一年生三七绿紫过渡地上茎黄金分割式紫化与其色素含量纵向变化的关系

为探究三七绿紫过渡地上茎黄金分割式紫化与其色素含量纵向变化的关系,用分光光度法检测了云南文山一年生三七植株绿紫过渡地上茎各茎段的叶绿素(Chl)、类胡萝卜素(Car)和总花色苷(TA)的含量。结果表明:从茎顶向茎基,茎段的叶绿素a(Chl a)、b(Chl b)和总叶绿素Chl(a+b)]含量均表现为"降—升—降三段式"曲线,叶绿素a和b的含量之比(Chl a/b)大致呈一不对称的"双峰"曲线,Car含量表现为"不规则波动—宽V型—阶梯型骤降三段式"曲线,总花色苷含量(TAC)、TA/Chl a、TA/Chl b、TA/Chl(a+b)和TA/(Chl+Car)均表现为单峰曲线,Chl(a+b)/Car大致表现为一"V-W形"曲线。在茎中上部的黄金分割点处,Chl a、Chl b和Chl(a+b)、Chl a/b均出现低值,而TAC、TA/Chl a、TA/Chl b、TA/Chl(a+b)和TA/(Chl+Car)却均出现最高值。在茎基部,Chl、Car和TA含量都急剧下降。不同茎段Chl a、Chl b、Chl(a+b)和Car含量之间的差异均达到极显著水平,而TAC之间的差异仅达到显著水平;此外,不同茎段Chl a、Chl b、Chl(a+b)、Car和TA的含量纵向变化之间呈不同的正相关性。所以,三七绿紫过渡地上茎的紫色源于其TA相对于Chl和Car的含量优势,但Car对茎段紫色的制约效应微小;茎的黄金分割式紫化既取决于茎的TAC,也取决于茎的TA/Chl a、TA/Chl b、TA/Chl(a+b)和TA/(Chl+Car)。

Relationship Between the Golden Section Purple and the Lengthwise Changes of Pigment Contents of Green-purple Transitional Aerial Stems of One-year-old Panax notoginseng

Different sections of green-purple transitional aerial stems of one-year-old Panax notoginseng plants cultivated in Wenshan, Yunnan, China were determined by using spectrophotometry in terms of contents of chlorophyll (Chl), carotenoid (Car) and total anthocyanins (TA) to explore the relationship between the golden section purple and the lengthwise changes of the pigment contents of the green-purple transitional aerial stems of the P. notoginseng plants. The results showed that the sections from the top to the basal stem displayed a "low-high-low" curve for the contents of chlorophyll a (Chl a), b (Chl b) and total chlorophyll (Chl (a+b)), an approximately asymmetrical biomodal curve for the content ratios of the chlorophyll a to b ((Chl a/b)s), an "irregular fluctuation-broad V-abrupt step" curve for the Car contents, a unimodal curve for the total anthocyanin content (TAC), TA/Chl a, TA/Chl b, TA/Chl (a+b) and TA/(Chl+Car), and roughly a "V-W" curve for the Chl (a+b)/Car. At the golden section point of the middle and upper sections of the stem, the Chl a, Chl b, Chl (a+b) and Chl a/b were all low, whereas the TAC, TA/Chl a, TA/Chl b, TA/Chl (a+b) and TA/(Chl+Car) were all the highest. At the basal section of the stem, the contents of Chl, Car and TA all decreased sharply. The contents of Chl a, Chl b, Chl (a+b) and Car in different stem sections were highly significantly different, while the TAC was significantly different between different stem sections. Moreover, different stem sections showed different positive correlation in the lengthwise changes in Chl a, Chl b, Chl (a+b), Car and TA contents. Thus, the purple of the green-purple transitional aerial stems of P. notoginseng results from the slightly higher TA content than the Chl and Car contents in the stem, and the Car content had very limited effect on the purple color. The golden section purple of the stems was determined not only by TAC but also by TA/Chl a, TA/Chl b, TA/Chl (a+b) and TA/(Chl+Car) of the stems.