PRELIMINARY EXPERIMENTS ON THE RELATION OF GROWTH-PROMOTING SUBSTANCES TO THE REST PERIOD IN FRUIT TREES

Abstract

Pear and cherry buds prolonged in their rest by warm greenhouse temps. contained no auxin or precursor of auxin; buds from orchard trees or trees held in cold storage for several weeks contained a precursor of auxin, or auxin, in significant amts. Growth of buds did not occur on greenhouse trees. Buds on trees in cold storage grew slowly after about 3 months. On apple, pear and peach trees held in a warm greenhouse attempts to induce bud growth were made by injecting auxin and other substances into the trees through cut branches. Water, [beta] indole acetic acid, tryptophane, trypta-mine, vitamin B1, dinitro-ortho-cyclo-hexyl-phenol and yeast extract were injected. Yeast extract stimulated the largest number of buds and the most vigorous growth. [beta] indole acetic acid produced much less stimulation than yeast extract but more than the other substances. The growth induced by yeast extract was vigorous but soon ceased.