Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Fabian D. Menalled. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 36-37). Also available via the Internet.

Thesis (Ph. D.)--Johns Hopkins University, 1927. / Vita. "Reprinted from Journal of agricultural research, 39 ... July 15, 1929." "Literature cited": p. 127-128.

Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2007. / Gethyllis multifo/ia and Gethyl/is villose (Family: AMARYLLIDACEAE) are indigenous geophytes, growing naturally in the Worcester area, Western Cape. G. muliiiolie falls in the Vulnerable category of the Red Data List of Southern African Plants while G. vil/osa is not threatened at all. Both these species are winter growers and start their growing phase between March and April. These bulbs start their dormant phase between September and October when their leaves start to die down. Flowers of both species are short-lived and borne towards the end of November and early December when no leaves are present. The leaves and berries are simultaneously pushed above ground at the onset of the new growing phase. The fruit of some Gethyl/is species is sweet, juicy, pleasantly aromatic and good to eat and has medicinal properties for the cure of various ailments. The genus is difficult to propagate asexually and very little is known about its propagation and cultivation. The fragrance and medicinal value of the fruit of G. multifolia necessitates future research in the commercial production of this species. A habitat observation study of the two species was conducted to assess the vulnerable status of G. multitolie. Asexual propagation experiments were conducted to find ways of reproducing these two species successfully. A hydro culture study was also conducted to ascertain whether this method of cultivation could be incorporated in the general cultivation of the two species. Finally an in vitro propagation study was conducted to look at faster methods of reproducing these two species. This is of extreme importance in the conservation of the vulnerable G. multitolie. Leaf, root and basal plate cuttings were unsuccessful with no rooting in both species. G. mulfifo/ia bulbs were propagated successfully using twin scaling, bulb cuttings, scooping and scoring propagation techniques with between 80% and 100% rooting success. G. vil/osa was unsuccessful using the above propagation techniques with a 0 - 40% rooting rate. Although Gefhyl/is species in general are sensitive to over-watering, the hydro culture experiment with the sub-irrigation system and leca pellet medium proved to be an effective method of cultivating both species throughout the growing phase. G. mulfifo/ia proved to be unsuccessful during the initial in vitro propagation experiments with no surviving explants during the initiation phase. Results improved with an increased number of trials. It is possible to grow both species by means of in vitro propagation, but more emphasis in future research, should be placed on the multiplication aspect of G. mu/tifo/ia, since not many new buibiets were produced. It was observed through this study that grazing domestic livestock, urban expansion (this includes agricultural extension) and in some cases the lack of interest shown in our indigenous plant species, are some of the main factors influencing the decline in numbers of this species. It is also recommended that more emphasis be placed on the conservation of South Africa's indigenous flora and that the vulnerable status of G. multifolia according to The Red Data List of Southern African Plants, be changed to the "Endangered category" as the factors causing its decline continue to increase.

Syncarpha recurvata (L.f.) B. Nord. (Asteraceae, Gnaphalieae) is listed as a vulnerable (intermediate priority) species. The propagation methods of achene germination, stem cuttings, air layering and micropropagation were investigated to obtain an efficient propagation method. Smoke water dilutions of 1:100, 1:50 and 1:10 significantly increased germination, with the 1:100 smoke water dilutions showing the highest germination percentage (22.4 percent). Achenes collected between August and October 2005 showed higher germination and viability than achenes collected between May and July 2006. Fifty percent of the stem cuttings and 32 percent of the airlayered branches rooted. Embryo culture was the only successful culture type out of the four attempted. Two embryos germinated and four became photosynthetic. Two of the germinated embryos also produced callus cells, a medium supplemented with 5 μM IAA may be used to test for a suitable plant regulator for organogenesis or embryogenesis. Syncarpha recurvata plants were also transplanted into pots and 60 percent survived. A growth rate of 1.466 mm y-1 was obtained from total shoot length measurements. In this study, it was found that air-layering branches of transplanted Syncarpha recurvata plants is the most efficient propagation method.

Phytoremediation is a tool that uses plants that can absorb and accumulate metals in harvestable portions of the plant to cleanse contaminated soils. Most metals are more soluble in soils with an acidic pH. Nitrogen fertilizers acidify pH by different reactions in the soil. Goals of this research were: (1) develop a zinc-contaminated soil; (2) determine effects of nitrogen fertilizers on soil-zinc availability; (3) determine Zn-phytoextraction potential of Brassica juncea Czern. and Festuca arundinacea Schreb.; and (4) determine concentrations of nitrogen fertilizers needed to maximize Zn solubility in soils. After a 14-day incubation period, very little Zn in the soil was water-extractable, which suggested that Zn was reacting with the soil; therefore, an incubation time of 14 days was utilized. Morgan's solution, extracted higher concentrations of Zn than water. If soils were sequentially extracted with water, Morgan's solution, and Mechlich-3 solution, water extracted the least amount of Zn, Morgan's solution extracted higher concentrations than water or Mehlich 3, but Mehlich 3 extracted higher concentrations than water. Lowest pH values occurred with additions of urea (pH 5.18), sludge (pH 4.89), or calcium nitrate (5.26) than with compost (pH 5.33), manure (pH 5.50), or no fertilizer (pH 5.40) or if N was supplied at 400 mg/kg (pH 4.91). Brassica did not germinate well or survive in soil-Zn concentrations greater than 125 mg/kg. Soil-Zn concentrations utilized with brassica were 0 to 100 mg/kg. Highest accumulation of Zn was 0.29% of the dry mass, which occurred at 100 mg Zn/kg or in soils with urea added. Water-extractable Zn at this level averaged 1.1 mg/kg and Morgan's extractable Zn averaged 18 mg/kg. Fescue germinated well in soil-Zn concentrations ranging from 0 to 2000 mg/kg. The soil-Zn concentrations utilized with fescue were 0 to 1000 mg/kg. Highest accumulation of Zn by fescue was 0.33%, which occurred at 1000 mg Zn/kg or in soils with urea or sludge added. Water-extractable concentrations of Zn at this level averaged 11 mg/kg and Morgan's extractable Zn concentrations averaged 290 mg/kg. This research showed that fescue has phytoremediation potential that is as good or better than that of brassica.

Field, greenhouse, and laboratory studies were conducted with the following objectives: (1) develop an efficient extraction and analytical method for determining concentration of major flavonoids in apple (Malus domestica Borkh.) leaves, (2) determine if differences exist in levels of these components in leaves of ten apple cultivars and if these differences explain variation in cultivar susceptibility to spider mites ( Acari: Tetranychidae), (3) understand the effects of varying light and nutritional regimes on apple leaf flavonoid levels, (4) assess if the flavonoid phloridzin, when applied to bush bean plants, affects Two Spotted Spider Mite population density, and (5) Determine if summer pruning of mature, field-grown apple trees influences levels of foliar phloridzin. An efficient extraction and HPLC analytical method is presented using commonly available and least toxic solvents and an isocratic HPLC run of short duration allowing calculation of unknown concentrations with a high degree of accuracy. Different cultivars showed significant differences in mite susceptibility and in phloridzin concentration in leaves. However, phloridzin differences do not appear to explain variation in cultivar susceptibility to spider mites. Greenhouse trials indicated that phloridzin concentration was significantly lower in leaves of potted trees of the four cultivars tested under 70% shade cloth than under full sun. All cultivars responded similarly to sun or shade in regard to percent dry weight phloridzin. Nutrition treatments appeared to have an effect on phloridzin levels only in 1995. Horticultural bush bean plants (Phaeseolus vulgaris) were either sprayed or injected through a cotton wick with 0.01 M phloridzin or distilled water, and seeded with 5 gravid female Tetranychus urticae mites. Phloridzin, either when applied topically to bean plants, or when introduced into the transpirational stream via a cotton wick, resulted in smaller numbers of T. urticae compared to plants which were not treated with phloridzin. Summer pruning of mature, field grown “McIntosh” apple had no effect on phloridzin concentration, likely indicating that summer pruning is not a stimulus of induced changes in flavonoid content.

No description available.

No description available.

<i>Clematis addisonii</i> Britton (Ranunculaceae) is a Virginia endemic restricted to calcareous soils in a four county region of the Ridge and Valley Province in Virginia. A two year study of the reproductive biology of this species reveals that it is self-compatible, showing no significant reduction in fecundity following self-pollinations. Morphological observations indicate that this species is protogynous. <i>In vivo</i> pollen tube growth supports this conclusion. Field observations suggest that the morphological pistillate phase lasts significantly longer than the staminate phase and is sufficient enough in length that cross-pollination is likely to occur during the time period preceding the staminate phase. The secretion of nectar from the onset of anthesis enhances the probability that outcrossing will occur prior to the presence of self-pollen in flowers. These findings suggest that, in spite of self-compatibility, populations of <i>Clematis addisonii</i> are capable of maintaining high levels of outcrossing by virtue of protogyny and nectar secretion from the onset of anthesis. / Master of Science