Types of phytomass — and leaf area index profiles in grassland vegetation

Various types of grasslands in the Netherlands were catagorized by their structure: phytomass and leaf area were measured in arbitrarily chosen vegetation layers with width intervals of 2.5, 5, 10 or 20 cm, depending on the height of the sward. Data were standardized for fixed width of layers (layer width set), and for equal numbers of layers of varying width (layer number set). Data were clustered by Ward's method as well as ordinated by Principal Components Analysis (PCA). The cluster method revealed 6 groups; those of the layer number sets could be contrasted in their vertical built-up of leaf area index (LAI) — and phytomass profiles and could be characterized ecologically. The ordinations confirmed the findings of the cluster analyses. In our data grassland structure varied mainly along a gradient from constant and sufficient to strongly varying soil water supply during the growing season, and a gradient in soil nutrients from rich to poor. Sites with constant water supply appeared more often nutrient-rich and those with a varying water supply more often poor in nutrients.Nomenclature of syntaxa follows Westhoff & Den Held (1969).Acknowledgements: Financial support for this study was obtained from the Foundation for Fundamental Biological Research (BION) under grant nr. 14.75.18. We thank R. K. Peet and M. P. Austin for their useful comments.Dedicated to Prof. H. F. Linskens (Nijmegen) on the occasion of his 65th birthday.     

Morphologie,Anatomie und Systematik carotinoidhaltiger Blätterpilze

Während Carotinoide innerhalb mehrerer natürlicher Verwandtschaftsgruppen der Heterobasidiomyceten charakteristisch und regelmäßig auftreten, ist das Vorkommen dieser Sekundärstoffklasse innerhalb der Homobasidiomyceten auf wenige Arten der corticioiden, clavarioiden, cantharelloiden, agaricoiden und gateroiden Organisationsstufen beschränkt (Tab. 1). Die Anatomie der Fruchtkörper und die Morphologie der Hyphen und Basidien der agaricoiden Vertreter, Phyllotopsis nidulans, Gerronema chrysophyllum, Haasiella venustissima wurden mit verschiedenen lichtmikroskopischen Methoden untersucht. Die gewonnenen Daten wurden mit Mikrophotographien und maßstabsgetreuen Zeichnungen belegt. Die Merkmale von Phyllotopsis nidulans — dickwandige Hyphen in der Fruchtkörpertrama, Medaillonschnallen in der Lamellentrama, sehr schmale Basidien, allantoide Sporen und der Besitz von Zystiden — können bei den anderen Arten nicht gefunden werden. Merulius, Phlebia, Gloeoporus, Auriculariopsis, Dictyoploca u. a. müssen als nah verwandte Gattungen angesehen werden. Die beiden anderen omphalinoid organisierten Blätterpilze, Gerronema chrysophyllum und Haasiella venustissima zeigen trotz Ähnlichkeiten in der Fruchtkörperform zueinander kaum Übereinstimmungen. Gerronema chrysophyllum besitzt Parallelen im Merkmalsbestand zu Cantharellus-Arten, vor allem zu Arten der Untergattung Phaeocantharellus. Dies kann durch den Aufbau der Huthaut, des verdickenden Hymeniums, der Basidien und der Stieltrama belegt werden. Besonders durch die Ontogenie der Fruchtkörper und der Lamellen wird diese Annahme unterstützt. Haasiella venustissima bleibt trotz neu dargestellter Merkmale der Fruchtkörpermorphologie — wenig differenzierte Huthaut, mehrschichtige Lamellentrama, Kaulozystiden in hymenialer Anordnung — und der Karyologie der Basidie in seiner systematischen Stellung isoliert, zumal Vergleichsdaten anderer, für einen Vergleich notwendiger Arten vielfach fehlen.     

Comparative leaf anatomy of Salix species and hybrids

Epidermal features, mesophyll differentiation and calcium oxalate characteristics of 19 species and 12 hybrids of Salix are described. The species and hybrids can be distinguished by the presence or absence of the following epidermal features: striated cuticle; stomata; covering trichomes; beaded anticlinal walls, and diosmin-like njstals. In or near marginal teeth, glandular trichomes are present in all cases. The leaf veins of all specimens examined have calcium oxalate prism sheaths and, with the exception of S. herbacea , cluster crystals in some cells of the mesophyll. Most sprcies studied in the subgenus Salix show: both adaxial and abaxial stomata; striated cuticle metopllyll of palisade cells, with little or no spongy mesophyll, but with a well-defined hypodermis, and absence of thick-walled, sinuous trichomes. Characteristic features of the subgenus Caprisalix are: abaxial stomata only; epidermal crystals; smooth cuticle; mesophyll diflerentiated into palisade cells and spongy mesophyll and without a hypodermis, and trichomes more numerous and varied than those of the subgenus Salix . Leaves of the two species of the subgenus Chaemelia examined and those of S. lapponum , have predominantly anomocytic stomata, whereas all the other leaves studied have predominantly paracytic stomata. The anatomical features described, in conjunction with the morphologiral characters, enable the species and hybrids of Salix studied to be autheenticated.     

Phylogenetic relationships between the families of recent Thysanoptera (Insecta)

One family, the Phlaeothripidae, is recognized in the suborder Tubulifera, whereas extant species of Terebrantia are classified into seven families: Uzelothripidae, Merothripidae, Aeolothripidae, Adiheterothripidae, Fauriellidae (stat. n.), Heterothripidae and Thripidae. A phylogenetic analysis of the relationships between these families is given, based on consideration of 35 imaginal characters; however, the relationships of Uzelothripidae and Phlaeothripidae to the rest of the Thysanoptera remain equivocal. The Phlaeothripidae are either derived independently from Protothysanoptera, or else are the sister-group of the Thripidae, the most specialized family of Terebrantia.
Diagnostic characters, diversity, distribution and relationships of each family are discussed. Keys to family and, in Fauriellidae, to genus are provided. Holarthrothrips Bagnall (= Adiheterothrips Ramakrishna, syn. n.) and Oligothrips Moulton are removed from Heterothripidae to Adiheterothripidae and Fauriella Hood, Opisthothrips Hood and Ropotamothrips Pelikan (= Osmanothrips Priesner, syn. n.) from Heteromripidae to Fauriellidae (stat. n.). These transfers leave Aulacothrips Hood, Heterothrips Hood and Scutothrips Stannard as the only genera in Heterothripidae.     

Systematik,Verbreitung und Karyologie derFestuca violacea-Gruppe (Poaceae) im Ostalpenraum

The biosystematics of theFestuca violacea group (F. rubra subsp.violacea sensuHackel) in the Eastern Alps is studied.F. picturata Pils (=F. picta Kit. exSchultes nonJ. F. Gmelin) is confirmed as diploid, whereas the chromosome numbers forF. nitida (diploid),F. puccinellii (hexaploid), andF. norica (diploid, tetraploid and hexaploid) are reported for the first time. Details of morphology, leaf anatomy, and epidermal structures now allow a better separation of these species; new maps illustrate their distribution. Karyological, chorological, morphological, and anatomical data form the basis for a discussion of the phylogeny of theF. violacea group and its position withinF. rubra s. latiss.

     

Beiträge zur Systematischen Anatomie derAsteraceae-Anthemideae: Die Trichome

Biseriate glandular trichomes and uniseriate flagellar covering hairs occur in all or most of the 20 genera examined and thus do not provide important taxonomical hints. In contrast, T- or Y-shaped hairs have been found inSantolina, Anthemis, Leucanthemopsis, Dendranthema, Tanacetum,Balsamita, Sphaeromeria (?),Artemisia, andAchillea clavenae only. Stellate hairs appear to be rare (inSantolina andArtemisia sect.Dracunculus). For details, additional hair types, and relationships see Tab.1 and Fig. 6.     

Morphological studies on the genusClematis linn. VIII. Floral and inflorescence anatomy inClematis patens with eight-sepaled flowers

The vascular anatomy of inflorescence axes and flowers ofClematis patens have been studied. The species shows a unique behaviour of the vascular bundles in the transition node from vegetative stem to pedicel: stelar bundles increase in number from six to eight as they ascend through the transition node so that the number of vascular bundles coincides with that of sepals. In the pedicel stele the resulting eight bundles are disposed opposite to eight sepals. respectively; each sepal receives its vascular supply from the bundle facing it. Morphological and anatomical evidence suggests that the calyx of eight sepals in this species should be interpreted as having consisted originally of four pairs of opposite organs, rather than as having been derived secondarily through chorisis of sepals from a calyx of four sepals as seen in most other species ofClematis.     

Metabolism and decarboxylation of glycollate and serine in leaf peroxisomes

The linked utilization of glycollate and L-serine has been studied in peroxisomal preparations from leaves of spinach beet (Beta vulgaris L.). The generation of glycine from glycollate was found to be balanced by the production of hydroxypyruvate from serine and similarly by 2-oxoglutarate when L-glutamate was substituted for L-serine. In the presence of L-malate and catalytic quantities of NAD⁺, about 40% of the hydroxypyruvate was converted further to glycerate, whereas with substrate quantities of NADH, this conversion was almost quantitative. CO₂ was released from the carboxyl groups of both glycollate and serine. Since the decarboxylation of both substrates was greatly in creased by the catalase inhibitor, 3-amino-1,2,4-triazole, and abolished by bovine liver catalase, it was attributed to the nonenzymic attack of H₂O₂, generated in glycollate oxidation, upon glyoxylate and hydroxypyruvate respectively. At 25–30° C, about 10% of the glyoxylate and hydroxypyruvate accumulated was decarboxylated, and the release of CO₂ from each keto-acid was related to the amounts present. It is suggested that hydroxypyruvate decarboxylation might contribute significantly to photorespiration and provide a metabolic route for the complete oxidation of glycollate, the magnitude of this contribution depending upon the concentrations of glyoxylate and hydroxypyruvate in the peroxisomes.     

14C fixation,metabolic labeling patterns,and translocation profiles during leaf development in Populus deltoides

The incorporation of photosynthetically fixed ¹⁴CO₂ and the distribution of ¹⁴C among the main chemical constituents of laminae and petioles were examined in cottonwood (Populus deltoides Bartr. ex Marsh.) leaves ranging in age from Leaf Plastochron Index (LPI) 3 (about one-quarter to one-third expanded) to LPI 30 (beginning of senescence). In addition, carbon flow among chemical fractions and translocation from leaves of LPI 7 and 14 were examined periodically up to 24 h after labeling. Specific activity of ¹⁴C (on dry-weight basis) increased in developing laminae to full leaf expansion, decreased in the mature leaves to LPI 16, then remained constant to LPI 30. In developing leaves (LPI 3-5), after 2 h, most of the ¹⁴C was found in protein, pigments, lipids, and other structural and metabolic components necessary for cell development; only 28% was in the sugar fraction of the lamina. In fully expanded leaves (LPI 6-8), after 2 h, the sugar fraction contained 50–60% and about 90% of fixed ¹⁴C in the lamina and the petiole, respectively. In a pulsechase kinetic series with recently mature leaves, 60% of the ¹⁴C was found in the sugar fraction after 15 min of ¹⁴CO₂ fixation. Over the 24-h translocation period, ¹⁴C decreased in sugars to 23% and increased in the combined residue fraction (protein, starch, and structural carbohydrates) to about 60% of the total activity left in the lamina. Within 24 h after labeling, the turnover of ¹⁴C-organic acids,-sugar, and-amino acids (either metabolzed or translocated from the leaf) was 30, 70 and 80%, respectively, of that initially incorporated into these fractions by a leaf at LPI 7 (turnover was 55% of ¹⁴C-organic acids, 80% of ¹⁴C-sugar, and 95% of ¹⁴C-amino acids at LPI 14). Anatomical maturity in cottonwood leaves is closely correlated with physiological maturity and with production of translocatable sugar.Abbreviations LPI leaf plastochron index - PI plastochron index Research Plant Physiologist and Chief Plant Physiologist, respectively     

Plantigrady and foot adaptation in African apes: implications for hominid origins.

In living primates, except the great apes and humans, the foot is placed in a heel-elevated or semi-plantigrade position when these animals move upon arboreal or terrestrial substrates. Heel placement and bone positions in the non-great ape primate foot are designed to increase mobility and flexibility in the arboreal environment. Orangutans have further enhanced foot mobility by adapting their feet for suspension and thus similarly utilize foot positions where the heel does not touch the substrate. Chimpanzees and gorillas represent an alternative pattern (plantigrady), in which the heel contacts the surface of the support at the end of swing phase, especially during terrestrial locomotion. Thus, chimpanzees and gorillas possess feet adapted for both arboreal and terrestrial substrates. African apes also share several osteological features related to plantigrady and terrestrial locomotion with early hominids. From this analysis, it is apparent that hominid locomotor evolution passed through a quadrupedal terrestrial phase.