The sensitivity of barley aleurone tissue to gibberellin is heterogenous and may be spatially determined

Sian Ritchie, Andrew McCubbin, Genevieve Ambrose, Teh Hui Kao, Simon Gilroy

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

In cereals, gibberellin (GA) enhances the synthesis and secretion of hydrolytic enzymes from aleurone cells. These enzymes then mobilize the endosperm storage reserves that fuel germination. The dose-response curve of aleurone protoplasts to GA extends over a range of concentrations from 10-11 to more than 10-6 M. One hypothesis is that subpopulations of cells have different sensitivities to GA, with each cell having a threshold concentration of GA above which it is switched on. The dose-response curve therefore reflects a gradual recruitment of cells to the pool exhibiting a full GA response. Alternatively, all cells may gradually increase their responses as the GA level is increased. In the present study we found that at increasing GA concentrations, increasing numbers of barley (Hordeum vulgare) cells showed the enhanced amylase secretion and vacuolation characteristic of the GA response. We also observed that the region of aleurone tissue closed to the embryo contains the highest proportion of cells activated at the GA concentrations thought to occur naturally in germinating grain. These data indicate that an aleurone layer contains cells of varying sensitivities to GA and that recruitment of these differentially responding pools of cells may explain the broad dose response to GA.

Original languageEnglish (US)
Pages (from-to)361-370
Number of pages10
JournalPlant physiology
Volume120
Issue number2
DOIs
StatePublished - Jun 1999

All Science Journal Classification (ASJC) codes

  • Physiology
  • Genetics
  • Plant Science

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