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Briefly, the rest-period perhaps begins to set in on account of the inhibition of the enzymes by the over- accumulation of the products of their work. This is the early rest of mid- or late summer. In the fall, excess supplies of carbohydrates continue to be accumulated and, with trees growing in the open, the further inhibition of the enzymes is actively aided by the approach of cool weather. These factors acting together bring about the main or middle state of rest. However, since dormant trees are never completely at rest, respiration continuing all the time, and doubtless enzyme activity too, the over-accumulation of carbohydrates is gradually reduced. Toward the last of this period occurs the after-rest, which, as the enzymes become more and more active, gives place to the beginning of growth.

Briefly, the rest-period perhaps begins to set in on account of the inhibition of the enzymes by the over- accumulation of the products of their work. This is the early rest of mid- or late summer. In the fall, excess supplies of carbohydrates continue to be accumulated and, with trees growing in the open, the further inhibition of the enzymes is actively aided by the approach of cool weather. These factors acting together bring about the main or middle state of rest. However, since dormant trees are never completely at rest, respiration continuing all the time, and doubtless enzyme activity too, the over-accumulation of carbohydrates is gradually reduced. Toward the last of this period occurs the after-rest, which, as the enzymes become more and more active, gives place to the beginning of growth.

Research has shown that diastatic, proteolytic, fat- splitting, and oxidizing enzymes all play a prominent part in bringing about, as well as ending, the rest- period in woody plants. Any forces or agents that will reduce the activity of these ferments will be the means of causing the rest-period to set in and, similarly, any agent that will stimulate the enzymes into activity will be the means of bringing the rest-period to an end. (See Research Bulletins Nos. 1, 15, 16, 17, 21, Missouri Agricultural Experiment Station.) W. L. Howard.

Research has shown that diastatic, proteolytic, fat- splitting, and oxidizing enzymes all play a prominent part in bringing about, as well as ending, the rest- period in woody plants. Any forces or agents that will reduce the activity of these ferments will be the means of causing the rest-period to set in and, similarly, any agent that will stimulate the enzymes into activity will be the means of bringing the rest-period to an end.

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