DA-6 对桃树叶片叶绿素合成途径的调控研究

 以‘香山水蜜桃’为试材，研究叶面喷施DA-6（二烷氨基乙醇羧酸酯N，N-diethylaminoethyl hexanote）对叶绿素（Chlorophyll，Chl.）合成过程中前体物质的含量以及合成关键酶活性的影响，探讨 DA-6 提高桃叶片Chl.含量的可能原因。结果表明：生长季叶面喷施20 mg · L^-1 DA-6 显著提高了Chl.的含量，Chl.b 含量的提高尤为显著，降低了Chl.的前体物质5–氨基酮戊酸（5-aminolevulinic acid，ALA）含量，增加了后续中间产物胆色素原（porphobilinogen，PBG）、尿卟啉原Ⅲ（uroporphyrinoge Ⅲ，Urogen Ⅲ）含量，表明DA-6 处理促进了ALA 向PBG 的转化和PBG 向Urogen Ⅲ的转化。以上两步骤的关键酶5–氨基酮戊酸脱水酶（5-aminolevulinate dehydratase，ALAD）和尿卟啉原Ⅲ合酶（uroporporphyrinogn Ⅲ synthase，UROS）的活性在处理后显著提高。叶面喷施DA-6 是通过提高ALA 向PBG 和PBG 向Urogen Ⅲ的转化效率，促进Chl.的合成，使Chl.含量增加。

Effects of DA-6 on Chlorophyll Biosythesis Pathway in Peach Leaves

Taken‘Xiangshan Honey’peach as the material,the change of chlorophyll precursor contents and activity of the key enzymes in chlorophyll biosynthesis pathway after DA-6 (N-diethylaminoethyl hexanote)application were investigated the underlying mechanism of DA-6 induced leaf chlorophyll content increase. Compared with the control,20 mg · L-1 foliar DA-6 spray significantly increased the contents of chlorophylls,especially that of chlorophyll b,and chlorophyll intermediate products porphobilinogen(PBG)and uroporphyrinoge(Urogen Ⅲ),whereas decreased the amount of chlorophyll precursor 5-aminolevulinic acid(ALA). The results suggested the transformation from ALA to PBG and PBG to Urogen Ⅲ was up-regulated. The key enzymes catalyzing the two reactions are 5-aminolevulinate dehydratase(ALAD)and uroporporphyrinogn Ⅲ synthase(UROS), their enhanced activity after DA-6 foliar spraying was assayed. Our study demonstrated that foliar spray DA-6 increased the conversion efficiency of ALA to PBG and PBG to Urogen Ⅲ,up-regulated the chlorophyll biosynthesis pathway and resulted in higher chlorophyll content in peach leaves.