杉抗逆性的负面影响大于山毛榉。相比之下，当病原体是唯一的应激源时，山毛榉受到的影响更大。选择胞外酶活性作为研究MR土样的土壤功能参数。在臭氧暴露第一年后，两个物种的MR土壤样品在臭氧处理中几乎所有被测的酶(酸性磷酸酶、几丁质酶、β-葡萄糖苷酶、纤维二糖水解酶)的活性都增加了。不同树种间存在差异，柑橘疫霉对山毛榉MR的影响较强，臭氧对云杉MR的影响较强。在第二年，臭氧和柑橘疫霉的联合处理显著提高了两种树种的大多数酶活性(纤维二糖水解酶除外)的活性。结果表明，MR土壤对臭氧和柑橘疫霉的响应与植物侵染的严重程度和地下生物量的减少有关，表明植物胁迫对MR土壤酶活性有很强的直接影响。还需要使用不同物种和组合胁迫进行更多研究，以确定根际酶变化的更广泛的生态相关性。
The aim was to analyze functional changes in the mycorrhizosphere (MR) of juvenile spruce and beech grown in a mixture under ambient and twice ambient ozone and inoculated with the root pathogen Phytophthora citricola. The phytotron experiment was performed over two vegetation periods, adding the pathogen at the end of the first growing season. Root biomass data suggest that the combined treatment affected spruce more than beech and that the negative influence of ozone on stress tolerance against the root pathogen P. citricola was greater for spruce than for beech. In contrast, beech was more affected when the pathogen was the sole stressor. The functional soil parameter chosen for studies of MR soil samples was activity of extracellular enzymes. After the first year of ozone exposure, MR soil samples of both species showed increased activity of almost all measured enzymes (acid phosphatase, chitinase, beta-glucosidase, cellobiohydrolase) in the O3 treatment. Species-specific differences were observed, with a stronger effect of P. citricola on beech MR and a stronger ozone effect on spruce MR. In the second year, the effects of the combined treatment (ozone and P. citricola) were a significant increase in the activity of most enzymes (except cellobiohydrolase) for both tree species. The results indicated that responsiveness of MR soils towards ozone and P. citricola was related to the severity of infection of the plants and the reduction of belowground biomass, suggesting a strong, direct influence of plant stress on MR soil enzyme activity. Additional research is needed using different species and combined stresses to determine the broader ecological relevance of shifts in rhizosphere enzymes.