The effects of abscisic acid and methyl jasmonate on 1-aminocyclopropane 1-carboxylic acid conversion to ethylene in hypocotyl segments of sunflower seedlings, and their control by calcium and calmodulin
✍ Scribed by C. Bailly; F. Corbineau; D. Come
- Publisher
- Springer Netherlands
- Year
- 1992
- Tongue
- English
- Weight
- 438 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0167-6903
No coin nor oath required. For personal study only.
✦ Synopsis
The conversion of 1-aminocyclopropane 1-carboxylic acid (ACC) to ethylene by hypocotyl segments of sunflower (Helianthus annuus L .) seedlings was inhibited by abscisic acid (ABA) and methyl jasmonate (Me-Ja), and this inhibitory effect increased with increasing concentration of both growth regulators . On the contrary, CaCIZ enhanced ACC conversion to ethylene at the concentrations of 10 -4 M and 5 x 10 -4 M, however lower and higher concentrations had no significant action . CaCIZ (5 x 10 -'M) seemed to magnify the inhibition of the reaction induced by ABA, whereas it reduced (5 x 10 -'M) and even abolished (10 -'M) the inhibitory action of Me-Ja . The results obtained with a Ca" chelator (EGTA), a Ca" channel blocker (nifedipine) and calmodulin antagonists (W7 and TFP), given in association with ABA or Me-Ja, suggested that calcium was involved in the inhibition of ACC conversion to ethylene by ABA and Me-Ja through an interaction with calmodulin. However, the mechanism of action of the two growth regulators seemed to be different, since all treatments which resulted in a decrease in cytosolic Ca" concentration or in calmodulin action induced a decrease in the effect of ABA and an increase in the effect of Me-Ja .