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71.
The epidermis of leaves of Degeneria vitiensis is described by reference to cuticular morphologies. Paracytic stomata and enlarged stomata are recorded and the detailed structure of the former is described. A variety of other epidermal structures characterized by radially exerted influences upon the general epidermal pavement is also described. On the basis of comparisons with published accounts of the epidermis of other 'ranaleans' the original separation of Degeneria from the Magnoliaceae is supported. Degeneria is considered to have a closer epidermal affinity with some members of the Illiciales than with members of the Magnoliales to which the Degeneriaceae is currently assigned.  相似文献   
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The incidence of Salmonella typhimurium in imported bone meal may be underestimated by conventional isolation techniques because of the presence of other salmonella serotypes. A method was developed with a serological bias towards recovery of serotypes with 'i'as H phase 1 antigen. By this technique, 44 strains of S. typhimurium were isolated from Argentinian bone meal compared with nine strains cultured by the unbiased method. The technique was less successful with Lebanese bone. The serological technique was most effective when several salmonella serotypes not possessing the 'i'antigen were present in a sample. S. kentucky (8, 20:i:z6), like S. typhimurium was also efficiently isolated by the serological method. In 12 specimens both S. typhimurium and S. kentucky were present. The two serotypes were easily separated by examining four 25 g sub-samples of the specimen.  相似文献   
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Displacement of native plant species by non‐indigenous congeners may affect associated faunal assemblages. In endangered salt marshes of south‐east Australia, the non‐indigenous rush Juncus acutus is currently displacing the native rush Juncus kraussii, which is a dominant habitat‐forming species along the upper border of coastal salt marshes. We sampled insect assemblages on multiple plants of these congeneric rushes in coastal salt marshes in Sydney, New South Wales, Australia, and compared the abundance, richness, diversity, composition and trophic structure between: (i) J. acutus and J. kraussii at invaded locations; and (ii) J. kraussii at locations either invaded or not invaded by J. acutus. Although J. acutus supported a diverse suite of insects, species richness and diversity were significantly greater on the native J. kraussii. Moreover, insect assemblages associated with J. kraussii at sites invaded by J. acutus were significantly different from, and more variable than, those on J. kraussii at non‐invaded sites. The trophic structure of the insect assemblages was also different, including the abundance and richness of predators and herbivores, suggesting that J. acutus may be altering consumer interactions, and may be spreading in part because of a reduction in herbivory. This strongly suggests that J. acutus is not playing a functionally similar role to J. kraussii with respect to the plant‐associated insect species assemblages. Consequently, at sites where this non‐indigenous species successfully displaces the native congener, this may have important ecological consequences for community composition and functioning of these endangered coastal salt marshes.  相似文献   
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Four methods of spray application were compared in 1986 with the recommended method of glyphosate application for pre-harvest retting of flax (Linum usitatissimum). Sampling individual plants immediately after application of glyphosate and dye demonstrated that spray penetration through the crop canopy, measured as dye deposition on the lower stem as a percentage of total deposition per plant, was the same for all methods of application. None of the methods of application improved the uniformity of dye deposition.
The following year, effects of deseeding prior to spraying and of using an air-assisted sprayer were investigated. Deseeding increased dye deposition on the lower stem but did not improve the efficacy of glyphosate. Application with an air-assisted sprayer increased the proportion of spray deposited on the lower stem but not the absolute amount deposited or the efficacy of glyphosate. Dye deposition on individual plants varied greatly for all methods of application and, when glyphosate was applied using the same methods, undesiccated plants occurred in all plots.
Considerable improvements in spray penetration and uniformity of spray deposition appear necessary for successful pre-harvest retting of flax with glyphosate.  相似文献   
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Abstract.  The stag beetle, Lucanus cervus , is Britain's largest beetle, with a patchy distribution in southern England. The literature suggests that it displays exceptional size variation, particularly in the males, but no analysis of size inequality has ever been conducted. In the present study, stag beetle adults are measured and allometric relationships derived between various parameters and total body length. Most of the specimens found each year are fragments and head width can be used as a good predictor of total body length in each sex. Body size differs between years and between localities and male beetles show a greater degree of size inequality than females. However, L. cervus does not show greater inequality in size than many other beetle species and populations of males are composed of a relatively large number of small individuals. These males are not at a disadvantage in mating because it is the ratio of male : female size that determines mating success. Very large males are less successful in mating and it is suggested that lack of mating success may act as an additional constraint on mandible size in this species. Size variation is most likely caused by variation in larval food resources, coupled with variation in local climatic conditions.  相似文献   
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