Life Sciences Commons^™

The Effect Of Environment And Cultural Practices On The Cold Hardiness Of Peach Wood, Larry A. Sagers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were conducted to better understand the effect of temperature, photoperiod, cultural practices, and growth regulators on the hardening and dehardening of peach tree wood.

Greenhouses were constructed to control temperatures to which peach trees were exposed. It was noted that hardening and dehardening usually followed the temperature fluctuation fairly closely. However, trees exposed to temperatures above 60 F (15.6 C) became hardy to 0 F (-17.8 C).

A photoperiodic response in regard to an increase or decrease in hardiness was not definitely observed in peach wood. Extended photoperiod did not produce any significant effect on hardiness. Defoliation, bloom date, …

Nitrogen Fixation In Arid Western Soils, Robert Charles Rychert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen fixation by blue-green algae-lichen crusts from South Curlew Valley, Utah, in the Great Basin Desert, was studied using the acetylene reduction technique. A molar ratio of 3 moles C₂H₄ produced/mole of N₂ fixed was used to estimate nitrogen (N₂) fixation by acetylene reduction. Nostoc was found to be present in many of the lichen thalli examined microscopically. Crust nitrogen fixation decreased rapidly below -1/3 bar pressure (water potential) which indicated that nitrogen fixation occurs only when the crust is wet. This would suggest that most of the crust nitrogen fixation in the Great …