Partitioning into Maize Grain N Fractions of N Absorbed Through the Roots Before and After Pollination

The abundance of N in various fractions in maize (Zea mays L.) grain was compared in two genotypes, a normal hybrid (Pioneer 3369A) and its opnque-2 (0-2) counterpart (L3369). Plants were grown in the greenhouse in sand cultures irrigated daily with nutrient solutions containing 3.75 mM N as NO, ion. At anthesis the plant cultures were divided into sets, one set continuing to be irrigated with the same solution, but with 15N added, and the other set irrigated with a solution of the same composition except that the N was omitted. The plants were sampled at 12, 24 and 36 days after pollination. Post-anthesis N nutrition affected the composition of the vegetative growth but had no effect during the sampling period on yields or amounts of N in the grain. At 12 days post-pollination there were no differences between the two genotypes in N partitioning, with about 50% of the N present as nonprotein N (NPN). At 24 and 36 days over 75% more N was present as zein in the normal genotype as in the 0-2, while the latter contained a much higher proportion of N as NPN. The albumin-globulin and glutelin fractions were slightly greater in the 0-2. The N absorbed after pollination was partitioned among the grain protein fractions similarly to N absorbed prior to pollination. The nature of the NPN fraction needs to be considered in evaluating effects on crop quality of an elevated N supply

Chemical Composition and Fertilizer Response of Two Range Plants in Relation to Grass Tetany

The chemical response of two species of annual range plants, soft chess and broad-leaf filaree, to nitrogen and potassium fertilization was studied in a field plot trial in Amador County, California. Heavy losses of cows due to grass tetany have been reported from that vicinity in recent years. The K/(Ca + Mg) ratio in soft chess was significantly higher than that in broad-leaf filaree, and fertilization with N and K increased the ratio in both species. Fertilization increased the concentration of K in broad-leaf filaree, but had little effect on the concentrations of Ca and Mg. In contrast, fertilization decreased the Ca and Mg percentages in soft chess but did not change the K concentration. The presence of alkaloids in soft chess was detected by a "spot-test" technique.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202