Showing papers on "Peduncle (anatomy) published in 1982"

A Potential Pathway for Galactose Metabolism in Cucumis sativus L., A Stachyose Transporting Species.

Abstract: Conversion of [14C]galactose (Gal) 1-P, UDP-[14C]Gal, or UDP-[14C]glucose to [14C]sucrose was observed when cell-free homogenates of cucumber (Cucumis sativus L.) fruit peduncles were incubated with individual 14C-labeled substrates, appropriate cofactors, and fructose. The sucrose product was labeled only in the glucose moiety. Conversion of [14C]Gal-1-P to [14C]sucrose was catalyzed by extracts of peduncles from all other stachyose transporting species tested, as well as green bean (a sucrose transporter) but was not catalyzed by peduncle extracts from three other sucrose transporting species. In cucumber, the ability of extracts to form [14C]sucrose from [14C]Gal-1-P was greater when peduncles were harvested from growing fruit than from unpollinated ovaries. [14C]Sucrose formation from [14C]Gal-1-P was inhibited by Mg · PPi, Mg · UDP, UMP, and sucrose. α-Galactosidase, galactokinase, UDP-gal pyrophosphorylase, UDP-Gal-4′-epimerase, UDP-glucose pyrophosphorylase, and sucrose synthase activities were detected in peduncle extracts. Neither sucrose phosphate synthetase nor hexose-1-P uridyltransferase were detected. Peduncle tissue contained a small pool of free galactose. These results suggest a potential pathway for the metabolism of galactose moieties hydrolyzed from stachyose, the major sugar transported by cucumber plants.

Phagotrophy in gymnodinium fungiforme (pyrrhophyta): the peduncle as an organelle of ingestion1

Abstract: The non-photosynthetic phagotrophic dinoflagellate, Gymnodinium fungiforme Anissimova, ingests prey cytoplasm through a highly extensible structure called the peduncle. Although the peduncle is not observable when G. fungiforme is swimming, it protrudes 8–12 μm from the sulcal-angular vicinity of the cell during feeding, and is approximately 3.3 μm wide when the cytoplasm of its prey is flowing through it. A circular-oval ring of overlapping microtubules, the ‘microtubular basket’ may be seen in transmission electron microscope sections of G. fungiforme and it is inferred that this structure is a cross section of a retracted peduncle. The microtubular basket-peduncle complex is discussed in relation to similar structures in other dinoflagellates and to the tentacle of the suctorian ciliates which have a homologous ingestion system.

Amphidinium cryophilum sp. nov. (dinophyceae) a new freshwater dinoflagellate. ii. ultrastructure1

Abstract: The dinoflagellate Amphidinium cryophilum sp. nov. is one of the few gymnodinians to be studied at the ultrastructural level. It resembles other dinoflagellates in the structure of the nucleus, trichocysts, storage materials, flagella, mitochondria, and microbodies. Other features of A. cryophilum less commonly observed in related organisms include a network of small interconnected vesicles, a system of large, peripheral vacuoles, chloroplasts bound by two rather than three membranes, an accumulation body, thylakoid-associated plastoglobuli, a vesiculated nuclear envelope, a complex tubular pusule, striated flagellar collars, collared pits, and a peduncle. The occurrence of a peduncle, a structure implicated in phagotrophy, in this autotrophic organism is noteworthy. The ultrastructure of the peduncle of A. cryophilum differs significantly from that reported in another dinoflagellate.

Phagotrophy and development ofPaulsenella cf.chaetoceratis (Dinophyta), an ectoparasite of the diatomStreptotheca thamesis

Abstract: Zoospores of the dinophytePaulsenella cf.chaetoceratis, parasitizing the marine diatomStreptotheca thamesis, attach to the girdle region of the host and drive a peduncle into the cell interior. The peduncle consists of a non-cytoplasmic “crook”, a cytoplasmic feeding tube, and a presumably cellulosic sheath around the proximal part of the feeding tube. The crook seems to be used for attachment and penetration of the host. The mobile feeding tube induces shrinkage of the host vacuoles and takes up the complete host cytoplasm within less than 1 h. Phagocytosis depends on an intact host plasmalemma, which is not penetrated by the feeding tube. The trophic phase ends with retraction of the feeding tube. While the food is digested within a large vacuole, the trophont transforms into a thick-walled primary cyst. After about 12 h the primary cyst divides to form 3 or 4 secondary cysts. Finally, about 24 h after attacking the host, each secondary cyst releases two zoospores which may be again ready for infection within 1 h, without passing through any intermediate stage. The developmental times (above referred to 20 °C) are highly dependent on the temperature and can vary considerably, even between sister cells.

NECTAR PRODUCTION AND FLORAL CHARACTERISTICS IN BIRDSFOOT TREFOIL (Lotus corniculatus L.)

Abstract: Nectar production was studied in several varieties of birdsfoot trefoil in relation to flower color, aroma, and some anatomical features in order to identify characteristics which might be of use in a program of selection for attractiveness to honeybee pollinators. Color did not appear to be an important variable; no major varietal differences in light reflectance were noted at any wavelength. There was a twofold varietal range in nectar yield per umbel and a larger difference in potential yield per plant. Selection within varieties increased the difference between high- and low-nectar plants by several times. Large varietal differences in aroma strength were also noted. While nectar and aroma production were not closely correlated in all varieties, those with weak aroma were generally low nectar yielders. Nectar yield per umbel was directly related to the cross-sectional area of functional phloem in the peduncle, and the amount of functional phloem and peduncle diameter were closely correlated. The ratio...

Epistatic, additive and dominance variation in a triple test cross of bread wheat (Triticum aestivum L.)

Abstract: Triple test cross progenies resulting from the crossing of three testers (‘Kloka’, ‘UP 368’ and an f1 intermediate between them) and 24 varieties of bread wheat have been studied for plant height (cm), peduncle length (cm), ear length (cm), number of spikelets per spike and harvest index (ratio between economic and total yield). Epistasis was not significant for any of the characters studied. The testers were inadequate for plant height and for peduncle length although the testers varied considerably for these traits. Additive variance played a significant role in the inheritance of all the characters except number of spikelets per spike. The dominance variance was important for plant height, ear length and harvest index. The degree of dominance was in the over-dominance range for plant height. Complete dominance was operative for ear length, number of spikelets per spike and harvest index whereas for peduncle length only partial dominance was observed. The possibility of the isolation of the recombinants with high harvest index has been stressed.

Assimilate distribution and the role of abscisic acid and zeatin in relation to flower-bud blasting, induced by lack of light, in Iris cv. Ideal

Abstract: Flower-bud blasting in Iris occurs in the winter when low light intensities and short days prevail. After introduction of 14CO2 to one leaf the transport of assimilates was studied under controlled culture conditions in a control light treatment and in a treatment of 7 days darkness followed by standard light conditions. Little assimilate transport was found in the direction of the bud in dark-treated plants. However, zeatin injection into the flower buds of the plants subjected to the dark treatment clearly promoted assimilate transport ot these buds. Abscisic acid levels, determined by gas chromatography, were found to increase in the buds of dark-treated plants. Zeatin injection into the flower bud resulted in a suppression of the abscisic acid level. The latter treatment also resulted in higher percentage of flowering. Removal of flower parts was found to inhibit peduncle elongation. The peduncle elongation of complete flowers started in a well defined period, and the fresh weight of buds was found to increase mainly in the last part of that period. Assimilate transport under low light intensities in relation to abscisic acid and supposed gibberellin is discussed.

Strain of Rhizobium effects on growth and seed yield of cowpeas (Vigna unguiculata)

Abstract: Plant of cowpea (Vigna unguiculata (L.) Walp.) cv. TVu 1469 were grown in a plastic house set to simulate tropical temperatures. They were inoculated with one of two strains of Rhizobium and irrigated each day with nutrient solution either devoid of inorganic nitrogen (N) or containing 2.14 mM (30 ppm) N. Strain of Rhizobium significantly affected rates of dry matter and N accumulation as well as the total N content of mature plants. Variations in seed yield were due largely to Rhizobium effects on peduncle production and pod set on each peduncle, wheres inorganic N did not change these yield-determining components significantly. The agronomic and physiological implications of these data are discussed.

Surgical Treatment for Cutaneous Tumour In Fish

Abstract: A gold fish, Carassius auratus (l), obtained from the Taraporevala Aqua­ rium, Bombay with cutaneou~ tumour on the caudal peduncle and conse·