草问荆(木贼科)的地理分布

通过整合全球植物志文献资料, 结合调查中国科学院植物研究所植物标本馆(PE)、北京林业大学森林植物标本馆(BJFC)和中国科学院沈阳应用生态研究所植物标本馆(IFP)馆藏腊叶标本, 以及进行野外观测, 获取了草问荆的地理分布数据。采用地理绘图软件MapInfo Profes sional 8.0, 绘制草问荆在中国及世界的资源分布图, 首次提供了其在中国的详细分布资料, 为深入理解和开发草问荆资源提供了必要的生物学基本数据。     

节节草化学成分的研究

应用柱层析、薄层层析及重结晶等方法,从木贼科问荆属植物节节草（Equisetum ramosissimum）的全草中分离得到17个化合物,经现代波谱技术鉴定了它们的结构,分别为：5α,6α-环氧-β-紫罗兰酮-3-O-β-D-葡萄糖甙（1）、loliolide（2）、环阿尔屯烷～24（30）-烯-3β-醇（3）、环阿尔屯烷-22（23）-烯-3β醇（4）、麦角甾-6,22-二烯-3β,5α,8α-三醇（5）、木栓醇（6）、芹菜素（7）、芫花素（8）、芫花素-5-O-β-D-葡萄糖甙（9）、芹菜素-5-O-β-D-葡萄糖甙（10）、木犀草素（11）、槲皮素-3-O-β-D-葡萄糖甙（12）、山奈酚-3-O-β-D-葡萄糖甙（13）、山奈酚-3-O-β-D-葡萄糖-7-O-β-D-葡萄糖甙（14）、腺嘌呤核苷（15）、β-谷甾醇（16）和β-胡萝卜甙（17）。其中化合物1～5、15为首次从该属植物中分离得到。     

中国木贼科植物化学分类学的研究

通过研究,确定山奈酚-3,7-双葡萄糖甙和山奈酚为木贼科的特征性成分; 山奈酚-3- 双葡萄糖甙为木贼属的特征性成分; 槲皮素为问荆属的特征性成分。此外,还分离、鉴定了 山奈酚-3-双葡萄糖-7-葡萄糖甙、异槲皮甙和琥珀酸等化合物。其中,山奈酚-3-双葡萄糖和琥珀酸系首次从中药木贼中分得。     

耳草属（茜草科）植物的两个新种

耳草属（茜草科）植物的两个新种=Two new species of the genus Hedyotis　(Rubiaceae) from China[刊,中]/ 王 瑞 江（中国科学院华南植物研究所 广州 510650）,邢 福 武//植物分类学报.—2002,41（1）.—85～88 摘要：描述了国产耳草属(茜草科)植物的两个新种,启无耳草Hedyotis wangii　R. J. Wang和崖州耳草H. yazhouensis　F. W. Xing et R. J. Wang。     

中国的草蛉及其地理分布（脉翅目：草蛉科）

本文讨论了中国草蛉科已知属种的地理分布及其特点,指出：属的分布以东洋成分比重较大,高山高原属分化明显;种类分布呈现东洋成分由东部沿海向北挺进、古北种类通过西北地区向西南延伸的格局,丰富的高山、高原种类及狭布种类,是我国草蛉区系的一大特点。     

中国边草蛉属研究（脉翅目，草蚜科）

检视和记述了我国边草蛉属Brinckochrysa Tjeder 5个种类（包括1新种）;桂边草蛉Brinckochrysa guiana sp.nov,琼边草蛉B.qionguna Yang,莲座边草蛉B.rasulata Yang et Yang,膨板边草蛉B.turgida(yang et Wang,1990)和秉氏边草蛉B.zina(Navas,1933),新种有详细的形态学描述、插图、种名词源以及与其近似种的区别。所有模式标本保存于中国农业大学标本馆。     

草蛉科纳草蛉属研究（Ⅱ）—六新种记述（脉翅目：草蛉科）

本文是纳草蛉属Navasius研究续报(研究Ⅰ见“动物分类学报”第15卷第3期)。报道了纳草蛉属6新种:跃纳草蛉N.igneus sp.nov.,冠纳草蛉N.lophophorus sp.nov.,黑角纳草蛉N.nigricornutus sp.nov.显沟纳草蛉N.phantosulcus sp.nov.康纳草蛉N.sanus sp.nov.及三齿纳草蛉N.tridentatus sp.nov.。     

木贼科气孔器的扫描电镜观察

首次用扫描电镜比较观察了木贼科不同生境的问荆(Equisetum arvense L.)、草问荆(E. pratense Ehrhart)、林问荆(E. sylvaticum L.)、水问荆(E. fluviatile L.)、木贼(Hippochaete hyemale L.)等5种植物地上茎气孔器的详细特征,提供了直观的立体图象,并从比较形态学的角度,初步讨论了木贼类的系统学和生态学意义。     

贵州及湖南楼梯草属（荨麻科）植物新记录

本文报道荨麻科(Urticaceae)楼梯草属(ElatostemaJ.R.&G.Forst.)植物贵州新记录2种:疏晶楼梯草(E.hookerianum Wedd.)和显脉楼梯草(E.longistipulum Hand.-Mazz.),以及湖南新记录1种:西畴楼梯草(E.xi-chouense W.T.Wang)。     

Desiccation-time limits of photosynthetic recovery in Equisetum hyemale (Equisetaceae) spores

The chlorophyllous spores of Equisetum survive desiccation, yet cannot tolerate this quiescent state for more than ~2 wk. The hypothesis that spore viability of Equisetum hyemale L. is limited by inhibition of photosynthetic recovery was tested using chlorophyll a fluorescence and oxygen-exchange analyses. Experimental spores were desiccated at 2% relative humidity and 25C for time periods of 24 h, 1 wk, and 2 wk, and then rehydrated at 200 mmol photons/m2s (PAR) and 25C for up to 24 h. Spores desiccated for 24 h recovered photosynthetic competence very rapidly during rehydration, reaching the O2 compensation point in 6.3 ~ 0.3 (mean +/- SE) min. Recovery of photosynthetic performance of spores desiccated for 1 wk was slower, as judged by significantly slower increases of (1) photochemical efficiency of photosystem (PS) II, (2) PS II quinoneB-reducing center concentration, (3) quinoneB concentration, (4) water-oxidation activity, (5) rate of light-induced O2 evolution, and (6) apparent quantum yield of net O2 exchange. Photosystem-II and whole-spore photosynthetic competence of 2-wk desiccated spores was increasingly impaired, and did not recover during rehydration. Origin fluorescence yield and dark respiration were not affected by desiccation time following rehydration. The results suggest that the extremely short viability of disseminated spores of Equisetum hyemale is due to the inability to recover losses of water oxidation and photosystem II-core function following 2 wk of desiccation.     

Triploidy in Equisetum subgenus Hippochaete (Equisetaceae, Pteridophyta)

BACKGROUND AND AIMS: The genus Equisetum is cytologically uniform, having a base chromosome number of x = 108. All previously known species and hybrids that have been counted represent diploids with a sporophytic chromosome number of 2n = 216. Biosystematic studies on Equisetum subgenus Hippochaete revealed evidence that triploids occur in nature. The objective of this study was to confirm that triploid plants exist in the natural environment. METHODS: Flow cytometry was used to establish nuclear DNA values and cytological investigations of meiosis were carried out to obtain information on chromosome number and pairing behaviour. KEY RESULTS: Triploidy exists in three morphologically different hybrid taxa. Two of these are morphologically intermediate between a primary diploid hybrid and a parent, while the third apparently combines genomes from all three Central European Hippochaete species. Nuclear 1C DNA values for the four European Hippochaete species range from 21.4-31.6 pg. For the hybrids, the 1C DNA values not only occupy the same range as the species, but their total DNA amounts agree closely with values predicted by adding the 1C DNA values of each parental genome. Chromosome counts confirm diploidy in the species E. hyemale and E. variegatum and in the hybrid E. xtrachyodon (= E. hyemale x E. variegatum). For the triploids (2n approximately 324), cytological information is presented for the first time. CONCLUSIONS: Triploid taxa may have originated by backcrossing or by crossing of a diploid hybrid with an unrelated diploid species. As tetraploid plants are unknown, these crossings probably involve diploid gametophytes that developed from unreduced diplospores. By repeated crossing events or backcrossing, reticulate evolution patterns arise that are similar to those known for a number of ferns and fern allies.     

Biomechanics and functional anatomy of hollow-stemmed sphenopsids. I. Equisetum giganteum (Equisetaceae)

The hollow stem of Equisetum giganteum owes its mechanical stability to an outer ring of strengthening tissue, which provides stiffness and strength in the longitudinal direction, but also to an inner lining of turgid parenchyma, which lends resistance to local buckling. With a height >2.5 m isolated stems are mechanically unstable. However, in dense stands individual stems support each other by interlacing with their side branches, the typical growth habit of semi-self-supporters.     

Genetic diversity and population structure in the outcrossing populations of Equisetum arvense and E. hyemale (Equisetaceae)

An allozyme examination was conducted to study the mating systems and genetic differentiation of populations of Equisetum arvense and E. hyemale. The study revealed that the rate of intragametophytic selfing in these homosporous pteridophytes is very low, i.e., on average 0.020 and 0.019, respectively, despite the potential hermaproditism and selfing of the gametophytes. Most populations consisted of numerous genotypes, and the average heterozygosities of E. arvense and E. hyemale equalled 0.092 and 0.134, respectively. The commonly observed excess of the heterozygote genotypes indicates that there are interclonal differences in the frequency of vegetative reproduction. The level of genetic divergence among populations was considerable even within a limited geographic area. It is suggested that the life history of Equisetum, characterized by the inefficiency of spore germination and gametophyte reproduction in noncolonizing situations, limits the level of gene flow and leads to a great genetic divergence between populations.     

Arrangement of microtubules during spore formation in Equisetum arvense (Equisetaceae)

The arrangement of cortical microtubules (MTs) during spore formation in Equisetum arvense was examined by immunofluorescence microscopy. The arrangement of MTs was observed to change during sporoderm formation. During exospore formation, the cortical MTs of the tapetum appeared along the tapetal plasma membrane that enclosed each developing spore cell. After exospore formation, the arrangement of the cortical MTs changed into one of separate bands of MTs arranged spirally (spiral bands of MTs). The spiral bands of MTs were superimposed on the developing elaters. This new pattern corresponded to the pattern of cellulose microfibrils deposited in the inner layer of the elater, suggesting that these spiral bands are involved in the deposition of the cellulose microfibrils in the elater. We conclude that the spiral bands of MTs are functionally equivalent to cortical MTs in secondary wall formation.     

红池坝地区草地红三叶草的空间分布型

植物种群的空间分布型是生物在特定的条件下形成的,它反映了植物种群个体的散布状态以及对环境的适应性和生境对植物影响的生态反映的生态学关系,是一条可以了解凭种类组成研究演替的研究途径 森下正明(Morisita,1959)提出了扩散指数Io(Morisita's index);美国的Lloyd,(1967)提出了平均拥挤度(Mean crowding,m)这个颇有兴趣     

Towards an understanding of sex determination in Equisetum: an analysis of regeneration in gametophytes of the subgenus Equisetum

Equisetum gametophytes possess extensive powers of regeneration without showing any signs of diminished vigour or abnormal development. Isolated lamellae, pieces of antheridial and archegonial branches were used to analyse gametophyte morphogenesis and sex determination. Intact individuals and subcultured sexual branches never revert to a vegetative state. Transplantation of apical pieces of archegonial branches on to fresh medium delays the onset of antheridium formation indicating phenotypic control. On the other hand, male branches invariably continue producing antheridia. Experimentally induced adventitious branches on lamellae are interpreted as the result of physiological isolation from inhibitors. In intact individuals these adventitious branches are always antheridial: after subculturing, archegonial branches are also produced, demonstrating that the gametophytes of Equisetum are all potentially bisexual. Isolated lamellae regenerate secondary gametophytes, the sexual ratios between which vary between species, but lamellae from archegonial tissues invariably produce more female individuals, probably reflecting the different sizes of the respective lamellae. The view that mixtures of intact male and bisexual Equisetum gametophytes result from inherent physiological differences between the spores is not supported.     

Biogeography and genome size evolution of the oldest extant vascular plant genus,Equisetum (Equisetaceae)

Background and AimsExtant plant groups with a long fossil history are key elements in understanding vascular plant evolution. Horsetails (Equisetum, Equisetaceae) have a nearly continuous fossil record dating back to the Carboniferous, but their phylogenetic and biogeographic patterns are still poorly understood. We use here the most extensive phylogenetic analysis to date as a framework to evaluate their age, biogeography and genome size evolution.MethodsDNA sequences of four plastid loci were used to estimate divergence times and investigate the biogeographic history of all extant species of Equisetum. Flow cytometry was used to study genome size evolution against the framework of phylogenetic relationships in Equisetum.Key ResultsOn a well-supported phylogenetic tree including all extant Equisetum species, a molecular clock calibrated with multiple fossils places the node at which the outgroup and Equisetum diverged at 343 Mya (Early Carboniferous), with the first major split among extant species occurring 170 Mya (Middle Jurassic). These dates are older than those reported in some other recent molecular clock studies but are largely in agreement with a timeline established by fossil appearance in the geological record. Representatives of evergreen subgenus Hippochaete have much larger genome sizes than those of deciduous subgenus Equisetum, despite their shared conserved chromosome number. Subgenus Paramochaete has an intermediate genome size and maintains the same number of chromosomes.ConclusionsThe first divergences among extant members of the genus coincided with the break-up of Pangaea and the resulting more humid, warmer climate. Subsequent tectonic activity most likely involved vicariance events that led to species divergences combined with some more recent, long-distance dispersal events. We hypothesize that differences in genome size between subgenera may be related to the number of sperm flagellae.