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Types and frequencies of pathologies were investigated in Crassostrea rhizophorae before and following heavy oyster mortality in Todos OS Santos Bay, Bahia, Brazil. The sporozoan Nematopsis sp. was the only parasite present in sufficient numbers to be an important mortality factor, but the intensity of Nematopsis infections remained low until after the major die-off. Pathologies such as ceroidosis, reduction or loss of stored glycogen, decreased gametogenesis, edema, and metaplasia of the digestive diverticula were consistent with the hypothesis of an external environmental stress factor that may have caused feeding to cease, the resultant weakness contributing to high mortalities. 8, 1986 Academic Press. Inc.

Six grass species were established in 1968 in rows within a seeding of alfalfa (Medicago sativa L.) at Arlington, Wisconsin. The mixtures were harvested two, three, or four times annually at two stubble heights, 4 and 10 cm, during 1969 and 1970. Alfalfa was eliminated by spraying with a selective herbicide during autumn of 1970. Grasses were then evaluated for stand persistence and dry matter yields during the first growth of 1971.Orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.), and meadow foxtail (Alopecurus pratensis L.) persisted well with alfalfa under all cutting schedules and stubble heights. Tall rescue (Festuca arundinacea Schreb.) was nearly eliminated by cutting twice at the short stubble height, but persisted well in other treatments. Stands of timothy (Phleum pratense L.) and bromegrass (Bromus inermis Leyss.) were affected most by the cutting practices. Stands of both grasses were reduced more by three than four cuts annually and were significantly lower with both cutting schedules at the short than at tall stubble height; stands were nearly eliminated with three cuts at the short stubble height. With two cuts annually, cutting height had no significant effect on stand persistence, but timothy stands were poor at both stubble heights.Survival of the grasses as related to stage of development at time of cutting and to tillering pattern is discussed, especially with regard to their persistence with alfalfa under the three‐cutting schedule used widely in the northern Great Lakes States. Of the grasses studied, orchardgrass and reed canarygrass showed wide adaptability to all cutting practices used and were most amenable for use in mixture with alfalfa harvested three times annually.

Extraction of the stem base tissue of timothy, orchardgrass, and redtop at near seed maturity with concentrations of ethanol from 95 to 0% yielded steadily increasing percentages of carbohydrates, indicating a series of fructosans of increasing chain length. Reed canarygrass and Kentucky bluegrass tissue also yielded increasing percentages, but not continuously so. Fructosans in all of the above species were predominantly of long‐chain length. Bromegrass,t all rescue, ryegrass, and quackgrass tissue yielded no additional carbohydrate at low ethanol concentrations, indicating that the fructosans present were relatively short‐chain polymers.Concentration of the ethanol must be considered in separating free sugars from low molecular weight fructosans, or otherwise some of the fructosans may De extracted along with the sugars. Thin layer chromatography showed that 85% ethanol was the most suitable concentration with which to extract the free sugars from the fructosans in those species containing predominantly long‐chain fructosans. With the species containing predominantly short‐chain fructosans, 90% ethanol was most suitable. More dilute ethanol solutions extracted short‐chain fructose polymers along with the glucose, fructose, and sucrose.Glucose, fructose, and sucrose constituted only a small part of the total water‐soluble carbohydrates in all of the grass species. Fructosans were the predominant carbohydrates.

No one method of drying can be relied upon for all plant species, plant parts, or form (e.g., fresh v. ensiled herbage). Least changes in nonstnictm'al carbohydrates appear to occur when fresh tissue is immersed in boiling alcohol. Freeze-drying provides results more similar to fresh tissue than beat-drying. Heat-drying at high temperatures (above 80°C) can cause thermo-cbemical degradation, wbile slow drying at low temperatures (below 50°C) allows time for DM losses by respiration and enzymatic conversions. Tbe most acceptable beat-drying results bave been obtained by drying for a sbort time at a bigb temperature (i.e. 100°C) and tbereafter at a moderate temperature (i.e. 70°C).Changes in nonstructural carbohydrate concentrations occur during the storage of either freeze-or heat-dried tissues. Thus, analyses should be conducted as soon as possible after tissue sampling. Tbe least cbanges occur during storage in alcohol, following killing of the tissue in boiling alcohol.

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Several perennial grass species commonly found or used in Canada and in the northern areas of the USA were studied. Most of the native species accumulated starch as the principal vegetative storage polysaccharide, indicating their possible tropical origin. All of the temperate‐origin introduced species accumulated fructosans. Species in the Hordeae, Aveneae, and Festuceae tribes, whether native or introduced accumulated fructosans. Species in the Hordeae tribe accumulated only short‐chain fructosans; species in the Aveneae tribe accumulated a series of fructosans predominantly of long‐chain lengths, while both types of fructosan accumulators occurred in the Festuceae tribe.