. Carnegie Institution of Washington publication. '.046 .609 perature, as far as the observations show, occurred very early, at 9h30m The temperatures at which the two minima occur are much more nearly in agreement than are the corresponding evaporation rates. Obviously light intensity can play no important role in the response. On the whole this curve of transpiration agrees fairly well with that of Experiment IV, and points to the same general conclusion. The variation in relative transpiration in the middle portion of the period of this experiment was from a maximum of to a
. Carnegie Institution of Washington publication. '.046 .609 perature, as far as the observations show, occurred very early, at 9h30m The temperatures at which the two minima occur are much more nearly in agreement than are the corresponding evaporation rates. Obviously light intensity can play no important role in the response. On the whole this curve of transpiration agrees fairly well with that of Experiment IV, and points to the same general conclusion. The variation in relative transpiration in the middle portion of the period of this experiment was from a maximum of to a minimum of , or from unity to about one-eighth, which is the same as in the other specimen of this form used in the last experi- ment. The present plant had more young leaves than did the previous one, and this fact may explain why its hourly rate of water loss per unit area was higher than in the former case. Experiment VI. — The sub- ject was a plant of Allionia incarnata, consisting of three shoots, each about 15 cm. long, coming from a single root. Flowers were opening during the experiment. The plant was sealed at ll"30m , August 15, and the record of weighings was continued until 3"30"', August 17, when wilting en- sued. The plant was exposed to bright sunshine during the daytime. The evaporimeter for use in sunshine was not available until 3"30m p. m., August 16, so that relative transpiration was not obtained till after that time. The total leaf area was sq. cm., and the average hourly rate of transpiration from the entire plant for the whole period of the experiment was gram, or gram per unit of leaf surface. Since the aver- age daily rate of transpiration remains practically uniform throughout the experiment, and does not fall toward its end, this hourly rate may. \I38 73.!.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and
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