Changes in the Leaf Surface Chemistry of Apium graveolens (Apiaceae) stimulated by jasmonic acid and perceived by a specialist insect
✍ Scribed by Volker Stanjek; Christian Herhaus; Ulf Ritgen; Wilhelm Boland; Erich Städler
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- German
- Weight
- 853 KB
- Volume
- 80
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Treatment of celery leaves (Apium graveolens, cv. secalinum) with Jasmonic acid (JA, 1) or analogues of amino‐acid conjugates of Jasmonic acid such as the leucine conjugate with 1‐oxoindan‐4‐carboxylic acid (IN‐ILE, 2) stimulated the biosynthesis of the furanocoumarins psoralen (6), xanthotoxin (8), bergapten (7), and isopimpinellin (9). Besides the increase of the compounds within the leaf, a significant amount (ca. 20%) of the total furanocoumarins was deposited on the surface of the leaf. The two monomethoxy furanocoumarins, 7 and 8, began to increase steadily and simultaneously within the leaf and on the leaf surface ca. 40 h after the onset of the jasmonic‐acid stimulus. Within the leaf, the ratio 7/8 was ca. 1.3:1.0, while among the surface lipids 8 dominated (7/8 0.8:1.0), indicating that the export of the compounds to the surface is not a simple diffusive translocation along the oil‐ducts. Females of the carrot fly (Diptera, Psilidae) responded with an increased oviposition to the altered leaf surface chemistry of the JA‐treated celery plants. The effect shown for total leaves was corroborated by surrogate leaves treated with leaf‐surface extracts of JA‐induced leaves. Based on the known stimulation of oviposition by furanocoumarins, we conclude that the enhanced amount of furanocoumarins on the surface can explain the insects' preference for the JA‐stimulated plants. This is the first report of a JA‐induced change of the surface chemistry of a plant and an increase of the acceptability of treated leaves for a specialist insect, like the carrot fly.