Iridoids in Hydrangeaceae

The content of glycosides in Kirengeshoma palmata and Jamesia americana (Hydrangeaceae) have been investigated. The former contains loganin and secoiridoids, including the alkaloid demethylalangiside. The latter contains no iridoids, but the known glucosides arbutin, picein and prunasin. In order to futher investigate the chemotaxonomy of the family Hydrangeaceae, the distribution of the iridoid and secoiridoid glucosides as well as the known biosynthetic pathways to these compounds have been reviewed. However, only a few genera of the family has been investigated. Loganin, secologanin, and derivatives of these are common. The genus Deutzia is characteristic in containing more structurally simple iridoids in which C-10 has been lost during biosynthesis. Such compounds have so far only been reported from the genus Mentzelia (Loasaceae). The taxonomic relationships between Hydrangeaceae and the closely related Cornaceae and Loasaceae is discussed and found to agree well with recent DNA sequence results.     

Flavonoids of the Hydrangeaceae Dumortier

Fourteen species representing nine genera of the Hydrangeaceae Dumortier were surveyed for their flavonoid pigments. All taxa exhibited profiles based upon common flavonols. Myricetin was seen in two genera: Jamesia and Decumaria. Jamesia was further distinguished by the absence of kaempferol or its glycosides. A complex array of 3-O-mono-, 3-O-di- and 3-O-triglycosides was observed, although not all species had all levels of glycosylation. Decumaria barbara was unique within the species studied in its possession of 3,7-di- and 3,7-triglycosides. The overall pattern of flavonol glycosides observed for the Hydrangeaceae closely resembles that found in herbaceous genera of Saxifragaceae. The comparatively low frequency of myricetin contrasts with its high occurrence in herbaceous genera.     

绣球属(Hydrangea L.)及近缘属花粉形态的研究

为深入研究绣球属植物花粉形态的分类学价值和系统学意义,厘清绣球属与近缘属之间的系统发育关系,该文利用扫描电子显微镜(SEM,scanning electron microscope)对国产绣球属及其近缘属41种绣球花科(Hydrangeaceae)植物的花粉形态以及表面纹饰进行了观察。结果表明:绣球属及其近缘属的花粉为三孔沟;形状多数为长圆体形或近球体形;赤道面观为椭圆形或圆形;极面观多为圆形,少数为三角形或圆三角形。花粉外壁纹饰可分为网状和孔穴状。网眼内的三级纹饰可分为光滑和具颗粒状突起。根据花粉形状和外壁纹饰类型将上述物种划分为4个组,即花粉的形状为长圆体形,表面纹饰为孔穴纹饰;花粉的形状为长圆体形,表面纹饰为网状纹饰;花粉的形状为近球体形,表面纹饰为孔穴纹饰;花粉的形状为近球体形,表面纹饰为网状纹饰。以上可进一步细分为8个类型。上述表明花粉形态证据可为绣球属及其近缘属的属下分类和种间界定提供重要佐证;但结合前人的系统发育重建分析该属植物花粉形态的系统学意义相对有限,如花粉形态证据对于该属及其近缘种属系统发育树上大支的界定难以提供有力的证据。     

Tylerianthus crossmanensis gen. et sp. nov. (aff. Hydrangeaceae) from the Upper Cretaceous of New Jersey

A fossil flower with affinities to the modern families of the saxifragalean complex is described. Fossils were collected at Old Crossman Pit, Raritan Formation, New Jersey, USA. These sediments are dated on the basis of palynology as Turonian (Upper Cretaceous, ~90 million years before present). Fossils are charcoalified and preserved with exceptional three- dimensional detail. The characters observed in these flowers, when compared with those of extant flowers of several families of the saxifragalean complex, suggest a close relationship with extant members of the Saxifragaceae and Hydrangeaceae. Hypotheses on the origin of petals and staminodes and a possible mechanism of pollination are discussed. This new taxon provides additional characters in the floral morphology of the fossil saxifragoids and extends their geographical distribution in the Cretaceous to North America.     

绣球属(Hydrangea L.)植物分子系统学及系统发育分析

该研究基于对绣球属(Hydrangea L.)的大尺度取样,选取国内外61种绣球属和近缘属植物,分别基于核基因片段(ITS)和叶绿体基因片段(rbcL,trnL-F,atpB)重建了绣球属及其近缘种属的系统发育关系。结果表明:(1)核基因与叶绿体基因树之间在树形上没有明显的冲突,进而基于核基因和叶绿体基因联合数据重建了绣球属及其近缘种属的系统发育关系。(2)基于联合数据构建的系统树确认了2个大分支,并得到了果实顶端截平与否这一形态学证据的强力支持;每个大分枝又分为4个类群,共确定了8个类群。部分类群也得到了广义宏观形态性状的支持,如第1类群得到了叶形、花粉以及种子形态的支持。因此,该系统发育关系的重建对于全面理解绣球属及其近缘种属的演化关系具有重要的启发。     

Early development of androecia in polystemonous Hydrangeaceae

Polystemonous androecia are diverse in both number and position of stamens. This investigation of polystemonous Hydrangeaceae uses developmental data to characterize (1) the range of developmental variations that account for the diverse androecial patterns and (2) how the expressions of polystemony among Hydrangeaceae compare to those found generally among other angiosperms and especially in their sister family, the Loasaceae, some of which have particularly complex androecia. All polystemonous Hydrangeaceae share the common element of stamen clusters in antesepalous positions. In each of these taxa, the first stamens are initiated opposite the medians of the sepals. Subsequently, stamens form laterally on the flanks of the initial antesepalous stamens, giving rise to the clusters designated as antesepalous triplets. The simplest elaborations based on those common initial developmental steps include (1) adding additional lateral flanking stamens and (2) adding a single stamen in each antepetalous position between adjacent antesepalous groups. More complex elaborations are characteristic of (1) Carpenteria and Philadelphus, which form common primordia at the beginning of androecial development and, subsequently, have stamen primordia form on them, and (2) Deinanthe, which has an elongate hypanthial region on which numerous whorls of stamens are initiated. Carpenteria is unique among Hydrangeaceae in having groups of stamens that are initiated centrifugally in antepetalous positions, and this is similar to complex elements found among some Loasaceae. Generally, the polystemony of Hydrangeaceae that is based in the formation of antesepalous triplets is very similar to that found to evolve in parallel among various clades of rosids and asterids.     

武夷山白粉菌新种

本文描述了武夷山白粉菌的3个新分类单位。它们是寄生于大戟科连氏野桐上的新种野桐白粉菌(Erysiphe malloti sp.nov.),忍冬科白马桑上的新种锦带花白粉菌(Erysipheweigelae sp.nov.),以及绣球科圆锥绣球上的新种绣球钩丝壳(Uncinula hydrangeae sp.nov.)。绣球科是钩丝壳属真菌寄主科的世界新纪录。新种均有汉文和拉丁文描述以及建立新种的讨论。     

Genome size variation and species relationships in the genus Hydrangea

Genome size and base composition in 16 species and subspecies of the Hydrangea, a woody ornamental genus of Hydrangeaceae, were evaluated by flow cytometry in relation to their chromosome number. This is the first such study concerning the genome size of these species together with a karyotype study of the most important species, Hydrangea macrophylla subsp. macrophylla (Hortensia), from an economical point of view. The 2C DNA content ranged from 1.95 pg in Hydrangea quercifolia to 5.00 pg in Hydrangea involucrata. The base composition ranged from 39.9% GC in Hydrangea aspera subsp. sargentiana to 41.1% in Hydrangea scandens subsp. scandens (significant difference at p < 0.05). The smallest genome sizes were those of the three species originating from North or South America. Most of the species studied presented a chromosome number of 2n = 2x = 36, except for those of the section Aspereae which showed 2n = 30, 34 and 36. A primary karyotype has been made for the first time for H. macrophylla subsp. macrophylla. Phylogenetic relationships between species, the origin of chromosome number and an exploration of the genetic diversity within the genus are discussed. Received: 24 July 2000 / Accepted: 31 October 2000     

广东常山,广东绣球花科一新种

首次发现并描述了中国广东省的绣球花科(Hydrangeaceae)常山属(Dichroa)一新种:广东常山(D.fistulosa)。该种具有空心的茎,这在常山属中是唯一的。该种与海南常山(D.mollissima)相似,但可以通过其叶上的毛被来区分。该种亦与菲律宾常山(D.philippinensis)相似,但其叶的形状及锯齿明显不同。     

Change of color and components in sepals of chameleon hydrangea during maturation and senescence

The sepal color of a chameleon hydrangea, Hydrangea macrophylla cv. Hovaria™ ‘Homigo’ changes in four stages, from colorless to blue, then to green, and finally to red, during maturation and the senescence periods. To clarify the chemical mechanism of the color change, we analyzed the components of the sepals at each stage. Blue-colored sepals contained 3-O-sambubiosyl- and 3-O-glucosyldelphinidin along with three co-pigments, 5-O-p-coumaroyl-, 5-O-caffeoyl- and 3-O-caffeoylquinic acids. The contents of glycosyldelphinidins decreased toward the green-colored stage, with a coincident increase in the number of chloroplasts. During the last red colored stage, the two species of 3-O-glycosyldelphinidin almost disappeared, and another two anthocyanins, 3-O-sambubiosyl- and 3-O-glucosylcyanidin, increased in amounts. Mixing of 3-O-glycosylcyanidins, co-pigments, and Al³⁺ in a buffered solution at pH 3.0-3.5 gave not a blue, but a red, colored solution that was the same as that of the sepal color of the 4th stage. Sepals of hydrangea grown in an highland area also turned red in autumn, and contained the same cyanidin glycosides. The red coloration of the hydrangea during senescence was due to a change in anthocyanin biosynthesis.