关于茭白黑粉菌的正名问题

茭白黑粉菌在文献中出现Yenia esculenta(P.Henn.)Liou及Ustilago esculenta P.Henn.两个名字。现经形态发生学的研究以明确新名字是否有效。此菌冬孢子没有休眠期,孢子成熟后在适宜的环境中即可萌发。萌发的最适pH值为6;最适温度为25％;不需要外界光的诱导,在黑暗条件下也能正常萌发;培养基中的营养成份对孢子萌发的速率有一定影响。冬孢子在不同的环境条件下,其萌发形态及方式都是稳定的:孢子萌发时产生有隔的担子或先菌丝(promycelium)。该先菌丝起初可以是无隔的,但生长到一定程度,便产生分隔,分隔多为2—4个。初生的先菌丝和小孢子是单核的,但成熟的先菌丝、小孢子及短菌丝细胞内均是双核的。可以认为,该菌的双核期在整个生活史中占有相当长的时间,它只有短暂的单核期。没有发现先菌丝、小孢子彼此之间或相互间融合的现象;未见到双核的融合及减数分裂过程。茭白黑粉菌在人工组合培养基上生成厚壁的孢子,较自然界中的冬孢子为大,但萌发方式则相同。最后作者等认为茭白黑粉菌仍应保留在Ustilago属中,而Yenia esculenta(P.Henn.)Liou的名字是无效的。     

NOTES ON THE APPLICATION OF THE FLUORINEDATING METHOD TO THE DATING OF SOME FOSSIL HUMAN REMAINS OF CHINA

Several new finds of fossilized human remains have been made in Chinaduring the last few years.As most of the materials were incidentally discover-ed and collected by amateur collectors,the stratigraphical position of thefossils and their relation with the associating vertebrate fossils were mostlyunknown or doubtful.     

中国南海栉水母类初志

(一)从作者此次在广东沿海的采集经验看来,我国南海最常见的栉水母类有三种,即球栉水母[Pleurobrachia globosa Moser]、瓜水母[Beroe cucumis Fabricius]和蝶水母[Ocyropsis crystallina(Rang)],其中以球栉水母产量最多,最为常见。 (二)本文对球栉水母的消化和运动方面作了较详细的报道。食物的消化,主要是在口道内进行的,口道内有一对口道囊(stomodael pouches),这对小囊在平时体积很小,口缘皱缩,因此很不容易识别,当摄食以後,此囊即扩大三四倍以上,其中充满消化液,较小的食物(如蟹的溞状幼体)可储於口道囊内,进行消化,较大的食物(如幼鱼)则在口道内消化。食物经消化後,沿着胃和各种水管分布於全身。不能消化的食物残馀,则仍由口排出。就作者所知,球栉水母的口道囊过去还没有人报道过,一般教科书称之为口道嵴(stomodael ridge)或口道褶(stomodael fold),显系观察的谬误,这里必须予以指出的。球栉水母的运动方法有三种:(1)利用栉毛不断的鼓动,结果口端朝前游动;(2)触手收缩,栉毛停止摆动,利用本身的比重比海水为大...     

中国的内囊霉科菌根真菌

本文报道了25种采集于我国广州、昆明、武汉、北京和哈尔滨等地农业土壤中的内囊霉科真菌。其中球内囊霉属(Glonus)16种,无柄内囊霉属(Acaulospora)4种,楯孢内囊霉属(Scutellospora)3种,巨孢内囊霉属(Giga-spora)1种,内养内囊霉属(Entrophospora)1种。此外还发现了硬内囊霉属(Sc-kerocystis)的孢子果。其中20种和除球内囊霉属外的另外5属为我国的新记录。     

Influence of typhoons on annual CO2 flux from a subtropical, humic lake

The Intergovernmental Panel on Climate Change predicts dramatic changes in precipitation patterns over the next century. One potential method for inferring how these changes in annual precipitation and intensity of storm events will influence aquatic ecosystems is to study and model present-day lakes that share climatic characteristics with future climate scenarios. A small lake in north-central Taiwan provided an excellent opportunity to explore the influence of intense meteorological events on CO₂ exchange between surface waters and the atmosphere. Each year Yuan Yang Lake (YYL) is influenced by multiple typhoons that pass near the island of Taiwan. This lake has been instrumented with a sensor network that monitors water column and meteorological parameters at a high temporal resolution (2–10 min intervals). Using this high-resolution data and manually collected CO₂ samples, a mass-balance model of CO₂ dynamics in YYL was developed. In addition, a generalized simulation model was used to explore how typhoon frequency, intensity, and timing impact CO₂ efflux to the atmosphere. Our findings suggest that increased annual precipitation and frequency of storm events results in greater epilimnetic interaction with the watershed and hypolimnion. These interactions resulted in elevated epilimetic CO₂ concentrations and therefore greater evasion of CO₂ to the atmosphere.     

Phylogeography of the marine macroalga Sargassum hemiphyllum (Phaeophyceae,Heterokontophyta) in northwestern Pacific

Sargassum hemiphyllum is commonly found in Japan and Korea, with a variety, var. chinense, that is found distributed in the southern Chinese coast. We previously reported distinct genetic differentiation between the two taxa based on the PCR‐RFLP data of plastid RubiscoL‐S spacer. The present study aims at elucidating the phylogeographic pattern of S. hemiphyllum based on more markers in the nuclear and extranuclear genomes, with a view to reveal the occurrence of hybridization. The two allopatrically distributed taxa were found to be genetically distinct in nuclear ITS2, plastidial Rubisco (Rbc) and mitochondrial TrnW_I (Trn) spacers. Their divergence was postulated to be attributable to the vicariant event which resulted from the isolation of the Sea of Japan during the late Miocene (6.58–11.25 Mya). Divergence within both S. hemiphyllum and the chinense variety was observed based on Trn spacer, while the divergence in S. hemiphyllum was further confirmed in Rbc spacer. This divergence appears to correspond to the separation of the Japanese populations between the Sea of Japan and the Pacific that occurred around 0.92–2.88 Mya (the early Pleistocene). The presence of an ITS2 clone resembling var. chinense sequences in a Japanese population of S. hemiphyllum (JpNS) raises the possibility of the introgression of var. chinense individuals into S. hemiphyllum population. Compared to that between S. hemiphyllum and the chinense variety, hybridization among the Japanese and Korean populations of S. hemiphyllum is highly probable as all these individuals share a pool of nuclear ITS2 sequences, possibly attributable to incomplete concerted evolution of ITS2.     

The Effect of Segment Length on Conductance Measurements in Lonicera fragrantissima

The effect of stem segment length on conductance measurementswas determined by repeatedly shortening the transport distancein isolated stem segments of Lonicera fragrantissima. If vesselends limit water flow, shorter segment lengths could resultin higher readings of K_h (hydraulic conductance per unit pressuregradient). The mean K_h in the successively shortened segmentsshowed no statistically significant change when shortened from20 to 2 cm, even though maximum vessel lengths ranged from 6to 14 cm. This suggests vessel ends may be less limiting towater flow than are vessel lumens. There was a statisticallysignificant drop in K_h (19%, s.e.=0·29%) when segmentswere shortened from 2 to 1 cm, regardless of the position ofthe segment within the branch. The K_h remained constant withapplied pressure in 2 cm segments while it was more variablewith applied pressure in 1 cm segments. Based on the paint-infusionmethod mean vessel lengths were from 0·6 to 1·2cm. The consistently lower K_h in 1 cm segments might be dueto an end effect in segments with a high percentage of cut openvessels. Within a branch, distal and proximal stem segmentshad lower K_h values than segments from intermediate positions,but nodes had no measurable impact on K_h. Longer segments allowfor more accurate and consistent measurements of K_h since theyintegrate localized variation in K_h while minimizing the segmentend effect. Key words: Vessel length, vessel end, hydraulic conductance, paint-infusion method, Lonicera fragrantissima     

川楝素对菜青虫中肠组织的影响

川楝素是从楝属植物树皮中提取出来的一种三萜烯类物质。过去主要作为医用药品驱除人体蛔虫,后来发现具有杀虫活性,已有较全面的综述(赵善欢和张兴,1987)。在杀虫作用研究中曾发现,川楝素对菜青虫(Pieris rapae L.)具有高的生物活性(赵善欢等,1985;张兴等,1988),可应用于田间防治。为了揭示川楝素对菜青虫幼虫致毒作用的毒理机制,曾从生理、生化等方面作了研究,本文主要报道对中肠组织病变的观察结果。     

黄杜鹃对美洲斑潜蝇的生物活性研究(英文)

试验结果表明 ,闹羊花素 Ⅲ 50 0mg/L对美洲斑潜蝇 2龄和 3龄幼虫的取食抑制率分别为 77 34%和6 7 6 6 % ,高于杀虫单的取食抑制率。对 2龄和 3龄幼虫的LC50 分别为 2 0 8 6 5mg/L和 30 0 6 2mg/L。药膜法测得对成虫 2 4h的LC50 为 159 0 7mg/L ;4 8h为 54 85mg/L。黄杜鹃花几种粗提物也表现出不同程度的取食抑制作用和毒杀作用。     

Seasonal dynamics,typhoons and the regulation of lake metabolism in a subtropical humic lake

1. We used high‐frequency in situ dissolved oxygen measurements to investigate the seasonal variability and factors regulating metabolism in a subtropical alpine lake in Taiwan between May 2004 and October 2005, specifically exploring how the typhoon season (from June or July to October) affects lake metabolism. 2. Gross primary production (GPP) and ecosystem respiration (R) both peaked in early summer and mid‐autumn but dropped during the typhoon season and winter. Yuan‐Yang Lake is a net heterotrophic ecosystem (annual mean net ecosystem production ?39.6 μmole O₂ m^?3). 3. Compared to the summer peaks, seasonal averages of GPP and R decreased by approximately 50% and 25%, respectively, during the typhoon season. Ecosystem respiration was more resistant to external disturbances than GPP and showed strong daily variation during typhoon seasons. 4. Changes in the quality and quantity of dissolved organic carbon controlled the temporal dynamics and metabolic regulation. External disturbances (typhoons) caused increased allochthony, increasing DOC and water colour and influencing lake metabolism. 5. Seasonal winter mixing and typhoon‐induced water mixing in summer and autumn play a key role in determining the extent to which the lake is a seasonal carbon sink or source to the atmosphere.