鸢尾属1新变型——白花宽柱鸢尾

描述了鸢尾科鸢尾属宽柱鸢尾(Iris latistyla Y.T.Zhao)的1个新变型——白花宽柱鸢尾(I.latistyla Y.T.Zhao f.albifloraJ.Luo)。原变型的花被为蓝紫色,而新变型花被为白色。并对其潜在的药用研究价值进行了讨论。     

藏区金腰种质资源调查与分析

金腰属植物因富含黄酮醇类化合物而具有显著的药效,通过对我国西藏、云南、四川、青海以及甘肃5个省(自治区)进行金腰属植物种质资源的科学考察,共收集到19种(含2变种)145份野生种质资源。此外四川省发现金腰新分布2种,分别为秦岭金腰(Chrysosplenium biondianum Engl.)、陕甘金腰(Chrysosplenium qinlingense Z.P.Jien&J.T.Pan),均为中国特有种;甘肃省发现金腰新分布3种,分别为毛金腰(Chrysosplenium pilosum Maxim.)、绵毛金腰(Chrysosplenium lanuginosum Hook.f.&Thomson)和蜕叶金腰(Chrysosplenium henryi Franch.),凭证标本存于中南民族大学植物标本馆(HSN)。金腰属植物作为传统藏药长期以来被用于治疗各种疾病,如长梗金腰(Chrysosplenium axillare Maxim.)的75%乙醇提取物具抗炎症、抗流感病毒活性,从灰花金腰(Chrysosplenium grayanum Maxim.)与裸茎金腰(Chrysosplenium nudicaule Bunge)提取的五环三萜对肿瘤细胞有较强抑制效果。本调查丰富了野生藏药金腰属植物种质资源,为深入研究金腰属植物的分类与药理活性提供了基础。     

西藏唐北地区湖泊动态及空间格局预测

本研究评估了西藏唐古拉山以北地区(唐北地区)湖泊动态并预测了湖泊空间格局变化.使用面向对象分类和光谱角向量变化检测方法生成了2000-2015年西藏唐北地区每5年一期的生态系统分布数据.以此为基础,分析了湖泊与其他生态系统之间的转换和空间格局特征,评估了湖泊空间格局的动态及其与相关自然地理因素的关系.通过增强回归树识别了不同因素对湖泊动态的贡献,使用GEOMOD模型预测了湖泊到2030年的空间变化.结果表明:唐北地区在2000-2015年间湖泊增加了14.2%,是唐北地区生态系统变化的主要形式之一.区域内15个面积大于10 km2的湖泊有10个增加,另有5个减少,且缩减量较低.通过空间格局分析发现,唐北地区湖泊斑块表现为面积和数量同时增加,大斑块面积比重略有上升.扩张幅度高的湖泊多分布于海拔高、坡度大、温度低、降水少、距离冰川近的区域.位于现有湖泊周边、温度低、降水少、坡度小的区域转变为湖泊的几率较高.根据过去15年的趋势,到2030年,唐北地区湖泊将继续增加119 km2,主要变化形式从大湖扩张转变为小型水面扩张.     

高原鼠兔瘦素蛋白乳腺特异表达载体的构建及细胞表达

瘦素(Leptin)蛋白是调节机体能量代谢的关键因子之一。前期研究显示高原鼠兔Leptin蛋白发生了适应性进化。功能实验表明,在温暖或寒冷条件下高原鼠兔Leptin通过减少食物摄取和增加能量消耗调节能量平衡,显示了其调节适应性产热过程的潜力。本研究以高原鼠兔Leptin cDNA为模板扩增高原鼠兔obese (ob)基因编码区序列504 bp,改造并构建哺乳动物真核细胞乳腺特异表达载体pBC1-lep,同时通过组织块法原代培养建立奶山羊乳腺上皮细胞系,并通过pBC1-lep质粒脂质体法转染及转基因细胞的筛选,成功获得转染Leptin的阳性细胞。本研究为利用转基因动物实现奶山羊乳腺中特异表达高原鼠兔Leptin提供了一条可能的途径,完成了乳腺特异真核表达载体的构建。     

Provenance analysis of Cenozoic conglomerates: Insights from Lower Cretaceous radiolarians in chert clasts from the Xigaze area,southern Tibet

Conglomerates, exposed on either side of the Yarlung Tsangpo suture zone (YTSZ) in southern Tibet, have attracted wide attention in elucidating uplift and erosion histories of the Himalayan-Tibetan orogen. However, the provenance of these conglomerates remains controversial. Although radiolarian-bearing chert clasts within these conglomerates have received little focus, identification of the radiolarian assemblages they contain could shed light on the provenance of these sedimentary units. We present the first report of Upper Jurassic to Lower Cretaceous (upper Kimmeridgian–lower Barremian) radiolarian assemblages recovered from chert clasts within the Liuqu and Gangrinboche conglomerates in the Xigaze area. To extract radiolarian fossils from independent clasts in the conglomerates, a detailed and efficient experimental process is illustrated. The assemblages are well correlated to those in the YTSZ and Tethyan Himalaya, showing typical Tethyan characteristics. The lithology of chert clasts and ages of constituent radiolarian faunas suggest that the chert clasts in Liuqu and Gangrinboche conglomerates were derived from the Bainang terrane. This interpretation implies that Early Cretaceous accretionary complexes in the YTSZ had been exposed and eroded before deposited as clasts in the Cenozoic Liuqu and Gangrinboche conglomerates.     

Availability and contributions of soil phosphorus to forage production of seeded alfalfa in semiarid Loess Plateau

The availability of soil phosphorus was studied in response to the forage production of seeded alfalfa (Medicago sativa L.), established by the ridge and furrow water-harvesting technique in the semiarid Loess Plateau of China. The following 5 treatments were set up in this study: (1) conventional cultivation in a flat plot without mulch (CK); (2) plastic mulched ridge with 30 cm width of ridge and furrow (M30); (3) plastic mulched ridge with 60 cm width of ridge and furrow (M60); (4) bare ridge with 30 cm width of ridge and furrow (B30); (5) bare ridge with 60 cm width of ridge and furrow (B60). The forage yield, evapotranspiration (ET), soil organic carbon (SOC), total phosphorus, available phosphorus and the ratio of soil organic C to available P (C/P) were measured in the experiment. Results showed that the positive correlation occurred between the decrease in soil available P and the total forage yield of alfalfa after three-year alfalfa stand. M30 and M60 were higher than those of conventional flat cultivation (CK) by 10.7% and 40.3%, respectively, whereas the yield of two bare treatments (B30 and B60) was lower than that of CK by 14.2% and 28.3%, respectively. After a 3-year alfalfa stand, the trend of the decrease in soil available P was in the order of M60 (55.5%) > M30 (51.5%) > CK (34.6%) > B30 (23.4%) > B60 (17.5%). Moreover, after 3-year alfalfa growth, the C/P ratio increased significantly in all of the treatments by comparing with that before sowing. The C/P ratios of M30 (1165.1) and M60 (1326.1) were significantly higher than those of the other treatments. More interesting finding was that the increase in SOC in dry years promoted the accumulation of soil available P. However, in wet years, the increase of SOC limited the accumulation of soil available P. Therefore, to further increase the forage yield of alfalfa, the effective technique must be developed to increase the soil available P.     

陇东黄土高原丘陵沟壑区天然草地植物多样性研究

以陇东黄土高原丘陵沟壑区天然草地30个植被样点的样方资料为依据,以相对生物量为指标,对该地区群落植物多样性进行了研究。结果表明,该地区天然草地可划分为长芒草草原、次生杂类草草原和杂类草草甸草原3个植被类型,16个群落按放牧程度分为禁牧草地、轻牧草地和过牧草地3个层次。多样性指数显示草甸草原>长芒草草原>次生杂类草草原,轻牧草地>禁牧草地>过牧草地的趋势。放牧程度可能是影响该区域天然草地植物多样性的关键因素,出现海拔增高和降水增加多样性指数降低的趋势可能是放牧干扰的结果。相关性分析显示物种的Shannon-wiener和Simpson多样性指数与Shannon和Simpson均匀度指数间均呈显著正相关,而与生物量之间呈显著负相关。