Abscisic acid and temperature modify the levels of calmodulin in embryonic axes of Cicer arietinum

Changes in calmodulin (CaM) levels in embryonic axes of Cicer arietinum L. cv. Castellana germinated under three different conditions were measured. Abscisic acid (ABA) and a temperature of 30°C, which delay chick-pea germination, respectively decreased and increased the concentration of CaM compared to the values obtained under normal germinating conditions (H₂O-25°C). The CaM concentration was higher in those zones of the axes undergoing an active cell division.
The compartmentalization of CaM in 36-h-old embryonic axes grown under these three conditions was also measured. Cytosolic and mitochondrial CaM was higher in axes where a delayed germination occurred as well as in the cell walls of normally grown ones. On the other hand, CaM was higher in nuclear and microsomal fractions extracted from H₂-O-25°C-treated axes. From these data we postulate that delayed germination could be an effect of altered CaM distribution in chick-pea embryonic axes.