Allen E B, Allen M F
Department of Range Science and Ecology Center, Utah State University, Logan, UT 84322-5230.
Department of Biology and Ecology Center, Utah State University, Logan, UT 84322-4500, USA.
New Phytol. 1986 Dec;104(4):559-571. doi: 10.1111/j.1469-8137.1986.tb00656.x.
The effects of vesicular-arbuscular mycorrhizal inoculum and competition from non-mycorrhizal annual plants were tested on Agropyron smithii Rydb. and Agropyron dasystachyum (Hook.) Scribn. growing in an inoculum-poor soil. Mycorrhizal A. smithii decreased stomatal resistance (r ) and increased leaf water potential compared to the non-inoculated plants, but only during the driest portion of the growing season. The presence of annuals caused increased r of A. smithii, but only of non-inoculated plants. Mycorrhizal plants had the same r with or without annuals, indicating that mycorrhizas may alleviate the detrimental effects of competition on r of A. smithii. By contrast, neither inoculation nor annuals significantly affected water relations of A. dasystachyum. Mycorrhizas also did not increase N and P concentrations or percentage cover of either grass, but both had delayed phenology when mycorrhizal. This research was done during a wet year when the effects of mycorrhizas may be subtle. Long-term observations are necessary to determine the importance of mycorrhizas under field conditions.
在接种菌根贫瘠的土壤中生长的史密斯冰草（Agropyron smithii Rydb.）和糙芒冰草（Agropyron dasystachyum (Hook.) Scribn.）上，测试了泡囊丛枝菌根接种物以及来自非菌根一年生植物竞争的影响。与未接种的植株相比，菌根化的史密斯冰草在生长季节最干旱的时期降低了气孔阻力（r）并提高了叶片水势。一年生植物的存在导致史密斯冰草的r增加，但仅在未接种的植株中出现这种情况。无论有无一年生植物，菌根化植株的r都相同，这表明菌根可能减轻了竞争对史密斯冰草r的不利影响。相比之下，接种和一年生植物都未对糙芒冰草的水分关系产生显著影响。菌根也未增加这两种草的氮和磷浓度或盖度百分比，但两种草在菌根化时物候期都延迟了。这项研究是在湿润年份进行的，此时菌根的影响可能不明显。需要进行长期观察以确定田间条件下菌根的重要性。
