Comparative Anatomical Studies on the Vessel Elements of Chinese Magnolia and Michelia

This paper deals mainly with comparative studies on elements of secondary xylem in 39 species of Chinese Magnolia and Michelia. The former plants present longer and slender vessels. Most of them have simple perforation and only a few scalariform perforation plates. In contrast, most of the Michelia species possess scalariform perforation plates and only one with simple perforation. The scalariform perforation plates of Magnolia species, if present, exhibit more bars than that of Michelia With few exceptions, there is no spiral thickening on the vessel wall in Magnolia, whereas in Michelia it is lust the opposite. In addition, some other differences in vessel elements between these two genera are also discussed.     

用matK序列分析探讨木兰属植物的系统发育关系

用木兰科Magnoliaceae 57种植物的matK基因序列构建了该科的系统发育分支图。结果表明: (1)木兰属Magnolia L.是一个因为性状的趋同演化而建立的多系类群; (2)木兰亚属subgen. Magnolia和玉兰亚属subgen. Yulania (Spach) Reichenb.亲缘关系较远, 支持将后者从该属中分出建立玉兰属Yulania Spach, 木兰亚属作为木兰属保留; (3)木兰亚属的sect. Splendentes Dandy ex Vazquez组与皱种组sect. Rytidospermum Spach的两个美洲种M. macrophylla Michaux和M. dealbata Zucc.亲缘关系较近, 荷花玉兰组sect. Theorhodon Spach与常绿组sect. Gwillimia DC.的亲缘关系较近; (4)盖裂木属Talauma Juss.可以成立, 而其分布于亚洲的Blumiana Blume组可归入木兰属; (5)拟单性木兰属Parakmeria Hu &; Cheng、华盖木属Manglietiastrum Law以及单性木兰属Kmeria (Pierre) Dandy形成一个单系群, 与玉兰亚属和含笑属Michelia L.的亲缘关系较近。花的着生位置不足以作为木兰科的分族依据, 含笑族Michelieae和木兰族Magnolieae的特征及其界定应做修改。将玉兰亚属从木兰属分出后, 木兰属与含笑属无性状交叉,成为两个区别明显的属。     

A chloroplast DNA Phylogenetic study of the eastern Asia-eastern North America disjunct section Rytidospermum of Magnolia (Magnoliaceae)

Chloroplast DNA restriction site variation of ten endonucleases was examined among all ten species or varieties of the eastern Asia–eastern North America disjunct section Rytidospermum of Magnolia. Representatives from seven of the other ten sections of Magnolia and four related genera (Liriodendron, Manglietia, Michelia, and Talauma) were also included in the survey. A cladistic analysis of 200 variable sites using Wagner parsimony yielded 11 equally most parsimonious trees with a consistency index of 0.793 and a retention index of 0.870. The section Rytidospermum is polyphyletic in these trees. Magnolia tripetala from the southeastern U.S. is the only American species that has a sister relationship to the Asian taxa, M. hypoleuca, M. officinalis var. officinalis, M. officinalis var. biloba, and M. rostrata. Other American taxa in the section fall into two lineages, with M. macrophylla var. macrophylla, M. macrophylla var. ashei, and M. macrophylla var. dealbata in one, and M. fraseri var. fraseri and M. fraseri var. pyramidata in the other. They are not related to the Asian species as previously believed. The relationships revealed here are in agreement with morphological, allozymic, and cross compatibility data. These results demonstrate that a robust phylogenetic hypothesis is an important prerequisite for understanding biogeographic patterns.     

Effects of neolignans from the stem bark of Magnolia obovata on plant pathogenic fungi

Aims:  To characterize antifungal principles from the methanol extract of Magnolia obovata and to evaluate their antifungal activities against various plant pathogenic fungi.
Methods and Results:  Four neolignans were isolated from stem bark of M. obovata as antifungal principles and identified as magnolol, honokiol, 4-methoxyhonokiol and obovatol. In mycelial growth inhibition assay, both magnolol and honokiol displayed more potent antifungal activity than 4-methoxyhonokiol and obovatol. Both magnolol and honokiol showed similar in vivo antifungal spectrum against seven plant diseases tested; both compounds effectively suppressed the development of rice blast, tomato late blight, wheat leaf rust and red pepper anthracnose. 4-Methoxyhonokiol and obovatol were highly active to only rice blast and wheat leaf rust respectively.
Conclusions:  The extract of M. obovata and four neolignans had potent in vivo antifungal activities against plant pathogenic fungi.
Significance and Impact of the Study:  Neolignans from Magnolia spp. can be used and suggested as a novel antifungal lead compound for the development of new fungicide and directly as a natural fungicide for the control of plant diseases such as rice blast and wheat leaf rust.     

中国木兰属部分种的核型分析

对我国木兰属（Ｍａｇｎｏｌｉａ）１２个种的核型进行了分析,ｘ＝１９,厚朴、凹叶厚朴、红花山玉兰、山玉兰、天目木兰、夜合为二倍体,２ｎ＝２ｘ＝３８;紫玉兰、玉兰、玉堂春为四倍体,２ｎ＝４ｘ＝７６;乐东木兰、荷花玉兰、狭叶荷花玉兰为六倍体,２ｎ＝６ｘ＝１１４,该属具有属内多倍体（次生多倍化）。核型分析结果表明：木兰属种间核型差异较小,大部分为中部着丝粒染色体（ｍ）,少数为具近中部着丝粒染色体（ｓｍ）,二倍体种中只有一对具近端部着丝粒染色体（ｓｔ）,其核型均为２Ｂ型。     

Molecular Phylogeny of Magnolia (Magnoliaceae) Inferred from cpDNA Sequences and Evolutionary Divergence of the Floral Scents

Magnolia (disjuncts), however, have similar chemical profiles. A molecular phylogeny of Magnoliaceae was constructed to reveal phylogenetic relationships of taxa by sequencing the trnK intron (including the matK coding region), psbA-trnH, and atpB-rbcL intergenic spacer regions of chloroplast DNA from 25 Magnolia, two Michelia, and two Liriodendron taxa. The psbA-trnH spacer region showed twice the sequence divergence (0.0157) of the trnK intron (0.0073) or the matK coding region (0.0077). The strict consensus tree constructed from the combined data set (ca. 3,700 bp) indicated the genus Magnolia was polyphyletic containing Michelia species as ingroup. The clade of Magnolia liliifera var. obovata, M. coco, and M. delavayi formed the first branch. Among the remaining species, two additional large clades were recognized, i.e., one comprised of American evergreen Magnolia species and another of subgenus Yulania. The relationship among sect. Rytidospermum taxa was not clearly resolved. Parsimonious mapping of the floral scent chemical characters was performed onto the molecular phylogenetic tree to discuss evolutionary trends of the floral scent chemistries. Received 7 December 1998/ Accepted in revised form 18 May 1999     

Pollination efficiencies of flower-visiting insects as determined by direct genetic analysis of pollen origin

The amount and genetic composition of pollen grains that are transported to flowers influence the reproduction and fitness of plants. Despite the importance of insect-pollination systems, an understanding of those systems is still lacking due to the absence of a genetic analysis of pollen grains that are transported to flowers. We evaluated the pollination efficiencies of bumblebees (Apidae, Bombus spp.), flower beetles (Scarabaeidae, subfamily Cetoniinae, Protaetia and Eucetonia sp.), and small beetles (Lagriidae, Arthromacra sp.) that visited the flowers of Magnolia obovata (Magnoliaceae) using quantitative (flower visitation frequency, amount of adherent pollen per insect) and qualitative (origin and genetic diversity of adherent pollen per insect) criteria. Most of the pollen adhering to bumblebees and small beetles was self-pollen. This result suggests that visitation by these insects may cause geitonogamous pollen flow and negatively affect the reproduction of M. obovata, causing inbreeding depression. In contrast, flower beetles transported large amounts of genetically diverse outcross pollen. Our results suggest that certain beetle species contribute quantitatively and qualitatively to the pollination of M. obovata. Direct genetic analysis of pollen grains will advance our understanding of plant mating systems and may shed light on the mutualism and coevolution of plants and flower visitors.     

Intraspecific Variation of Floral Scent Chemistry in Magnolia kobus DC. (Magnoliaceae)

Magnolia kobus was examined at 32 sites in Japan (109 female-stage flowers from 52 plants) by GC-MS. Major chemical compounds (a total of 36 chemicals) emitted from the flowers were: linalool (and its oxides), limonene, cis- and trans-β-Ocimene, benzaldehyde, benzyl alcohol, benzyl cyanide, and 2-aminobenzaldehyde. Linalool and its oxides were the most abundant components of floral scents in 21 individuals. The rate at which chemical volatiles were emitted ranged from 0.002 to 0.929 μg/flower/hour (average 0.211). High quantitative and qualitative variation in floral scent chemistry among individuals was found throughout the range of M. kobus, especially in central Honshu. The high variability in floral scent chemistry may be due to the importance of visual cues in the reproductive biology of M. kobus which flowers in early spring, resulting in decreased selection for specific floral scent profiles. Alternatively, different scent compounds or chemical profiles may be equally effective in attracting pollinators. Received 25 June 2001/ Accepted in revised form 25 August 2001     

北方城市12种常见树木落花分解及其养分释放特征

城市绿化产生的树木落花量日益增加,由于落花富含养分,所以研究落花的分解及其养分释放特性,可以为落花作为施肥材料和制备生物质有机肥等农业再利用提供科学依据。以樱花(Cerasus sp.)、海棠(Malus spectabilis)、白玉兰(Magnolia denudata)、紫玉兰(Magnolia liliflora)、桃(Amygdalus persica)、红叶李(Prunus cerasiferaⅠ)、紫叶李(Prunus cerasiferaⅡ)、含笑(Michelia figo)、紫荆(Cercis chinensis)、杏梅(Prunus mume)、银杏(Ginkgo biloba)和栾树(Koelreuteria paniculate)等12种树木落花为研究对象,通过室内落花分解模拟试验,结果表明:(1)粗蛋白含量以桃花和白玉兰落花中较高(251.44—274.94 mg/g)(P<0.05),木质素含量以紫荆和银杏落花中较高(47.35—49.95μg/g)(P<0.5),N含量以桃花和白玉兰落花中较高(40.23—43.99 mg/g)(P<0.5),P含量以桃花和白玉兰落花中较高(1.37—1.58 mg/g)(P<0.5),K含量以红叶李、紫叶李和白玉兰落花中较高(4.53—4.72 mg/g)(P<0.5),Cu含量以白玉兰落花中较高(22.74μg/g),Zn含量以紫叶李落花中较高(249.06μg/g)(P<0.5),Fe含量以紫荆、樱花、紫叶李、杏梅、海棠和桃花中较高(85.81—118.34μg/g)(P<0.5),Mn含量以杏梅、樱花、桃花和海棠落花中较高(24.09—25.71μg/g)(P<0.5)。(2)12种落花中,除了银杏分解稍慢(周转期1.12 a)之外,其他落花分解均较快(周转期为1.00—1.05 a)。(3)落花养分释放速率较之分解速率表现为:N在樱花、海棠、紫玉兰、红叶李、含笑和紫荆落花中呈超速释出状态,而在其他落花中呈慢速释出状态,P在白玉兰、桃花、紫叶李、紫荆和银杏落花中呈超速释出状态,而在其他落花中呈慢速释出状态,K除了在紫荆落花中呈超速释出状态之外,在其他落花中均呈慢速释出状态。(4)相关性分析表明,落花中含有较高的粗蛋白、N、P和K含量可以加快落花分解,而落花中含有较高的木质素含量、木质素/N和N/P则导致落花分解速度减慢。研究结果将为落花的资源化利用奠定理论基础。     

红花玉兰与玉兰亚属几个种亲缘关系的AFLP分析

应用AFLP分子标记技术对红花玉兰与玉兰亚属几个种之间的亲缘关系,以及红花玉兰的分类地位进行了分析。9对引物对7个玉兰种的36个代表样株进行选择性扩增,共得到扩增谱带874条,其中多态性谱带635条。分析结果表明：各玉兰种间,红花玉兰与白玉兰、武当木兰的遗传相似度较高;玉兰亚属种间基于AFLP分析的聚类结果与形态学对种的划分基本吻合。红花玉兰不仅形态上与其它玉兰种有明显区别,AFLP分子标记也支持红花玉兰为一个独立的新种,多瓣红花玉兰变种与红花玉兰原变种为一个种。     

Magnolia denudata var. glabrata var. nov. (Magnoliaceae) from Hunan,China

Magnolia denudata var. glabrata Y. L. Wang et S. Z. Zhang var. nov. is described and illustrated from Hunan, China. The variety occurs mainly in semi‐evergreen forest of south Hunan at altitudes between 700 and 1260 m a.s.l. It differs from M. denudata var. denudata by its green and glabrous twigs and leaves which are glabrous above and have some white pubescence underneath. With its white flowers consisting of mostly 9 tepals, it differs from M. sprengeri Pamp. which mainly has 12 tepals in various shades of red/pink to white. The new variety is rare and considered endangered due to habitat destruction.     

中国木兰属和含笑属导管分子的比较解剖

本文对我国木兰科的39种木兰属和含笑属植物次生木质部的导管分子进行了初步分析。两属导管分子的长度和宽度略有差异。木兰属中多数种的导管分于有单穿孔板,但有的可见到梯状穿孔板。含笑属植物的导管分子大多具有梯状穿孔板,仅有一种可看到单穿孔板。在具有梯状穿孔板的木兰属植物中,穿孔板的横隔数目较含笑属的多。木兰属的导管壁上一般无螺纹加厚;含笑属则相反。此外,在两属之间,导管尚存在一些其它差异。     

Constituents of the essential oils from three tetraploid species of Chrysanthemum

The chemical constituents of the volatile oils from Chrysanthemum indicum, C. yoshinaganthum and C. cuneifolium, three botanically related tetraploid species, are described. By spectroscopic methods, 42 compounds were identified, including 22 monoterpenoids, 17 sesquiterpenoids and 3 acetylenic compounds. The sesquiterpenoids estafiatin (C. yoshinaganthum) and valeranone (C. indicum) have been found for the first time in Chrysanthemum species.     

中国蒿属植物化学分类的初步研究――精油化学成分与系统分类的相关性

分析了171个中国蒿属植物样品的精油化学成分,鉴定出305个化合物。这些样品代表64个种,其中蒿亚属47种,龙蒿亚属17种。 分析结果表明,这些化合物在两亚属中的分布有一定的规律性。在蒿亚属精油中主要含单萜类和倍半萜类化合物,而在龙蒿亚屑精油中主要含倍半萜类化合物和芳香族化合物。这种分布与中国蒿属植物从较原始到进化划分为7个组的系统分类有一定的相关性,即蒿亚属:莳萝蒿组(单萜类化合物)→艾蒿组(单萜类化合物)→艾组(单萜类化合物)→腺毛蒿组(单萜类化合物和倍半萜类化合物)→白苞蒿组(倍半萜类化合物)。龙蒿亚属:龙蒿组(倍半萜类化合物和芳香族化合物)→牡蒿组(倍半萜类化合物和芳香族化合物)。     

Phylogenetic relationships in family Magnoliaceae inferred from ndhF sequences

The ndhF sequences of 99 taxa, representing all sections in extant Magnoliaceae, were analyzed to address phylogenetic questions in the family. Magnolia macrophylla and M. dealbata, North American species of Magnolia section Rytidospermum, are placed at the base in the subfamily Magnolioideae although its supporting value is low. In the remaining taxa, several distinctive lineages are recognized: (1) Magnolia, the biggest genus in the family, is not monophyletic; (2) Michelia, including section Maingola of Magnolia subgenus Magnolia, is closely related with Elmerrillia and sections Alcimandra and Aromadendron of Magnolia subgenus Magnolia; (3) the associates of Michelia are grouped with Magnolia subgenus Yulania and section Gynopodium of Magnolia subgenus Magnolia; (4) Pachylarnax forms a clade with sections Manglietiastrum and Gynopodium of Magnolia; (5) a well-supported Manglietia clade is recognized; (6) Caribbean species of section Theorhodon of Magnolia subgenus Magnolia, which are section Splendentes sensu Vázquez-Garcia, are closely allied with New World members of Magnolia subgenus Talauma; and (7) section Rytidospermum of Magnolia subgenus Magnolia and subgenus Talauma are polyphyletic. The separated clades in the molecular tree are considerably different from traditional taxonomic dispositions in the family. The molecular data strongly suggest that a taxonomic realignment of infrafamilial delimitations and compositions should be considered.     

Flowering and Fruiting Phenology of Magnolia hypoleuca

Abstract The floral biology of Magnolia hypoleuca , a tall tree species widely distributed in Japan, was studied in a deciduous broad-leaved forest in Hokkaido near the northern limit of distribution of the species. The flower is large, protogynous and nectarless. Its petals close after the female stage and again after the male stage. The mean duration of flowering of an individual flower is 3–4 days, while the flowering period of an individual tree lasts up to 40 days. The main pollinators of the flowers were beetles. Success of pollination is assumed to be affected by weather conditions at anthesis. Average fruit sets (ratios of fruits to flowers) were 13–25%. Hand-pollination of 44 flowers produced a significantly higher fruit set (28 fruits) than control flowers (33/133). These results suggest that the fruit set is limited by pollination. The frequency of infertile ovules was higher in controls than in hand-pollinated fruits, indicating that the seed set was also limited by pollination. We propose a mimicry hypothesis in which the non-rewarding female-stage flower mimics the rewarding male-stage flower to explain the short life-span of an individual flower, the long flowering period of an individual tree, and the coexistence of flowers of various stages on a single tree.     

Spatial fragrance patterns in flowers of Silene latifolia: Lilac compounds as olfactory nectar guides?

Floral odour can differ qualitatively and quantitatively between different parts of the flowers, and these spatial fragrance patterns within the flowers can be used by pollinators for orientation on flowers. Here we present results of spatial fragrance patterns within flowers of the dioecious Silene latifolia (Caryophyllaceae). Volatiles were collected and analysed using a highly sensitive dynamic headspace method, which allows dramatically reducing the sample time. From all flower parts, especially the petals and the anthophore emitted the typical flower volatiles of S. latifolia. However, compounds emitted from the petals differed from compounds emitted by the anthophore. The anthophore emitted the monoterpenoids lilac aldehydes and alcohols, whereas, all other typical scent compounds (e.g. benzoids, other monoterpenoids) were emitted by the petals. Lilac aldehydes are known to be behaviourally very attractive for noctuid moths, and they may serve as nectar guides in S. latifolia.     

Direct and indirect defences induced by piercing-sucking and chewing herbivores in Medicago truncatula

Direct and indirect defences against feeding induced by chewing (Spodoptera littoralis) and piercing-sucking (Tetranychus urticae) herbivores, as well as components of signal transduction, were investigated in the model legume Medicago truncatula. Emitted volatiles, representing a mechanism of indirect defence, were measured and identified by gas chromatography/mass spectrometry (GC-MS). As elements of direct defence, the accumulation of phenolic compounds and of reactive oxygen species (ROS) was assessed using microscopic techniques. Jasmonic acid (JA) and salicylic acid (SA) concentrations were assessed as putative components of signal transduction. Volatile profiles revealed a sizeable number of different substances emitted, particularly sesquiterpenoids. The qualitative composition clearly differed depending on the type of herbivory. The same held true for JA and SA concentrations. Also, deposition of phenolic compounds and the production of ROS around the wounding sites could be detected. Conspicuous differences were found in indirect defence and signalling for different types of herbivory. In contrast, no divergence in direct defences was observed; furthermore, the traits investigated exhibited striking similarities to reactions known to occur upon pathogen attack.     

Comparative floral anatomy and ontogeny in Magnoliaceae

Floral anatomy and ontogeny are described in six species of Magnoliaceae, representing the two subfamilies Liriodendroideae (Liriodendron chinese and L. tulipifera) and Magnolioideae, including species with terminal flowers (Magnolia championi, M. delavayi, M. grandiflora, M. paenetalauma) and axillary flowers (Michelia crassipes). The sequence of initiation of floral organs is from proximal to distal. The three distinct outermost organs are initiated in sequence, but ultimately form a single whorl; thus their ontogeny is consistent with a tepal interpretation. Tepals are initiated in whorls, and the stamens and carpels are spirally arranged, though the androecium shows some intermediacy between a spiral and whorled arrangement. Carpels are entirely free from each other both at primordial stages and maturity. Ventral closure of the style ranges from open in Magnolia species examined to partially closed in Michelia crassipes and completely closed in Liriodendron, resulting in a reduced stigma surface. Thick-walled cells and tannins are present in all species except Michelia crassipes. Oil cells are normally present. Floral structure is relatively homogeneous in this family, although Liriodendron differs from other Magnoliaceae in that the carpels are entirely closed at maturity, resulting in a relatively small stigma, in contrast to the elongate stigma of most species of Magnolia. The flower of Magnolia does not terminate in an organ or organ whorl but achieves determinacy by gradual diminution.     

厚朴基原植物及其4个近缘种的花粉鉴定

采用扫描电镜对2种厚朴基原植物(厚朴Magnolia officinalis Rehd.et Wils.、凹叶厚朴M.officinalis Rehd.et Wils.var.biloba Rehd.et Wils.)及4种近缘植物(玉兰M.denudata Desr.、紫玉兰M.liliiflora Desr.、望春玉兰M.biondii Pampan.、荷花玉兰M.grandiflora L.)的花粉形态、表面纹饰和大小进行了观察研究。结果显示:(1)6种植物的花粉粒均为单粒,具远极单萌发沟,沟长,直达两端,左右对称,异极;侧面观均为舟形,两端较尖,赤道面观为椭圆形或近椭圆形,极面观均为近圆形;外壁均具小穴状或网状纹饰。(2)厚朴的小穴状纹饰小而浅,不明显;凹叶厚朴的小穴状纹饰小但较深,也不甚明显;相比之下,紫玉兰、玉兰、望春玉兰和荷花玉兰的花粉粒表面密布不规则隆起及深穴点,明显。(3)6种植物花粉粒由大至小依次为:荷花玉兰凹叶厚朴厚朴玉兰紫玉兰望春玉兰。3种不同的花粉处理方法中,自然干燥法能清晰地观察到花粉的扫描电镜特征,此方法优于戊二醛固定法和叔丁醇真空冷冻干燥法。本研究结果为厚朴中药资源的基原植物及其近缘种鉴定提供了新的证据,也为现代植物从种及亚种级水平分类提供了参考。