Total and nitrate nitrogen determinations were made on various organs of parthenocarpic Mission and Adriatic fig varieties and nonparthenocarpic Calimyrna and Stanford varieties. Total and nitrate nitrogen fluctuated in definite cycles which were associated with season and plant part. All organs analyzed had the highest percentage of nitrogen relative to dry-weight at the start of growth and the lowest when growth had ceased. Three distinct phases appeared in the nitrogen cycle of the developing fruit; these were shown as a double sigmoid curve of opposite directional trend to the curve showing fruit growth in diameter.

High nitrate nitrogen was present in all plant parts analyzed, particularly in current-season’s growth and leaves. While the values for total nitrogen were not greatly different, those for nitrate nitrogen in all plant parts of parthenocarpic varieties were several times higher than in identical parts of nonparthenocarpic varieties. Thus, there was a positive relation between nitrate level and the expression of parthenocarpy.