. The chemistry and mode of action of plant growth substances; proceedings of a symposium held at Wye College, University of London, July 1955. Plant regulators; Auxin; Growth (Plants). Natural auxins Similar investigations concerning the effect of pH and buffer concentration gave the results shown in Figures 15 and 16. Accordingly, a pH of 5-0 was used in all our experiments and a concentration of 10~^ M for KgHPO^ in the buffer was adopted. This is not the optimal concentration as far as the i ^â 0- 3-0 I 80 10 Ai^ena coleoptile 0-1 (b) Sorjhum first infernode. Alpena f/nsf inhnnode 10 0 0-1
. The chemistry and mode of action of plant growth substances; proceedings of a symposium held at Wye College, University of London, July 1955. Plant regulators; Auxin; Growth (Plants). Natural auxins Similar investigations concerning the effect of pH and buffer concentration gave the results shown in Figures 15 and 16. Accordingly, a pH of 5-0 was used in all our experiments and a concentration of 10~^ M for KgHPO^ in the buffer was adopted. This is not the optimal concentration as far as the i ^â 0- 3-0 I 80 10 Ai^ena coleoptile 0-1 (b) Sorjhum first infernode. Alpena f/nsf inhnnode 10 0 0-1 1 10 0 0-1 Buffer concentration ^ fO'^ M Figure 16. Effect of concentration of citrate-K phosphate buffer at pH 5-0 in the presence of sucrose on the growth of 4 mm sections. The lAA concentration was 50 yjl. in the case of oat coleoptiles and 10 yjl. for sorghum and oat first internodes. The concentration given along the abscissa is that of the K2HPO4 component; the concentration of citric acid is one half of it. coleoptile sections are concerned, but it was feared that lowering the con- centration would diminish the buffering capacity to such an extent that certain compounds separated on the chromatograms of plant extracts would change the pH considerably. -^3-0 E-0 ^ 1-0 I ^1-0 0 Coleoptile First internode (a) lAASoJl. / ^ (1)) Cc) IAAiOy/l. Con. 15 18^21 Bf 39 15 18 ^y 39 Time Hrs Figure 17. Effect o/^length of incubation on growth of oat sections in buffer -\- sucrose without added lAA {white circles, dotted lines) and with lAA {black circles, solid lines), and on the difference between these growths {curves {b) and {d)). Before time 0, the coleoptile sections had been presoaked for 3-5 hours in MnS04 â H2O (1 mg\l.) and the internode sections for 1 hour in glass-distilled water. To exclude the effect of light during the measurements, 5 replicates of 10 sections each were started at the same time; at each time interval, one of these dishes was measured and discarded. Th
Size: 1878px × 1331px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiver, booksubjectgrowthplants
