Pinkerton J N, Schreiner R P, Ivors K L, Vasconcelos M C
J Nematol. 2004 Sep;36(3):193-201.
Previous surveys of vineyards had indicated that Mesocriconema xenoplax was present in 85% of vineyards in western Oregon, but yields were not depressed in established vines. Microplot studies were initiated in 1997 in a Willamette Valley vineyard to determine the impact of M. xenoplax on vine establishment. Plots were infested with 0.03, 0.6, and 3.0 M. xenoplax g(-1) soil and planted with self-rooted Chardonnay and Pinot Noir vines. In November 2000, four growing seasons after planting, pruning weights, fine root weights, and fruit yield of vines planted in infested soil were reduced by 58%, 75%, and 33%, respectively, relative to control vines (planted in noninfested soil). In 1998 with ca 2000 degree-day base 9 degrees C accumulation, population densities increased 32-fold and 44-fold on 1-year-old Chardonnay and Pinot Noir vines, respectively. Nematode population dynamics and pruning data suggested that the carrying capacity of vines in microplots was 5 to 8 M. xenoplax g(-1) soil. In November 2000, more than 80% of the fine root length was colonized by arbuscular mycorrhizal fungi in all treatments. The frequency of fine roots containing arbuscules (the site of nutrient transfer between plant and fungus), however, was depressed from 5% to 65% in plants infested initially with M. xenoplax as compared to controls. Competition for photosynthate within the root system is proposed as a possible mechanism by which nematodes suppressed arbuscule frequency.
此前对葡萄园的调查表明，在俄勒冈州西部85%的葡萄园中都有奇异中环线虫，但成年葡萄藤的产量并未降低。1997年在威拉米特谷的一个葡萄园开展了微型小区研究，以确定奇异中环线虫对葡萄藤定植的影响。小区分别用每克土壤含0.03、0.6和3.0条奇异中环线虫进行侵染，然后种植自根霞多丽和黑皮诺葡萄藤。2000年11月，即种植后的四个生长季节，与对照葡萄藤（种植在未侵染土壤中）相比，种植在侵染土壤中的葡萄藤的修剪重量、细根重量和果实产量分别降低了58%、75%和33%。在1998年，以9℃为基础温度积累了约2000度日，在一年生霞多丽和黑皮诺葡萄藤上，线虫种群密度分别增加了32倍和44倍。线虫种群动态和修剪数据表明，微型小区中葡萄藤的承载能力为每克土壤5至8条奇异中环线虫。2000年11月，在所有处理中，超过80%的细根长度被丛枝菌根真菌定殖。然而，与对照相比，最初受到奇异中环线虫侵染的植株中，含有丛枝（植物与真菌之间养分转移的部位）的细根频率从5%降至65%。根系内对光合产物的竞争被认为是线虫抑制丛枝频率的一种可能机制。
