AuthorAriffin, Radziah Bt.
KeywordsDesert flora as food.
Desert plants as food.
Desert plants -- Arizona.
Desert plants -- Mexico.
Desert plants -- California.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Degree ProgramGraduate College
Nutrition and Food Science
Degree GrantorUniversity of Arizona
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Horticultural characteristics of seven Sonoran Desert woody legumes which show potential for southwestern landscapingJohnson, Matthew Brian, 1958- (The University of Arizona., 1988)Many plants are not commercially produced due to a lack of accessible information on their horticultural requirements and landscape potential. Members of the Legume Family (Leguminosae) are often conspicuous components of the vegetation of arid and semi-arid subtropical regions. Many of these plants are suitable for landscaping use in areas suited to their cultivation. Coursetia glandulosa, Erythrina flabelliformis, Eysenhardtia orthocarpa, Haematoxylon brasiletto, Lysiloma watsonii, Pithecellobium mexicanum, and Sophora arizonica are woody legumes native to the Sonoran Desert region which offer a variety of form, texture, color and function. All of these plants grow readily from scarified seed. E. flabelliformis and E. orthocarpa are easy to propagate from stem cuttings. Some irrigation is necessary for establishment and reasonable growth in the landscape. Maintenance and pests are minimal. Freezing temperatures are the primary limiting factor to several of the plants. S. arizonica is slow growing and is prone to rot in the nursery.
Adaptation, history, and development in the evolution of a desert annual life history.Fox, Gordon Allen. (The University of Arizona., 1989)Individuals of Eriogonum abertianum Torr. (Polygonaceae) flower in spring, or following onset of summer rains, or both. Within populations flowering time is mainly environmentally determined: there is little genetic variance for flowering time, and experimental moisture limitation significantly delays flowering. In the field a Sonoran Desert population experienced significantly more mortality during the foresummer droughts, and had a significantly greater proportion of spring-flowering plants, than a Chihuahuan Desert population. Greenhouse experiments suggest a genetic basis for differences in size and time of flowering between these populations. Fossil and biogeographic evidence support an adaptive interpretation of earlier flowering in the Sonoran Desert. A model of selection comparing spring-plus-summer flowering with spring-only flowering suggests that expected summer fecundity may not offset the risk of foresummer mortality in the Sonoran population. Rather than switching to a spring-only habit as predicted by the model, the species' range ends where summer rainfall declines abruptly. The invariance of the spring-plus-summer habit is not explained by the demographic, historical, or genetic data. Plants which live for more than a year in the wild have offspring which, in the greenhouse, live longer than the offspring of the general population. This suggests a genetic basis for the occasional observed perennation. Analysis of a quantitative genetic model suggests that when adult survivorship is low, selection will generally reduce perennation. The annual habit is thus likely to persist even in the presence of genetic variation for perennation. Optimal control models of plant carbon allocation are extended to include within-season mortality and allometric growth constraints. When parameters are varied in numerical experiments, resulting predictions for easily measurable characters (e.g., time to first flower) often vary only slightly; most differences are in fitness, suggesting that satisfactory empirical tests may be difficult to conduct. Arbitrary mortality functions can optimally lead to multiple flowering episodes, and this can depend sensitively on parameter values. Optimal trajectories with allometric constraints are divided into a period of vegetative growth and another period of mixed growth.
Transpiration and conductance responses of salt-desert vegetaion in the Owens Valley of California in relation to climate and soil moistureWarren, Daniel Cram. (The University of Arizona., 1991)Work presented in this dissertation was performed in the salt-desert environment of the Owens Valley of California. The area experiences low-rainfall, hot summers, but has a high water table, seldom more than 5 meters from the surface. To test differences in plant species wateruse, a steady-state porometer was used for transpiration measurements while a 2-meter point-frame was used to estimate leaf area index on each species studied. The five species studied (Atriplex torreyi, Chrysothamnus nauseosus, Distichlis stricta, Sporobolus airoides, and Sarcobatus vermiculatus) varied with regard to photosynthetic pathways and leaf morphology. Water-use differences among species are hypothesized to be related to the differing physiological and morphological characteristics observed in the different species studied. This work focuses upon methods for integrating porometric transpiration rates and point-frame measured leaf area to estimate daily plant water-use. Daily water-use values are correlated with environmental growth conditions. A computer program was developed for scenario testing so that conclusions could be drawn concerning how given plants respond to different conditions of soil moisture and atmospheric evaporative demand. The computer-aided calculations led to conclusions that low water-use behavior characterizes A. torreyi, and high water-use behavior characterizes C. nauseosus. C4 photosynthesis and low leaf conductance may contribute to the success of A. torreyi on fine-textured soils when water transfer rates to roots are limiting to transpiration. Fine-textured soils may inhibit production in C. nauseosus because the species requires higher rates of transpiration to achieve optimal growth than soil hydraulic conductivity allows. These conclusions have implications for land managers who should recognize that climax plant communities in saltdesert regions are better at conserving water and stabilizing soil than is colonizing vegetation. Management should seek to maintain climax vegetation cover because restoration is difficult once vegetation disturbance occurs.