Relation of Seededness and Ringing to Gibberellin-like Activity in Berries of Vitis vinifera.

(ibl)berellinl-like stulstances occtlr in mianv higher pllants (1 2, 17, 20). and sexeral have beenl idenitified (12). Tlhe presence of gibberelliln-like activity in seedless fruit, of V'itis v'iiifcra L. was (lenlonstrated in 1960 by Coombe (1). Although it seemiis probable that sulch a widely spread hormonie also would be invxolved in the groxwth of seede(d fruit, Coombe was unable to demnonstrate the presence of gibberellin in crude extract fromii such frtuit. One objective of the present research was to study clhromnatographed extracts of both seeded and(i seedless varieties of grap)es to determinie the presence of gibberellin-like activity. In the plast. much extraction for gibberellinis wvas donie at low pH. In our work we tuse(d 3 acid( fractionls. In ad(litioni a netutral extract was obtained, as several investigators have (lenlonlstrate(l the presence of gibberellin-like actixityin nieutral portionis of extracts (2, 3, 4, 5. 6, 21). To l)roadlen the spectrumiii a basic fraction \ as also examinied. A secol(l ol)jective \\-as to (leteriinie the effect of ringing (girdling ) oni gibberellin-like activity in the berries. It is wvell knlownN-i that a temporary riniginig of certain varieties of fruit trees anid grapes increases the size of (leveloping fruits. Ringing lonlg hCas beeni lracticed to inicrease the size of lBlack Corinith anid Thompson Seedless berries (7 ). The classical theorv is the enilargemiienit of the fruit resuilts from the ilncreased suppl)l of elaborated food miiaterial trappe(l above the rinlg. Aniother possibility. however. is that planlt hormilonies trappedl above the rinig cause fruiit enlargemiient. Onle miietho(d for greatly enlarginig fruits of these varieties is to treat unirinlged vines With exogenious gibberellins (19). Since both ringinlg and treatment wvith gibberellins result in enlarged fruiit, it is likely that riniging may affect tlle enidogellotus gibberellin colntenlt of the lberries.