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Role of ethylene in stimulating stylar abscission in pistil explants of lemons
Author(s) -
Sipes Deborah L.,
Einset John W.
Publication year - 1982
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1982.tb04891.x
Subject(s) - abscission , ethephon , ethylene , picloram , botany , gynoecium , 1 aminocyclopropane 1 carboxylic acid , explant culture , chemistry , biology , horticulture , biochemistry , in vitro , pollen , stamen , catalysis
Abscission in styles of excised Citrus limon (cv. Lisbon) pistils was stimulated by addition of 70 μ M 2‐chloroethylphosphonic acid (ethephon) or 0.1 m M 1‐aminocyclopropane‐1‐carboxylic acid (ACC) to the defined medium of cultures. To study the relationship between ethylene and abscission, we used gas chromatography to analyze ethylene in cultures containing a test medium plus or minus abscission‐active chemicals. In the presence of ethephon or ACC, ethylene levels in sealed tubes increased rapidly, suggesting that these compounds stimulated abscission because they were converted to ethylene. In the presence of test medium or the inhibitor of abscission 2 μ M picloram, the low ethylene levels found in sealed tubes did not differ strikingly in the two treatments. Ethylene production rates measured prior to abscission with test medium or in the presence of picloram were not markedly different either, although picloram completely inhibited abscission. Stylar abscission was delayed but not prevented by 50 μ M aminoethoxyvinylglycine, an inhibitor of ethylene biosynthesis, and by hypobaric conditions (280 mm Hg) which removed ethylene from cultures. We concluded that ethylene is an important factor regulating stylar abscission in vitro and suggest that the inhibitory effect of picloram involves a process other than detectable ethylene production. Our results do not exclude the possibility that picloram affects enodgenous ethylene biosynthesis and/or metabolism and/or tissue retention.