Influence of the nitrogen level on root growth and morphology of two potato varieties differing in nitrogen acquisition

Two potato (Solanum tuberosum L.) cultivars (Astrid and Bodenkraft) differing in their nitrogen acquisition from the soil (Hunnius, 1981) were used in nutrient solutions to study the effect of increasing concentrations of nitrate (0.05; 0.5; 5.0 mol m^-3) particularly on root growth and morphology. In each variety increasing nitrogen concentrations stimulated shoot growth more than root growth. At all nitrate concentrations, the variety with higher nitrogen acquisition (Astrid) had a significantly larger root system. The larger root system of Astrid compared to Bodenkraft was particularly evident when surface area and total length of the roots, instead of root dry weight were used as parameters. The results stress the importance of root length and surface area for nitrogen acquisition from soils.     

Root traits, nutrient uptake, multi-location grain yield and benefit–cost ratio of two lentil (Lens culinaris, Medikus.) varieties

Lentil is a protein-rich pulse, grown mainly in developing countries as a rain-fed crop in nutrient-poor soils. Hence, the importance of root traits for efficient capture of soil nutrients and water can be crucial to its economical yield. Little is known about the lentil root system and even less about its relationship to grain yield. We compared the root system of two Bangladeshi lentil varieties, Barimasur-3 (BM-3) and Barimasur-4 (BM-4), in a pot experiment and related it to their multi-location grain yield in the fields. BM-4 maintained faster root development both at an early growth stage (20days after sowing) and at flowering (60days) compared to BM-3. The roots of BM-4 penetrated the 25cm depth of the soil profile after 19±1days and while those of BM-3 took 24±2days to reach the same depth. The roots of BM-4 were covered with denser (26±3mm^–1) and longer (0.48±0.11) root hairs than BM-3 (density 17±2mm^–1, length 0.32±0.09mm). The differential presence of root hairs increased the effective length of root system of BM-4 by 12 times and that of BM-3 by five times. The lentil varieties did not differ in their ability to induce pH change and acid phosphatase activity in rhizosphere. In the pot experiment, the uptake of macro-nutrients (K, P, Ca, and Mg) as well as micro-nutrients (Fe, Mn, Zn, Cu, B and Mo) by BM-4 was significantly higher, compared to BM-3. The varieties produced the same amount of shoot biomass. At five of six agro-ecological distinct field locations in Bangladesh, BM-4 gave significantly higher (10–20%) grain yield than BM-3. Linked with the higher grain yield, the benefit-cost ratio (BCR) of BM-4 was 3.14 and that of BM-3 were 2.62, indicating that BM-4 provided better return per unit investment, compared to BM-3, supported by the better root morphology and higher nutrient uptake. This may be one of the reasons supporting the popularity and preferred adoption of BM-4 among the Bangladeshi farmers, who grow lentil mainly on nutrient-poor soils. The results indicate the benefits of selection and breeding for superior root traits for better agro-economics.     

Fine root biomass,production and turnover in a fertilized <Emphasis Type="Italic">Larix leptolepis</Emphasis> plantation in central Korea

The effects of fertilization [control (C), 200kgNha^–1+25kgP ha^–1 (LNP) and 400kgNha^–1+ 50kgP ha^–1 (HNP)] on fine root dynamics were examined in a 40-year-old Larix leptolepis plantation in central Korea. The average fine root biomass during the growing season for C, LNP and HNP was 957, 934 and 814kgha^–1, respectively, whereas the fine root production for C, LNP and HNP was 2103, 2131 and 2066kgha^–1, respectively. Nitrogen and P inputs into the soil via fine root turnover for C, LNP and HNP were 23.0 and 1.2, 23.3 and 1.2 and 22.6 and 1.2kgha^–1, respectively. There were no significant differences in fine root biomass, production and N and P inputs through fine root turnover between the fertilization treatments during the first growing season after fertilization.     

Carbon dynamics and budget in a <Emphasis Type="Italic">Miscanthus sinensis</Emphasis> grassland in Japan

We investigated the carbon dynamics and budget in a grassland of Miscanthus sinensis, which is widely distributed in Japan, over a 2-year period (2000–2001). Plant biomass began to increase from May and peaked in September, then decreased towards the end of the growing season (October). Soil respiration rates also exhibited seasonal fluctuations that reflected seasonal changes in soil temperature and root respiration. The contribution of root respiration to total soil respiration was 22–41% in spring and summer, but increased to 52–53% in September. To determine the net ecosystem production (carbon budget), we estimated annual net primary production, soil respiration, and root respiration. Net primary production was 1207 and 1140gCm^–2 in 2000 and 2001, respectively. Annual soil respiration was 1387gCm^–2 in 2000 and 1408gCm^–2 in 2001; root respiration was 649 and 695gCm^–2 in 2000 and 2001, respectively. Moreover, some of the carbon fixed as net production (457–459gCm^–2) is removed by mowing in autumn in this grassland. Therefore, the annual carbon budget was estimated to be –56gCm^–2 in 2000 and – 100gCm^–2 in 2001. These results suggest that the Miscanthus sinensis grassland in Japan can act as a source of CO₂.     

Effects of light on nitrate-limited Oscillatoria agardhii in chemostat cultures

The effects of the average light irradiance (I) on growth and nitrate uptake kinetics of the cyanobacterium Oscillatoria agardhii, in nitrate-limited chemostat cultures, were studied. Light was nonsaturating for I <9.4 Wm^–2, for all growth rates () studied. However, was throughout limited by the availability of nitrate. Under light-saturating conditions the kinetics of nitrate-limited growth could be adequately described by both the Monod and Droop equations. Under light-non-saturating conditions the internal nitrogen content (Q) was a function of both and I, for which new formulas were derived. The high uptake capacity (V _max) of nitrate-limited cells was independent of , but was significantly increased for cells growing at I <9.4 Wm^–2. The half-saturation constant for nitrate uptake (K _s ^u ) increased with increasing , but was independent of the prevailing light conditions. The effects of light during nitrate-limited growth were associated with the regulation in the nitrogen-containing pigments.The results reported herein have important consequences for the use of Q, K _s ^u and V _max values as indicators of nutrient-deficiency of natural populations.     

Amyloid beta-peptide promotes permeability transition pore in brain mitochondria

In this work the effect of the neurotoxic amino acid sequence, A_25–35, on brain mitochondrial permeability transition pore (PTP) was studied. For the purpose, the mitochondrial transmembrane potential (m), mitochondrial respiration and the calcium fluxes were examined. It was observed that A_25–35, in the presence of Ca²⁺, decreased the m, the capacity of brain mitochondria to accumulate calcium and led to a complete uncoupling of the respiration. However, the reverse sequence of the peptide A_25–35 (A_35–25) did not promote the PTP. The alterations promoted by A_35–25 and/or Ca²⁺ could be reversed when Ca²⁺ was removed by EGTA or when ADP plus oligomycin were present. The pre-treatment with CsA or ADP plus oligomycin prevented the m drop and preserved the capacity of mitochondria to accumulate Ca²⁺. These results suggest that A_25–35 can promote the PTP induced by Ca²⁺.     

Wuchsform,Infloreszenz- und Blütenmorphologie vonEpithema (Gesneriaceae)

The shoot organization and inflorescence structure ofEpithema is analyzed. On the main axis micro- and macrocotyledon (the latter falling off early) are followed by a ± long epicotyl, then a large, solitary leaf (B₃) and above this a dimerous leaf whorl (B₄, B₅). The last internode of the main axis is the basic internode of the main florescence (Troll). Peculiarly enough, the latter includes only one partial florescence which is embraced by its subtending bract (B₆) and represents a capitulum-like, congenital, pair-flowered cincinnus. Paracladia arise from the axils of B₃ to B₅ (sometimes also from the macrocotyledon); they are either reduced to their co-florescence (with the same structure as the main florescence), or carry further shoots resp. co-florescences from the axils of a dimerous leaf whorl.—Epithema can be interpreted as anisophyllous.—From flower morphology and ontogenesis a number of new differential characters are revealed. Together with shoot and inflorescence characters their systematic and possible functional significance is discussed.

Frau Univ.-Prof. Dr. E.Tschermak-Woess zum 60. Geburtstag gewidmet.     

A quantitative method for separating reaction components of CMP-sialic acid: Lactosylceramide sialyltransferase using Sep Pak C18 cartridges

A rapid procedure is described for the separation of CMP-sialic acid:lactosylceramide sialyltransferase reaction components using Sep Pak C₁₈ cartridges. The quantitative separation of the more polar nucleotide sugar, CMP-sialic acid, and its free acid from the less polar G_M3-ganglioside is simple and rapid relative to previously described methods. Recovery of G_M3 is optimized by the addition of phosphatidylcholine to the reaction mixture prior to the chromatographic step. Using rat liver Golgi membranes as a source of CMP-sialic acid: lactosylceramide sialyltransferase activity (G_M3 synthase; ST-1), the transfer of [¹⁴C] sialic acid from CMP-[¹⁴C] sialic acid to lactosylceramide can be quantified by this assay. The procedure is reliable and may be applicable to the isolation of ganglioside products in otherin vitro glycosyltransferase assays.Abbreviations G_M3 G_M3-ganglioside - II³NeuAc-LacCer NeuAc2-3Gal1-4Glc1-1Cer - G_D1a G_D1a-ganglioside, IV³NeuAc, II³NeuAc-GgOse₄Cer, NeuAc2-3Gal1-3GalNac1-4(NeuAc2-3)Gal1-4Glc1-1Cer - G_D3 G_D3-ganglioside, II³(NeuAc)₂LacCer, NeuAc2-8NeuAc2-3Gal1-4Glc1-1Cer - GgOse₄Cer asialo-G_M1 Gal1-3GalNAc1-4Gal1-4Glc1-1Cer - FucG_MI fucosyl-G_MI-ganglioside, Fuc1-2Gal1-3GalNAc1-4Gal1-4 Glc1-1Cer - ST-1 G_M3 synthase, CMP-sialic acid:lactosylceramide sialyltransferase - LacCer lactosylceramide, Gal1-4Glc1-1Cer - CMP-NeuAc cytidine 5-monophospho-N-acetylneuraminic acid - PC phosphatidylcholine - PMSF phenylmethylsulfonyl fluoride     

α-Thalassemia in Saudi Arabia: deletion pattern

Summary -Thalassemia exists at a high prevalence in several regions of Saudi Arabia. The restriction endonucleases Bam HI and BglII were used to investigate the molecular basis of deletion type of -thalassemia in 226 subjects from the eastern and 61 subjects from the northwestern regions of the country. The arrangements-/ and-/- were common. BglII digestion revealed the existence of rightward deletion in a majority of the cases. Leftward deletions, both homozygous and heterozygous, were also identified. Triple -gene arrangements -/ and -/- were observed at a low frequency in both regions.     

Plant regeneration via somatic embryogenesis in Styrian pumpkin: cytological and biochemical investigations

Somatic embryo formation was induced from cotyledon explants of Styrian pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) by using a solid MS medium supplemented with 16.11M NAA and 4.44M BA or 26.85M NAA and 13.32M BA. The callus proliferation was more efficient on medium supplemented with 26.85M NAA and 13.32M BA. In contrast, the embryogenic response was higher on medium with lower concentrations of growth regulators (16.11M NAA and 4.44M BA). The time needed for embryo induction did not depend on medium composition. Embryos in globular stage were transferred to three different maturation media, containing 2.89M GA₃ in combination with 0.54M NAA, 11.42M IAA and growth regulator-free medium. The germination rate was the highest when embryos were cultured on medium with 11.42M IAA. Plantlets grown on this medium achieved maturity suitable for transplantation into soil within 9 to 10weeks. The regenerated plants were successfully transferred into field and developed fertile flowers and set fruits. Biochemical analysis showed significant lower total glutathione levels among in vitro grown plantlets compared to seedlings grown in soil. When the plantlets were transferred into soil, they reached a normal size within a month and the glutathione concentration was comparable to seed-derived plants at the same developmental stage. Transmission electron microscopy was used to investigate possible differences in the ultrastructure of cells from callus cultures, and leaf cells of regenerated and seed-derived plants. Differences in the ultrastructure were found within chloroplasts which contained only single thylakoids, large starch grains and small plastoglobuli in callus cells in comparison to leaf cells, which possessed a well developed thylakoid system, small starch grains and large plastoglobuli.     

Relationships between external nitrate availability,nitrate uptake and expression of nitrate reductase in roots of barley grown in N-limited split-root cultures

Despite the large number of studies of nitrate metabolism in plants, it remains undetermined to what extent this key plant system is controlled by overall plant N nutrition on the one hand, and by the nitrate ion itself on the other hand. To investigate these questions, V _max for nitrate uptake (high-affinity range), and nitrate reductase (NR) mRNA and activity, were measured in roots of N-limited barley (Hordeum vulgare L. cv. Golf) grown under conditions of constant relative addition of nitrate, with the seminal roots split between two culture compartments. The total amount of nitrate added per unit time (0.09·d^-1) was distributed between the two root parts (subroots) in ratios of 1000, 982, 955, 9010, 8020, and 5050. These nitrate-addition ratios resulted in nitrate fluxes ranging from 0 to 23 mol nitrate·g^-1 DW root·h^-1, while the external nitrate concentrations varied between 0 and 1.2 M. The apparent V _max for net nitrate uptake showed saturation-type responses to nitrate flux maintained during preceding growth. The flux resulting in half-maximal induction of nitrate uptake was approximately 4 mol nitrate·g^-1 DW root·h^-1, corresponding to an external nitrate concentration of 0.7 M. The activity of NR and levels of NR mRNA did not saturate within the range of nitrate fluxes studied. None of the parameters studied saturated with respect to the steady-state external nitrate concentration. At the zero nitrate addition — the 0%-root — initial uptake activity as determined in short-term ¹⁵N-labelling experiments was insignificant, and NR activity and NR mRNA were not detectable. However, nitrate uptake was rapidly induced, showing that the 0%-root had retained the capacity to respond to nitrate. These results suggest that local nitrate availability has a significant impact on the nitrate uptake and reducing systems of a split-root part when the total plant nitrate nutrition is held constant and limiting.Abbreviation NR nitrate reductase This work was supported by the Lars Hierta Memory Foundation, the Royal Swedish Academy of Sciences, and by the Swedish Natural Science Research Council via project grants (to C.-M.L. and B.I.) and visiting scientist grant (to W.H.C.). We thank Mrs. Ellen Campbell for technical advice, and Mrs. Judith V. Purves, Long Ashton Research Station, Long Ashton, UK, for analyses of ¹⁵N-labelling in tissue samples.     

Early development of the self-fertilizing mangrove killifish <Emphasis Type="Italic">Rivulus marmoratus</Emphasis> reared in the laboratory

The mangrove killifish Rivulus marmoratus was reared at 25°±1°C and 17ppt salinity from 0 to 100 days after hatching (DAH), and its early development was described by examining growth and morphometric parameters, meristic characters (vertebral and fin-ray counts), bone-cartilage development, and pigmentation. Growth was isometric for preanal length, head length, snout length, body depth, pectoral-fin length, dorsal-fin length, anal-fin length, and caudal-peduncle depth. Negative allometric growth was observed in eye diameter and gape size. Meristic counts (mean±SD) for vertebrae (34.2±0.4) and dorsal- (8.6±0.5), anal- (11.4±0.5), and caudal-fin rays (30.2±0.8) were complete at 0 DAH (n=5), whereas pectoral-fin rays and pelvic-fin rays were complete by 30 DAH (14.5±0.4, n=5) and 60 DAH (4.2±0.8, n=5). Full ossification of meristic elements proceeded in the following sequence: vertebrae (by 30 DAH), caudal-, dorsal-, and anal-fin rays (by 60 DAH), pectoral-fin rays (between 60 DAH and 100 DAH), and pelvic-fin rays (by 100 DAH). Both morphological characters and meristic counts indicate that this species can be considered to be a juvenile after 9.8mm in standard length (20 DAH).     

Quantification of soil carbon inputs under elevated CO2: C3 plants in a C4 soil

The objective of this investigation was to quantify the differences in soil carbon stores after exposure of birch seedlings (Betula pendula Roth.) over one growing season to ambient and elevated carbon dioxide concentrations. One-year-old seedling of birch were transplanted to pots containing C₄ soil derived from beneath a maize crop, and placed in ambient (350 L L^–1) and elevated (600 L L^–1) plots in a free-air carbon dioxide enrichment (FACE) experiment. After 186 days the plants and soils were destructively sampled, and analysed for differences in root and stem biomass, total plant tissue and soil C contents and ¹³C values. The trees showed a significant increase (+50%) in root biomass, but stem and leaf biomasses were not significantly affected by treatment. C isotope analyses of leaves and fine roots showed that the isotopic signal from the ambient and elevated CO₂ supply was sufficiently distinct from that of the C₄ soil to enable quantification of net root C input to the soil under both ambient and elevated CO₂. After 186 days, the pots under ambient conditions contained 3.5 g of C as intact root material, and had gained an additional 0.6 g C added to the soil through root exudation/turnover; comparable figures for the pots under elevated CO₂ were 5.9 g C and 1.5 g C, respectively. These data confirm the importance of soils as an enhanced sink for C under elevated atmospheric CO₂ concentrations. We propose the use of C₄ soils in elevated CO₂ experiments as an important technique for the quantification of root net C inputs under both ambient and elevated CO₂ treatments.     

Transfer of Hessian fly resistance from rye to wheat via radiation-induced terminal and intercalary chromosomal translocations

Summary A new Hessian fly (Mayetiola destructor) resistance gene derived from Balbo rye and its transfer to hexaploid wheat via radiation-induced terminal and intercalary chromosomal translocations are described. Crosses between resistant Balbo rye and susceptible Suwon 92 wheat and between the F₁ amphidiploids and susceptible TAM 106 and Amigo wheats produced resistant BC₂F₃ lines that were identified by C-banding analysis as being 6RL telocentric addition lines. Comparative chromosomal analyses and resistance tests revealed that the resistance gene is located on the 6RL telocentric chromosome. X-irradiated pollen of 6RL addition plants was used to fertilize plants of susceptible wheats TAM 106, TAM 101, and Vona. After several generations of selection for resistance, new sublines were obtained that were homogeneous for resistance. Thirteen of these lines were analyzed by C-banding, and three different wheat-6RL chromosomal translocations (T) were identified. Wheat chromosomes involved in the translocations were 6B, 4B, and 4A. Almost the complete 6RL arm is present in T6BS · 6BL-6RL. Only the distal half of 6RL is present in T4BS · 4BL-6RL, which locates the resistance gene in the distal half of 6RL. Only a very small segment (ca 1.0 m) of the distal region of 6RL is present in an intercalary translocation (Ti) Ti4AS · 4AL-6RL-4AL. The 6RL segment is inserted in the intercalary region between the centromere of chromosome 4A and the large proximal C-band of 4AL. The break-points of the translocations are outside the region of the centromere, indicating that they were induced by the X-ray treatment. All three translocations are cytologically stable and can be used directly in wheat breeding programs.Cooperative investigations of the Kansas Agricultural Experiment Station, Departments of Entomology and Plant Pathology, the Wheat Genetics Resource Center, Kansas State University, and the US Department of Agriculture, Agricultural Research Service. Contribution No. 91-117-JDeceased     

Influence of phosphate and nitrate supply on root hair formation of rape,spinach and tomato plants

Summary Experiments with tomato, rape and spinach in nutrient solutions have shown that the formation of root hairs is strongly influenced by phosphate and nitrate supply. Decreasing the phosphate concentration of the nutrient solution from 100 to 2 M P resulted in an increase of root hair length from 0.1–0.2 to 0.7 mm of the three plant species. Root hair density also increased by a factor of 2–4 when the P concentration was lowered from 1000 to 2 M. The variation of these two root properties raised the root surface area by a factor of 2 or 3 compared to plants well supplied with P. Root hair length was closely related to the phosphate content of the root and shoot material. On the other hand, spinach plants grown in a split-root experiment produced root hairs in solutions of high P concentration (1000M P) if the major part of the total root system was exposed to low P concentration (2 M P). It is therefore concluded that the formation of root hairs does not depend on directly the P concentration at the root surface but on the P content of the plant.Similar experiments with nitrate also resulted in an increase in length and density of root hairs with the decrease of concentration below 1000 M. In this case marked differences between plant species occurred. At 2 M compared to 1000 M NO₃ root hair length of tomato increased by a factor of 2, of rape by a factor of 5 and of spinach by a factor of 9. Root hair length was correlated, but not very closely, to the total nitrogen content of the plants. It is concluded, that the influence of nutrient supply on the formation of root hairs is a mechanism for regulating the nutrient uptake of plants.Dedicated to Prof. Dr. E. Welte on the occasion of his 70th anniversary.     

Multiple shoot regeneration from root organ cultures of Populus alba x P. grandidentata

Excised roots of various ages from Crandon and Hansen clones of Populus alba x P. grandidentata were tested for their regeneration capacity. Sixty-day-old excised roots that contained root tips were found to be most suitable. The highest number of shoots (an average of 111 shoots/root segment with Crandon and 98 with Hansen) was obtained by adding 22M and 14M zeatin to the medium, respectively. The two clones of hybrid poplar responded similarly to growth regulator treatments; however, the number of shoots produced was greater from the root organs derived from Crandon clones. Regenerated shoots were rooted in basal Woody Plant Medium without any growth regulators. Successful transplantation into soil and growth was achieved with all plants.     

Carbohydrates of influenza virus. Structure of the oligosaccharides linked to asparagines 406 and 478 in the hemagglutinin of fowl plague virus,strain dutch

Fowl plague virus, strain Dutch, was metabolically labeled withd-[2-³H]mannose, or withd-[6-³H]glucosamine, and the small subunit (HA₂; 0.8 mg in total) of the viral hemagglutinin was isolated by preparative sodium dodecylsulfate-polyacrylamide gel electrophoresis. After proteolytic digestion, the radioactive oligosaccharides were sequentially liberated from the glycopeptides by treatment with different endo--N-acetylglucosaminidases and with peptide:N-glycosidase or, finally, by hydrazinolysis. In this manner, four groups of glycans could be obtained by consecutive gel filtrations and were subfractionated by HPLC. The structures of the individual oligosaccharides were analyzed by micromethylation, by acetolysis or by digestion with exoglycosidases. The major species amongst the high mannose glycans at Ans-406 of the viral glycopolypeptide were found to be Man1-2Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNac1-4GlcNAc and Man1-3(Man1-2Man1-6)Man1-6(Man1-2Man1-2Man1-3)Man1-4GlcNAc1-4GlcNAc, while the complex glycans at Asn-478 are predominantly GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc (lacking, in part, one of the outerN-acetylglucosamine residues) and GlcNAc1-2Man1-3(Gal1-4GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc.Abbreviation BSA bovine serum albumin - endo D (F,H) endo--N-acetyl-d-glucosaminidase D (F,H) - HA hemagglutinin (HA₁, large subunit of HA - HA₂ small subunit - FPV fowl plague virus - PNGase F peptide:N-glycosidase F - SDS sodium dodecylsulfate     

Studies on aneuploids of Petunia

Summary The seven possible primary trisomics of Petunia (2 n= 14) located in the progenies of triploid, hypertriploid and hypotriploid plants were distinguished from one another and from diploid on the basis of cytological and morphological criteria. They were provisionally named as Oval, Semi, Slender, Pseudonormal, Arrow, Narrow and Giant. In three of the trisomics, the extra chromosome was identified for the first time at pachytene stage. Postpachytene studies revealed no precise relationship between the length of extra chromosome and the frequency of multiple association.     

Fertility ofFusarium moniliforme from maize and sorghum related to fumonisin production in Italy

Forty-three strains ofFusarium moniliforme isolated from infected maize and sorghum plants in Italy were assayed for their ability to produce fertile crosses with A and F mating population tester strains, in relation to their ability to produce fumonisins on maize substrate. Most of the strains isolated from maize (ear and stalk rot and maize-based feed), producing fumonisin B₁ (FB₁) and B₂ (FB₂) (up to 4,100 and 855 mg/kg, respectively), belonged to the A mating population. All of the strains isolated from sorghum belonged to the F mating population and produced little or no FB₁ and FB₂. This is the first report of the occurrence of mating population F in Europe. Our data on strains from Italy are consistent with previous studies from the United States that found significant differences in sexual fertility and fumonisin production between strains from maize and sorghum.     

Protoplasmic streaming in the giant unicellular green algaAcetabularia mediterranea

Summary Protoplasmic Streaming inAcetabularia mediteranea has been studied by microcinematography in 1. germinating zygotes, 2. germlings before the differentiation of rhizoids and apices, 3. young cells with rhizoids and apices, 4. vegetative cells-several centimeters in length, 5. cells with a maximum sized cap, containing secondary nuclei, and 6. cells after cyst formation. Intracellular transport is found to occur at a network-system of thin filaments and at a different system of headed streaming bands. At the network of filaments chloroplasts are found to move at a velocity of 1–2 m/sec. Headed streaming bands move along the filaments and may lead without interruption from the rhizoid to the apex of the cell andvice versa. The front zone of the streaming bands is occupied by a leading cytoplasmic head-structure. Small vesicles, polyphosphate granula and secondary nuclei are the predominant moving structures in headed streaming bands. The velocity of these particles is found to be 3–11 m/sec. The filament system is found during all developmental stages. Headed streaming bands are undetectable in germinating zygotes and develop from small cytoplasmic droplets in germlings to broad heavily loaded bands in the huge vegetative cell.Transport of secondary nuclei by headed streaming bands is not observed during mitotic divisions and after cyst formation, though moving bands are still present for several weeks after cyst formation.