You're so vein: bundle sheath physiology,phylogeny and evolution in C3 and C4 plants

Bundle sheath (BS) anatomy is found in most C4 lineages, associated with low inter‐veinal distances (IVD) and high BS:mesophyll ratio (BS:MC). The origins, function and selective advantages of the BS in C3 lineages are relevant for understanding the environmental, molecular and phylogenetic determinants of C4 evolution. Suggested functions for BS have included structural support, hydraulic isolation, storage for water, ions, and carbohydrates, and photorespiratory carbon metabolism; we propose a central role for cavitation repair, consistent with the BS as a control centre on regulating stem and leaf hydraulic continuity. An analysis of BS traits in the phylogenetic lineages giving rise to C4 grasses (the ‘PACMAD’ clade) shows an initial enhancement in BS:MC ratio in C3 lineages, although IVD is similar to the Pooideae sister group. Using a global database, a well‐developed BS in the C3 PACMAD lineages was associated with higher precipitation and temperatures in the habitat of origin on an annual basis, with the C3 to C4 progression defined by the aridity index (AI). Maintaining leaf hydraulic conductance and cavitation repair are consistent with increased evaporative demand and more seasonal precipitation as drivers, first for the C3 BS, and then C4 diversification, under declining CO₂ concentrations in the Palaeogene and Neogene.     

A new genus of mantidflies discovered in the Oriental region,with a higher‐level phylogeny of Mantispidae (Neuroptera) using DNA sequences and morphology

A remarkable new genus and two new species of Mantispidae (Neuroptera) are described from the Oriental region. Allomantispa Liu, Wu, Winterton & Ohl gen.n. , currently including A. tibetana Liu, Wu & Winterton sp.n. and A. mirimaculata Liu & Ohl sp.n. The new genus is placed in the subfamily Drepanicinae based on a series of morphological characteristics and on the results of total evidence phylogenetic analyses. Bayesian and Parsimony analyses were undertaken using three gene loci (CAD, 16S rDNA and COI) combined with 74 morphological characters from living and fossil exemplars of Mantispidae (17 genera), Rhachiberothidae (two genera) and Berothidae (five genera), with outgroup taxa from Dilaridae and Osmylidae. The resultant phylogeny presented here recovered a monophyletic Mantispidae with ?Mesomantispinae sister to the rest of the family. Relationships among Mantispidae, Rhachiberothidae and Berothidae support Rhachiberothidae as a separate family sister to Mantispidae. Within Mantispidae, Drepanicinae are a monophyletic clade sister to Calomantispinae and Mantispinae. In a combined analysis, Allomantispa gen.n. was recovered in a clade comprising Ditaxis McLachlan from Australia, and two fossil genera from the Palaearctic, ?Promantispa Panfilov (Kazakhstan; late Jurassic) and ?Liassochrysa Ansorge & Schlüter (Germany; Jurassic), suggesting a highly disjunct and relictual distribution for the family. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:464B06E8‐47E6‐482E‐8136‐83FE3B2E9D6B .     

WIREWORM POPULATIONS IN RELATION TO CROP PRODUCTION: III. POPULATION CHANGES AFTER SUMMER PLOUGHING

Six permanent pastures broken up in the summer of 1943 were sampled once a fortnight after ploughing in order to study changes in the wireworm populations.
The graphs of the running means of four consecutive counts showed the chief trends in population. On four of the fields, a slight increase in population was apparent up to December. Only in February and March was a definite decline apparent. On the other two fields, the counts declined by about 30 % during the autumn and winter.
A marked fall in population (from 30 to 70%) was evident on all the fields only after the first crop had been harvested. The new population at this time was characterized by an absence of larvae less than 4 mm. in length.
The results considered alone indicate that after summer ploughing the wireworm population remains unaffected until the following spring and summer during the cropping period. When the results are considered in relation to the grass 'controls', it appears that a net decline in population occurs during the autumn and winter and that the decline in spring and summer is not more marked than that which normally occurs at this time in grass fields. Unlike the grass fields, however, the reduction is permanent.     

THE FIBROBLAST AND WOUND REPAIR

This review of connective tissue repair has attempted to place into historical perspective information obtained by newer approaches. The literature review is incomplete, as it was unfortunately necessary to leave many interesting studies out of the discussion. Emphasis has been placed upon what is known of the inflammatory response, the fine structure of the connective tissue cells in healing wounds and with correlated chemical findings in these tissues. An optimal inflammatory response appears to be an important, rapid, non-specific stimulus for fibroplasia. It is not clear how inflammation exerts this effect. The inflammatory cells and their enzymes markedly alter the extracellular matrix of injured tissue. The matrix of connective tissue may itself participate in the control of its own synthesis and degradation. It is possible that modification of this environment by injury and/or inflammation with ensuing matrix alteration may provide a stimulus for cell migration and protein synthesis. The converse may also be true, that is, a given level of matrix concentration may have an inhibitory effect upon the connective tissue cells. The inter-relationships between the connective tissue matrix and the cells, and the possibilities of feedback mechanisms playing a role in maintaining a balance between these two are important areas for future investigation. In this regard, additional questions may be asked concerning the role of the fibroblast in remodelling and degradation of connective tissue. It is not yet clear how important a balance between collagenolytic enzymes and the solubility states, or stability, of collagen are in each connective tissue. It will be interesting to determine which cells make collagenolytic and/or proteolytic enzymes upon appropriate stimulus. It is possible to distinguish between the fibroblast and the monocyte, or potential macrophage with the electron microscope. The rough endoplasmic reticulum with its large numbers of attached ribosomes is extensively developed in the fibroblast in contrast to the monocyte. The endoplasmic reticulum sequesters collagen precursors and other secretory proteins for transport either directly to the extracellular space, as appears to be the case for collagen, or to the Golgi complex as is the case for other exportable proteins. Collagen precursors are secreted into the environment and are not shed from within the cell surface. A number of cytoplasmic alterations have been described for fibroblasts and other cells during various pathological states. The significance of these alterations is not clear. It will be important to distinguish between specific and non-specific responses to injury, if these alterations are to aid us in understanding the various cellular responses. The source of the fibroblasts in granulation tissue appears to be mesenchymal cells from adjacent tissues rather than blood-borne precursors. Although contact inhibition can be demonstrated in vitro, it is not clear how important this phenomenon is in vivo, nor are the reasons for the ability of some tissues to heal by regeneration rather than by scar tissue formation understood. These and many other questions remain to be answered. The healing wound is multifaceted and presents the opportunity for systematic investigation into the problems of cell proliferation, cell and matrix interactions, and protein synthesis in vivo and it also can help to further our understanding of the ubiquitous fibroblast and its complex extracellular matrix.     

Winter Avian Community and Sparrow Response to Field Border Width

Abstract: Transformations of agricultural practices in the southeastern United States have drastically reduced preexisting quantities of strip-cover habitat along field margins. The National Conservation Buffer Initiative has promoted the establishment of herbaceous field borders to restore wildlife benefits once provided by such habitat. We evaluated effects of native warm-season grass field border establishment and width on winter bird response. Narrow (approx. 8-m) field borders represented a marginal improvement to non-bordered margins that were cropped ditch to ditch, whereas wide (approx. 30-m) borders significantly enhanced total avian conservation value, abundance, species richness, and sparrow abundance compared to non- or narrow borders. Furthermore, presence of wide borders altered bird use of row-crop fields. We observed increased sparrow (Emberizidae) abundances in agricultural fields adjacent to wide borders, which likely resulted from enhanced waste grain foraging opportunities. Given these benefits to wintering farmland birds, we advocate the integration of herbaceous field border habitat in agricultural landscapes, particularly borders of enhanced width.