HORMONE AND HISTOLOGICAL DIFFERENCES BETWEEN NORMAL AND MALEIC HYDRAZIDE TREATED ONIONS STORED OVER WINTER

F.M.R. Isenberg, T.H. Thomas, M. Pendergrass, M. Abdel-Rahman
Two studies are reported in this paper, one a histological series showing the sequence of events in the development of onion shoot apices into speath and leaves in normal bulbs stored at low temperatures over a 9-month period and the abnormal development in bulbs treated prior to storage with 3,6-dihydroxy-pyrridazine (MH) and stored under the same conditions. The second study consisted of a bioassay series for auxins, gibberellins, growth inhibitors, and cytokinins performed on similar normal and treated bulbs, grown and stored in the same manner. Three major periods were characterized: rest, dormancy, and regrowth. During rest there was no visible cellular activity, while cytokinin, gibberellin and auxin activity were at very low levels and inhibitor activity high. Growth promoter activity was less in MH treated bulbs than in normal ones. Dormancy in normal bulbs was characterized by renewed cellular activity manifested by mitotic figures and cell divisions. There were great increases in cytokinin activity beginning in December, followed by greatly increased gibberellin activity thought to be associated with vernalization in January, and greatly increased auxin activity in February, thought to be associated with rest termination. Inhibitor activity disappeared. In treated bulbs, cellular activity consisted of rapid enlargement without division during
Isenberg, F.M.R., Thomas, T.H., Pendergrass, M. and Abdel-Rahman, M. (1974). HORMONE AND HISTOLOGICAL DIFFERENCES BETWEEN NORMAL AND MALEIC HYDRAZIDE TREATED ONIONS STORED OVER WINTER. Acta Hortic. 38, 95-126
DOI: 10.17660/ActaHortic.1974.38.11
https://doi.org/10.17660/ActaHortic.1974.38.11
38_11
95-126

Acta Horticulturae