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Accueil du site → Doctorat → États-Unis → 1973 → A PHYSIOLOGICAL GENETIC STUDY OF THE POPULATIONS OF IDRIA COLUMNARIS (KELLOGG) OF BAJA CALIFORNIA AND SONORA, MEXICO

University of Arizona (1973)

A PHYSIOLOGICAL GENETIC STUDY OF THE POPULATIONS OF IDRIA COLUMNARIS (KELLOGG) OF BAJA CALIFORNIA AND SONORA, MEXICO

Hall, Robert Lee

Titre : A PHYSIOLOGICAL GENETIC STUDY OF THE POPULATIONS OF IDRIA COLUMNARIS (KELLOGG) OF BAJA CALIFORNIA AND SONORA, MEXICO

Auteur : Hall, Robert Lee,

Université de soutenance : University of Arizona

Grade : Doctor of Philosophy (PhD) 1973

Résumé
Idria columnar !s Kellogg is a plant found only in the Sonoran Desert and is restricted in its distribution to the peninsula of Baja California, Mexico, and to a site in Sonora, Mexico on the Gulf of California. This study was undertaken to determine possible genetic varia tions in four morphological types of these plants. These morphological types have been designated : (l) Baja Pacifico, on the Pacific coast of the peninsula ; (2) Baja Interior, in the interior of the peninsula from San Ignacio north to E1 Socorro ; (3) Las Arrastras, about 25 km inland from the Gulf of California and east southeast of Santa Catarina on the peninsula ; and (4) Sierra Bacha, approximately 15 km south of Puerto Libertad, Sonora, Mexico. Twenty-one separate populations were utilized, ten of the Baja Interior type, six of the Baja Pacifico type, three classified as intermediate between interior and pacific types, one of the Las Arrastras type, and one Sonoran collection. The twenty-one collections were sub divided into four major groups consisting of three collections each and nine minor groups of one collection each. The major groupings were based on similarities in morphological type and geographical location. Comparisons were made on a basis of the weights of seeds and twenty-four-hour-old seedlings, the amount of protein in the seeds and i seedlings, and the electrophoretic patterns of amylase and esterase isozymes resolved on polyacrylamide gel for seeds and seedlings. The isozymic patterns were compared on a basis of polymorphism as indicated by the number of isozymic bands and the frequency of each band in a given population ; the frequency of each band in a particular morpholog ical type ; and a concordance comparison based on the percentage of similar isozymic bands. The results indicated an increase in the amount of protein and tissue weight with a decrease in latitude. All collections were highly polymorphic for the amylase and esterase isozymes observed. The comparisons of isozymic band frequencies and band similar ities found in the concordance measurements indicated that reproductive isolation that was correlated with geographic isolation and the result ing changes caused by genetic drift could best explain the high degree of diversity in the populations. It was also concluded, from analyzing these comparisons, that the Sonoran population was probably derived from the morphological type plants classed as Baja Interior.

Mots clés : Idria columnaris. ; Fouquieriaceae. ; Plant population genetics — Mexico. ; Plant physiology — Genetic aspects.

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