Mycorrhizae increase the uptake of Zn and Cn by many plants, but mycorrhizal activity is suppressed by P fertilization. Soybean (Glycine max Mer.) and two lines of corn (Zea mays L.) were used to determine if this mechanism is a major cause of P-induced Zn and Cu deficiencies. Shoot dry weights and concentrations or total uptake of P, Zn, Cu, Fe, Mn, K, Ca and Mg were determined for mycorrhizal and nonmycorrhizal plants given 0, 25, 75, or 200 ppm P. Phosphorus fertilization significantly reduced Zn and Cu concentrations in mycorrhizal soybeans, but concentrations in nonmycorrhizal treatments were not affected. Concentrations of Zn and Cu in mycorrhizal and nonmycorrhizal corn were reduced by P fertilization, but the reduction for mycorrhizal plants was significantly greater than the decrease for nonmycorrhizal plants. Reductions in Zn and Cu concentrations in nonmycorrhizal corn were the result of a dilution effect and could be attributed to increased plant size rather than increased P fertility per se. The concentrations of the other analyzed elements were all affected by P level and/or mycorrhizal condition. In general, mycorrhizal and nonmycorrhizal dry weights and element concentrations converged as soil P was increased. Patterns of response to P and mycorrhizae differed slightly between corn lines, and such differences were marked for certain elements when corn was compared with soybean.

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Soil in earthworm casts (Lumbricus terrestris L.), ant castings (Formicidae), robin nests (Turdus migratorius L.), barn swallow nests (Hirundo erythrogaster Bodd.), and mud dauber wasp nests (Trypoxyloninae, Sphecinae) was examined for spores of Endogonaceae. Air-dried samples of worm casts, robin nests, or swallow nests added to steamed soil resulted in development of vesicular-arbuscular (VA) mycorrhizae in the roots of soybean (Glycine max (L.) Merr. 'Amsoy 71'). The results obtained indicate that organisms which transport soil may also disperse spores of Endogonaceae. In view of the large quantities of soil turned over by earthworms annually, these organisms may play a direct role in the vertical distribution of Endogonaceae in soil profiles. In addition through transport of castings by water runoff earthworms may play an indirect role in lateral distribution.

SUMMARYIn three field soils, birdsfoot trefoil {Lotus cormculatus L.) transplants infected with mycorrhizal fungi from 42 soils showed no clear superiority of strains from these individual soils after a year's growth. Differences among strains decreased with time and were only significant for all three soils at the first cutting. There were Jow-level correlations between yield and various chemical properties of the soils from which the cultures were derived. In the greenhouse, with sterilized soils low in P, trefoil yield was always greatest when the inoculum used was indigenous to the soil in which the plants were grown as compared to inocula from five different soils. These results suggest that indigenous strains of mycorrhizal fxingi ma.y possess an adaptation to edaphic factors and that the performance and persistence of strains otherwise more efficient in nutrient uptake may be limited hy their lack of adaptation.

Preplant incorporated treatments of 2 and 4 kg/ha of trifluralin and diazinon had no significant effect on growth, P accumulation or root colonization by mycorrhizal fungi in soybeans planted in an Andover clay loam. At 4 kg/ha, alachlor and trifluralin inhibited root development of 25 day-old plants. The 4 kg/ha alachlor treatment reduced shoot weight of 25 day old plants significantly and suppressed mycorrhizal development of 25 to 60 day old plants. At currently used commercial rates neither alachlor, trifluralin, nor diazinon affected mycorrhizal development under the conditions of the experiment.

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Nearly every hour, a patient in the USA dies while waiting for an organ transplant (Degenholtz et al., 2019). According to data from the Organ Procurement and Transplantation Network (OPTN), the number of transplant operations performed every year has increased steadily since 1995, but the number of people added to the waiting list has consistently exceeded