Rapid Auxin-induced Decrease in Free Space pH and Its Relationship to Auxin-induced Growth in Maize and Pea.
نویسندگان
چکیده
A pH microelectrode has been used to investigate the auxin effect on free space pH and its correlation with auxin-stimulated elongation in segments of pea (Pisum sativum) stem and maize (Zea mays var. Bear Hybrid) coleoptile tissue. Auxin induces a decrease in free space pH in both tissues. In maize coleoptiles, free space pH begins to fall within about 12 minutes of exposure to auxin and decreases by about 1 pH unit by approximately 30 minutes. In pea, pH begins to decrease within an average of 15 to 18 minutes of exposure to auxin and falls by about 0.9 pH unit by approximately 40 minutes. Auxin-stimulated elongation, measured in the same two tissues similarly prepared, appears in maize at the earliest 18 minutes after auxin application, while in pea it appears at the earliest 21 to 24 minutes after auxin application. The auxin analogs p-chlorophenoxyisobutyric acid and phenylacetic acid do not stimulate elongation above control levels in maize or pea tissue segments and do not cause a decrease in free space pH in either tissue. These findings are consistent with the acid secretion theory of auxin action.
منابع مشابه
On the Relationship between Extracellular pH and the Growth of Excised Pea Stem Segments.
Studies with stem segments of peas (Pisum sativum L. var. Alaska) suggest that the pH of the medium bathing elongating tissue does not always reflect intramural (cell wall) conditions or that pH is not a controlling factor in elongation. Peeled, green segments, and peeled or nonpeeled etiolated segments appear to regulate the pH of their bathing medium causing it to become acidified with or wit...
متن کاملAuxin-induced growth of Avena coleoptiles involves two mechanisms with different pH optima.
Although rapid auxin-induced growth of coleoptile sections can persist for at least 18 hours, acid-induced growth lasts for a much shorter period of time. Three theories have been proposed to explain this difference in persistence. To distinguish between these theories, the pH dependence for auxin-induced growth of oat (Avena sativa L.) coleoptiles has been determined early and late in the el...
متن کاملInfluence of Auxins on in vitro Incorporation of Glycine-C'4 in Pea Shoot Proteins
Radlioactive amiino aci(ds have been utilized in the stu(ly of protein synthesis in both detached plant tissues and plant mitochondria. When a plant tissue is incubated in the presence of a radioactive amino acid, the radioactivity is rapidly accumulated in the cells (1, 7, 8, 11, 12, 13, 14). The accunmulation process is dependent on respiration and varies somewhat according to the amino acid ...
متن کاملInhibition of RNA synthesis and auxin-induced cell wall extensibility and growth by Actinomycin D.
A linear stress strain analyzer was used to determine the effects of inhibitors of RNA and protein synthesis on auxin-induced increases in cell wall extensibility. With etiolated soybean hypocotyl, maize mesocotyl and Avena coleoptile sections and light-grown pea internode sections, inhibition of RNA synthesis resulted in inhibition of auxin-induced extensibility changes and cell expansion. The...
متن کاملReexamination of the Acid Growth Theory of Auxin Action1
Some crucial arguments against the acid growth theory of auxin action (U Kutschera, P Schopfer [1985] Planta 163: 483-493) have been reinvestigated by simultaneous measurements of proton fluxes and growth of maize (Zea mays L.) coleoptiles. Special care was taken to obtain a mild, effective, and reproducible abrasion of the cuticle. Proton secretion rates were determined in a computer-controlle...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Plant physiology
دوره 58 2 شماره
صفحات -
تاریخ انتشار 1976