3 years ago

The role of reactive oxygen species in pollen germination in Picea pungens (blue spruce)

Nikita Maksimov, Anastasia Evmenyeva, Maria Breygina, Igor Yermakov

Key message

Endogenous ROS, including those produced by NADPH oxidase, are required for spruce pollen germination and regulate membrane potential in pollen tubes; \({\mathbf{O}}_{{\mathbf{2}}}^{{{\mathbf{ \cdot - }}}}\) and H 2 O 2 are unevenly distributed along the tube.

Abstract

Recently, the key role of reactive oxygen species (ROS) in plant reproduction has been decisively demonstrated for angiosperms. This paper is dedicated to the involvement of ROS in pollen germination of gymnosperms, which remained largely unknown. We found that ROS are secreted from pollen grains of blue spruce during the early stage of activation. The localization of different ROS in pollen tube initials and pollen tubes demonstrated the accumulation of H2O2 in pollen tube apex. Colocalization with mitochondria-derived \({\text{O}}_{2}^{ \cdot - }\) showed that H2O2 is produced in mitochondria and amyloplasts in addition to its apical gradient in the cytosol. The necessity of intracellular ROS and, particularly, \({\text{O}}_{2}^{ \cdot - }\) for pollen germination was demonstrated using different antioxidants. ·OH and extracellular ROS, on the contrary, were found to be not necessary for germination. Exogenous hydrogen peroxide did not affect the germination efficiency but accelerated pollen tube growth in a concentration-dependent manner. The optical measurements of membrane potential showed that in spruce pollen tubes there is a gradient which is controlled by H+-ATPase, potassium- and calcium-permeable channels, anion channels and ROS, as demonstrated by inhibitory analysis. An important role of NADPH oxidase in the regulation of ROS balance in particular, and in germination in general, has been demonstrated by inhibiting the enzyme, which leads to the reduction in ROS release, depolarization of pollen tube plasma membrane, and blocking of pollen germination.

Publisher URL: https://link.springer.com/article/10.1007/s00497-018-0335-4

DOI: 10.1007/s00497-018-0335-4

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.