HPLC法测定杨梅叶中杨梅苷的含量

目的:建立HPLC法测定杨梅叶中杨梅苷含量的方法。方法:采用Diamonsil C18(150 mm×4.6 mm,5μm)柱,流动相乙腈-0.1%磷酸水溶液梯度洗脱,流速1.0 mL/min,检测波长358 nm,柱温30℃。结果:杨梅苷在0.088-0.880 mg/mL内与峰面积呈良好线性关系,A=36113C-401.56,r=0.9994;平均回收率为102.4%,RSD=1.9%(n=9)。测得杨梅叶中杨梅苷含量为1.43%。结论:该测定方法准确,可靠,对于杨梅的进一步开发利用具有重要的参考意义。     

秀叶苏铁——广西苏铁属一新种

本文发表了一苏铁属新种,即秀叶苏铁,对其特征进行了阐述。     

四川石斛属一新种

描述了四川夹江（兰科）石斛属植物一新种,即夹江石斛。     

虎杖不同部位白藜芦醇含量的分析

白藜芦醇(反-3,4,5-三羟基二苯乙烯,resveratrol)是一种活性多酚物质,也称芪三酚,1940年从毛叶藜芦(Veratrum puberulum Loes. f.)的根中最先得到.有研究认为,白藜芦醇及其苷是植物体在恶劣环境下或遇到病原侵害时自身分泌的一种抗毒素,因此有“植物杀菌素”之称[1].     

海菜花（水鳖科）-新变种-嵩明海菜花

报道了海菜花-新变种-嵩明海菜花（Ottelia acuminata var．songmingensis Z．T．Jiang,H．Li et Z．L．Dao）。该变种与原变种的区别在于叶片带状厚纸质,不透明,叶尖钝圆或具短尖。     

绿绒蒿属一新变种

报道了绿绒蒿属一新变种,即椭圆叶红花绿绒蒿(MeconopsispuniceaMaxim.var.ellipticaZ.J.Cui etY.Sh.Lian)。     

野生软枣猕猴桃总黄酮含量的测定

利用分光光度法,测定了软枣猕猴桃中总黄酮的含量,建立了芦丁浓度-吸光度关系的回归方程.     

Recruitment and growth of herb‐layer species with different colonizing capacities in ancient and recent forests

Abstract. Forest herbs differ greatly in their capacity to recolonize secondary forests established on former agricultural land. We investigated whether interspecific differences in recruitment or growth can account for differences in colonization success. Seeds and adults of two species with limited colonization capacities (Anemone nemorosa and Primula elatior) and two species with high colonization capacities (Ranunculus ficaria and Geum urbanum) were introduced in ancient and recent forest sites within the Muizen forest (Belgium). At all sites, half of the plots were also cleared of above‐ground vegetation. Seedling establishment was similar in recent and ancient forest sites. However, both the number and subsequent survival of seedlings of the two hemicryptophytes (G. urbanum and P. elatior) were significantly lower when vegetation cover was present, while seedling number and survival of the two geophytes (A. nemorosa and R. ficaria) were less influenced by vegetation cover. Adult performance of P. elatior and G. urbanum was significantly better in the nutrient enriched recent forest stands and in the absence of vegetation cover. Performance of A. nemorosa and R. ficaria was not affected by any of these factors. We conclude that the extent of seed limitation is probably the main cause for the different colonization capacities of the species investigated.     

亚贡叶中营养成分和功能性化学成分分析

亚贡[Smallanthus sonchifolius (Poepp. et Endl.) H. Robinson]为多年生草本植物[1],原产南美洲安第斯山脉,是当地印第安人的传统根茎食品, 在我国海南、台湾等地有种植.亚贡生长在亚热带气候、无霜冻、湿度大、常年云雾缭绕且海拔1 000 m以上的高山中.亚贡可生长至2～3 m,根茎在生长7～12个月后成熟.根茎中果寡糖含量丰富[2],其低热量、高甜度的特性适合糖尿病人及减肥者食用[3].     

Herbaceous vegetation change in variable rangeland environments: The relative contribution of grazing and climatic variability

Abstract. A 44‐yr record of herbaceous vegetation change was analysed for three contrasting grazing regimes within a semi‐arid savanna to evaluate the relative contribution of confined livestock grazing and climatic variability as agents of vegetation change. Grazing intensity had a significant, directional effect on the relative composition of short‐ and mid‐grass response groups; their composition was significantly correlated with time since the grazing regimes were established. Interannual precipitation was not significantly correlated with response group composition. However, interannual precipitation was significantly correlated with total plant basal area while time since imposition of grazing regimes was not, but both interannual precipitation and time since the grazing regimes were established were significantly correlated with total plant density. Vegetation change was reversible even though the herbaceous community had been maintained in an altered state for ca. 60 yr by intensive livestock grazing. However, ca. 25 yr were required for the mid‐grass response group to recover following the elimination of grazing and recovery occurred intermittently. The increase in mid‐grass composition was associated with a significant decrease in total plant density and an increase in mean individual plant basal area. Therefore, we failed to reject the hypotheses based on the proportional change in relative response group composition with grazing intensity and the distinct effects of grazing and climatic variability on response group composition, total basal area and plant density. Long‐term vegetation change indicates that grazing intensity established the long‐term directional change in response group composition, but that episodic climate events defined the short‐term rate and trajectory of this change and determines the upper limit on total basal area. The occurrence of both directional and non‐directional vegetation responses were largely a function of (1) the unique responses of the various community attributes monitored and (2) the distinct temporal responses of these community attributes to grazing and climatic variation. This interpretation supports previous conclusions that individual ecosystems may exist in equilibrial and non‐equilibrial states at various temporal and spatial scales.