Production of reactive oxygen species and reactive nitrogen species by angiosperm stigmas and pollen: potential signalling crosstalk?
Article first published online: 22 SEP 2006
Volume 172, Issue 2, pages 221–228, October 2006
How to Cite
McInnis, S. M., Desikan, R., Hancock, J. T. and Hiscock, S. J. (2006), Production of reactive oxygen species and reactive nitrogen species by angiosperm stigmas and pollen: potential signalling crosstalk?. New Phytologist, 172: 221–228. doi: 10.1111/j.1469-8137.2006.01875.x
- Issue published online: 22 SEP 2006
- Article first published online: 22 SEP 2006
- Received: 23 May 2006 Accepted: 28 July 2006
- hydrogen peroxide (H2O2);
- nitric oxide (NO);
- pollen–stigma interactions;
- reactive oxygen species (ROS);
- • Angiosperm stigmas exhibit high levels of peroxidase activity when receptive to pollen. To explore possible function(s) of this peroxidase activity we investigated amounts of reactive oxygen species (ROS), particularly hydrogen peroxide, in stigmas and pollen. Because nitric oxide (NO) was recently implicated in pollen tube growth, we also investigated amounts of NO in pollen and stigmas.
- • Reactive oxygen species accumulation was assessed with confocal microscopy and light microscopy using ROS probes DCFH2-DA and TMB, respectively. NO was assayed using the NO probe DAF-2DA and confocal microscopy.
- • Stigmas from various different angiosperms were found to accumulate ROS, predominantly H2O2, constitutively. In Senecio squalidus and Arabidopsis thaliana high amounts of ROS/H2O2 were localized to stigmatic papillae. ROS/H2O2 amounts appeared reduced in stigmatic papillae to which pollen grains had adhered. S. squalidus and A. thaliana pollen produced relatively high amounts of NO compared with stigmas; treating stigmas with NO resulted in reduced amounts of stigmatic ROS/H2O2.
- • Constitutive accumulation of ROS/H2O2 appears to be a feature of angiosperm stigmas. This novel finding is discussed in terms of a possible role for stigmatic ROS/H2O2 and pollen-derived NO in pollen–stigma interactions and defence.