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51.
N. Richard Knowles W. M. Iritani L. D. Weller 《American Journal of Potato Research》1985,62(6):289-300
Plant growth from Russet Burbank seed-tubers of different ages was compared as affected by source of meristematic tissue (apical or basal) and NAA treatment. In controlled environment studies, single-eye seedcores from 17-mo-old seed-tubers produced twice as many shoots compared to those from 5-and 29-mo-old seed-tubers. Seed-tuber age and shoot dry weight/core were inversely related. Dry weight/shoot decreased as age increased to 17 mo and then remained unchanged from 17 to 29 mo. Apical meristems lost growth potential faster than basal meristems as age advanced. Meristem physiological age apparently depends on relative position of the buds as well as on the chronological age of the seed-tuber. NAA (10–40 mg/l) decreased the number of shoots/core, had no effect on shoot dry weight/core but increased the dry weight/shoot when applied to seedcores from 20-mo-old seed-tubers. On seedcores from 8-mo-old seed-tubers. NAA decreased the shoot dry weight (g/core, g/shoot). In field studies, NAA (100 mg/l) increased the total tuber yield of plants grown from seedpieces cut from 8-and 20-mo-old seed-tubers. These increases were manifested in age-specific effects on tuber grade. The effects of seedtuber age on plant growth and tuber yield were partially overcome by seedpiece treatment with NAA. 相似文献
52.
Toby G Knowles Steve N Brown Paul D Warriss Jeff Lines Ambrose Tinarwo Marta Sendon 《Aquaculture Research》2008,39(16):1731-1738
Food quality aspects of farmed turbot (Psetta maxima) were compared following two methods of slaughter: the current commercial method, by immersion in an ice slurry, which is then dewatered after approximately 20 min, or by first humanely, electrically stunning the fish using a prototype commercial stunner, before immersion in an ice slurry, which is dewatered after 20 min. Quality was assessed for up to 10 days of storage on ice following slaughter. No differences were found between the slaughter methods in terms of an overall carcass quality: overall appearance, haemorrhage, damage, burst gall bladder, staining of the body cavity by leakage from the gut or damage to the spine. No detectable difference was found between the treatments using the industry standard freshness scoring system, the Quality Index Method. Both groups of fish were classified as ‘Fresh’ after 10 days of storage on ice. Using objective measurements of colour, no differences between fish from either treatment were found in fillet colour. Changes in flesh pH were similar in electrically stunned and traditionally killed fish with a mean pH (±SE) at 2 h post‐mortem of 6.80±0.027 declining to 6.44±0.032 at 24 h post‐mortem. Humane electrical stunning of turbot at slaughter neither detectably improved nor decreased product quality as measured between 1 and 10 days of storage on ice. 相似文献
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Reduction of N2O in moist soil was inhibited completely by 10?2 atm C2H2 and partially by 10?5 atm C2H2. The effect of C2H4 was 104 times less than that of C2H2. Denitrification of NO?3 occurred in anaerobically or aerobically incubated waterlogged soil and in anaerobic but not in aerobic moist soil. In the absence of C2H2 there was transient accumulation of N2O. In the presence of C2H2 there was stoichiometric conversion of NO?3 to N2O. Some kinetics of the reduction of N2O and of NO?3 to N2O are presented. Denitrification of 1 μg added NO?3-N.g? could be measured within 1 h. Stoichiometries of production of N2O from NO?2 and NO?3, respectively, and production of CO2 attributable to denitrification were consistent with reported energy yields. Reduction of C2H2 to C2H4 occurred immediately following complete denitrification of added NO?3. The incubation of soil in the presence and in the absence of C2H2 thus permits assay of both denitrification and N2 fixation and provides information on the mole fraction of N2O in the products of denitrification. 相似文献
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Sandy loam soil was amended with different concentrations of glucose and was incubated at different pO2 levels. Under many conditions of incubation time and treatment, N2 ase activity as determined by 1-h aerobic C2H2 reduction assay (flushed with Ar:O2, 4:1 before assay) was significantly less than that determined by means of ambient assay (carried out at the pO2 of incubation without flushing with Ar:O2, 4:1 before assay). The difference between the N2ase activity in aerobic assay and that in ambient assay increased with decreasing glucose and O2 concentrations imposed during incubation. The inhition in aerobic assays was analogous to O2-induced shut-off of N2ase and amounted to 75 per cent inhibition after incubation at 0.06 atm pO2 of samples amended with 0.75% glucose (w/w). Similar O2 inhibition was observed after amendment with mannitol and with lactate. Times of incubation were chosen such that development of anaerobic N2ase activity was either absent or too low to account for the observed effects of O2 during assay. It was shown that 0.05 atm pC2H2 was adequate for routine 1-h assays of the soil system employed. Individual soil samples could be subjected to repeated 1-h assays (with removal of C2H2 and C2H4 by evacuation after each assay) thus avoiding side-effects of long exposure to C2H2. 相似文献
56.
Pigs could be moved along a race 120 cm wide more quickly than along a race 45 cm wide. The presence of a bend with an angle of 45 degrees slowed their progress by about 10 per cent, a bend of 90 degrees or 120 degrees slowed them by 19 per cent and a 180 degrees bend slowed them by 44 per cent. There was little evidence of any interaction between the effects of width and angle of bend; the effect of a sharp bend could not be compensated for by increased width. The pigs became accustomed to the races and moved more quickly in later runs. 相似文献
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A method for measuring the prevalence of leg weakness by assessing the walking ability of broilers was developed. Walking ability was divided into six categories, from completely normal to immobile. The method was found to give consistent results when performed by the same people. In a survey of commercial, intensively reared broilers, 90 per cent had a detectable gait abnormality and 26 per cent suffered an abnormality of sufficient severity for their welfare to be considered compromised. The prevalence of leg weakness in free range broilers, and three commercial breeds of broilers was determined. The results indicated that genetic factors were an important cause of leg weakness in broilers and also identified a possible relationship between liveweight and leg weakness. 相似文献
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