FRUIT MATURATION IN THE SHRUB LIGUSTRUM-VULGARE (OLEACEAE) - LACK OF DEFOLIATION EFFECTS

The effects of four levels of defoliation (12, 25, 50, and 75%) of ind ividual branches at the time of flowering on fruit and seed production of a shrub, Ligustrum vulgare L., were studied. The experimental desi gn also allowed examination of the extent of branch independence, the effects of the positions of leaves removed, and the influence of leaf number on fruit and seed production. In contrast with most previous ex periments of this type, the defoliation treatments had no effect on th e percentage of flowers producing ripe fruits; they also had no effect on the phenology of fruit abortion or abortion rate. Either the fruit s were filled from stores in the stem, or other branches supplied the assimilates needed. On control plants the variation in fruit productio n between branches within plants was larger than that between whole pl ants. The most important source of variation for fruit size and seed n umber per fruit was found in the within-branch component of variance. Leaf number per branch was important in determining flower number, and indirectly affected fruit number. The number of flowers per branch ac counted for 54% of the variation in fruit production.