摘要:

This paper is mainly concerned with the anatomical and morphological features of over 15 teratological samples of honeysuckle showing diverse types of "concaulescence."Most frequently, "concaulescence" is the only abnormality present and three different morphological–anatomical types of adnation may be distinguished. (1) The adnated sprigs (hypopodia) are attached to the main axis by a narrow strip of cortex; both the sprig gap and the seriated buds are located at their usual level. (2) The vascular bundles of the adnated axes separate themselves progressively, and frequently there is no seriated bud at the axil of the adnated sprigs. (3) The lateral sprigs remain closely fused with the main axis until they free themselves abruptly and then the seriated buds appear at the free axil.Studies of the other samples are complicated by the occurrence of some phyllotaxic anomalies below the adnation area. Among these anomalies the most frequent are (1) the vertical displacement between the opposite petiole insertion area of the node and (2) the stretching of the foliar bases and the accompanying sessile leaves at this abnormal node.

ISSN:0008-4026    

DOI:10.1139/b74-257

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Leaves of ocotillo, a shrub of southwestern North America, lack xeromorphic features. After rain, a few leaves at each node expand and function for a short period, then abscise. This cycle may be repeated several times each year. Palisade layers occur interior to both epidermal surfaces, and the spongy mesophyll is reduced. Venation is camptodromous, with many vein endings. In the distal lamina half, sclerified bundle sheath cells ("veinlet elements") become increasingly common in minor veins and vein endings. Near the leaf tip, adjacent mesophyll cells also become sclerified, to such an extent that some areoles appear filled with these cells ("accessory veinlet elements"). Phloem is conspicuous because it stains intensely and occupies more volume than xylem in most bundles. In minor veins and vein endings, sieve tube members become increasingly more slender than associated phloem cells, and xylem frequently changes its position, becoming parallel with, or even abaxial to, the phloem. Phloem mostly ends before, less commonly with, the xylem.

ISSN:0008-4026    

DOI:10.1139/b74-258

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Absorption of14CO2and distribution of14C-photosynthate from cotyledons and foliage leaves were studied for 35 days after seed germination inAcer rubrum, Robinia pseudoacacia, andUlmus americanaseedlings. Differences occurred among species in total carbohydrate requirements, strengths of various carbohydrate sinks, and importance of cotyledons or foliage leaves as sources of carbohydrates.Robiniacotyledons fixed appreciable14C 2 to 4 days after seedling emergence.AcerandUlmuscotyledons fixed only small amounts of14C 2 days after seedling emergence, but a significant increase in fixation occurred 4–6 days after seedling emergence. Photosynthesis in very young cotyledons was inhibited more by lack of stomata than by a deficiency of chlorophyll. As cotyledons reached maximum size, and as other plant parts were rapidly expanding, the cotyledons retained less14C-photosynthate, and a higher proportion of label was translocated basipetally to the stem and roots and acropetally to the stem and leaves. Compared with cotyledons, young hypocotyls fixed small quantities of14C and insignificant14C was fixed by stems 10 days after seedling emergence. Fully expanded foliage leaves accounted for an increasingly larger percentage of total14C fixation, and eventually more label was exported from leaves than from cotyledons. In 10- to 15-day-old plants much more14C was fixed by cotyledons of youngRobiniaplants than by cotyledons ofAcerorUlmus. This difference was largely the result of more cotyledon tissue inRobiniarather than in more efficient photosynthesis per unit of cotyledon tissue.

ISSN:0008-4026    

DOI:10.1139/b74-259

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Leaf tissue ofPhaseolus vulgarisL. andPlantago majorL. was prepared by the freeze-etch technique and examined in the electron microscope for the presence of ectodesmata. No structures analagous to ectodesmata observed with light microscopy could be found in freeze-etched preparations of chemically unfixed material or in material fixed only in glutaraldehyde. Objects appearing as broad, shallow, granular areas in the epidermal cell wall beneath the cuticle were observed in leaf replicas after fixation in complete sublimate fixative, the acid components of the sublimate fixative, or mercuric chloride alone. Because of their distribution and location, these objects can be considered analagous to ectodesmata observed by light microscopists. Because these areas occur only in chemically fixed walls and are localized within the walls in discrete areas, their presence supports the contention that ectodesmata are sites in the outer cell wall with defined physicochemical characteristics.

ISSN:0008-4026    

DOI:10.1139/b74-260

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Bound soybean hypocotyl cell wall proteins can be released from the cell wall by incubation with a culture filtrate of the fungal pathogenSclerotium rolfsii. The released cell wall proteins were then separated by disc electrophoresis or isoelectric-focusing techniques in polyacrylamide gel columns and tested for peroxidase and esterase activity. Released cell wall proteins showed considerable peroxidase multiplicity, which was totally absent in the separation of fungal culture filtrate. Peroxidase patterns of some released cell wall peroxidases were similar to soybean cytoplasmic peroxidase patterns. In separate experiments, esterase bands were detected in the released cell wall proteins, but this was probably due to esterase activity of the fungal culture filtrate. Cytoplasmic esterases exhibited much higher isoelectric points than cell wall and culture filtrate esterases, which were concentrated between pH 3 and 6.

ISSN:0008-4026    

DOI:10.1139/b74-261

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Tomato plants 21 days old were inoculated withAgrobacterium tumefaciens, the causative organism of crown gall, and 72 h later [3-14C]cinnamic or [carboxyl-14C]benzoic acid was administered by wick-feeding to these and to uninfected control plants. After a further 48 h both groups were examined for incorporation of label into phenolic acids. The pattern of incorporation into bound phenolic acids of the controls was in accord with biosynthetic pathways previously demonstrated in normal plants, but qualitative and quantitative divergence from this pattern was observed in the bound phenolic acids of the infected plants. The data suggest interference by the pathogen with β-oxidation of at least two phenylpropanoid acids of the lignification pathway. In infected plants, lowered incorporation of14C from cinnamic acid into phenylpropanoid acids of the lignification pathway and their β-oxidation products was accompanied by the appearance of labelledo-coumaric acid, consistent with some diversion of cinnamic acid metabolism toward ortho-hydroxylation. Incorporation of14C from benzoic acid into gentisic and especially salicylic acid of infected plants was much lower than in the controls.

ISSN:0008-4026    

DOI:10.1139/b74-262

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

In inhibited lateral buds ofTradescantia paludosa, interphase nuclei in the apical zone of inhibition contain higher levels of arginine per unit DNA than those of mitotically active cells in interphase or prophase. Supplementary dye-binding experiments suggest that this reflects a corresponding difference between the composition of the histone complement of chromatin in the two cells populations. The possible implications of this phenomenon are discussed.

ISSN:0008-4026    

DOI:10.1139/b74-263

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Nuclear divisions in the hyphae and gametangia ofPhytophthora capsiciand in hyphae ofPhytophthora megaspermavar.sojaeresembled those of typical mitosis. The chromosomal configurations in prophase are similar to classical angiosperm prophase configurations. However, in metaphase the linear alignment of chromosomes resembled the pattern reported in pollen tubes ofLiliumandTradescantia. The relative size of nuclei and numbers of chromosomes per nucleus remained constant during gametangial development. Somatic and gametangial nuclei were about equal in size and chromosome number. Chromosome numbers in somatic and gametangial nuclei ofP. capsiciandP. megaspermavar.sojaewere about six and eight, respectively. There was no evidence of reduction division in gametangia.

ISSN:0008-4026    

DOI:10.1139/b74-264

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Didymella festucae(Weg.) Holm (imperfect statePhleospora idahoensisSprague), endemic on nativeFestucaspp. in western North America and reported from a few arctic–alpine regions in Europe, is the cause of a major destructive stem eyespot disease in seed crops of red fescue,Festuca rubraL., in the Peace River region of northern Alberta and British Columbia. The original description of the disease as a leaf and pedicel blight requires modification because eyespots, staining, and later extensive blackening of culms and inflorescences are the common symptoms. The size range of ascospores, 18–63 × 4.5–14.0 microns (μ), and conidia, 18–105 × 3.0–9.0 μ, considerably exceeded dimensions previously given forD. festucaefrom Europe andP. idahoensisfrom North America and Europe. Although the morphology of fungal structures was highly variable, dimensions of ascospores and conidia from the Swiss type material fell into the size range established for North American material. Swiss type material of the perfect stage also yielded typical conidia ofP. idahoensis. Microconidia are uncommon in natural material and cultures and their function is uncertain. Pathogenicity tests confirmed the wide natural-host range. Host immunity or physiologic specialization of the fungus is not indicated, but there is some evidence that isolates differ in degree of pathogenicity. For the present,P. idahoensisis suitably accommodated inPhleosporaandD. festucaeinDidymella, although both genera are ill-defined, requiring further study.

ISSN:0008-4026    

DOI:10.1139/b74-265

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Vegetative shoots initiate leaves and lateral branches continuously from mid-April until the end of September. No buds with bud scales are formed and the vegetative apex is enclosed by leaf primordia at various stages of development. Pollen cones are initiated on proximal vegetative shoots during a 3-week period from mid-June to early in July. Transition to a pollen-cone apex is marked by an increase in mitotic activity in the apex and by the formation of a lateral branch in the axil of one of the last-formed leaf primordia, causing the apex to appear to branch dichotomously. The lateral branch remains at the base of the pollen cone and may resume growth the next year after the pollen cone is shed. Pollen-cone development continues until the end of September. Meiosis occurs during the last 2 weeks of August, and pollen develops during September. Seed cones are initiated on newly formed, distal axillary vegetative shoots during a 3-week period from late June to mid-July. Transition to a seed-cone apex is marked by an increase in mitotic activity followed by bract-scale initiation. Usually three ovules are initiated in the axil of each bract scale. Seed-cone development is complete by early September and the seed cones become dormant. The pattern of reproduction in yellow cedar is compared to other conifers and the possible relationships are discussed between time of cone initiation, sexuality of cones, and day length.

ISSN:0008-4026    

DOI:10.1139/b74-266

出版商:NRC Research Press    

年代:1974

数据来源: NRC