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University of Arizona (1972)

CARBOHYDRATE RESERVES AND PHOTOSYNTHESIS IN THE HILARIA GENUS

Pinkney, Fred Coatsworth,

Titre : CARBOHYDRATE RESERVES AND PHOTOSYNTHESIS IN THE HILARIA GENUS

Auteur : Pinkney, Fred Coatsworth,

Université de soutenance : University of Arizona

Grade : Doctor of Philosophy (PhD) 1972

Résumé partiel
During 1970 and 1971, carbohydrate reserves in stem bases and photosynthesis and respiration rates of the Hilaria species and sources were measured. The objectives were : (1) to determine the annual total nonstructural carbohydrate (TNSC) levels in stem bases of the Hilaria species and sources, (2) to quantitatively compare net photosynthesis and respiration rates at three temperature regimes for three seasons of the year, and (3) to relate the net photosynthesis and respiration rates to the TNSC study. Annual TNSC curves of curly mesquite (Hilaria belangeri), tobo sa (H. mutica), big galleta (H. rigida), and galleta (H. jamesii) sources from Arizona, New Mexico, Nevada, Utah, and Wyoming were deter mined from stem base samples collected from plants grown in a trans plant garden at the Plant Materials Center (PMC), Tucson. Annual TNSC curves also were determined for all four Hilaria species growing in their natural habitat in the Yavapai County area of Arizona. Stem base samples were collected at 2-week intervals during the active growing season from March to October, 1970, and at 1-month intervals from Decem ber, 1970, to April, 1971. The TNSC of the stem bases were determined by digestion with takadiastase enzyme, extracted with water, and measured colorimetrically using the anthrone reagent technique. Laboratory studies of net photosynthesis and respiration rates of potted Hilaria plants collected from both the PMC, Tucson, and the Yavapai County sites were measured at 5, 21, and 38 C during the spring 1970, fall 1970, and summer 1971 growing seasons. Rates were determined using temperature controlled aluminum chambers and infrared gas analyzer apparatus. The annual TNSC curve of curly mesquite at PMC, Tucson, exhibited both a spring and fall pattern of TNSC accumulation. Spring TNSC accumu lation was accentuated by late spring drought in Yavapai County area. Annual TNSC curve for Arizona galleta at PMC, Tucson, showed late fall or winter maximum TNSC accumulation. Net photosynthesis and respiration rates helped explain differences in TNSC accumulation patterns of curly mesquite and Arizona galleta. Arizona galleta had higher photosynthesis rates than curly mesquite at 5 C, whereas curly mesquite had higher photosynthesis rates than Arizona galleta at 21 and 38 C. Tobosa grown under a good moisture regime at the PMC, Tucson, exhibited an annual TNSC curve similar to that of Arizona’ galleta. In the Yavapai County area, however, the annual TNSC curve for tobosa was intermediate to the TNSC patterns of curly mesquite and Arizona galleta. The annual TNSC curve for big galleta in the Yavapai County area was similar to the tobosa annual TNSC curve in Yavapai County.

Mots clés : Tobosa grass. ; Plants — Metabolism. ; Photosynthesis.

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Page publiée le 23 février 2018