Effects of gibberellin on senescence of rose flower petals

It has been previously found that the longevity of harvested rose flowers of cv. Mercedes, but not of cv. Madelon, has been promoted by application of GA₃. Use of labeled GA₃ revealed that there were no disruptions of GA₃ transport in the stem. The leakage of electrolytes from the GA₃-treated petals of 'Mercedes' was lower in comparison with the untreated ones, whereas the leakage of electrolytes from 'Madelon' petals was not affected by the GA₃ treatment. The proportion of various elements leaked from GA₃ treated 'Mercedes' petals differed significantly from these leaked from untreated petals, whereas the composition of elements leaked from 'Madelon' petals was not affected by the GA₃ treatment. Light and electronic microscopy of untreated 'Mercedes' petals showed that 8 days after detachment the anatomical structure of cells differed from the structure of cells at day 0. On the other hand, the cell structure in GA₃ treated petals was similar to that of day 0. In contrast to 'Mercedes' the cell structure in 'Madelon' petals was not affected by GA treatment and at day 8 similar to that of day 0. The gibberellins content in 'Mercedes' petals differed from that in Madelon petals.