. Auxins and plant growth. Auxin; Plant growth promoting substances. Theories of Auxin Action 177 of obtaining the values is based on an elaboration of the assumptions made in the equation given. The derivation methods are described clearly by Foster et al (1952) and by Bonner (1953). By measuring growth rates over a range of auxin concentrations, and plotting the results by the double inverse method of Lineweaver and Burk (1934), the maximal growth rate may be estimated as the intercept of the plotted line with the abscissa. The method is illustrated in figure 78. The K value may be estimated
. Auxins and plant growth. Auxin; Plant growth promoting substances. Theories of Auxin Action 177 of obtaining the values is based on an elaboration of the assumptions made in the equation given. The derivation methods are described clearly by Foster et al (1952) and by Bonner (1953). By measuring growth rates over a range of auxin concentrations, and plotting the results by the double inverse method of Lineweaver and Burk (1934), the maximal growth rate may be estimated as the intercept of the plotted line with the abscissa. The method is illustrated in figure 78. The K value may be estimated by the slope of the plotted line. An auxin with a weak attraction for the receptor should have a relatively steep slope of the plotted line. Also a weak auxin should yield a low maximum velocity of growth, the intercept of the plotted line with the abscissa should be high, the growth rates being plotted on an inverse scale. Maximal growth rates and K values have been measured for several auxins by Foster et al (1952), who found that auxins which produced the greatest maximal growth rates also had the highest affinity for the LjJ I- 2i". Auxin Promotion max 20 40 60 80 100 INVERSE OF AUXIN CONC. (l/g) Fig. 78. The promotion and inhibition of ;3^owth by indoleacetic acid plotted by the double inverse method. Growth rate of Avena coleoptile sections as inverse of mm. per 12 hrs., auxin concentration as inverse of mg. per 1. (from Foster et al, 1952).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Leopold, A. Carl (Aldo Carl), 1919-. Berkeley, University of California Press
Size: 1849px × 1352px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublisherberkeleyuniversityofcaliforniapre
