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991.
An investigation was made to determine possible effects of gypsum and sulfur for control of common scab of potato [Streptomyces scabies (Thaxt.) Waksman and Henrici] in a highly buffered calcareous soil. This investigation included a comparison of the effectiveness of gypsum and sulfur with Terraclor and Terraclor Super-X. Both gypsum and sulfur reduced potato scab and measurements indicate that change of soil pH was slight (0.1–0.4 pH reduction). Band applications of sulfur in the sulfate (gypsum) or elemental form were effective at 600 lbs/A (672.5 Kg/ha) but not at lower rates. The weight of tubers thrown out of grade with scab was reduced by 53% with the effective sulfur rate. Treatment effects of gypsum (600 lb S/A-672.5 Kg/ha) were not significantly different from sulfur dust (600 lb/A-672.5 Kg/ha), Terraclor or Terraclor Super-X (both at 25.0 lb PCNB/A-28.0 Kg/ha). Tissue analyses of tuber peelings showed a significant reduction in calcium from treatments involving sulfur and gypsum, indicating that calcium levels in tuber peelings were positively correlated with scab susceptibility. 相似文献
992.
The milk yields obtained from 845 herd-years within the ICI Recorded Farms Scheme have been correlated, by multiple regression analysis, with the N fertilizer supplied to the grassland, the quantities of concentrates fed and the stocking rates. The large quantity of data gave highly significant correlations which indicated that, over the whole period, the supply of an extra 1 kg N from fertilizer was associated with an average extra yield of 9·9 1 milk. 4·9 1 were associated with the extra N independently of any simultaneous changes in either stocking rate or concentrate feeding, and 4-5 1 were ascribable to a simultaneous increase in stocking rate. There was a substantial variation in the ‘milk yield per kg N’ response from year to year, but the average value over 6 years agreed closely with that observed in the period 1949–52. 相似文献
993.
The summer-donnancy period among collections of Phalaris tuberosa L. from the eastern Mediterranean region when grown at Davis, California, ranged from 30 to 127 days. Plants from the more arid sites of origin tended to exhibit the longer dormancy. There were exceptions, however, and these, together with the diversity of behaviour in this material, suggest that genotypes with a potential for increased summer growth may be selected for use on rangelands. 相似文献
994.
Maize silages made in October were fed to forty-three autumn-calving cows during a 20-week winter feeding trial. The control silage received no additive whereas a non-protein nitrogen (NPN) additive was applied to the other silage at harvest time. The four experimental feeding treatments were: A, maize silage + 6 kg d?1 barley; B, maize silage with NPN + 6 kg d?1 barley; C, maize silage + 5 kg d?1’barley + 1 kg d?1 extracted decorticated groundnut cake; D, maize silage with NPN. The mean daily milk yields of cows on the treatments were 14.7, 15.1, 15.3 and 15.0 kg respectively. All cows received maize silage ad libitum. There were no significant differences in milk yield but the milk produced by the cows on treatment D had significantly lower concentrations of milk fat, protein and solids-not-fat when compared to the other three treatments. The cows on treatment D had a negative liveweight change which was significantly different (P < 0.05) from those of the cows on treatments B and C. 相似文献
995.
H. H. Hoppe 《Plant foods for human nutrition (Dordrecht, Netherlands)》1980,30(3-4):289-302
Phytoalexins are antimicrobial compounds accumulating in infected plants. Accumulation of phytoalexins has been observed after infections by fungi, bacteria, viruses, and nematodes. Their formation is often associated with cellular necrosis. Evidence exists that the accumulation is based on enhanced de novo synthesis of phytoalexins in living cells adjacent to the necrotic tissue. Antifungal activity of phytoalexins is directed against different pathogenic and nonpathogenic fungi. In some instances, they may contribute to nonhost resistance; in other cases, they might be involved in plant resistance against pathogens. Numerous abiotic inducers of phytoalexin formation are known and highly potent elicitors of phytoalexins have been isolated from fungal cell walls and culture fluids. Keen and associates reported that races ofPhytophthora megasperma produce specific elicitors of phytoalexin formation which are active only in resistant interactions. Albersheim and associates purified and characterized phytoalexin-eliciting -glucans from the same fungus which unspecifically induce phytoalexin accumulation in resistant, susceptible, and also in nonhost plants. Research on elicitors should provide powerful tools for the elucidation of phytoalexin biosynthesis and the role of phytoalexins in plant resistance.
Vortrag, gehalten auf der XVI. Vortrags-Tagung der Deutschen Gesellschaft für Qualitätsforschung (Pflanzliche Nahrungsmittel) (DGQ), am 20.3.1980 in Hamburg. 相似文献
Vortrag, gehalten auf der XVI. Vortrags-Tagung der Deutschen Gesellschaft für Qualitätsforschung (Pflanzliche Nahrungsmittel) (DGQ), am 20.3.1980 in Hamburg. 相似文献
996.
Abrahamsen B Zhao J Asante CO Cendan CM Marsh S Martinez-Barbera JP Nassar MA Dickenson AH Wood JN 《Science (New York, N.Y.)》2008,321(5889):702-705
Peripheral pain pathways are activated by a range of stimuli. We used diphtheria toxin to kill all mouse postmitotic sensory neurons expressing the sodium channel Nav1.8. Mice showed normal motor activity and low-threshold mechanical and acute noxious heat responses but did not respond to noxious mechanical pressure or cold. They also showed a loss of enhanced pain responses and spontaneous pain behavior upon treatment with inflammatory insults. In contrast, nerve injury led to heightened pain sensitivity to thermal and mechanical stimuli indistinguishable from that seen with normal littermates. Pain behavior correlates well with central input from sensory neurons measured electrophysiologically in vivo. These data demonstrate that Na(v)1.8-expressing neurons are essential for mechanical, cold, and inflammatory pain but not for neuropathic pain or heat sensing. 相似文献
997.
试验旨在评价饲粮处理对猪肉中脂肪酸组成、硒和VE含量的影响。将60头杜洛克杂交母猪随机分配到4个饲粮处理组中(每组15头),4种试验饲粮以动植物原料或植物原料为基础,添加或不添加饲粮添加物(0.614%),饲粮添加物舍共轭亚油酸、硒和VE。动植物饲粮组与植物饲粮组相比,体重达100kg的生长性能类似,饲粮添加物对其也没有显著影响。 相似文献
998.
Farmers account for yield and soil variability to optimize their production under mainly economic considerations using the
technology of precision farming. Therefore, understanding of the spatial variation of crop yield and crop yield development
within arable fields is important for spatially variable management. Our aim was to classify landform units based on a digital
elevation model, and to identify their impact on biomass development. Yield components were measured by harvesting spring
barley (Hordeum vulgare, L.) in 1999, and winter rye (Secale cereale, L.) in 2000 and 2001, respectively, at 192 sampling points in a field in Saxony, Germany. The field was stratified into
four landform units, i.e., shoulder, backslope, footslope and level. At each landform unit, a characteristic yield development
could be observed. Spring barley grain yields were highest at the level positions with 6.7 t ha−1 and approximately 0.15 t ha−1 below that at shoulder and footslope positions in 1999. In 2000, winter rye harvest exhibited a reduction at backslope positions
of around 0.2 t ha−1 as compared to the highest yield obtained again at level positions with 11.1 t ha−1. The distribution of winter rye grain yield across the different landforms was completely different in 2001 from that observed
in 2000. Winter rye showed the highest yields at shoulder positions with 11.1 t ha−1, followed by the level position with 0.5 t ha−1 less grain yield. Different developments throughout the years were assumed to be due to soil water and meteorological conditions,
as well as management history. Generally, crop yield differences of up to 0.7 t ha−1 were found between landform elements with appropriate consideration of the respective seasonal weather conditions. Landform
analysis proved to be helpful in explaining variation in grain yield within the field between different years. 相似文献
999.
1000.
Role of land-surface changes in arctic summer warming 总被引:2,自引:0,他引:2
Chapin FS Sturm M Serreze MC McFadden JP Key JR Lloyd AH McGuire AD Rupp TS Lynch AH Schimel JP Beringer J Chapman WL Epstein HE Euskirchen ES Hinzman LD Jia G Ping CL Tape KD Thompson CD Walker DA Welker JM 《Science (New York, N.Y.)》2005,310(5748):657-660
A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude warming trends. Pronounced terrestrial summer warming in arctic Alaska correlates with a lengthening of the snow-free season that has increased atmospheric heating locally by about 3 watts per square meter per decade (similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2). The continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating by two to seven times. 相似文献