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Production of reactive oxygen species and reactive nitrogen species by angiosperm stigmas and pollen: potential signalling crosstalk?
Author(s) -
McInnis Stephanie M.,
Desikan Radhika,
Hancock John T.,
Hiscock Simon J.
Publication year - 2006
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2006.01875.x
Subject(s) - pollen , reactive oxygen species , biology , botany , hydrogen peroxide , peroxidase , microbiology and biotechnology , biochemistry , enzyme
Summary• 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 DCFH 2 ‐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 H 2 O 2 , constitutively. In Senecio squalidus and Arabidopsis thaliana high amounts of ROS/H 2 O 2 were localized to stigmatic papillae. ROS/H 2 O 2 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/H 2 O 2 . • Constitutive accumulation of ROS/H 2 O 2 appears to be a feature of angiosperm stigmas. This novel finding is discussed in terms of a possible role for stigmatic ROS/H 2 O 2 and pollen‐derived NO in pollen–stigma interactions and defence.