Anatomy of the Dicotyledons.
About: This article is published in American Midland Naturalist.The article was published on 1950-11-01. It has received 2511 citations till now.
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01 Jan 1999
TL;DR: Twenty years ago, Brian Gunning began his analysis of the role of plasmodesmata in short-distance transport of assimilates to the phloem by stating that the “relevant evidence is both meagre and circumstantial” for a comprehensive discussion of the subject.
Abstract: Twenty years ago, Brian Gunning began his analysis of the role of plasmodesmata in short-distance transport of assimilates to the phloem (Gunning1976) by stating that the “relevant evidence is both meagre and circumstantial” for a comprehensive discussion of the subject. At that time there were very few quantitative analyses of plasmodesmata along the assimilate pathway from the mesophyll to the phloem (Geiger et al.1973; Gunning et al.1974; Kuo et al.1974). There was also considerable controversy regarding the probable pathway(s) and mechanism(s) of phloem loading. Today, there is an extensive body of information on everything from plasmodesmal frequency and distribution in dicot and monocot species to detailed aspects of various phloem-loading models (Riesmeier et al.1993,1994; Sauer and Stolz1994; Grusak et al.1996; Rentsch and Frommer1996; Kiihn et al.1997). We also know much more about the fundamentals of plasmodesmal structure (Ding et al.1992b; Lucas et al.1993a) and the development and possible function of secondary plasmodesmata (Monzer1990,1991; Kollmann and Glockmann1991; Ding and Lucas1996; Ehlers and Kollmann1996; Ehlers et al.1996; Volk et al.1996). Analysis of alteration in carbon allocation and biomass partitioning in transgenic tobacco plants expressing native and mutated forms of the tobacco mosaic virus movement protein has led to the proposal that plasmodesmata in a leaf form a special communication network between the mesophyll and the phloem (Lucas et al.1996).
22 citations
22 citations
TL;DR: Fossil twigs from the Lower Eocene, London Clay Formation of south-east England are described here for the first time and placed in the organ genus Vitaceoxylon Wheeler and LaPasha and Menispermoxylon Vozenin-Serra, Prive-Gill & Ginsburg, with which, respectively, they have the greatest similarity.
22 citations
TL;DR: A new genus and species of fossil wood with Leguminosae (Mimosoideae) affinities from the Late Miocene Chiquimil Formation in Catamarca Province, Argentina, shows that Prosopis was an important element of Miocene floras of northwestern Argentina and would explain its high extant diversity.
22 citations
TL;DR: It is demonstrated that leaf anatomy can provide evidence to assist with the taxonomy of Salicaceae, at family, generic, and specific levels.
Abstract: The taxonomy of neotropical Salicaceae, a family that now includes the majority of the former Flacourtiaceae, has been problematic, especially because they display very diverse morphology and have several characteristics in common with many other families. Recent phylogenetic studies have proposed substantial changes at both family and generic levels. Considering the importance of anatomy as an aid for taxonomy, the gathering of anatomical data for the family is fundamental to help clarify the taxonomic problems. Leaves belonging to Abatia americana (four samples), Banara brasiliensis (2), Casearia arborea (4), C. decandra (5), C. gossypiosperma (2), C. obliqua (1), C. sylvestris (3), C. ulmifolia (3), Prockia crucis (3), and Xylosma prockia (4) and the closely related Carpotroche brasiliensis (3) from Achariaceae, were studied by standard microscopy techniques. The leaves were anatomically described, emphasizing their differences and similarities. Similar characters for the neotropical Salicaceae (former Flacourtiaceae) and Salicaceae strictu sensu were recognized, such as the presence of salicoid leaf teeth, brachyparacytic stomata, secondary growth of the petiole, abundance of crystals, collateral and arch-shaped vascular system at the midrib, and sclerenchyma accompanying the bundles. These data demonstrate that leaf anatomy can provide evidence to assist with the taxonomy of Salicaceae, at family, generic, and specific levels.
22 citations