Dose effect in the dual inoculation of an ectomycorrhizal fungus and a mycorrhiza helper bacterium in two forest nurseries
Dose effect in the dual inoculation of an ectomycorrhizal fungus and a mycorrhiza helper bacterium in two forest nurseries
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两个森林苗圃外生菌根真菌和菌根辅助菌双重接种的剂量效应
DOI：
10.1016/s0038-0717(99)00079-6
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发表时间：
1999
影响因子：
9.7
通讯作者：
J. Garbaye
中科院分区：
文献类型：
--
作者：
P. Frey;J. Churin;J. Pierrat;J. Garbaye
将3种剂量(8×10~5、8×10~7和8×10~9cfu m−~2)的抗利福平菌根辅助菌荧光假单胞菌BBc6R8和外生菌根真菌双色漆树菌S238N接种于两个黄杉林苗圃的消毒土壤中。在两个苗圃之一，测试了两种剂量的真菌接种(50和100mgm−2干重(DW)菌丝体以恒定剂量1：L m−2包裹在藻酸盐微珠中)。在所有细菌处理中，稀释法测定的荧光假单胞菌BBc6R8在土壤中的密度在接种后2周降至检测下限(10−2cfu g−1DW土壤)以下。接种15周后，只有在接种最高细菌剂量的处理中才能通过培养检测到引入的细菌。接种2年后，在所有细菌处理的土壤中均未检测到荧光假单胞菌BBc6R8。接种和播种5个月后，在两个苗圃中的一个苗圃中，接种细菌显著提高了接种低剂量或高剂量双色乳杆菌的植株的菌根短根率。最低细菌接种量使菌根定殖率从45%提高到70%，使菌根定殖率从77%提高到77%。最低细菌剂量比最高细菌剂量对菌根定植的促进作用更强。添加50 mg m−2DW菌丝体的双色乳杆菌菌根指数(70%)与不加菌剂(%)的菌根指数相同。接种2年后，接种最低菌量(40.7~42.6 cm)时，其他苗圃的菌根高度显著增加。这些结果表明，辅助菌和外生菌根真菌共接种是优化控制菌根化技术生产优质豆科杉木砧木的有效方法。他们还证实，BBC6R8在低种群密度(小于102cfu g−1土壤)下起作用；这与文献中讨论的大多数−效应形成对比，在文献中，需要最小接种量105cfu g pGPR 1土壤才能获得有益效果。
We inoculated disinfected soil at two Douglas-fir bareroot forest nurseries with three doses (8×105, 8×107and 8×109cfu m−2) of the rifampin-resistant mycorrhiza helper bacterium Pseudomonas fluorescens strain BBc6R8 and the ectomycorrhizal fungus Laccaria bicolor strain S238N. In one of the two nurseries, two doses of fungal inoculum (50 and 100 mg m−2dry weight (DW) mycelium entrapped in alginate beads at the constant dose of 1 l m−2) were tested. For all bacterial treatments the density of P. fluorescens BBc6R8 in the soil, determined by dilution plating, dropped below the detection limit (10−2cfu g−1DW soil) 2 weeks after inoculation. Fifteen weeks after inoculation, the introduced bacterium could be detected by enrichment only in the treatments inoculated with the highest bacterial dose. Two years after inoculation, P. fluorescens BBc6R8 could not be detected in the soil of any of the bacterial treatments. Five months after inoculation and sowing, bacterial inoculation significantly increased the percentage of mycorrhizal short roots on plants inoculated with either low or high amounts of L. bicolor, in one of the two nurseries. The lowest bacterial dose increased mycorrhizal colonization from 45 to 70% in plants inoculated with the low amount of fungal inoculum, and from 64 to 77% in plants inoculated with the high amount of fungal inoculum. The lowest bacterial dose increased mycorrhizal colonization more than the highest bacterial dose. The same L. bicolor mycorrhizal index (70%) was obtained with 50 mg m−2DW mycelium plus the bacterium than with twice this fungal dose and no bacterium (64%). Two years after inoculation, the height of the mycorrhizal Douglas-firs in the other nursery was significantly increased by the lowest bacterial dose (from 40.7 to 42.6 cm). These results indicate that co-inoculating a helper bacterium together with an ectomycorrhizal fungus can be an efficient way of optimizing controlled mycorrhization techniques for the production of high-quality Douglas-fir planting stocks. They also confirm that BBc6R8 acts at a low population density (less than 102cfu g−1soil); this contrasts with most PGPR effects discussed in the literature, where the minimal inoculation dose of 105cfu g−1soil is required to obtain the beneficial effect.