Hydrogen peroxide affects ion channels in lily pollen grain protoplasts.
Ion homeostasis plays a central role in polarisation and polar growth. In several cell types ion channels are controlled by reactive oxygen species (ROS). One of the most important cells in the plant life cycle is the male gametophyte, which grows under the tight control of both ion fluxes and ROS balance. The precise relationship between these two factors in pollen tubes has not been completely elucidated, and in pollen grains it has never been studied to date. In the present study we used a simple model - protoplasts obtained from lily pollen grains at the early germination stage - to reveal the effect of H2 O2 on cation fluxes crucial for pollen germination. Here we present direct evidence for two ROS-sensitive currents on the pollen grain plasma membrane: the hyperpolarisation-activated calcium current, which is strongly enhanced by H2 O2 , and the outward potassium current, which is modestly enhanced by H2 O2 . We used low concentrations of H2 O2 that do not cause an intracellular oxidative burst and do not damage cells, as demonstrated with fluorescent staining.
Lomonosov Moscow State University, Moscow, Russia.|Pirogov Russian National Research Medical University, Moscow, Russia.
M A
MA
Breygina
Lomonosov Moscow State University, Moscow, Russia.|Pirogov Russian National Research Medical University, Moscow, Russia.
D V
DV
Abramochkin
Lomonosov Moscow State University, Moscow, Russia.
N M
NM
Maksimov
Lomonosov Moscow State University, Moscow, Russia.
I P
IP
Yermakov
D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D018525:Germination / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D027762:Lilium / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D011058:Pollen / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D053205:Pollen Tube / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism; D011523:Protoplasts; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism*
D015220:Calcium Channels; D015221:Potassium Channels; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D011188:Potassium; D002118:Calcium
Ca2+-permeable cation channels; K+ channels; ROS; patch-clamp; pollen germination