Relation Between Fruit Size and Food Supply in the Tomato

Abstract

Recently GUSTAFSON and STOLDT (2) made a study of the relation between leaf area and fruit size of the tomato. In this study it was found that by increasing the leaf area per fruit, the size of the fruit produced was also increased. In their experiments the leaf area was not adjusted until after the ovary had completed its growth and the fruits had set. It has therefore seemed desirable to attempt to influence the size of the fruit while the ovary is being formed as well as during the period of its development into a fruit. In the present study we have measured the volume of the ovaries at the time of blossoming, the volume of the mature fruits, the cell size of these ovaries and mature fruits, and the diameter of the pith of the stem just below the insertion of the flower cluster; and we have also counted the number of locules in the fruits measured. ProcedureAbout 700 experimental plants (John Baer) were set out in the field and 200 were left in the greenhouse, in 8-inch pots. These were all pruned to one stem and staked; and as new buds appeared in the leaf axils they were removed to keep the plant in the one-stem condition. Next to the experimental plants in the field were available, for comparison, other John Baer plants grown in the usual way with many branches and not staked. These bore heavily during the early part of the season. Beginning with the third cluster all fruits set were allowed to develop on the control plants. The experimental plants, on the other hand, were permitted to bear fruits in only one cluster per plant, and not more than eight fruits per cluster. At the time of blossoming 117 plants were selected for bearing in the third cluster, 120 for the fourth, 124 for the fifth, and 97 plants bore fruits in the sixth cluster. Many of these plants did not develop properly and the number of plants from which the fruits were harvested was somewhat smaller than the original number of plants selected at the time of blossoming. Attempts were made to select uniform plants which had unbranched flower clusters; but this was not entirely feasible for the fifth and sixth clusters.The growing conditions were very satisfactory until about the middle of July when the temperature became quite high and remained so for several weeks. There was also very little rain during this time but the latter con-

Anatomical aspects of blossom-end rot in the tomato with special reference to calcium nutrition

“…When the fruit enters the period of ontogeny in which it may show symptoms of blossom-end rot, its development is characterized by cell enlargement. In this regard Houghtaling (1935) and Gustafson and Houghtaling (1939) found that little or no cell division occurs after anthesis in the ovary wall. Smith (1935), in a less detailed study of this aspect of development, reports that cell division continues until about 14 days after pollination.…”