西藏植物区系地理区域分异的探讨

本文应用数量统计方法及植物区系分布区型谱图探讨西藏植物区系地理的地域分异。中国-喜马拉雅成分在藏东和藏东南占优势,热带成分集中分布于喜马拉雅南翼的低海拔地区;在高原内部青藏高原成分占统治地位,而中亚成分则在高原的西北部起重要的作用。植物区系成分的这种水平地域分异和西藏境内自东南向西北植被由森林、草甸、草原至荒漠的地带更迭是相吻合的。海拔1800米可以看作是热带成分占优势的垂直系列的上界。根据优势植物区系成分确定的几条界线,西藏可划归如下植物区系区域:古热带植物区印度马来亚植物亚区的喜马拉雅南翼亚地区,泛北极植物区的中国-喜马拉雅亚区和青藏高原亚区。     

新疆早寒武世Lapworthella一新种及本属有关问题探讨

西藏海相下第三系,广泛断续地出露于雅鲁藏布江断裂带南北。本文概略论述西藏海相下第三系,列举一些新的地层剖面,划分对比地层,简述沉积岩相古地理,提出双壳类化石组合特征并描述5个双壳类化石新种。它的研究对了解喜马拉雅地质历史的发展,海水退出该区的最后时限,以及探讨古地理、古气候等,都具有一定的理论与实际意义。     

用中国春双端二体分析西藏小麦的染色体构成

用普通小麦“中国春”双端二体系列(double ditelosomics)作母本分别与西藏小麦杂交,对全套21个F_1的PMC在MI进行端体配对分析。在(“中国春”双端二体7B×西藏小麦)F_1中,含有(t′,t1″)构型的PMC占观察总数的87.3％,7BS常不参与配对,显示出有较大差异。“中国春”3A、7A、2D—7D等8条染色体的两臂可以分别同时与西藏小麦对应染色体配成异型三价体(tt1′′′)的PMC频率达80.0—95.5％,表明西藏小麦与“中国春”之间这8条染色体差异很小。在涉及其余12条染色体的组合中,出现(tt1′′′)、(t′t1″)和(t′,t′)构型的PMC分别占观察细胞总数的42.3—77.6％、21.9—55.5％和0—8.0％,表明它们之间仅某个染色体臂间有轻度变异或分化。从总体来看,西藏小麦与“中国春”之间除7BS有较大差异外在染色体构成上基本相似。     

西藏鹅膏菌属的分布特征

西藏地区已知鹅膏菌属(Amanita)真菌28种。西藏东南部的生态环境有利于该属种类的繁殖生长,约有90%以上的种集中分布在这里,同时反映了十分明显的垂直分布和对高山的适应特征。绝大多数种分布在海拔2500～3500m的森林带。另外该属全部种均属树木的外生菌根菌。本文还将鹅膏菌属的菌托初步划分为袋状型(Saccate type)、浅杯型(Vadosocupulatetype)、领口型(Collared type)、颗粒型(易碎型Granulate type)、小托型(Microvolvate type)、粉托型(Pulverulent type)等六种类型,并简要讨论了各种菌托类型与所处生态环境的适应性。     

Strong evidence for changing fish reproductive phenology under climate warming on the Tibetan Plateau

Phenological responses to climate change have been widely observed and have profound and lasting effects on ecosystems and biodiversity. However, compared to terrestrial ecosystems, the long‐term effects of climate change on species’ phenology are poorly understood in aquatic ecosystems. Understanding the long‐term changes in fish reproductive phenology is essential for predicting population dynamics and for informing management strategies, but is currently hampered by the requirement for intensive field observations and larval identification. In this study, a very low‐frequency sampling of juveniles and adults combined with otolith measurements (long axis length of the first annulus; LAFA) of an endemic Tibetan Plateau fish (Gymnocypris selincuoensis) was used to examine changes in reproductive phenology associated with climate changes from the 1970s to 2000s. Assigning individual fish to their appropriate calendar year class was assisted by dendrochronological methods (crossdating). The results demonstrated that LAFA was significantly and positively associated with temperature and growing season length. To separate the effects of temperature and the growing season length on LAFA growth, measurements of larval otoliths from different sites were conducted and revealed that daily increment additions were the main contributor (46.3%), while temperature contributed less (12.0%). Using constructed water‐air temperature relationships and historical air temperature records, we found that the reproductive phenology of G. selincuoensis was strongly advanced in the spring during the 1970s and 1990s, while the increased growing season length in the 2000s was mainly due to a delayed onset of winter. The reproductive phenology of G. selincuoensis advanced 2.9 days per decade on average from the 1970s to 2000s, and may have effects on recruitment success and population dynamics of this species and other biota in the ecosystem via the food web. The methods used in this study are applicable for studying reproductive phenological changes across a wide range of species and ecosystems.     

珠穆朗玛地区伞形科植物的分类学研究

Five species new for Chinese flora have been shown on the basis of the gatherings from northern slopes of Qomolangma Feng (Everest Mt. ). They belong to the genera Physospermopsis, Pleurospermum, Pimpinella, and Schulzia. A new genus, Oreocomopsis and its new species, O. xizangensis, have been described. Critical comments on these and some other South Xizang Umbelliferae are presented.     

西藏鸢尾兰属(兰科)植物5个新记录种

通过对西藏兰科鸢尾兰属植物进行的系统调查、标本采集、查阅、整理和鉴定,发现了西藏鸢尾兰属植物5个新记录种,分别为:长苞鸢尾兰(Oberonia longibracteata Lindl.)、短耳鸢尾兰(O. falconeri Hook. f.)、裂唇鸢尾兰(O. pyrulifera Lindl.)、条裂鸢尾兰(O. jenkinsiana Griff. ex Lindl.)和长裂鸢尾兰(O. anthropophora Lindl.),并附有这些新记录种的特征照片。凭证标本保存于西藏高原生态研究所标本室(XZE)。目前西藏鸢尾兰属植物共有14种,编写出西藏鸢尾兰属植物的分种检索表,以期达到对该区鸢尾兰属植物资源鉴定识别和有效保护的目的。     

西藏紫草科1新记录属——微果草属

该文报道了西藏地区紫草科1新记录属微果草属(Microcaryum)及1新记录种微果草(Microcaryum pygmaeum (Clarke)Johnst.)。该种发现于西藏隆子县,生于海拔约5 000 m的高山草甸。研究了其外部形态、小坚果微形态及花粉形态,并与形态相近种毛果草 （Lasiocaryum densiflorum (Duthie)Johnst.） 进行了比较。凭证标本保存于北京师范大学动植物标本馆植物标本室(BNU)。     

西藏贞琵甲属二新种记述(鞘翅目:拟步甲科)

记述西藏贞琵甲属Agnaptoria Reitter2新种:黑头贞琵甲A.nigriceps,sp.nov.和单刷贞琵甲A.apicopilosa,sp.nov.。模式标本保存于河北大学博物馆。     

A New Species and a Newly Recorded Species of Adoxa L. from Xizang

A new species and a new record for China of the genus Adoxa L.are reported from Xizang, China. They are Adoxa xizangensis G.Yao and Adoxa inodora (Falc.ex C.B.Clarke) Nepomn.