三七花色苷对三七的生态生理作用

The Radix notoginseng produced in Wenshan Eparchy of Yunnan Province is the genuine medical material of Radix notoginseng. The aerial stems, rhizomes and adventitious roots of Panax notoginseng growing in Wenshan hold a popular phenomenon of Purpling. Being regarded as the rare one of Radix notoginseng by the folk herbalists, Purple Radix notoginseng refers to the Wenshan Radix notoginseng whose epidermis is purple or purplish red, with the purplish red or red and yellow interior. Previous researches showed that the Purpling of P. notoginseng results from the anthocyanin accumulation, and especially, the anthocyanin contents of the rhizomes are positively related to the total saponin contents of the rhizomes at the significant level. Taking the objective facts that the anthocyanins from other plants have various intense ecophysiological functions as the background and being based on the penetrating analyses of the key factors such as the strong ultraviolet (UV), low temperature and drought in the ecological niches of Wenshan where P. notoginseng distributes, this project purposefully and pointedly explores the effectiveness that P. notoginseng anthocyanins (PNA) act as the UV-sunscreen and the in vivo anti-oxidant and the degrees that PNA regulates the photosynthetic rate, alleviates the photoinhibition and strengthens the resistances of aphids, desease, cold and drought of P. notoginseng, with the aim to elucidate the unique and indispensable ecophysiological effects of PNA on P. notoginseng as well as to reveal the ecologically adaptative superiority of the Purpling of P. notoginseng. This project would enrich the connotation of the ecophysiological functions of anythocyanins, and from the angle of the ecologically adaptative ability reveal that Purple Radix notoginseng should be taken as the breeding target of P. notoginseng. Meanwhile, the project would also provide a new idea for the pharmacodynamic optimization and the improvement of the commercial value of the medicinal plants of Panax genus and for the product-exploiting of P. notoginseng.

云南文山三七是三七的道地药材，其地上茎、根状茎及其不定根普遍存在"紫化"现象；'紫三七'是指表皮紫或紫红、内部红黄相间或紫红的文山三七，被民间草药医生视为三七珍品。研究表明，三七"紫化"源于花色苷的积累，特别是，三七根状茎花色苷与其总皂苷含量间呈显著正相关。本项目以其他植物花色苷具多种强烈生态生理功能的客观事实为背景，立足于对文山州三七分布地域生态环境中强紫外线、低温、干旱等关键因素的深刻剖析，有针对性地探索三七花色苷充当三七紫外线遮光剂和体内抗氧化剂的有效性和调控三七光合速率、减轻三七光抑制和强化三七抗蚜虫取食、抗病、抗寒和抗旱的程度，以明确三七花色苷对三七独到而不可缺的生态生理效应，并揭示三七"紫化"的生态适应优越性。本项目将丰富花色苷生态生理功能的内涵、从生态适应能力角度揭示'紫三七'应被作为三七育种目标，并为人参属药用植物药效的优化、商业价值的提升和三七的产品开发提供一个新思路。

前人研究表明，三七地上茎等器官普遍发生的紫化现象是源于花色苷的合成与积累。本项目研究发现：三七花色苷主要为酰化的锦葵色苷，主要积累在地上茎的中上部；在地上茎、叶、叶柄和根状茎中，花色苷均主要定位在紧贴表皮细胞的1~3层皮层薄壁细胞中，故能充当地上茎和叶的UV遮光剂；三七地上茎积累花色苷可提高其叶细胞的RNA总量和鲨烯环氧酶基因（squalene epoxidase gene, SE）、达玛烯二醇合酶基因（dammarendiol synthase gene, DS）及鲨烯合酶基因（squalene synthase gene, SS）、SE和DS之和的转录水平，并略微提高叶的总叶绿素含量，但会降低叶净光合速率（Pn）和SS的转录水平，且不能明显强化叶抗蚜虫取食的能力；花色苷可抑制三七根腐病、黑斑病和圆斑病的主要病原真菌，且效果为：双孢柱孢（Cylindrocarpon didymium）＞人参链格孢（Alternaria panax）＞槭菌刺孢（Mycocentrospora acerina）；低温胁迫下，地上茎积累花色苷能提升其叶面温度和地上茎内部温度，利于胁迫过程中叶过氧化氢酶（CAT）比活力的速升和丙二醛（MDA）含量的速降、滞缓过氧化物酶（POD）、超氧化物歧化酶（SOD）比活力的降速、并利于胁迫结束时细胞中高POD和SOD比活力及低MDA含量的维持；干旱胁迫下，地上茎积累花色苷利于叶CAT和POD比活力在胁迫过程中的速升、滞缓SOD比活力的下降和MDA含量的上升，并利于胁迫结束时细胞高CAT和SOD比活力水平的维持；低温和干旱胁迫下，地上茎积累花色苷能维持叶Pn，通过增加叶细胞可溶性糖和脯氨酸等渗透调节物的含量而提高细胞的渗透调节能力；在UV-B、低温和干旱胁迫下，地上茎积累花色苷能提升叶SS、SE和DS的总转录强度。三七紫地上茎植株（三七品种‘滇七一号’）营养器官的皂苷积累能力强于绿地上茎植株（三七品种‘苗乡三七一号’）的。因此，三七地上茎积累花色苷利于三七植株耐寒和耐旱，并利于叶在强UV-B下合成和积累皂苷。本项目明确了三七花色苷的基本生态生理功能，为三七优良品种选育的标准构建提供了重要依据，并为“三七红酒”的研发提供了新思路。