摘要:

Qualitative analysis of lipid extract fractions of mycelium ofTrichothecium roseumfrom 2- to 4-day-old cultures, showed the presence of mono-, di-, and tri-glycerides, and phosphatidyl-choline (lecithines), phosphatidyl-ethanolamines and cardiolipides. Fatty acids are represented by myristic (C 14:0), palmitic (C 16:0), stearic (C 18:0), oleic (C 18:1), linoleic (C 18:2), and linolenic (C 18:3) acids.

ISSN:0008-4026    

DOI:10.1139/b72-034

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The growth habit of "grass-clump" dwarf wheat plants can be affected by extremely short 16° treatments if given repeatedly. To localize the earliest growth responses in plants of one such hybrid (Mql × KF 1), the temperature sensitivity of plants of different ages, and the earliest temperature-induced changes in growth, development, and shoot physiology were investigated and compared with the responses of normal wheat plants.Mql × KF 1 plants growing at 26° responded to progressively shorter 16° treatments as they aged and plants exposed to 16° after 10 days growth at 26° were unable to recover from low temperature treatments of 3–5 days duration. Although shoot growth (as dry weight) of Mql × KF 1 stopped abruptly after 7 days at 16°, root growth (as dry weight) continued for at least 15 days. The rates of CO2and water vapor exchange in individual leaves responded to low temperature similarly in both the dwarf and normal plants and did not markedly decrease until after 4 days at 16°. The most rapid low temperature response specific to Mql × KF 1 plants was cessation in primary tiller development immediately after the beginning of 16° exposure. It is proposed that the primary 16° effect is on the shoot meristematic region and that other changes in growth and physiology result from the lack of meristematic activity in the young growing region.

ISSN:0008-4026    

DOI:10.1139/b72-035

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Poa semilatent virus (PSLV), which caused chlorosis and rapid death of inoculated wheat, infected a number of grasses susceptible to barley stripe mosaic virus (BSMV); but it also infectedAgropyron trachycaulumandPoa palustriswhich were not susceptible to a barley strain or two oat-infecting strains of BSMV. Conversely BSMV caused local lesions on several species ofChenopodiumthat did not become infected with PSLV. BSMV protected wheat from infection by PSLV, but PSLV caused only partial protection from BSMV.The normal length and thickness of particles in leaf-dip preparations was 161 × 26 mμ for PSLV and 133 × 25 mμ for BSMV.Serological relationship was not indicated by the Ouchterlony agar double-diffusion test or leaf-dip serology. A distant relationship was shown with the microprecipitin test and the ring interface precipitin test. In cross absorption tests the titers of the antisera to the homologous viruses were not reduced by absorption with the heterologous viruses.PSLV and BSMV appear to be distantly related serotypes.

ISSN:0008-4026    

DOI:10.1139/b72-036

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Zoospores ofP. cactorumwere added to air-dry soil and recovered periodically on soil-dilution plates. Such inoculum survived longer in relatively dry soil than in wet soil. Temperature at which soil was stored after infestation had little effect on persistence but survival tended to be longer at 10 °C than at 26.7 °C. Adding dextrose or sucrose, and ammonium sulfate, alone or together, had no appreciable effect on fungus survival. Addition of urea, 500 ppm N w/w air-dry soil, shortened considerably the period through which cysts were recovered on dilution plates. This effect was not obtained with urea 250 ppm N. Other common nitrogen fertilizers had no consistent effect on fungus survival. When sprouted apple seeds were planted in soil infested with zoospores, the number of propagules increased substantially and the fungus was recovered for several weeks longer from planted than from non-planted soil. Soil may be infested withP. cactorummore readily by using zoospores than by using other propagules.

ISSN:0008-4026    

DOI:10.1139/b72-037

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Chromosome numbers are reported for 94 collections of grasses representing 61 species and 27 genera. Meiosis was analyzed and irregularities were noted. The probable reproductive method is discussed for some species with irregular meiosis. First chromosome counts are given for the following species:Luziola bahiensis, Aristida implexa, Briza rotundata, Gouinia guatemalensis, Bouteloua alamosana, Pentarrhapis scabra, Panicum cyanescens, P. incumbens, P. olivaceum, P. pantrichum, P. tenerum, Paspalum adoperiens, P. plenum, P. serpentinum, Thrasya campylostachya. Counts different from previous counts for the same taxon are reported forAxonopus capillaris, A. compressus, A. poiophyllus, Leptocoryphium lanatum, Paspalum centrale, P. pectinatum, Pennisetum setosum, andHemarthria altissima.

ISSN:0008-4026    

DOI:10.1139/b72-038

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Marquillo × Kenya Farmer 1 (Mql × KF 1) wheat plants respond to very short 16° treatment by decreased meristematic activity of the apical meristem and extensive cellular destruction in young leaf and stem tissues. By radiotracer techniques the metabolism of3H-thymidine,32P, and14C-leucine fed to intact shoot tissues of Mql × KF 1 and normal Marquillo (Mql) plants were studied.Immediately after the onset of 16° treatment, the incorporation of both3H-thymidine and32P into the DNA of Mql × KF 1 meristematic regions began to decline rapidly although the total uptake of label into the meristematic tissue remained constant. The incorporation of32P into the RNA, the acid-soluble organic phosphate compounds, and phospholipids of the Mql × KF 1 meristems also declined during the first 24 h and the inorganic phosphate radioactivity increased. After the initial decrease, the proportion of radioactivity in the RNA and acid-soluble organic compounds increased to near control levels. The distribution patterns of both3H-thymidine and32P were unchanged in the meristematic region of Mql × KF 1 plants at 26° or Mql plants at 16° or 26°. Protein synthesis in meristematic regions, measured by the incorporation of14C-leucine, responds to temperature similarly in Mql × KF 1 and Mql plants.The inhibitions of mitosis, phospholipid synthesis, and DNA synthesis were extremely rapid and reversible after short 16° exposures, and are thought to be close to the primary process of temperature lethality of Mql × KF 1 plants. Although it is not known if any of these processes are responsible for the others, it is proposed that the cellular destruction is caused by the inability of cells in the elongating regions to synthesize the phospholipid components of membranes.

ISSN:0008-4026    

DOI:10.1139/b72-039

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Incubation of leaf disks of certain genera of Asteraceae on phosphate-buffered, 5% sugar solutions resulted in thede novosynthesis of a homologous series of inulin-type fructosans. Fructo-oligosaccharides of degree of polymerization 3 to 21 or 22 were present in dandelion, chicory, lettuce, hawkweed, and sow thistle leaf disks after 72 h, but not in dahlia or sunflower. Synthesis occurred with media containing either fructose, glucose, or sucrose, but not with mannose or galactose. Fructosan formation began after about 36 h and continued with the sequential synthesis of homologs of increasing chain length. After 72 h, the relationship between the amount of polymer synthesized and the chain length appeared to be logarithmically biphasic, consisting of two series of exponentially decreasing values. Incubation for 120 h however, resulted in a distribution more closely resembling that found naturally in fructosan storing tissues.14C-tracer studies showed that both the endogenous and exogenous carbohydrate sources contribute to fructosan synthesis. Fructo-oligosaccharide formation was blocked by cycloheximide, puromycin, and actinomycin D but not chloramphenicol, indicating that cytoplasmic protein and nucleic acid synthesis was required. Analysis of fructosan formation during incubation suggests a close correlation between transfructosylation mechanisms observed in vitro and thede novosynthesis of fructosans in vivo.

ISSN:0008-4026    

DOI:10.1139/b72-040

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Evidence is presented from autoradiographic experiments, indicating that the onset of protein synthesis in newly imbibed mature aleurone cells ofAvena fatuaL. is independent of the synthesis of "new" RNA. It is concluded that all fractions of RNA which are essential for protein synthesis survive for periods of several weeks, and probably for several years in caryopses held in dry storage. The results are consistent with previous reports of long-lived template-active RNA in mature, dry plant embryos.

ISSN:0008-4026    

DOI:10.1139/b72-041

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Enzyme changes in root initials ofHydrangea macrophylladuring adventitious root formation are described. Extensive changes in enzyme activity were demonstrated by histochemical staining and all enzymes investigated showed increased activity in the tissue responsible for root initiation.The earliest change observed was that of peroxidase in the phloem and xylem ray cells. This was followed by a change in the activity of cytochrome oxidase and succinic dehydrogenase. Alpha-amylase was localized by the substrate film method. The highest amylase activity was demonstrated in the epidermal tissues and vascular bundles. As the root primordia developed, enzyme activity shifted from the vascular bundles to the periphery of the bundles. A positive correlation was found between the starch content and root number of cuttings.

ISSN:0008-4026    

DOI:10.1139/b72-042

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The particulate fatty acid synthesizing system from the developing castor bean endosperm was separated using sucrose density gradients. The particulate fatty acid synthesizing enzymes were associated with a particle of peak density 1.21 g∙(cm3)−1. Based on the presence of triosephosphate isomerase and the appearance of the particles in electron micrographs the major constituent of this fraction was identified as proplastids. It appears that in this tissue the proplastid contains the complete enzyme complement for oleic acid synthesis from acetyl or malonyl-Co

ISSN:0008-4026    

DOI:10.1139/b72-043

出版商:NRC Research Press    

年代:1972

数据来源: NRC