雌、雄株和金叶银杏光合生理及黄酮成分年动态变化研究

【目的】为了解黄酮类化合物在银杏叶片中的合成代谢规律,确定银杏合适采摘期,以及选育优良的银杏品种,探讨了雌、雄株和金叶(芽变品种)银杏叶片光合生理与黄酮含量的周年变化及相关性。【方法】以银杏种质资源圃的雌株、雄株及嫁接的金叶银杏为材料,对4—11月银杏的光合色素、叶绿素荧光参数、黄酮成分及含量间的变化进行了研究。【结果】在整个叶片生长周年动态变化中,雄株银杏的含水量低于雌株和金叶银杏,特别是在6—9月夏季高温时期的差异更显著;雌株银杏的含水量、相对叶面积、叶绿素含量都大于雄株与金叶银杏,特别是在5—8月,但雄株与金叶银杏的相对叶面积增加速度较快;雌株银杏的光化学淬灭系数(qP) 及非光化学淬灭系数(NPQ)高于雄株和金叶银杏,雌株具有更强的抗氧化能力。银杏叶中黄酮苷含量及总黄酮含量的高点分别出现在4—5月和9月,各银杏叶总黄酮的含量依次为金叶银杏>雄株>雌株;雄株的叶绿素、类胡萝卜素与槲皮素之间,雌株的叶绿素a、类胡萝卜素与总黄酮之间都存在极显著正相关。金叶银杏叶色在4—6月为金黄色,其叶绿素含量均比雄株、雌株银杏低,7月转绿后与雌株和雄株差异不大,其光合、黄酮代谢的变化更接近于雄株,且其黄酮合成的能力高于雄株及雌株。【结论】银杏叶的最佳采收期在9月,雄株和金叶银杏更适用于叶用林的培育,雌株的抗逆性高于雄株与金叶银杏,金叶银杏既有观赏价值,又有优良的经济性状,因而具有良好的开发利用前景。

Annual dynamic changes in photosynthetic physiology and flavonoid components in female,male and golden-leaf Ginkgo biloba trees

【Objective】 The annual variations and the correlation between the photosynthetic properties and flavonoids content in the leaves of female, male and golden-leaf (varieties of bud mutation) Ginkgo biloba were investigated to provide a references for the selection and breeding of robust G. biloba species, promotion of new varieties, and cultivation seedlings for harvesting leaves. 【Method】 Changes in photosynthetic pigments, chlorophyll fluorescence parameters, and flavonoid composition and content from April to November were studied in the leaves of female, male and grafted golden-leaf G. biloba trees. 【Result】 During the entire year, the water content in male trees was lower than that in female and golden-leaf trees in three G. biloba species, especially during the high-temperature summer period from June to September. Although the water content, relative leaf area and chlorophyll content in the male and golden-leaf G. biloba trees were lower than those in female trees, especially from May to August, their relative leaf area increased faster than the female trees. Furthermore, although the photochemical quenching (qP) and non-photochemical quenching (NPQ) coefficients were higher in the female trees than those in the male or golden-leaf tree, the maximum photochemical efficiency (F_v'/F_m') was lower in the female trees than that in the male and gold leaf tree. The annual variations in three flavonoid glycosides such as quercetin and total flavonoid contents in three G. biloba species revealed two high points, one in April to May and another in September. The highest level of the total flavonoid content in leaves was observed in September, and the total flavonoid content in the three tree species was in the following order: golden-leaf > male > female. The chlorophyll, carotene and quercetin contents in male trees were positively correlated with each other; however, a significant positive correlation between chlorophyll a, carotene, and total flavonoids was found in the female trees. The golden-leaf tree leaves maintained a golden yellow color from April to June owing to the lower chlorophyll content than their male and female counterparts during this period. However, their leaves changed from yellow to green after July, and their photosynthetic, flavonoid changes were closer to those of the male trees. Furthermore, the flavonoid content in golden-leaf trees was higher than that in the male and female trees. 【Conclusion】 The best harvesting stage for ginkgo leaves was in September in the Nanjing region of China; male and golden-leaf trees exhibited greater conduciveness to the cultivation of leaf-using forest; and the female trees exhibited higher stress resistance than male and golden-leaf trees. Golden-leaf G. biloba tree has an ornamental value and excellent economic characteristics, which makes it worth developing and utilizing vigorously in the future.