桑树斑叶突变体叶绿素合成特性的初步研究

以新发现的桑树斑状叶色突变体Cty-Sm为材料,分析叶片中3种光合色素与叶绿素合成中间产物δ-氨基酮戊酸、胆色素原含量的变化状况,探讨突变体叶色差异的生理原因及其调控机制。与正常生长的原始材料(对照桑)相比,突变体叶片黄化部分的叶绿素a、叶绿素b和类胡萝卜素含量均有不同程度的下降,其中叶绿素a的减少最显著,仅为对照桑的5.43%~10.23%,这是导致突变体叶色黄化的直接原因。其次,突变体黄化部分的δ-氨基酮戊酸含量明显升高,而胆色素原含量明显降低,推测其叶绿素a的减少是由于δ-氨基酮戊酸与胆色素原之间合成代谢受阻的缘故。

Primary Investigation on Properties of Chlorophyll Synthesis of a Leaf-variegated Mutant in Mulberry (Morus L.)

Changes of contents of 3 photosynthetic pigments and 2 intermediates in chlorophyll biosynthesis,δ-aminolevulinic acid(ALA) and porphobilinogen(PBG),were analyzed in the newly identified leaf-variegated mulberry mutant to explore their physiological basis and control mechanism.The results showed that the content of chlorophyll a,b and carotenoid were decreased obviously,especially the content of chlorophyll a dramatically declined to just about 5.4% ~ 10.2% of the control,which may result in the etiolation directly.On the other hand,the ALA content increased while the PBG content decreased obviously,suggesting that the reduction of chlorophyll a was due to a metabolic block between ALA and PBG synthesis pathway.