不同采收期银杏叶总内酯及黄酮甙的含量测定

采用ＨＰＬＣ法对不同采收期银杏叶总内酯及黄酮甙含量进行测定,结果表明,八至九月采收的银杏叶总内酯及黄酮甙含量均较高。     

银杏叶精油的化学成分

采集３－５年银杏苗叶,经常压水蒸汽蒸馏制得浅黄色精油,通过ＧＣ和ＧＣ／ＭＳ鉴定出４４个化学成分,主要由３１．１４％烃类、５．６１％醇类、１．７８％醛类、４６．１７％酮类、５．４１％酸类和１．１％酯类组成。在酮类中以六氢法呢酮含量最高,占１１．１５％,其次为橙花基酮（８．６８％）和β－紫罗兰酮（５．２４％）。     

高效液相色谱法测定银杏叶提取物中黄酮甙含量

用高效液相色谱法测定银杏叶提取物经酸水解后黄酮甙元含量．采用Ｃ１８柱,甲醇：水：磷酸（５５：４４．５：０．５）为流动相,检测波长３７０ｎｍ,方法回收率９５．１％～１０３．２％,变异系数（ＣＶ）３．１７％,１０批样品含测平均为２５．４％．     

不同生长季节及生长年限银杏叶总黄酮甙含量的相关性研究

了银杏叶总黄酮工厂民不同生长季节及生长年限的相关性,结果表明,叶中总黄酮甙含量在８月份最高,幼苗叶的含量明显高于老树。     

银杏叶的研究开发概况

本文对银杏叶的化学、药理、临床和制剂等进行了综述。     

ANASTOMOSES IN THE VENATION OF GINKGO BILOBA

Arnott , Howard J. (Northwestern U., Evanston, Ill.) Anastomoses in the venation of Ginkgo biloba. Amer. Jour. Bot. 46(6): 405–411. Illus. 1959.—Although the vasculature of the lamina of Ginkgo biloba has been described as open dichotomous and devoid of anastomoses, vein unions were found in a survey of 1065 leaves collected from both long and short shoots of 11 trees. When studied by directing a strong light through the lamina and by clearings, 9.9% of the leaves possessed 1 or more anastomoses. Long shoot-leaves showed 13.4% anastomoses while short shoot-leaves showed 8.2% anastomoses. Multiple anastomoses were found in almost half of the leaves bearing anastomoses. In the 105 leaves having vein unions, 163 anastomoses were counted. These anastomoses could be grouped into 4 types which are easily distinguished by the number of dichotomies involved and by the presence or absence of dichotomies above the point of vein union. Other deviations were found from the “normal” venation pattern; these consisted of unconnected veins, veins anastomosed marginally but unconnected basally, and veins ending a considerable distance from the margin. It was speculated that the anastomoses found in Ginkgo biloba are of a simple, archaic type and are apparently analogous to the anastomoses in the leaves of certain ferns and in the leaflets of various cycads. The evolutionary significance of these anastomoses must be assessed by a broad study of venation patterns in the seed-plants.     

不同季节中香荚兰叶片的光合作用特征

通过对生长于人工阴蔽下香荚兰(Vanilla planifolia)不同部位叶片的气体交换、可滴定酸度和叶绿素含量等四个不同季节的观测,较为详细地研究了叶龄和光合作用类型之间的关系及其季节性的变化规律。成熟叶片在四个季节中表现为稳定的景天酸代谢(CAM),且光期有较长时间的CO_2吸收,几乎无CO_2向外释放,有显著的昼夜酸度波动。幼叶以C_3代谢为主,但在较高昼夜温差和较低空气相对湿度的条件下也能进行CAM代谢,且不同季节中表现了不同程度的酸积累。我们认为,香荚兰叶片随叶龄的增长有一个从C_3代谢到CAM代谢的光合作用途径的转移,幼叶在对环境因子变动的反应中也有一个类似的转移现象。叶片的光合作用能力也表现了季节性的差异,尤其对温度反应敏感,低温季节(日均温<20℃),CO_2的固定作用大大减弱。     

PHOTOSYNTHESIS IN THE FEMALE GAMETOPHYTE OF GINKGO BILOBA

The female gametophyte of Ginkgo biloba is the only seed plant gametophyte known to contain chlorophyll. Measurements of photosynthetically active radiation (PAR) indicate that a gametophyte growing within an ovule can receive significant quantities of light (70 μmol photons m^–2 s^–1). Under the conditions of our experiments, whole gametophytes dissected free from ovules were capable of gross photosynthesis, but not net photosynthesis. On a dry wt basis, the maximum rate of carbon fixation under near saturating light intensities was 3.64 × 10^–3 μmol CO₂g^–1 s^–1. The unique ability of the female gametophyte of Ginkgo biloba to produce chlorophyll and engage in photosynthesis appears to result from its exposure to sufficient levels of light and a predisposition to react to this stimulus by the development of a functional photosynthetic apparatus.     

银杏根际丛枝菌根真菌生长与根系黄酮含量的相关性研究

试验通过调查银杏根际丛枝菌根真菌的菌丝体长度、孢子密度及根系菌根侵染率,并测定银杏根系黄酮含量的季节性变化,研究二者的变化规律,分析相关关系。试验结果表明,年周期内银杏根际丛枝菌根真菌菌丝体长度、孢子密度与根系黄酮类化合物含量呈规律性变化:1月~3月根际丛枝菌根真菌菌丝长度有限,孢子密度、根系菌根侵染率与根系黄酮类化合物含量都最低;3月上中旬皆迅速增加,到9月达到全年最高峰;11月后,丛枝菌根真菌菌丝长度、孢子密度及根系菌根侵染率与根系黄酮类化合物含量均有所下降。通过数学模型分析,银杏根际丛枝菌根真菌菌丝长度、孢子密度及根系菌根侵染率与根系黄酮类化合物含量表现显著的正相关。