Master's Theses

Date of Award

Summer 1957

Degree Name

Master of Science (MS)

Department

Biology

Advisor

Dr. Harold Hopkins

Abstract

Salt Cedar (Tamarix gallica L.) is a phreatophyte which creates a mamor water conservation problem in the Southwest. This study, which is a portion of a study conducted by Fort Hays Kansas State College for the Bureau of Reclamation, was designed to determine various aspects of the life history of this species. The research consisted of studies in the campus greenhouse and at Cedar Bluff Reservoir about 30 miles southwest of Hays. Seed was collected weekly or hi-weekly from a windbreak just west of the college and at the reservoir from the middle of June until the last of September. A final collection vas made at the reservoir on November 10. The seed was stored at temperatures of -17 deg. C., 10 deg. C. and 25 to 30 deg C. Germination tests were conducted in petri dishes between damp blotter pads. In order to have plants available for study during the winter months, plants were transplanted to the greenhouse on August 14 and during late January. In addition, seeds were planted in 30-inch phytometers and flower pots of various sizes on February 23 and March 17. Growth measurements were made in the field and development of roots and shoots were studied under both field and greenhouse conditions. The cylindrical seeds averaged about 0.45 mm. long and 0.17 mm. in diameter. Each consisted of an embryo covered by a nearly transparent seed coat with numerous unicellular hairs about 2.12mm. long attached to the apex. Swelling of the seed of ten became evident within the first 12 hours of germination. After 24 hours the cotyledons were usually freed of the seed coat and had begun to separate. During the second day, emergence of the primary root was usually evident. Hair-like structures appeared in the hypocotyl region and the first leaf' primordia developed during the first week. The germination rate of all seeds was 32.5 per cent and 19.6 per cent from the reservoir and windbreak, respectively. Germination averaged 57.1 per cent complete by the end of 24 hours and 98.0 per cent complete after 5 days. Highest viability vas from seed produced in August (51.4 per cent) followed by July (40.3), November (26.6), and June (19 .0). As the age of seeds increased, viability tended to decrease. The greatest loss in viability was during the third and fourth month following collection. Fluctuations in germination rate of seed from the reservoir and windbreak were quite similar. Seed stored at 10° C maintained higher viability than that stored at -17 deg C or 25 deg to 30 deg C. Root development appeared to be greatly dependent upon soil moisture conditions. The primary root averaged about 16 mm. long after 3 weeks. During the third week secondary root development often started. After 6 weeks the primary roots often reached a length of 35 mm. and by the end of 10 weeks some of the roots had reached the bottom of 30-inch phytometers. Roots were not found extending into the water table except where it had recently risen. However, adventitious roots developed on portions of plant stems covered water or moist soil. Early shoot development was limited mainly to the production of new scale-like leaves in an alternate arrangement. The cotyledons appeared to function in most cases between 5 and 7 weeks. At this age the plants were about 6 in. tall. Also the first buds, which later formed basal shoots, were formed in the axis of the older leaves. Young shoots often grew prostrate along the soil surface until they were 1 to 10 cm. long. During this t1llle they often reproduced by layering. Flowers are produced in racemose clusters that form panicles at or near the end of vegetative branches. There are usually about 20 flowers per inch of raceme length. A flower averages about 22 ovules, each of which is capable of developing into a seed. Several hundred thousand seeds may be produced on a large mature plant during a season. Seed is often produced during the first year.

Rights

Copyright 1957 Daniel L. Merkel

Comments

Notice: This material may be protected by copyright law (Title 17 U.S. Code).

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