Strategic placement of P32 and root excavations revealed that roots of orchardgrass and bromegrass reached a greater depth when no N was applied. Nitrogen increased the root diameter and decreased the rate of elongation causing the plants to feed near the soil surface for a longer period of time. Defoliation stopped root growth within 24 hours and induced decomposition of the existing roots within 36 to 48 hours. Uptake of P32 placed in the existing root zone 24 to 48 hours after clipping was not detected until new roots reached the activated zone. New roots were initiated from basal leaf nodes of orchardgrass and rhizome nodes of bromegrass. Removal of all roots at the time of defoliation did not influence the rate of regrowth from transplanted sod plugs under optimum soil moisture conditions.

No abstract

Synopsis Nitrogen was a major factor influencing yields the year of treatment. Close clipping reduced the stand of nitrogen‐fertilized orchardgrass. Potassium effects were most striking for the longer growing periods during the year of treatment. Potassium carry‐over effects were highly significant for all growing periods.

Synopsis Nitrogen increased orchardgrass yields significantly throughout the season. However, potassium produced a significant yield increase only at the third harvest. Both nutrients depressed the percent total fructose of the sheaths during the first two growth periods. This effect was reversed for nitrogen during the third growth period. Asparagine accumulated abnormally in the second and third harvests when potassium fell below 1.6% of the dry weight.

A corn (Zea mays L.) hybrid sensitive to a phosphoruszinc interaction was grown hydroponically in the greenhouse at several P levels in the presence of 65Zn, to determine if P affected the distribution of Zn within the root and affected Zn movement into the cytoplasm. Lyophilized root tissue was serially extracted with chemical and enzyme extractants. High P was found to increase the amount of 65Zn in the ethanol‐soluble fraction and pectate fraction of the cell wails. This binding of Zn to the cell wall may reduce the amount of Zn available for transport to the upper portions of the plant, resulting in Zn deficiency.