NATURAL GROWTH SUBSTANCES IN CONCORD AND CONCORD SEEDLESS GRAPES IN RELATION TO BERRY DEVELOPMENT

Nitsch, J. P., C. Pratt, C. Nitsch, and N. J. Shaulis (Cornell U., Ithaca, N. Y.) Natural growth substances in Concord and Concord Seedless grapes in relation to berry development. Amer. Jour. Bot. 47(7): 566–576. Illus. 1960.—A comparative study was made of the development of the grape berry in the ‘Concord’ variety and its presumed mutant, ‘Concord Seedless.’ This study included fresh and dry weight determinations, embryological observations, measurements of growth substances active on the oat first-internode test and preliminary determination of other growth factors stimulating the growth of excised Jerusalem artichoke tissues in aseptic cultures. Four phases could be distinguished in the growth of the ‘Concord’ berry: Period O—limited growth and low growth-substance content; Period I—rapid growth and high growth-substance concentration; Period II—marked slowing down in growth and sudden drop in the growth-substance level; and Period III—resumption of active increase in fresh and dry weight with no increase in growth-substance concentration. In the ‘Concord Seedless’ variety, growth of the nucellus and production of growth substances increased faster during Period 0 than in ‘Concord,’ but degeneration of the endosperm and reduction in the growth-substance level followed during the middle of Period I. Period II was inconspicuous. Early growth-substance production in both varieties seemed to be associated with nucellus rather than with endosperm development. Some 6 different substances promoting growth in the Avena first-internode test could be separated on paper chromatograms. None of them was chemically identified.