Responses of Vegetative Parts of Plants Following Application of Extract of Pollen from Zea mays

1. Extracts from pollen of Zea mays mixed with lanolin were applied to certain vegetative parts of various species of plants, particularly to those of Phaseolus. 2. Application of the extract in the form of a ring around the stems of bean plants resulted in marked internodal elongation, which was associated mainly with an increase in the length of the cells of the various tissues, rather than with an increase in the rate of cell division. Small amounts of indoleacetic acid applied in a similar way also resulted in increased linear growth of internodes, but to a less extent. 3. Greatest increase in linear growth of bean stems resulted when the extract was applied to internodes of plants grown in light of an intensity and quality most favorable for the development of short sturdy stems, and there was little or no difference between internodal elongation of treated and control plants grown under light conditions that favored etiolation. 4. Small tumors generally resulted following application of the pollen extract to the cut surface of decapitated second internodes of bean plants. Histological responses associated with the growth of these tumors were unlike those that resulted following the application of relatively concentrated mixtures of indoleacetic or naphthaleneacetic acids and lanolin, but more closely resemble those recorded for tryptophane.