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. 1992 Apr 15;89(8):3591–3595. doi: 10.1073/pnas.89.8.3591

Gibberellic acid and abscisic acid coordinately regulate cytoplasmic calcium and secretory activity in barley aleurone protoplasts.

S Gilroy 1, R L Jones 1
PMCID: PMC48914  PMID: 1533046

Abstract

The effects of gibberellic acid (GA3) and abscisic acid (ABA) on the temporal and spatial dynamics of cytosolic calcium concentration ([Ca2+]i) in aleurone protoplasts of barley (Hordeum vulgare L. cv. Himalaya) were measured by using fluorescence ratio analysis and confocal microscopy. After 4-6 h of treatment, GA3 induced a sustained increase in [Ca2+]i from 50 to 150 nM in aleurone protoplasts. The increase in [Ca2+]i preceded the GA3-induced increase in alpha-amylase synthesis and secretion by 4 h. The elevation of [Ca2+]i was highest in the peripheral cytoplasm and may play a role in coordinating the secretory events there. Reducing Ca2+ levels in the incubation medium to below 500 microM inhibited the increase in [Ca2+]i and the GA3-induced stimulation of alpha-amylase synthesis and secretion. These data suggest that GA3 may increase [Ca2+]i by increasing the influx of Ca2+ at the plasma membrane. ABA reversed the effect of GA3 on [Ca2+]i within 3 h, 2 h before its effect on alpha-amylase production could be detected. Thus changes in [Ca2+]i may play a role in mediating the effects of GA3 and ABA on the synthesis and secretion of alpha-amylase in the aleurone cell.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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