Papyrus swamp development in the Upemba Basin, Zaïre: studies of population structure in Cyperus papyrus stands

The ecology and distribution of papyrus swamps are briefly reviewed together with the ecology, distribution structure and growth characteristics of Cyperus papyrus.
Three age-classes of culm are recognized and girth and density of each are recorded along transects through mree swamps in the Upemba Basin of Zaïre. A regression of culm-unit biomass on culm girth, developed for Ugandan swamps, is used to convert Upemba measurements into biomasses. It is shown that simple measurements, taken at only a single point in time, yield much information on both the structure and the dynamics of papyrus populations.
It is suggested that the standing-crops of such populations are determined by available light, and by local temperature regimes, and are therefore constant, irrespective of site quality (nutrient status), for any particular climatic zone. Culm-duration (life-time) is not significantly influenced by climate and the ratio culms/rhizomes provides a useful indicator of comparative productivity. Unlike community biomass, productivity can be limited by site quality.     

Phospholipids and the Phospholipid Fatty Acids of Germinating Hazel Seeds (Corylus avellana L.)

An analysis of the phospholipids and phospholipid fatty acidsof germinating hazel seeds has been carried out. The phospholipidcontent of the cotyledons and embryonic axes increased duringgermination. Early increases in the relative amounts of phosphatidylglycerol and decreases in the relative amounts of phosphatidylethanolamine occurred in both cotyledons and axes. The laterstages of germination were accompanied by further changes inthe phospholipid composition of the axes. Increases in the degreeof unsaturation of the C₁₈ fatty acids occurred in both tissues.     

Somaclonal Variation in the Gliadin Patterns of Grains of Regenerated Wheat Plants

Maddock, S. E., Risiott, R., Parmar, S., Jones, M. G. K. andShewry, P. R. 1985. Somaclonal variation in the gliadin patternsof grains of regenerated wheat plants.—J. exp. Bot. 36:1976–1984. The banding patterns of the gliadin storageproteins of the grains of 590 regenerated plants from six wheatcultivars were examined by polyacrylamide gel electrophoresisusing lactate buffer. Variation additional to that present incontrol material was observed at a low frequency (1%). Two variantlines showed extensive changes in banding patterns which wereaccompanied by morphological variation of the plants. More limitedvariation in the form of an extra –gliadin band was observedin a third line. Differences in the seed gliadins were not foundin four lines which had shown stable phenotypic changes in heightin field trials. Key words: Wheat, somaclonal variation, gliadins, tissue culture, seed proteins     

Characterization of Prolamins from Meadow Grasses: Homology with those of Wheat, Barley and Rye

Prolamin fractions were extracted from seeds of five speciesof temperate meadow grasses. SDS-PAGE showed the presence ofpolypeptidcs with M_rs of 20–30000 in Phieum pratense andDactylis glomerata, and between 30000 and 65 000 in Lolium perenneand in two species of Festuca (F. rubra and F. arundinacea).The fractions had broadly similar amino acid compositions withhigh glutamate+glutamine (29 to 35 mol %) and phenylalaninc(8 to 10 mol %), but there was some variation in the contentsof prolinc (10 to 23 mol %) and several other amino acids includinglysine (0.3 to 1.9 mol %). Automated Edman degradation of twogel filtration fractions from L perenne and one fraction eachfrom the other four species showed single major N.terminal aminoacid sequences. These were homologous with each other, and withthe -typc prolamins of wheat, barley and rye. Key words: Prolamins, meadow grasses, SDS-PAGE     

The Development of Protein Bodies in the Storage Tissues1

Homogenates of the developing endosperms of maize, wheat, andbarley and of developing cotyledons of peas have been separatedon sucrose density gradients. Protein bodies have been recognizedby their content of storage proteins, their density, and theirappearance under the electron microscope. The distribution ofthe endoplasmic reticulum was followed by measuring NADH-cytochromec reductase. Glutamate dehydrogenase, catalase, and triose phosphatedehydrogenase—respectively marker enzymes for mitochondria,microbodies, and plastids—were also present in the gradients.Differences were found between the different species with respectto the association between the endoplasmic reticulum and thestorage proteins. There was no evidence for any vacuolar markerenzymes associated with the cereal protein bodies. The proteinbodies of wheat and barley appear to be similar to each otherbut differ from maize in that the latter have much more endoplasmicreticulum associated with them. In contrast the protein bodiesof peas co-sediment with vacuolar marker enzymes.     

The Purification and Characterization of Two Groups of Storage Proteins (Secalins) from Rye (Secale cereale L.)

Two groups of polypeptides, which together represented over90% of the secalin fraction, were purified by ion exchange chromatographyand gel filtration. These fractions had molecular weights of40 000 and 75 000 by SDS-PAGE and 33 000 and 54 000 by sedimentationequilibrium ultracentrifugation respectively. Isoelectric focusingshowed that each fraction contained a number of polypeptides.Amino acid analysis showed that the two groups had similar compositionswith high glutamate + glutamine and proline and low lysine.The N-terminal sequences of the two groups were identical at17 of the first 20 positions and were similar to those reportedfor ₂ and ₃-gliadins of wheat. Both groups had C-terminal histidine.These results are discussed in relation to prolamin evolutionand homology in barley, rye and wheat.     

The Structure of Normal and High-Lysine Barley Grains

The structure of the starchy endosperm of normal and high-lysinebarleys has been examined by light and scanning electron microscopy.The small granules (1-5 µm) seen using the latter methodhave been demonstrated to be small starch granules rather thanprotein bodies. Certain of the high-lysine mutations (Risø1508, Notch-2, lys 449 and lys 95) cause dramatic shrinkageof the endosperm structure whilst others (Risø 7 and56) cause little change. In particular Risø 1508 causesa decrease in small starch grains whereas those grains presentin Notch-2 are all much smaller than normal. The endosperm oflys 449 shows considerable disruption of the cells.     

湖北推广小麦品种(系)高分子量麦谷蛋白亚基组成分析

应用SDS-PAGE技术分析了45份湖北推广小麦品种(系)籽粒的高分子量麦谷蛋白亚基组成。40份材料的高分子量麦谷蛋白亚基组成为同质,5份为异质。在Glu-1位点共检测到9种等位基因变异类型,其中Glu-A1位点有“1、2^ 、Null”3种变异类型,Glu-B1位点有“7、7 8、7 9、14 15”4种,Glu-D1位点有“2 12、5 10”2种。“Null、7 8、2 12”是主要亚基,它们的频率分别是62．5％、60％和72．5％。亚基组合类型有12种,其中(Null,7 8,2 12)亚基组合占30．0％,(1,7 8,2 12)、(1,14 15,2 12)、(Null,7 9,2 12)、(Null,7 8,5 10)4种组合的频率都在10％以上,这5种亚基组合占总组合的72．5％。供试小麦材料品质评分在5～10之间,平均评分为7．0。含5 10亚基的品种(系)所占比例低,是湖北小麦烘烤品质较差的部分原因。     

The Preparation and Characterization of an Aggregated Gliadin Fraction from Wheat

An aggregated gliadin fraction was prepared by gel filtrationon Sephacryl S300 in a solvent containing 6.0 M guanidine hydrochloride.This was reduced, alkylated, and separated by ion exchange chromatography.SDS-PAGE of the resulting fraction showed a number of polypeptides,mostly with apparent M¹s of around 44 000. The amino acid compositionwas similar to those reported previously for monomeric -, ß-and -gliadins. Automated amino acid sequencing from the N-terminusalso showed the presence of sequence types characteristic of-, ß-, and -gliadins, but the major sequence typewas not related to any described previously. This sequence wasNH₂-Ser-His-Ile-Pro-Gly-Leu-Glu-Arg-Pro-Ser-Gln-Gln-Gln-Gln-Leu-. Key words: Wheat, Gluten, Gliadin, Seed