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Endophytic fungi, especially asexual, systemic endophytes in grasses, are generally viewed as plant mutualists, mainly through the action of mycotoxins, such as alkaloids in infected grasses, which protect the host plant from herbivores. Most of the evidence for the defensive mutualism concept is derived from studies of agronomic grass cultivars, which may be atypical of many endophyte-host interactions. I argue that endophytes in native plants, even asexual, seed-borne ones, rarely act as defensive mutualists. In contrast to domesticated grasses where infection frequencies of highly toxic plants often approach 100%, natural grass populations are usually mosaics of uninfected and infected plants. The latter, however, usually vary enormously in alkaloid levels, from none to levels that may affect herbivores. This variation may result from diverse endophyte and host genotypic combinations that are maintained by changing selective pressures, such as competition, herbivory and abiotic factors. Other processes, such as spatial structuring of host populations and endophytes that act as reproductive parasites of their hosts, may maintain infection levels of seed-borne endophytes in natural populations, without the endophyte acting as a mutualist.

This book abounds with high-definition, informative photos, accurately demonstrating the taxonomical characteristics of bamboo's organs, particularly those of culm sheaths. Photos are supplemented with descriptions and a dozen hand-drawn, colored diagrams.

There has been a rapidly increasing recent interest in the effects of biological diversity on ecosystem properties, and while some studies have recently concluded that biodiversity improves ecosystem function, these views are based almost entirely on experiments in which species richness of live plants has been varied over all the species diversity treatments. However, most net ecosystem primary productivity eventually enters the decomposition subsystem as plant litter where it has important \"afterlife effects\". We conducted a field experiment in which litter from 32 plant species (i.e. eight species of each of four plant \"functional groups\" with contrasting litter quality) was collected and placed into litter-bags so that each litter-bag contained between one and eight species; the species which were included in the multiple (≥2) species litter-bags were randomly selected. This litter diversity gradient was created within each functional group and across some functional groups. We found large non-additive effects of mixing litter from different species on litter decomposition rates, litter nitrogen contents, rates of nitrogen release from litter and the active microbial biomass present on the litter. The patterns and directions of these non-additive effects were dependent upon both plant functional group and time of harvest, and these effects could be predicted in some instances by the initial litter nitrogen content and the degree of variability of nitrogen content of the component species in the litter-bag. There was no relationship between litter-bag species richness and any of the response variables that we considered, at least between two and eight species. Within plant functional groups our results provide some support for the species redundancy and idiosyncratic hypotheses about how biodiversity alters ecosystem function, but no support for the ecosystem rivet hypothesis or the view that species richness of plant litter is important for ecosystem function. We suggest that increased species diversity of plant litter is less important than that of live plants for determining ecosystem properties (and provide possible reasons for this) and conclude that perceived relationships between biodiversity and ecosystem function may be of diminished significance when the ecological importance of plant litter is fully appreciated.

This work reviews the historical and current pest risks and research concerning seed storage in the Czech Republic (CR). Stored seed pests (i.e. animals causing injuries to the germ and endosperm) represent a high risk of economic damage due to the high value of seeds coupled with long-term seed storage in small storage units (e.g., boxes, satchels). Rodents represent a significant risk to all types of seeds, especially seeds stored in piles or bags. Mites, psocids, and moths are the main pests of stored grass and vegetable seeds: mites can decrease seed germinability by 52% and psocids caused 9.7% seed weight loss in broken wheat kernels after 3 months of infestation under laboratory conditions. Although beetles (Sitophilus sp., Tribolium sp., Oryzaephilus sp.) and moths (Plodia sp.) are common pests of grain seeds (e.g., wheat, barley, maize), two serious seed pests, Sitotroga cereallela and S. zemays, are rare in the CR. Bruchus pisorum is a common pest of pea seeds, while other Bruchids are rare in the Czech legume seed stores. Currently, the control of seed pests is becoming difficult because the efficient pesticides (e.g., methylbromide, dichlorvos, drinking anticoagulant rodent baits) for seed protection have been lost without the development of adequate substitutes. New research on seed protection in the CR using biological control (mite predators Cheyletus sp.), low pressure, modified atmospheres, and hydrogen cyanide is overviewed.

Perhaps the most contentious issues discussed at a recent Keystone Symposium (\"The Evolution of Plant Development\"; held in Taos, NM, in January 1997) were the origin and significance of variations in plant genome size. During these discussions, it became clear that most (perhaps all) of the participants had not grasped many of the central observations that should inform any debate of genome size variation, partly due to the diversity of disciplines (i.e., evolutionary biology, genetics, genomics, and population biology) that contribute to these essential points. Hence, we felt that a short presentation on this subject would be of value to the plant science community.

Carbon-isotope values of bulk organic matter from high-altitude lakes on Mount Kenya and Mount Elgon, East Africa, were 10 to 14 per mil higher during glacial times than they are today. Compound-specific isotope analyses of leaf waxes and algal biomarkers show that organisms possessing CO2-concentrating mechanisms, including C4 grasses and freshwater algae, were primarily responsible for this large increase. Carbon limitation due to lower ambient CO2 partial pressures had a significant impact on the distribution of forest on the tropical mountains, in addition to climate. Hence, tree line elevation should not be used to infer palaeotemperatures

The grass family includes some 10,000 species, and it encompasses tremendous morphological, physiological, ecological, and genetic diversity. The phylogeny of the family is becoming increasingly well understood. There were two major radiations of grasses, an early diversification leading to the subfamilies Pooideae, Bambusoideae, and Oryzoideae, and a later one leading to Panicoideae, Chloridoideae, Centothecoideae, and Arundinoideae. The phylogeny can be used to determine the direction of changes in genome arrangement and genome size