摘要:

Impatienscrosses were made among the following: P.I. 349629 (Java), P.I. 349586 (New Guinea),I.Itolstii, and "Tangerine." All crosses were successful except those made withI.Itolstii. Chromosome counts were as follows: P.I. 349629 = 16, P.I. 349586 = 32,I.Itolstii = 16, and "Tangerine" = 8. Chromosome counts of the hybrids were midway between the respective parents. Cytological studies indicated a similarity in chromosome morphology and size among all parents exceptI.holslii. A new genome count of 4 is reported for the genusImpatiensindicating a ploidy series in whichx = 4.

ISSN:0008-4026    

DOI:10.1139/b74-117

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The mature spores ofFunaria hygrometricaHedw. contain proplasts that are transformed into chloroplasts in about 24 h, during germination on an inorganic medium in the light. The formation and aggregation of thylakoids are observed by electron microscopy. Studies on chlorophyll synthesis, CO2fixation during germination, Hill's reaction (2,6-dichlorophenol–indophenol (DP1P)) by isolated chloroplasts, and electron paramagnetic resonance (EPR) signals suggest further correlations between plastid formation and functions.The results onFunariaspores are compared with results onBryumspores. MatureBryum capillareHedw. spores contain chloroplasts that change only slightly during germination. The photosynthetic system ofFunariaspores is compared with that of the chloroplasts ofBryumspores.

ISSN:0008-4026    

DOI:10.1139/b74-118

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Girdling ofCitrus aurantiumseedlings inhibited translocation of14C-sucrose from leaves to roots, yet starch accumulation was observed in all parts of the seedlings including roots. Results indicated that girdling triggered starch accumulation in roots independent of carbohydrate transport from the leaves. The increase in starch content of leaves was accompanied by a decrease in the specific activity of the accumulated starch. Girdling also caused an increase in fresh weight in all parts of the seedling and a decrease in percentage dry weight of rootlets.

ISSN:0008-4026    

DOI:10.1139/b74-119

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Cinematographic analysis of encysting primary zoospores ofSaprolegnia terrestrisshowed asynchronous flagellar retraction. The data are most compatible with a retraction model involving mainly asynchronous microtubule depolymerization with "wrap-around" of the final fragment of each flagellum.

ISSN:0008-4026    

DOI:10.1139/b74-120

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Growth and development of embryos, starting from zygotes, ofFucus edentatusDe la Pyl. andF. distichusL. ssp.distichus(nomenclature is that used by McLachlanet al. 1971) were investigated under a variety of temperatures combined with various light conditions; both species appeared to respond in a similar manner. Growth was more rapid with increase in temperature up to 15°; at 20° embryos developed abnormally under prolonged incubation. Light (cool-white fluorescent lamps) saturation for growth occurred at about 3000 μW/cm2at 15°, and no inhibition was noted up to 12 000 μW/cm2. In darkness or under light-deficient conditions, the primary rhizoid became relatively long but apical hairs were suppressed or reduced, and additionally in darkness there was little increase in the size of the thallus over that of the original zygote. Below 15° growth and development were limited by temperature. At 15° and a photoperiod exceeding 16 h or at 20° and a photoperiod exceeding 12 h aberrant morphological development of the embryo occurred. Incubation on a 6-, 36-, or 48-h day at 15° did not result in abnormal development where the light:dark (L:D) ratio was kept at 2:1. Under 36- and 48-h days growth was slower, indicating an inefficient use of light during the long light periods. The laboratory results suggest that distribution of this species in nature is largely controlled by factors acting on the embryo and that these responses may be different from those of the mature plant.

ISSN:0008-4026    

DOI:10.1139/b74-121

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Ctenosporites, Granatisporites, andPesavisare described as new form genera of fossil fungal spores and spore-like fossils;StriadiporitesandPluricellaesporitesare emended.PesavisandCtenosporitesare geographically restricted to the northwest Pacific and Arctic region.Granatisporitesis described to facilitate the classification of fungal spore types ubiquitous over at least the Western Hemisphere.

ISSN:0008-4026    

DOI:10.1139/b74-122

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The use of displacement transducers coupled with suitable recording equipment is described for high resolution (0.1 µm) automatic measurements of plant growth. Systems are described for measurements on intact seedlings or isolated sections and for measuring mechanical properties of cell walls. The equipment can be used simultaneously for several channels and is suitable for on-line computer calculation and plotting of results. Examples of typical results are given for the different applications.

ISSN:0008-4026    

DOI:10.1139/b74-123

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The ultrastructure of the hyphae characteristic of five species ofSeptobasidiumwas examined and general features were noted. The septa were found to resemble those in the rusts rather than the type characteristic of the Tremellales and the homobasidiomycetes.

ISSN:0008-4026    

DOI:10.1139/b74-124

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The temperature dependence of the balance pressure is reported for shoots ofTsuga canadensisat constant volume, i.e., when water is neither added to nor removed from the shoot. Since the balance pressure closely equals minus the water potential, the temperature dependence of the balance pressure should reflect the combined temperature dependence of the osmotic and turgor pressures. Both the osmotic and the turgor pressures decline with decreasing temperature; frequently the turgor pressure declines 2 to 3 times more rapidly than the osmotic pressure, causing the balance pressure to rise with decreasing temperature. Only when the turgor pressure is zero (only beyond incipient plasmolysis) does the temperature dependence of the balance pressure closely follow the temperature dependence of the osmotic pressure; this occurs when the balance pressure equals or exceeds 24 bars.

ISSN:0008-4026    

DOI:10.1139/b74-125

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Eight strains of alfalfa mosaic virus (AMV) were studied by electron microscopy in alfalfa (Medicago sativaL.) leaf tissue and after purification. The virus occurred in the cytoplasm and occasionally in the vacuoles of mesophyll and vascular parenchyma cells; it was not associated with cell organelles. One strain of AMV (U5) did not incite symptoms in the alfalfa leaves and caused no ultrastructural damage to the infected cells. Two strains (U10 and U21) caused no symptoms in alfalfa, but the tonoplast of infected cells was not closely attached to the cytoplasm and floated in the vacuole; cell organelles were not damaged. The other five strains of AMV (F1, NY1, R6, B1, and W1) regularly or occasionally produced symptoms in alfalfa leaves. In leaves that were symptomless, as well as in the apparently healthy parts of leaves with symptoms of AMV infection, there was no apparent ultrastructural damage to the infected cells. Within the part of a leaf where there were symptoms, the tonoplast was detached from the cytoplasma and was folded within the vacuole in various patterns, along with bits of cytoplasm and virus particles. Cell organelles were often found in various stages of disintegration. Three different aggregations of the virus were recognized. The eight AMV strains were grouped into three general classes on the basis of the range in virus particle sizes. Mycoplasm was not associated with any of the AMV strains.

ISSN:0008-4026    

DOI:10.1139/b74-126

出版商:NRC Research Press    

年代:1974

数据来源: NRC