SO_2胁迫对金色叶植物叶片叶绿素合成代谢的影响

Chlorophyll biosynthesis metabolism of golden-leaf plants to SO_2 stress

以金叶女贞(Ligustrum×vicaryi)和金森女贞(Ligustrum japonicum‘Howardii’)2种金色叶女贞为试材,采用人工静态熏气的方法,研究SO2胁迫对金色叶植物叶片叶绿素含量及其合成代谢的影响,探讨SO2胁迫影响金色叶植物叶绿素合成的可能位点。结果表明:20和40 mg·m-3的SO2熏气提高了叶绿素、尿卟啉原Ⅲ(UrogenⅢ)、原卟啉Ⅸ(ProtoⅨ)、镁原卟啉Ⅸ(Mg-protoⅨ)的含量,使δ-氨基酮戊酸脱水酶(ALAD)和尿卟啉原Ⅲ合酶(UROS)活性升高,δ-氨基酮戊酸(ALA)和胆色素原(PBG)含量降低;80 mg·m-3的SO2熏气使叶绿素含量降低,引起ALA和PBG含量的积累,降低了UrogenⅢ、ProtoⅨ和Mg-protoⅨ的含量,抑制了ALAD和UROS的活性。研究发现,金叶女贞叶绿素合成关键前体物质含量和相关酶活性随熏气浓度的变化趋势较金森女贞明显,前者对SO2较为敏感,后者抗SO2的能力强于前者,SO2胁迫影响金色叶植物叶绿素合成的可能位点位于UrogenⅢ的合成过程。

In order to understand the effects of SO2 stress on chlorophyll biosynthesis of two golden-leaf shrubs （ Ligustrum × vicaryi and Ligustrum japonicum ＇ Howardii＇ ） and investigate possible acting sites of SOs stress on chlorophyll biosynthesis, the activities of key enzymes involved in chlorophyll biosynthesis, the contents of chlorophyll and its intermediates were analyzed under different SO2 treatments through an artificial static fumigation system. The results showed that the contents of Urogen III, Proto IX, Mg-proto IX, and chlorophyll a and b were increased with the rising of SO2 concentration, then decreased at SO2 concentration of 80 mg· m-3. Furthermore, the activities of ALAD and UROS exhibited a similar trend. In contrast, the contents of ALA and PBG in the control were significantly lower than under the 20 and 40 mg · m-3 treatments, and greatly higher than under 80 mg · m-3. The results also indicated that changes of these factors related to chlorophyll biosynthesis were greater in Ligustrum x vicaryi than in Ligustrum japonicum ＇ Howardii＇ , which implied that the latter was more resistant to SO2 stress than the former. All the results predicated that chlorophyll biosynthesis in leaves of two gold-leaf species was presumably blocked at the step from PBG to Urogen III under the SO2 stress.