Embryo Abortion in the Peach in Relation to Chemical Composition and Season of Fruit Ripening

Embryos of ten varieties of the peach, whose several seasons of fruit ripening extend from early to late, were examined and chemically analyzed at or near the time the fruit was ripe. For comparison, embryos of a single late-ripening variety (Elberta) were analyzed periodically throughout the season. 2. Embryos of Elberta were flaccid and only partially filled the integuments during stage II of fruit development, so that seed became shriveled when removed from the fruit. At the time of fruit ripening, embryos were firm and completely filled the integuments. 3. Embryos of the earliest-ripening variety were abortive and disintegrated at fruit ripening. Embryos of each successively later-ripening variety were larger, firmer, and more nearly filled the integuments. 4. At fruit ripening, embryos of a late-ripening variety contained 45.03 per cent moisture, 30.67 per cent fat, 2.60 per cent nitrogen, 2.32 per cent sucrose, and 0.23 per cent reducing sugars. Embryos of early-ripening varieties showed a higher moisture content and lower content of fat, nitrogen, reducing sugars, and sucrose. 5. There is a steady increase in growth, loss of moisture, and accumulation of storage materials in embryos of all varieties, and an abrupt check in these processes as the ripening date for each successive variety is reached. 6. If the moisture, fat, and nitrogen content of the embryos of the nine varieties are plotted with reference to the time of fruit ripening, the composite graph so formed is similar to that for the development of a single variety. 7. The close similarity already observed in growth of embryos in different varieties, regardless of season of fruit ripening, extends to chemical changes within the developing embryos as well.