观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不...观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不同的方式适应干旱环境,表现出系统上的差异,如四合木初生根为四原型,而霸王及蒺藜科绝大部分类群的根为二原型;四合木次生木质部为同型单列射线,多生活纤维而少木薄壁细胞,而霸王为同型单列和同型多列两类射线,以后者为主,并且多木薄壁细胞而不见生活纤维;四合本叶表皮的角质膜薄。密度丁字毛,气孔极下陷,而霸王叶表皮角质膜厚,无表皮毛,气孔下陷较小;此外,四合木基本组织中富含簇品细胞,茎中具特殊的油细胞,而霸王中不存在。这些差异特征支持一些分类工作者把四合木属从霸王亚科分出,新成立四合木亚科(Tetranenoideae Maet S. Z. zhang)。展开更多
Secondary xylem characteristics and horizontal variations were described in three xerophytic species, Zygophyllum xanthoxylon, Nitraria tangutorum, Tetraena mongolica of Zygophyllaceae native to western China. All the...Secondary xylem characteristics and horizontal variations were described in three xerophytic species, Zygophyllum xanthoxylon, Nitraria tangutorum, Tetraena mongolica of Zygophyllaceae native to western China. All the species have obvious growth ring boundaries except sometimes discontinuous in T. mongolica and Z xanthoxylum ring to semi-ring-porosity; simple perforation plate; alternate intervessel pitting; non-septate fibres; paratracheal confluent axial parenchyrna; helical thickenings and heterocellular rays. However the vessel arrangement and quantitative features of vessels were different. Vessel elements tend to be shorter and narrower and more frequent in T. mongolica than in other two species that are hardly different could lead to greater conductive safety. The variation of vessel element length and fibre length along radial direction showed irregular tendency. There was significant difference in both fibre length and vessel element length among-tree and within-tree. Furthermore, the relationships between anatomical features and adaptability to desert environments were also discussed.展开更多
为定量分析蒺藜科属间花粉形态差异,采集了内蒙古西部地区蒺藜、唐古特白刺、霸王、骆驼蓬、四合木、蝎虎驼蹄瓣等植物的现代植物花粉,研究其光学显微镜下花粉特征,并将主要特征量化进行回归树分析(classification and regression tree,...为定量分析蒺藜科属间花粉形态差异,采集了内蒙古西部地区蒺藜、唐古特白刺、霸王、骆驼蓬、四合木、蝎虎驼蹄瓣等植物的现代植物花粉,研究其光学显微镜下花粉特征,并将主要特征量化进行回归树分析(classification and regression tree,CART),对比探讨了花粉形态分类与《中国植物志》分类间的关系。结果表明,蒺藜科花粉形态以小粒为主,形状为球形、近球形、长球形,萌发孔为三孔沟、三拟孔沟、散孔,表面纹饰有网状、条纹状,多数具沟膜;四合木和蝎虎驼蹄瓣花粉趋向近球形化;基于量化花粉形态特征参数的CART分类树结果与《中国植物志》分类结果差异较大,表明受外界环境影响进化变异较小的植物花粉形态可能更多地揭示了物种间的亲缘关系。展开更多
Two new furostanol glycoside,26-O-β-D-glucopyranosyl-(25S)-5α-furost-3β,22α,26-triol-3-O-β-D-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside(1) and 26-O-β-D-glucopyranosyl-(25S)-5α-fu...Two new furostanol glycoside,26-O-β-D-glucopyranosyl-(25S)-5α-furost-3β,22α,26-triol-3-O-β-D-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside(1) and 26-O-β-D-glucopyranosyl-(25S)-5α-furost-20(22)-en-2α,3β,26-triol-3-O-β-D-glucopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside(2) were isolated fromthe fruits of Tribulus terrestris L.The structures of two new furostanol saponins were elucidated by spectroscopic methods.展开更多
Relationships between genome size and environmental variables suggest that DNA content might be adaptive and of evolutionary importance in plants.The genus Larrea provides an interesting system to test this hypothesis...Relationships between genome size and environmental variables suggest that DNA content might be adaptive and of evolutionary importance in plants.The genus Larrea provides an interesting system to test this hypothesis,since it shows both intra-and interspecific variation in genome size.Larrea has an amphitropical distribution in North and South American deserts,where it is most speciose.Larrea tridentata in North America shows a gradient of increasing autopolyploidy;while three of the four studied South American species are diploids,Larrea divaricata,Larrea nitida,Larrea ameghinoi,and the fourth is an allopolyploid,Larrea cuneifolia.We downloaded available focal species’georeferenced records from seven data reservoirs.We used these records to extract biologically relevant environmental variables from WorldClim at 30 arc seconds scale,to have a broad characterization of the variable climatic conditions of both regions,and a climatic envelope for each species.We estimated relative DNA content index and relative monoploid genome values,by flow cytometry,of four most abundant Larrea species throughout their respective ranges.Then we winnow the bioclimatic dataset down to uncorrelated variables and sampled locales,to analyse the degree of association between both intra-and interspecific relative DNA content and climatic variables that are functionally relevant in arid environments using Pearson correlations,general linear and mixed effects models.Within the genus Larrea,relative DNA content increases with rising temperature and decreases with rising precipitation.At the intraspecific level,all four species show relative DNA content variation across climatic conditions.Larrea is a genus that shows genome size variation correlated with climate.Our results are also consistent with the hypothesis that extreme environmental pressures may have facilitated repeated whole genome duplication events in North America,while in South America,reticulate evolution,as allopolyploidization,and speciation might have been climate-depe展开更多
文摘观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不同的方式适应干旱环境,表现出系统上的差异,如四合木初生根为四原型,而霸王及蒺藜科绝大部分类群的根为二原型;四合木次生木质部为同型单列射线,多生活纤维而少木薄壁细胞,而霸王为同型单列和同型多列两类射线,以后者为主,并且多木薄壁细胞而不见生活纤维;四合本叶表皮的角质膜薄。密度丁字毛,气孔极下陷,而霸王叶表皮角质膜厚,无表皮毛,气孔下陷较小;此外,四合木基本组织中富含簇品细胞,茎中具特殊的油细胞,而霸王中不存在。这些差异特征支持一些分类工作者把四合木属从霸王亚科分出,新成立四合木亚科(Tetranenoideae Maet S. Z. zhang)。
文摘Secondary xylem characteristics and horizontal variations were described in three xerophytic species, Zygophyllum xanthoxylon, Nitraria tangutorum, Tetraena mongolica of Zygophyllaceae native to western China. All the species have obvious growth ring boundaries except sometimes discontinuous in T. mongolica and Z xanthoxylum ring to semi-ring-porosity; simple perforation plate; alternate intervessel pitting; non-septate fibres; paratracheal confluent axial parenchyrna; helical thickenings and heterocellular rays. However the vessel arrangement and quantitative features of vessels were different. Vessel elements tend to be shorter and narrower and more frequent in T. mongolica than in other two species that are hardly different could lead to greater conductive safety. The variation of vessel element length and fibre length along radial direction showed irregular tendency. There was significant difference in both fibre length and vessel element length among-tree and within-tree. Furthermore, the relationships between anatomical features and adaptability to desert environments were also discussed.
文摘为定量分析蒺藜科属间花粉形态差异,采集了内蒙古西部地区蒺藜、唐古特白刺、霸王、骆驼蓬、四合木、蝎虎驼蹄瓣等植物的现代植物花粉,研究其光学显微镜下花粉特征,并将主要特征量化进行回归树分析(classification and regression tree,CART),对比探讨了花粉形态分类与《中国植物志》分类间的关系。结果表明,蒺藜科花粉形态以小粒为主,形状为球形、近球形、长球形,萌发孔为三孔沟、三拟孔沟、散孔,表面纹饰有网状、条纹状,多数具沟膜;四合木和蝎虎驼蹄瓣花粉趋向近球形化;基于量化花粉形态特征参数的CART分类树结果与《中国植物志》分类结果差异较大,表明受外界环境影响进化变异较小的植物花粉形态可能更多地揭示了物种间的亲缘关系。
基金the New Century Excellent Talents in University((No.NCET-08-0746)Cooperation Program of Beijing Municipal Education Commission,and National Natural Science Foundation of China(No. 30873357)
文摘Two new furostanol glycoside,26-O-β-D-glucopyranosyl-(25S)-5α-furost-3β,22α,26-triol-3-O-β-D-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside(1) and 26-O-β-D-glucopyranosyl-(25S)-5α-furost-20(22)-en-2α,3β,26-triol-3-O-β-D-glucopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside(2) were isolated fromthe fruits of Tribulus terrestris L.The structures of two new furostanol saponins were elucidated by spectroscopic methods.
基金supported by Argentine National Found for Science and Technology,under Grant PICT 2014-3478-BID and 20190149 BIDCouncil of Science and Technology-CONICET under Grant PIP-0712.R.V.R.,M.T.,and C.P.S.are members of CONICET. Grant Agency of the Czech Republic 17-12420S
文摘Relationships between genome size and environmental variables suggest that DNA content might be adaptive and of evolutionary importance in plants.The genus Larrea provides an interesting system to test this hypothesis,since it shows both intra-and interspecific variation in genome size.Larrea has an amphitropical distribution in North and South American deserts,where it is most speciose.Larrea tridentata in North America shows a gradient of increasing autopolyploidy;while three of the four studied South American species are diploids,Larrea divaricata,Larrea nitida,Larrea ameghinoi,and the fourth is an allopolyploid,Larrea cuneifolia.We downloaded available focal species’georeferenced records from seven data reservoirs.We used these records to extract biologically relevant environmental variables from WorldClim at 30 arc seconds scale,to have a broad characterization of the variable climatic conditions of both regions,and a climatic envelope for each species.We estimated relative DNA content index and relative monoploid genome values,by flow cytometry,of four most abundant Larrea species throughout their respective ranges.Then we winnow the bioclimatic dataset down to uncorrelated variables and sampled locales,to analyse the degree of association between both intra-and interspecific relative DNA content and climatic variables that are functionally relevant in arid environments using Pearson correlations,general linear and mixed effects models.Within the genus Larrea,relative DNA content increases with rising temperature and decreases with rising precipitation.At the intraspecific level,all four species show relative DNA content variation across climatic conditions.Larrea is a genus that shows genome size variation correlated with climate.Our results are also consistent with the hypothesis that extreme environmental pressures may have facilitated repeated whole genome duplication events in North America,while in South America,reticulate evolution,as allopolyploidization,and speciation might have been climate-depe
