利用表皮条生物分析、激光扫描共聚焦显微术、显微注射等技术,研究观察了蚕豆气孔关闭过程,结果表明,SA浓度在1~1000μmol/L时诱导的气孔关闭具有可逆性,而10^-2mol/L时导致的气孔关闭不可逆;20U/mL的过氧化氢酶(catalase,CAT)与SA共同处理时可逆转SA诱导气孔关闭作用的83%~90%。以H2O2荧光探针H2DCFDA结合激光扫描共聚焦显微术,直接检测保卫细胞内H2O2的产生,结果表明,与外源10^-5mol/L的H2O2的处理结果类似。外施或通过显微注射技术而在保卫细胞内引入100μmol/L的SA均可引起保卫细胞内DCF荧光快速增强。在保卫细胞内显微注射CAT可完全阻止SA导致的DCF荧光增强。表明SA诱导的气孔关闭可能与H2O2的产生有关。
In the experiment, SA induced stomatal closure with a concentration-dependent manner,and the changes in stomata apertures were reversible when the concentration of SA was 1- 1 000μmol/L, but irreversible when the concentration of SA was 10^-2mol/L. The treatment with SA and CAT of 20 U/mL reversed the SA-induced stomatal closure by 83%-90%. The protoplasts of guard cells in Vicia faba L. were isolated by two-step enzyme digestion. We directly examined the production of H2O2 by laser scanning confocal microscopy based on H2 DCFDA, similar to the result of H2O2 at 10^-5mol/L. The external application or microinjection of SA at 100μmol/ L could induce the rapid increase in fluorescence of DCF in guard cells. Moreover, time-course experiments showed that the increase of fluorescence intensity in the chloroplast occurred significantly earlier than in other regions of guard cells. The production of H2O2 was completely inhibited in guard cells by microinjection of CAT 20 U/mL into them. This indicated that H2O2 may adjust the SA-induced stomatal closure.