. Carnegie Institution of Washington publication. Imbibition and Growth of Opuntia. 135 tion or absorption action of the plasmatic colloids, which in the case of Opuntia are probably low in The growth of etiolated shoots of Opuntia is of an indefinite char- acter, as the length which such members may reach depends to a large extent upon the amount of available material and other features. Shoots which were already a few weeks old, and which had developed in a dark chamber kept at 16° to 18° C. were found to be growing at the rate of mm. daily. These were removed to a second cham
. Carnegie Institution of Washington publication. Imbibition and Growth of Opuntia. 135 tion or absorption action of the plasmatic colloids, which in the case of Opuntia are probably low in The growth of etiolated shoots of Opuntia is of an indefinite char- acter, as the length which such members may reach depends to a large extent upon the amount of available material and other features. Shoots which were already a few weeks old, and which had developed in a dark chamber kept at 16° to 18° C. were found to be growing at the rate of mm. daily. These were removed to a second chamber, in which the temperature was kept steadily at 16° C. for 3 days, during which time the rate varied from mm. to mm. daily. The temperature was brought up to 21° to 23° C. in 3 hours, and the rate was 5 mm. for the first day. During the second and third days at this temperature the rate rose to 7 mm. per day. The rate was mm. daily during the next 2 days and about 8 mm. daily for a final period of 16 hours. The temperature now being raised to 30° C. in 2 hours, and after that varying from 30° to ° C., the rate was 11 mm. daily during the first 16 hours, then at the rate of mm. during the succeeding 12 hours, during which time the elongation pro- gressed in a remarkably uniform manner. 46 8 10 m. 2 46 6 10 FIG. 24.—Auxographic record of varia- tions of length of etiolated shoot of Opuntia X26, at temperatures as be- low, sheet ruled to 10 mm. intervals: (a) downward movement of pen 7h30m a. m. to 9h40m a. m. denoting growth at tem- peratures of the stem of 45° to 49° C.; (b) growth checked for 20 minutes at 49° C.; (c) growth resumed at temper- ature of 49° C.; (d) shortening at ° to 52° C.; (e) stationary at ° C.; (/) growing at temperatures of 48° to 49° C.; (ff) shortening at 49° C.; (h) growing at 38° to 41° C.; (i) shorten- ing at 49° C. The rate itself was one which might have been identified with that of
Size: 1455px × 1718px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1900, bookyear1902
