Lipids of oak galls

The nutrient tissues of oak galls accumulate a great amount of lipids. The neutral lipids (essentially triacylglycerol) are the most abundant storage form but some membrane lipids (mainly phospholipids) also occur. However, the galactolipids are very poorly represented. Among the fatty acids, oleic acid is predominant. These data correlate well with the cytological features of gall nutrient cells.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen:Ranunculaceae,Hamamelidaceae, Platanaceae undFagaceae

Transfer of fresh pollen either by wind or by insects is strongly related to the degree of its stickiness. The sticky substances involved should be understood as pollenkitt. Ultrastructural investigations indicate that the sticky pollen of entomophilous angiosperms (in this publicationHamamelis vernalis andH. virginiana, Corylopsis platypetala) results from the deposition of usually electron-dense, homogeneous pollenkitt mainly on the outside layer of the exine. In contrast, the pollen of anemophilous angiosperms (in this publicationParrotia persica, Platanus orientalis, Thalictrum flavum andQuercus robur), but also of some entomophilous angiosperms with special pollination ecology (e.g.Aquilegia vulgaris) is rather dry and powdery. In these cases the pollenkitt often is electron-transparent and inhomogeneous and is mainly removed into the cavities of the exine. Ultrastructure and deposition of pollen and pollenkitt in ambophilous angiosperms (in this publicationThalictrum minus, Castanea sativa) are ± intermediate.

     

中国大陆北热带及亚热带地区樟科、壳斗科物种多样性及其生物地理格局分析

以中国大陆北热带及亚热带地区优势科樟科、壳斗科植物为研究对象,利用专著发表大量的样方数据和物种分布数据,分析樟科、壳斗科与群落构建的关系、它们各大属的地理分布格局,探讨影响其分布的可能历史原因。结果表明:中国大陆北热带及亚热带地区森林乔木层优势科为樟科、壳斗科、山茶科、杜鹃花科。樟科、壳斗科物种丰富度均与其所在群落的物种丰富度呈现一定的正相关,樟科对群落构建的贡献较大。樟科、壳斗科植物种的空间多样性分布中心均出现在我国亚热带中部偏南地区。樟科的厚壳桂属、琼楠属以及壳斗科的锥属物种多样性分布中心主要在南亚热带及北热带区域,以广西、云南省份的南部为主。樟科的樟属、新木姜子属、润楠属、木姜子属及壳斗科的柯属、青冈属主要分布在我国大陆北热带及亚热带中部偏南的地区,其多样性分布中心与樟科、壳斗科科水平的物种多样性分布中心极为相似。樟科的山胡椒属、楠属、黄肉楠属,壳斗科的栎属主要分布在研究区域中部以西的地区。研究结果佐证物种的生态学特性以及生物地理学历史综合作用导致目前樟科和壳斗科植物的生物多样性分布格局。     

γ-Glutamylwillardiine and γ-glutamylphenylalanylwillardiine from seeds of Fagus silvatica

γ-l-Glutamyl-l-willardiine [γ-l-glutamyl-3-(1-uracil)-l-l-alanine] and γ-glutamylphenylalanylwillardiine have been isolated from seeds of Fagus silvatica. The structures have been established by spectroscopy, hydrolysis to give the constituent amino acids, and for the tripeptide end-group determination and partial hydrolysis to give the two constituent dipeptides.     

Conservation of (GA)n microsatellite loci between Quercus species

Microsatellite (simple sequence repeat, SSR) amplification was performed in eight different members of the Fagaceae family by using sets of primers developed from sessile oak, Quercus petraea . In total, 136 cases of heterologous amplification were carried out, and 66% resulted in interpretable amplification products. From these, 12 PCR amplification products were sequenced and all 12 contained a sequence homologous to the original locus from Q. petraea . Although SSR primers worked even across different genera, with increasing evolutionary distance there was a clear tendency for decreasing ability to successfully amplify loci and a decreasing proportion of polymorphism amongst those markers which could be amplified. Two of the loci, ssrQpZAG46 and ssrQpZAG110, were polymorphic in all Quercus species tested. Only at one locus, ssrQpZAG58, a specific PCR product could be amplified in all species analysed. For four loci found in two species, we observed significant interspecies differences in the size range of the amplified alleles. Sequence analysis of two alleles showed that the size differences are not only due to variations in the number of (GA) repeats but also to an insertion of approximately 80 nucleotides in the flanking region. Our findings prove the usefulness of SSR markers within and amongst closely related genera of plants.     

Phylogenetic analyses of "higher" Hamamelididae based on plastid sequence data

Phylogenetic relationships were examined within the "higher" Hamamelididae using 21 species representing eight families and related outgroups. Chloroplast DNA sequences encoding the matK gene (/1 kilobase) provided 258 informative nucleotide sites. Phylogenetic analysis of this variation produced one most parsimonious tree supporting three monophyletic groups. In this tree, Nothofagus was basal to a well supported clade of remaining "higher" hamamelids, in which Fagaceae, including Fagus, were sister to a clade of core "higher" hamamelids that share wind-pollination, bicarpellate flowers, granular pollen walls, and reduced pollen apertures. Within the core "higher" hamamelids three subclades were resolved, Myricaceae, (Casuarina-(Ticodendron-(Betulaceae))), and (Rhoiptelea-Juglandaceae). Each subclade was well supported but relationships among them were not. The basal position of Nothofagus within the matK tree is consistent with the fossil record of "higher" hamamelids in which Nothofagus pollen appears earlier than microfossils with affinities to other modern "higher" hamamelids. This placement supports the exclusion of Nothofagus from Fagaceae and suggests two hypotheses for the origin of the cupule. The cupule may be ancestral within "higher" hamamelids and subsequently lost in core members of the clade or there may have been two independent origins. It is suggested that the three clades (1) Nothofagaceae, (2) Fagaceae, and (3) Juglandaceae, Rhoiptelea, Myricaceae, Casuarina, Ticodendron, and Betulaceae be considered at the ordinal level and that traditional orders, such as Fagales sensu Cronquist (Fagaceae, Nothofagaceae, and Betulaceae) be abandoned. Comparative analyses of matK sequences with previously published rbcL sequences demonstrate that for the taxa considered here matK sequences produced trees with greater phylogenetic resolution and a higher consistency index.     

Anatomical and developmental study of petrified Quercus (Fagaceae) fruits from the Middle Miocene, Yakima Canyon, Washington, USA

The first reported petrified acorns to show internal anatomical structure are here described from Middle Miocene (～15.6 million years old) chert of the Columbia River Basalt Group in Yakima Canyon, Washington. Quercus hiholensis Borgardt et Pigg sp. nov. is described from anatomical and morphological fruit features, as well as a little recognized anatomical feature, the umbilical complex. Acorns, each comprising a nut and its cupule, are up to 15.3 mm long and 18.8 mm wide with helically arranged, imbricate, tuberculate cupule scales. They show basal aborted ovules, short styles, broad stigmas, and lack grooves in their cotyledons. These characters and the developmental pattern seen in these fossil acorns demonstrate that Q. hiholensis conforms to genus Quercus (Fagaceae), subgenus Quercus, section Quercus (the white oaks). The correspondence of Q. hiholensis to the modern section Quercus reveals that the derived floral and fruit characters that distinguish section Quercus within the genus had evolved by the Middle Miocene.