UV-B辐照下拟南芥突变体npq4、vtc2、ndr1叶绿素荧光特性研究

通过对野生型拟南芥及npq4（非光化学猝灭减弱）、vtc2（抗坏血酸生物合成途径受阻）、ndr1（NDR1基因突变导致系统获得性抗性上游信号途径中断）3种拟南芥突变体进行UV-B周期性处理,探究其在UV-B辐照下的叶绿素荧光特性并检测其叶绿素含量。结果表明：随着UV-B辐照辐射时间的延长,野生型和突变体的NPQ、Fv/Fm、ΦPSⅡ、qN、qP、叶绿素含量及叶绿素a/b均有所降低。npq4、vtc2两个突变体的NPQ、Fv/Fm、ΦPSⅡ、叶绿素a含量及叶绿素a/b值较野生型和ndr1下降幅度大而且差异显著,表现出更严重的伤害症状。据推测,这是因为非光化学猝灭途径及抗氧化物质在植物抵抗短期高强度UV-B辐照中起重要作用,而系统获得性抗性途径不能被短期的UV-B辐照所启动,因而在植物抵抗UV-B辐照中作用较弱。

Chlorophyll Fluorescence Characteristics of Arabidopsis mutant npq4,vtc2,ndr1 under UV-B radiation

The chlorophyll fluorescence characteristics of wild-type Arabidopsis and three mutants of npq4（non-photochemical quenching decreased）,vtc2（ascorbic acid biosynthetic pathway blocked）,and ndr1（NDR1 gene mutant,leading to upstream signaling pathways of systemic acquired resistance interrupt） were studied under periodic ultraviolet irradiation.The results showed that NPQ,Fv / Fm,ΦPSⅡ,qN,qP and Chlorophyll content,Chlorophyll a/b were decreased with extending ultraviolet irradiation in the wild-type Arabidopsis and mutants.NPQ,Fv / Fm,ΦPSⅡand Chlorophyll content,Chlorophyll a/b of npq4 and vtc2 decreased sharply compared with the wild-type and ndr1 and the injury symptoms presented on plant.It is speculated that non-photochemical quenching pathways and antioxidants play an important role in plant resistance to short-term high-intensity ultraviolet irradiation,however systemic acquired resistance pathway cannot be triggered by short-term ultraviolet irradiation and may play an unimportant role in plant resistance to ultraviolet irradiation.