过氧化氢在水杨酸诱导的蚕豆气孔关闭中的作用(英文)

The Role of Hydrogen Peroxide in Salicylic Acid-induced Stomatal Closure in Vicia faba Guard Cells

许多植物病原菌可通过气孔进入叶片组织 ,因此减小气孔开度有利于提高植物的抗性。我们通过表皮条分析和激光扫描共聚显微镜得到的证据表明在保卫细胞中过氧化氢可能是水杨酸信号的中间环节。SA可以浓度依赖的方式诱导气孔关闭 (图 1A) ,H2 O2 也有类似的作用 (图 1B)。 1 0 0μmol/L的水杨酸诱导的气孔关闭作用可明显地被2 0U/ml的过氧化氢酶或 1 0 μmol/L的Vc逆转 ,但CAT和Vc单独处理时诱导气孔开放的作用很微弱。单细胞中基于荧光探针DCFH的时间进程实验表明直接外加 (图版I)或显微注射 1 0 0 μmol/L的SA均可诱导保卫细胞中H2 O2 产生 ,但以显微注射双蒸水作为对照时对DCFH荧光无影响 (图版II)。这些结果暗示了植物被病原菌感染时可能通过产生H2 O2

Many plant pathogens can penetrate leaf tissues through stomatal opening, so narrowing stomatal apertures may be advantageous for plant defense. Here we provide the evidence that H 2O 2 may function as an intermediate in salicylic acid (SA) signal in guard cells by epidermal strips bioassay and laser scanning confocal microscopy. SA can induce stomatal closure with a concentration dependent manner (Fig.1A), and H 2O 2 has the similar effect as SA (Fig.1B). The effect of stomatal closure induced by SA at 100 μmol/L could be reversed evidently by CAT 20 U/ml (Fig.2A) or Vc 10 mmol/L(Fig.2B), respectively , but CAT or Vc alone treatment promoted stomatal opening slightly over the control. Time course experiments of single cell assay based on fluorescent probe DCFH showed that the generation of H 2O 2 in guard cells could be induced by exogenous (Plate I) or endogenous SA 100 μmol/L (Plate II) by directly addition or microinjection into one guard cell of a stoma, but distilled water microinjection as control caused no changes in DCFH fluorescent (Plate II). These results suggest that the plant infected by pathogens may close their stomata via a pathway involving H 2O 2 production, thus interfering with the continuous invasion of pathogens through the stomatal pores.