柴达木盆地北缘宗马海湖地区始新统下干柴沟组在一道沟剖面出露良好,本文详细描述了该剖面下干柴沟组的岩性特征,该组以棕红色泥岩为主,局部夹浅灰绿色含石膏中细砂岩、含钙质粉砂质细砂岩及少量含砾中粗砂岩、褐红色灰岩。在该剖面发现轮藻化石2属2种:Lamprothamnium ganchaigouensis(Tang and Di)Li et al.comb.nov.和Lychnothamnus vectensis(Groves)Soulié-M?rsche,前者为新联合属种。L.vectensis主要发现于欧洲始新统渐新统,在我国始新统系首次报道。本文以居群为单位,讨论了L.vectensis的种内形态变化,包括藏卵器尺寸和顶部装饰的连续变化。欧洲L.vectensis居群的藏卵器尺寸随着纬度的升高有变大的趋势,而柴达木盆地的纬度低于欧洲埃布罗盆地和巴黎盆地的纬度,它所产的L.vectensis居群藏卵器尺寸却更大,推测与柴达木盆地古湖泊水体清澈度和/或温度更高相关。
Phytophthora capsici is a phytopathogen that causes a destructive pepper blight that is extremely difficult to control. Using a fungicide application against the disease is costly and relatively ineffective and there is also a huge environmental concern about the use of such chemicals. The genus Trichoderma has been known to have a potential biocontrol issue. In this paper we investigate the mechanism for causing the infection of T. asperellum against P. capsici. Tnchoderma sp. （isolate CGMCC 6422） was developed to have a strong antagonistic action against hyphae of P. capsici through screening tests. The strain was identified as T. asperellum through using a combination of morphological characteristics and molecular data. T. asperellum was able to collapse the mycelium of the colonies of the pathogen through dual culture tests by breaking down the pathogenic hyphae into fragments. The scanning electron microscope showed that the hyphae of T. aspere/lum surrounded and penetrated the pathogens hyphae, resulting in hyphal collapse. The results show that seven days after inoculation, the hyphae of the pathogen were completely degraded in a dual culture. T. asperel/um was also able to enter the P. capsici oospores through using oogonia and then developed hyphae and produced conidia, leading to the disintegration of the oogonia and oospores. Seven days after inoculation, an average 10.8% of the oospores were infected, but at this stage, the structures of oospores were still intact. Subsequently, the number of infected oospores increased and the oospores started to collapse. Forty-two days after inoculation, almost all the oospores were infected, with 9.3% of the structures of the oospores being intact and 90.7% of the oospores having collapsed.
