ISHS Acta Horticulturae 179: V International Symposium on Growth Regulators in Fruit Production
MALUS DOMESTICA BORKH: HISTOLOGICAL STRUCTURE AND GIBBERELLIN ACTIVITY OF OVULES OF CONTROL AND OF "JUNE DROP" AFFECTED FRUITS |
| Authors: | S. Avanzi, L.M.C. Forino, A.M. Tagliasacchi, R. Bonomo, N. Ceccarelli, R. Lorenzi, P. Vernieri |
| Abstract:
The purpose of the present study was to investigate the relation between histological structure and gibberellin activity of ovules of control fruits (samples A) and "June drop" affected ones(samples B). Fruits have been gathered at different collection times in the period 16 may-15 June 1984, and fixed in alcohol: acetic acid (3:1). Ovaries have been thereafter isolated, embedded in paraffin and sectioned at 6 μm. Sections have been stained by the emathoxylin method. For gibberellin activity determination, isolated ovules have been macerated in 80% methanol and centrifuged at 5000 x g for 10 min. The supernatant has been reduced to the aqueous phase (pH 2.6) and partitioned with ethyl ester. The solutions have been subjected to TLC, using 0,25 mm slabs. The developing solvent was a solution of ethyl ester, chloroform and acetic acid (15:5:1). To measure the biological activity, lettuce hypocotyl test has been used. The results of histological analyses are collected in table 1. As seen from the table, samples A ovules bear generally a developing embryo; samples B show, on the contrary, only degenerating ovules, holding, or not, a degenerating embryo. Ovules of samples B, gathered in may 1984, seems to be very often unfertilized; the frequency of ovules bearing degenerating embryos increases abruptly in the following period. The gibberellin activity, in the investigated period, is very low. Quantitative and qualitative differences in the pool of gibberellins, between samples A and samples B ovules, are only detectable in samples collected at 16 June 1984 (see figs 1 and 2). It seems therefore possible to conclude that, whether gibberellin activity is responsible for the "June drop" phenomenon, the fact is true only for temporally limited aspects of the investigated process. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
