Cotton Seedling Preemergence Damping-Off Incited by Rhizopus oryzae and Pythium spp. and Its Biological Control with Trichoderma spp

ABSTRACT Planting the cotton cv. Sure-Grow 747 in cotton seedling disease plots during the 2001 growing season resulted in high levels of preemergence damping-off among the seedlings. Four cotton pathogens, Pythium aphanidermatum, P. ultimum, an unidentified Pythium sp., and Rhizopus oryzae, were isolated from diseased seed embryos and seedlings. Disease incited by the Pythium spp. could be controlled by seed treatment with Metalaxyl, but disease incited by R. oryzae could not. Seed treatment with Metalaxyl in naturally infested field soil was only partially effective; therefore, symptoms in 47% of the diseased seedlings could be attributed to R. oryzae. Susceptibility to disease appeared to be related to release in the spermosphere, by the germinating seeds, of compounds that stimulate pathogen propagule germination, because exudates from seed of the suscept Sure-Grow 747 and extracts from wheat bran induced pathogen germination and growth, whereas exudates from resistant cv. Stoneville 213 did not. However, even Stoneville 213 became susceptible when infested soil was amended with wheat bran. Seed treatment with preparations of Trichoderma virens parent, mutant, and hybrid strains gave effective biological control of preemergence damping-off. Disease control was attributable to metabolism by the biocontrol agent of pathogen germination stimulants released by the seed, because amendment of pathogen-infested soil with the propagule germination stimulants in wheat bran negated the protective effect of the seed treatment.     

Short-term biological variation of clinical chemical values in Dumeril's monitors (Varanus dumerili).

Plasma biochemical values are routinely used in the medical management of ill reptiles, and for monitoring the health of clinically normal animals. Laboratory tests, including clinical biochemical values, are subject to biological and analytical variation, the magnitude of which determines the utility of population-based reference ranges for the detection of abnormal results in the individual animal. Nested analysis of variance of repeated measurements allows the variance to be broken into within-individual, between-individual, and analytical variation. When the within-individual variation is large and the interindividual variation is low, a sample may be accurately classified as normal or abnormal based on a population-based reference interval. However, if the intraindividual variation is low and the interindividual variation high, population-based reference intervals are of limited value as the ranges for an individual encompass only a part of the conventional reference interval. Between-lizard, within-lizard, and analytical components of variance were assessed by nested analysis of variance for 16 commonly measured plasma biochemical parameters in eight healthy adult Dumeril's monitors (Varanus dumerili). Albumin, cholesterol, phosphate, calcium, sodium, and total protein demonstrated levels of individuality suggesting that comparison of a single measurement to a conventional population-based reference range may be too insensitive to detect small but significant alterations in the value for that animal. Only for potassium and AST did the index of individuality suggest that the use of reference values may be warranted. Uric acid, globulin, glucose, and amylase fell in a gray zone, where population-based ranges should be used with caution. The critical difference indicates the difference between two consecutive analytical results that may be safely ascribed to natural variation. In the present study critical difference varied from 7 and 11%, respectively, for sodium and chloride to 75 and 125% for uric acid and AST.     

Changes in Plasma Cortisol, Glucose, and Selected Blood Properties in the Summer Flounder Paralichthys dentatus Associated with Sequential Movement to Three Experimental Conditions

To determine the changes in blood chemistry associated with sequential transfer of summer flounder Paralichthys dentatus (320–480 g), 300 hatchery-reared fish were moved to three different environmental conditions during a 20-d period. Fish were transferred in progression from a recirculating seawater system (22 ppt, 22.5 C) to a flow-thru seawater system (31 ppt, 20.0 C), to three small coastal net pens (33 ppt, 15.5 C), and finally to a large open ocean net pen (33 ppt, 16.0 C). For this study, eight random fish were captured at each progressive step (environmental condition), anesthetized (MS222), and bled from the caudal vein (2 mL). Transferred flounder were bled every 12 h for 48 h to collect plasma cortisol and glucose samples. Fish were bled 24 h after transport and every 3 d thereafter for osmolarity, hematocrit, hemoglobin concentration, mean corpuscular hemoglobin content, glucose, cortisol, and the electrolytes Cl^- Na⁺, K⁺ and Ca⁺. The most significant perturbations to blood chemistry (P < 0.05) occurred within 24 h of initial transfer from the recirculating to flow-thru seawater systems, suggesting an osmoregulatory rather than handling or transfer related stress. Osmolarity, electrolyte, and hematological parameters fluctuated and then recovered to stable levels by day 8 in the flow-thru seawater system. However, unlike the initial transfer, successive movement to the coastal and then the open ocean net pens produced transient increases in both plasma cortisol and glucose levels, suggesting a high level of stress associated with extended flounder handling and transfer.     

Factors influencing the survival and growth of turbot larvae, Scophthalmus maximus L., during the change from live to compound feeds

In a series of 14 trials the survival of turbot larvae during transfer from a live to an inert food ranged from 45% to 95%. The time taken for up to 50% of each batch to establish feeding was also highly variable, ranging from 1 to 11 days. The potential to accept inert food was probably established during the initial stages of weaning or even earlier. Final survival could reliably be predicted from survival and feeding response during the first few days of weaning. Evidence was presented which suggests that the quality of the live food (Artemia salina L.) influenced the subsequent acceptance of an inert diet. For example, larvae reared on San Francisco Bay nauplii accepted an artificial diet less readily than those reared on Artemia which had first been fed on the unicellular alga Isochrysis for 2 days. Dietary water content was not an important factor governing weaning success.     

Use of advanced recombinant lines to study the impact and potential of mutations affecting starch synthesis in barley

The effects on barley starch and grain properties of four starch synthesis mutations were studied during the introgression of the mutations from diverse backgrounds into an elite variety. The lys5f (ADPglucose transporter), wax (granule-bound starch synthase), isa1 (debranching enzyme isoamylase 1) and sex6 (starch synthase IIa) mutations were introgressed into NFC Tipple to give mutant and wild-type BC₂F₄ families with different genomic contributions of the donor parent. Comparison of starch and grain properties between the donor parents, the BC₂F₄ families and NFC Tipple allowed the effects of the mutations to be distinguished from genetic background effects. The wax and sex6 mutations had marked effects on starch properties regardless of genetic background. The sex6 mutation conditioned low grain weight and starch content, but the wax mutation did not. The lys5 mutation conditioned low grain weight and starch content, but exceptionally high β-glucan contents. The isa1 mutation promotes synthesis of soluble α-glucan (phytoglycogen). Its introgression into NFC Tipple increased grain weight and total α-glucan content relative to the donor parent, but reduced the ratio of phytoglycogen to starch. This study shows that introgression of mutations into a common, commercial background provides new insights that could not be gained from the donor parent.     

UK deep‐sea conservation: Progress,lessons learned,and actions for the future

1. Despite a relatively long history of scientific interest fuelled by exploratory research cruises, the UK deep sea has only recently emerged as the subject of targeted and proactive conservation. Enabling legislation over the past 10 years has resulted in the designation of marine protected areas and the implementation of fisheries management areas as spatial conservation tools. This paper reflects on progress and lessons learned, recommending actions for the future.
2. Increased investment has been made to improve the evidence base for deep‐sea conservation, including collaborative research surveys and use of emerging technologies. New open data portals and developments in marine habitat classification systems have been two notable steps to furthering understanding of deep‐sea biodiversity and ecosystem functioning in support of conservation action.
3. There are still extensive gaps in fundamental knowledge of deep‐sea ecosystems and of cause and effect. Costs of new technologies and a limited ability to share data in a timely and efficient manner across sectors are barriers to furthering understanding. In addition, whilst the concepts of natural capital and ecosystem services are considered a useful tool to support the achievement of conservation goals, practical application is challenging.
4. Continued collaborative research efforts and engagement with industry to share knowledge and resources could offer cost‐effective solutions to some of these barriers. Further elaboration of the concepts of natural capital and ecosystem services will aid understanding of the costs and benefits associated with human–environment interactions and support informed decision‐making in conserving the deep sea.
5. Whilst multiple challenges arise for deep‐sea conservation, it is critical to continue ongoing conservation efforts, including exploration and collaboration, and to adopt new conservation strategies that are implemented in a systematic and holistic way and to ensure that these are adaptive to growing economic interest in this marine area.