中国兰科二新记录种

报道了中国兰科2新记录种,大花大苞兰（Sunipia grandiflora (Rolfe) P.F. Hunt）及小花石豆兰(Bulbophyllum parviflorum C.S.P. Parish &; Rchb.f.)。     

中国兰科独蒜兰属植物增补

报道了中国兰科独蒜兰属2个未详知种:藏南独蒜兰(Pleione arunachalensis Hareesh, P.Kumar M.Sabu)和矮小独蒜兰[P.humilis (Sm.) D.Don],并提供了详细的形态描述和照片。凭证标本保存于云南省林业和草原科学院植物标本馆(YAF)。     

中国兰科耳唇兰属补志

在《中国植物志》第18卷中记载了四种国产耳唇兰属Otochilua植物。其中的白花耳唇兰O.albus系根据某些植物学家的引证,而不是作者自己检视的标本。在第一作者近来的一次赴欧访问中,仔细检视了保存在那里的耳唇兰属标本,特别是Smith与Seidenfaden所引证的标本：Forrest 9493(E)、16168(K,E)、27753(K,P,E)与F．E．Younghusband s．n．(K)。其中只有F．E. Younghusband s．n．是真正的白花耳唇兰,其余的应是宽叶耳唇兰O．lancilabius和耳唇兰O．porrectus。作为对《中国植物志》第18卷的补充,本文对白花耳唇兰作了订正,并根据西藏标本进行了描述。     

中国巾唇兰属(兰科)一新记录种——鸵鸟巾唇兰

报道中国兰科(Orchidaceae)巾唇兰属一新记录种---鸵鸟巾唇兰(Pennilabium struthio Carr ),并提供了详细的形态描述和照片.该种与巾唇兰(P ．yunnanense S．C．Chen&Y．B．Luo)较接近,区别点在于花梗和子房不旋转,萼片为椭圆形,花瓣为卵状椭圆形,花瓣外端具短齿,距近末端膨大.     

中国鹿角兰属(兰科)植物新资料

报道了中国兰科(Orchidaceae)鹿角兰属(Pomatocalpa)一新记录种——纹瓣鹿角兰［P. tonkinense (Gagnep.) Seidenf.］,凭证标本保存于广西植物研究所标本馆(IBK)。纹瓣鹿角兰的花序疏生多数花,萼片、花瓣均具2条紫色条纹,中萼片及花瓣远长于侧萼片,与中国原记录的2种鹿角属植物容易区分。该研究提供了新记录种的形态描述、中国鹿角兰属植物图版及分种检索表。     

中国西藏兰科植物新资料

中国西藏东南地区位于东喜马拉雅和印缅的交接处,是全球生物多样性的热点地区,尤其是位于该地区的墨脱,由于巨大的海拔高差,使该地区的植被类型呈显著的垂直地带性,且植物种类繁多、植被结构复杂。该文报道了西藏野生兰科植物新记录属3个,即线柱兰属(Zeuxine)、爬兰属(Herpysma)和槽舌兰属(Holcoglossum);新记录种27个,即白肋线柱兰(Zeuxine goodyeroides)、爬兰(Herpysma longicaulis)、小花槽舌兰(Holcoglossum himalaicum)、西南齿唇兰(Anoectochilus elwesii)、窄唇蜘蛛兰(Arachnis labrosa)、短足石豆兰(Bulbophyllum stenobulbon)、尖角卷瓣兰(B. forrestii)、南方虾脊兰(Calanthe lyroglossa)、泰国牛角兰(Ceratostylis siamensis)、金唇兰(Chrysoglossum ornatum)、格力贝母兰(Coelogyne griffithii)、云南贝母兰(C. assamica)、斑舌兰(Cymbidium tigrinum)、梳唇石斛(Dendrobium strongylanthum)、狭叶金石斛((D. angustifolium)、厚唇兰(D. mariae)、粗茎苹兰(Pinalia amica)、垂叶斑叶兰(Goodyera pendula)、绿花斑叶兰(G. viridiflora)、狭叶羊耳蒜(Liparis perpusilla)、小花羊耳蒜(L. platyrachis)、三裂羊耳蒜(L. mannii)、镰叶鸢尾兰(Oberonia falcata)、阔瓣鸢尾兰(O. latipetala)、凹唇石仙桃(Pholidota convallariae)、大苞兰(Sunipia scariosa)、滇南矮柱兰(Thelasis khasiana)。这些植物新资料的发现,对于丰富西藏植物种类以及对该地区物种多样性的保护和研究具有重要意义。     

15种独蒜兰属植物叶表皮微形态特征及分类学意义研究

为解决兰科(Orchidaceae)独蒜兰属(Pleione D. Don)植物分类学问题并探索叶片超微结构在分类学中的意义,该研究利用扫描电子显微镜,对独蒜兰属15种植物成熟叶片的细胞界限、角质层纹理、气孔器分布等15个叶表皮超微特征进行观测分析,以明确它们的分类学意义。结果表明：(1)细胞界限、表皮细胞蜡质量、角质层纹理、气孔器分布、气孔器周围蜡质、气孔器外拱盖内缘、角化现象、气孔器相对高度、表皮细胞长度、表皮细胞面积、保卫细胞长度和保卫细胞面积这9个指标对于该属分类具有重要价值和意义。(2)利用上述特征可以对春花独蒜兰组(S. Humiles)、独蒜兰组(S. Pleione)和独蒜兰复合体(P. bulbocodioides complex)的组内区分进一步细化。(3)聚类分析将15种独蒜兰属植物聚类为4个分支,与传统分类学和分子系统学分类结果基本一致。研究认为,大理独蒜兰(P. × taliensis P. J. Cribb & Butterfield)与云南独蒜兰［P. yunnanensis (Rolfe) Rolfe］、黄花独蒜兰(P. forrestii Schltr.)在多个叶片微观特征方面表现出高度的一致性,大理独蒜兰的亲本有待于进一步研究确认。     

中国鹤顶兰属(兰科)一新记录种

报道了中国鹤顶兰属Phaius一新记录种——中越鹤顶兰P.tonkinensis(Aver.)Aver.。该种与紫花鹤顶兰P.mishmensis(Lindl.et Paxton)Rchb.f.相似,不同在于该种的花萼和花瓣均为象牙白色,唇盘的脊上无毛,脊两侧具稀疏白色长毛。该文提供了该新记录种的形态描述和墨线图。     

甘肃省杓兰属植物资源调查及2新记录种

通过对甘肃省杓兰属植物进行系统的调查和资料整理,共发现甘肃省杓兰属植物15种,占中国杓兰属植物种类的39.47%,其中9种为中国特有种。调查发现2种甘肃省杓兰属植物分布新记录种——巴郎山杓兰(Cypripedium palangshanense T.Tang et F.T.Wang)和离萼杓兰(Cypripedium plectrochilum Franch.)。通过整理重新编制了甘肃省杓兰属植物的分种检索表。     

中国兰科杓兰属一新种及一新变种

对云南东南部兰科新种麻栗坡杓兰(Cypripodium,malipoense)和新变种大围山杓兰(Cypripedium lichiangense var.datveishanense)作了描述。麻栗坡杓兰与文山杓兰(C.lentiginosum)相近,区别点在于新种叶淡黄色而有紫斑,色泽与花瓣及唇瓣极为相似;花瓣明显较短,仅稍长于唇瓣。新变种大围山杓兰与原变种的不同在于中萼片黄绿色,疏生紫红色斑点;花瓣仅稍长于唇瓣;唇瓣囊口有一黑色圈。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.