No abstract

Inoculants prepared with presterilized peat were enumerated by the pour, spread, and drop plate techniques. Results indicated that the three plating methods were interchangeable. The drop plate method was preferred because of its economy in materials and labor.

ABSTRACIUsing a split-root technique, roots of soybean plants were divided between two pots. In one of the two pots, two maize plants were grown and half of those pots were inoculated with the vesicular arbuscular mycorrhizal (VAM) fungus, Glomus fasciculatas. Fifty-two days after planting, "5N-labeled ammonium sulfate was applied to the pots which contained only soybean roots. Forty-eight hours after application, significantly higher values for atom per cent 'IN excess were found in roots and leaves of VAM-infected maize plants as compared with the non-VAM-infected maize plants. Results indicated that VAM fungi did enhance N transfer from one plant to another.ined VAM mediated transfer ofN from a soybean to maize using highly labeled ('5NH4)2SO4 and a split-root technique. MATERIALS AND METHODSSurface sterilized (2 min in 3% NaOCI seeds of soybeans (Glycine max [L.] Merr) and maize (Zea mays L.) were germinated in vermiculite. The last 0.5 cm of the soybean tap roots were removed and the two seedlings were placed in two separate plastic elbows (pvc elbow, 21 mm o.d., 13 mm diameter hole) (16). At the same time, two pregerminated maize seedlings were planted in pot B (Fig 1).Half of the B pots were inoculated with a VAM fungi, Glomus fasciculatus, maintained in a course sand pot culture with each inoculated pot receiving 30 g ofinoculum which contained small Vesicular arbuscular mycorrhizal fungi are ubiquitous and infect plant roots of most species under a wide variety of soil conditions (8). The fungi form a symbiosis with host plants in which the plant provides carbon for VAM2 growth and in turn the VAM fungi provide plant nutrients, especially phosphorus, from the soil solution (1 1). Growth responses of host plants to infection by VAM may be dramatic in nutrient-poor environments (7). Hyphae of mycorrhizae may also spregd from one infected plant and enter the roots of one or more other plants (9). It has been shown that assimilates may be transported from one plant to another through VAM hyphal connections. Transfer of '4C photosynthate from one plant to another was primarily through VAM hyphae rather than leakage from the roots of the donor plants (2,6,14). Similar results were obtained in a 3p experiment where hyphal linkage between plants was the dominant factor for transferring P (3, 17).Leguminous plants infected with both Rhizobium and VAM showed an increase in nodulation and N2-fixation as compared with VAM-uninfected legumes (4, 5). The increase in total N has been explained mainly by an increase in N2-fixation as a result of a higher P uptake through the VAM hyphae rather than increased soil N uptake (15). Although the role of VAM on N uptake and transport has been studied, the results are inconclusive. Rhodes and Gerdemann (15)

No abstract