二乔玉兰开花过程中花色变化的生理生化机制

摘要

With four-year-old outer petals of Yulania ×soulangeana on different flowering stages as materials, floral color index, anthocyaniniflavonoid, soluble sugar content,pH index and relative enzymes were studied to explain the chromogenic mechanism of floral color in Yulania × soulangeana. The results showed that:(l)As the flowering stage progresses, PAL and CHI activity become lower, pH index of petals are higher,and the contents of soluble sugar,anthocyanin and flavonoid become lower. The light of the petal strengthened,the red chroma,multi-colored chroma decreased. And every parameter in different flowering stages had significant difference. (2)With correlation analysis the variation of soluble sugar content,PAL and CHI activity and anthocyanin and flavonoid contents showed significantly positive correlation. The variation of pH index, the lightness L* -value and anthocyanin and flavonoid contents showed significantly negative correlation. The chromatic component a* -value and anthocyanin contents showed significantly positive correlation. In conclusion, the contents of anthocyanin and flavonoid can affect the floral color of Magnolia×.soulangeana. The petals of different color need soluble sugar content,PAL and CHI,pH index to complete normally physiological metabolism that regulate anthocyanin forming,and change petal color of Yulania × soulangeana.%以4年生二乔玉兰不同花期外层花瓣为试材,测定其在开花过程中花瓣色度值、花色苷、类黄酮、可溶性糖含量、细胞pH值以及相关酶活性的变化,以探讨二乔玉兰花色呈色机理.结果显示:(1)随著花期的推移,苯丙氨酸解胺酶(PAL)和查尔酮异构酶(CHI)活性逐渐减弱,细胞pH值逐渐变大,可溶性糖、花色苷、类黄酮含量不断降低,而花瓣明亮度增强,红色度以及彩色度减弱,且不同花期各参数值之间差异显著.(2)花瓣可溶性糖含量、PAL和CHI的活性与其花色素苷、类黄酮含量变化之间呈显著正相关关系,花瓣pH值的变化、明亮度L*值与花色素苷、类黄酮含量之间呈显著负相关,色相值a*与花色苷含量的变化呈显著正相关.研究表明,二乔玉兰花瓣花色苷和类黄酮含量的高低可以影响其花色的深浅,可溶性糖含量、PAL和CHI活性、细胞pH通过参与一定的生理代谢来调节花色素的形成,进而引起二乔玉兰花色色调的改变.