Life Sciences Commons^™

Root System Characteristics Of Two Soybean Isolines Undergoing Water Stress Conditions, A. F. Garay, Wallace Wilhelm

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Environmental stress may have a differential influence on root development of soybean [Glycine max (L.) Merr.] isolines which vary in pubescence density. Root length density and root dry matter distribution as a function of depth and distance from the row were s determined for two isolines of 'Harosoy' soybean in association with an experiment designed to evaluate the influence of epidermal pubescence on root development, water use, and photosynthetic characteristics of the two isolines. The isolines, Harosoy normal (HN) and Harosoy dense (HD), differed in the density of trichomes on the epidermal surfaces of leaves, stems, and pods. The …

Root System Characteristics Of Two Soybean Isolines Undergoing Water Stress Condition, A. F. Garay, Wallace Wilhelm

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Environmental stress may have a differential influence on root development of soybean [Glycine max (L.) Merr.] isolines which vary in pubescence density. Root length density and root dry matter distribution as a function of depth and distance from the row were determined for two isolines of 'Harosoy' soybean in association with an experiment designed to evaluate the influence of epidermal pubescence on root development, water use, and photosynthetic characteristics of the two isolines. The isolines, Harosoy normal (HN) and Harosoy dense (HD), differed in the density of trichomes on the epidermal surfaces of leaves, stems, and pods. The study …

An Experimental Center-Pivot Irrigation System For Reduced Energy Crop Production Studies, James R. Gilley, Lloyd N. Mielke, Wallace Wilhelm

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

An experimental 52.6 ha center-pivot irrigation system for studies of reduced energy crop production systems is described. The system consists of high pressure impact sprinklers, low pressure impact sprinklers, and low pressure spray nozzles that are automatically turned on or off at preselected locations in the field. The control procedures of the system operation are described. The system also has the capability of applying different depths of water per irrigation as a function of position radially outward from the pivot point. Four years of data indicate that the system controls function properly and the design irrigation depths are being met. …

Fate Of Turkey Spermatozoa After Intrainfundibular And Intramagnal Inseminations, M. R. Bakst

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

About 92% of the spermatozoa recovered after intrainfundibular inseminations of turkey hens were in the infundibulum and 6% in the magnal segments 24 h later. Of the spermatozoa recovered after intramagnal inseminations, about 67% were in the infundibulum, 26% in the magnal segments, and a total of about 8% in the isthmus, uterus, and vagina. It is suggested that spermatozoa in the infundibulum and magnum are not transported in significant numbers in an abovarian direction.

Pulsatile Luteinizing Hormone Secretion In The Castrate Male Bovine: Effects Of Testosterone Or Estradiol Replacement Therapy, B. D. Schanbacher, M. J. D'Occhio, T. W. Gettys

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Luteinizing hormone (LH) secretory profiles have been determined for the male bovine following castration and steroid replacement therapy. Serum LH concentrations increased approximately threefold during the first week following castration and thereafter remained elevated (6.6 ± .7 ng/ml). Castrates not receiving steroid replacement showed a rhythmic pattern of LH release that was of high frequency (mean pulse interval; 85 ± 5 min) and high amplitude (mean peak concentration, 11.2 ± 1.4 ng/ml). Chronic administration of estradiol-17β via subdermal Silastic implants reduced mean serum LH concentrations (2.1 ± .3 ng/ml) and blocked the pulsatile pattern of LH release in all steers. …

Physiology Of Male Reproduction, R. P. Amann, B. D. Schanbacher

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The major advances over the past 25 yr in male reproductive physiology of cattle, sheep, swine and horses are reviewed. Those findings which have allowed efficient culling of subfertile males and exploitation of the reproductive capacity of genetically superior sires are emphasized.

Hormones secreted by the male gonad early in gestation induce regression of potentially female structures and development of the male reproductive tract. Compartmentalization of the testis and formation of the bloodtestis barrier during prepubertal development permit the steroidogenic and gametogenic activities of the adult testes to proceed normally. The role of the central nervous system, hypothalamus and anterior …

Semiautomated X-Y-Plotter-Based Method For Measuring Root Lengths, Wallace Wilhelm, J. M. Norman, R. L. Newell

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Root-length measurements are an important aspect of many agronomic research programs. Several automated systems have been reported which use modifications of the line-intersect technique to estimate root length; however, most of these systems are very costly. This paper describes an inexpensive automated system using a modified line-intersect technique to estimate root length. An X-Y plotter was used to move a light sensor in a grid pattern through the projected photographic image of a root system, recording intersections with an event counter. Compared to manual counting using the Line-intersect technique, the system described accurately estimated root length of samples up to …

Semiautomated X-Y-Plotter-Based Method For Measuring Root Lengths, Wallace Wilhelm, J. M. Norman, R. L. Newell

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Root-length measurements are an important aspect of many agronomic research programs. Several automated systems have been reported which use modifications of the line-intersect technique to estimate root length; however, most of these systems are very costly. This paper describes an inexpensive automated system using a modified line-intersect technique to estimate root length. An X-Y plotter was used to move a light sensor in a grid pattern through the projected photographic image of a root system, recording intersections with an event counter. Compared to manual counting using the Line-intersect technique, the system described accurately estimated root length of samples up to …

Reproductive Effects Of Immunizing Heifers Against Androstenedione And Oestradiol-17Β, T. H. Wise, B. D. Schanbacher

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Heifers were treated with saline (Group I, N = 10), keyhole limpet haemocyanin (KLH ; Group II, N = 10), androstenedione-KLH antigen (Group III, N = 14), or oestradiol-17β-KLH antigen (Group IV, N = 14). Booster injections were given to produce binding of > 10% at dilutions of 1:100 to 1:1000 (50% binding = 14·4pg androstenedione and 9·5pg oestradiol). The heifers were mated and killed at ~46days of gestation to establish ovulation rates, calf numbers, blood hormone relationships and ovarian morphology.

Ovulation rate in animals immunized against androstenedione (Group III) was significantly greater than in the other groups; 4 of the …