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Effect Of Blue Light And Temperature On Leaf Expansion, Stem Elongation, And Growth, Tracy A. O. Dougher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Short height and high yield per unit energy in controlled environments are essential to the success of a food production system for spaceflight. Temperature and light quality can be manipulated in controlled environments to reduce plant height and increase yield. Although the effects of temperature on height and yield are well studied at ambient CO₂, temperature effects at elevated CO₂ with a hydroponic root zone are not well characterized. We studied soybean yield and height under two lamp types over a broad range of temperatures. Temperature had little effect on yield or height, but lamp type had …

The Effects Of The Spatial Pattern Of Defoliation On Regrowth Of A Tussock Grass, Warren G. Gold

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The influence of the spatial pattern of foliage removal on regrowth was investigated in the field with a tussock grass, Agropyron desertorum. Tussocks were hand clipped in different spatial patterns that represented extremes of defoliation patterns which could be inflicted by natural herbivores. All defoliated tussocks exhibited increases in specific growth rates following clipping in mid-May. When foliage was removed from the upper portion of the canopy (younger foliage), regrowth rates and season-long aboveground biomass production were less than if the same amount of foliage was removed from low in the canopy (older foliage). The spatial pattern of defoliation …

Effect Of Gibberellic Acid And Chilling On Nucleic Acids During Germination Of Dormant Peach Seed, Yuh-Nan Lin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study of nucleic acid changes influenced by gibberellic acid and chilling treatments in peach seed was performed in an attempt to reach a better understanding of the mechanism involved in breaking seed dormancy.

Gibberellic acid and the chilling treatment increased the RNA content. These two treatments which break dormancy also increased RNA, suggesting a similar mechanism involving RNA. Chilled seeds contained more RNA than did the gibberellic acid treated seeds.

DNA content remained unchanged regardless of treatment.

Dry seed had a greater ribonuclease activity than with soaked seeds. Enzyme changes did not correlate well with the RNA content in …

Effect Of Stage Of Seedling Development On Absorption Of Selected Pre-Emergent Herbicides, Pairoj Suchinda

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Using radioautography ¹⁴C simazine, ¹⁴C EPTC, ¹⁴C 2,4-D, ¹⁴14 DCPA and ¹⁴C pyrazon absorption by seeds of bean (Phaseolus vulgaris L.), squash (Cucurbita maxima), corn (Zea mays), onion (Allium cepa) and oat (Avena sativa) was studied. Simazine, EPTC, 2,4-D and pyrazon were absorbed through the seed coat of bean, squash, corn and onion, the amount increasing with time. Little DCPA was absorbed by seeds of bean, squash, onion and oat. Distribution and translocation of ¹⁴C simazine, ¹⁴C EPTC and ¹⁴C pyrazon occurred in …

The Effect Of Changing Temperatures On Hardiness, Respiration, And Intensity Of Rest Of Dormant Peach And Apricot Buds, Anthony H. Hatch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

studies were conducted to better understand the influence of temperature on the rest period of dormant peach and apricot buds. Gleason Elberta peach and Chinese apricot trees in the field at Howell Experiment Station in Ogden were used to evaluate rest intensity, respiration, and cold hardiness in relation to temperature.

A rest intensity curve was obtained for both species using various concentrations of gibberellic acid. It was found that temperature had no direct effect on the depth of rest and that the depth of rest had no measurable influence on respiration and cold hardiness.

Respiration of flower and leaf buds …

The Effect Of Limited Moisture Supply At Various Stages Of Growth On The Development And Production Of Hybrid Corn, Ralph E. Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Corn occupies from 25 to 30 percent of the crop land harvested in the United States. In recent years the acreage devoted to corn in this country has been decidedly greater than that devoted to any other cultivated crop. In 1944 its dollar value exceeded the combined values of wheat, barley, rye, grain sorghums, and cotton.

Although South Dakota lies on the northwestern fringe of the corn belt, the corn crop is one of the most important in that state. Corn production in that area is somewhat unstable because of drought. Corn often fails to reach full maturity before the …

The Effect Of Time, Quantity, And Kind Of Irrigation On The Yield Of Sugar Beets, Delos Boyd Archibald

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigations on factors affecting yield of sugar beets during the past two years at Newton and Garland, Utah, have shown two outstanding facts about irrigating sugar beets. First, the amount of water applied may not be as important as the time at which they receive it. Second, sugar beets should not be made to suffer for water in the early part of their growing season.

These observations suggest the need for further studies on method, time and quantity of irrigation. Further information on the most economical use of irrigation water for sugar beets would be of great value to the …

The Effect Of Alternate Freezing And Thawing On Impermeable Alfalfa And Dodder Seeds, A. R. Midgley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It is surprising to know the small amount of work that has been done on alternate freezing and thawing of seeds. Many experiments, however, have been conducted to see the effect of very low temperatures on seeds and to notice the effect it had on their vitality. Some experimenters subjected seeds to temperatures as low as liquid hydrogen with very interesting results but in very few cases, if any, was the effect of alternate freezing and thawing studied.

The work that follows deals directly with the effects of alternate freezing and thawing on impermeable seeds of alfalfa and of dodder. …

The Effect Of Dry Heating On Alfalfa Seed And Adulterants, Ernest V. Staker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The relationship of artificial heating to the germination of seeds has been a subject of more or less interest for the last 75 years. Like other research work, experimenters first had their attention called to the problem largely as the result of innate curiosity. They were interested in the result as measured by germinative power, of the application to seeds of different amounts of heat for varying periods of time, consequently many divergent and sundry experiments were carried out. Seeds of a large number of plants have been subjected to tests and the results recorded. The investigations include the effect …