花粉管
NADPH氧化酶
活性氧
花粉
氮氧化物
超氧化物
过氧化氢
化学
生物化学
氧化酶试验
细胞生物学
生物物理学
植物
生物
酶
授粉
燃烧
有机化学
作者
Martin Potocký,Mark Jones,Radek Bezvoda,Nicholas Smirnoff,Viktor Žárský
标识
DOI:10.1111/j.1469-8137.2007.02042.x
摘要
Tip-localized reactive oxygen species (ROS) were detected in growing pollen tubes by chloromethyl dichlorodihydrofluorescein diacetate oxidation, while tip-localized extracellular superoxide production was detected by nitroblue tetrazolium (NBT) reduction. To investigate the origin of the ROS we cloned a fragment of pollen specific tobacco NADPH oxidase (NOX) closely related to a pollen specific NOX from Arabidopsis. Transfection of tobacco pollen tubes with NOX-specific antisense oligodeoxynucleotides (ODNs) resulted in decreased amount of NtNOX mRNA, lower NOX activity and pollen tube growth inhibition. The ROS scavengers and the NOX inhibitor diphenylene iodonium chloride (DPI) inhibited growth and ROS formation in tobacco pollen tube cultures. Exogenous hydrogen peroxide (H2O2) rescued the growth inhibition caused by NOX antisense ODNs. Exogenous CaCl2 increased NBT reduction at the pollen tube tip, suggesting that Ca2+ increases the activity of pollen NOX in vivo. The results show that tip-localized ROS produced by a NOX enzyme is needed to sustain the normal rate of pollen tube growth and that this is likely to be a general mechanism in the control of tip growth of polarized plant cells.
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