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41.
The effects of the herbicide glyphosate [N-(phosphonomethyl)glycine]on seedling growth of Pinus resinosa and on the ectomycorrhizal development of the symbiotic fungus Paxillus involutus were investigated under greenhouse and field conditions. Glyphosate at 0–54 and 3–23 kg ha?1 did not reduce seedling growth or ectomycorrhizal development under greenhouse conditions. There was no seedling mortality due to glyphosate treatment at either rate. Under field conditions, seedling growth of P. resinosa and ectomycorrhizal development of P. involutus were not affected by the above rates. Seedlings (46–48%) failed to survive in non-glyphosate-treated plots, presumably because of weed competition, whereas all survived in glyphosate-treated plots. All the non-mycorrhizal seedlings were colonized bv indigenous mvcorrhizal fungi within 2 months after planting in both control and glyphosate-treated plots. The injection rates varied from 74–86 %.  相似文献   
42.
Phellinus tremulae is the most important decay fungus on Populus tremuloides. In forest industries using aspen wood chips, two blue-stain fungi Ophiostoma crassivaginatum and Ophiostoma piliferum cause considerable reduction in the value of the end product. Thirty-eight homologues and analogues of 4-phenyl-3-butenoic acid were studied against P. tremulae, O. crassivaginatum, and O. piliferum. Varied inhibition of the in vitro growth of these fungi was observed at 1–1000 μg/ml. The wood-chip colonization by P. tremulae was not affected by the six most active compounds at 1 μg/ml, however, at 10 and 100 μg/ml the growth of P. tremulae on wood chips was totally arrested. 4-Phenyl-3-butenoic acid and 4-phenyl-3-butynoic acid prevented blue-stain development on wood chips at 1 μg/ml.  相似文献   
43.
We examined the changes in body weight (BW), back-fat thickness (BFT) and blood metabolites in relation to postpartum (PP) ovarian activity status in twenty female yaks raised under semi-intensive system. BFT and ovarian activities, like follicle development, ovulation (OV) and corpus luteum (CL) development, were monitored from 4 to 15 weeks (wk) PP using ultrasonography. Resumption of ovarian activity was confirmed with ovulation of dominant follicle (DF) and subsequent CL development, and >1 ng/ml progesterone concentration in blood plasma sample after 1week of ovulation. Yaks were further classified as cyclic (with CL), acyclic (without CL), and cystic (with >25 mm follicular cyst; FC). Within 20 weeks PP, 60% yaks resumed cyclic ovarian activity, while 25% failed to initiate cycling activity, and 15% developed follicular cysts. In all categories of yak, BW gradually decreased (p < .05) till nadir; however, nadir reached earlier (p < .05) in acyclic yaks. BFT differed (p < .05) among the yak groups, but it tended to be higher in cyclic yaks as compared to acyclic and cystic. No difference (p > .05) in non-esterified fatty acids (NEFA) values was found among the different categories of yaks, whereas, beta-hydroxy butyrate (BHB) levels were higher in cystic animals as compared to acyclic and cyclic. Blood glucose levels decreased in all yaks during initial 2 weeks after calving. Our findings suggest that yaks with low BW, BFT and glucose levels, and higher BHB values were at risk of delayed resumption of ovarian activity and concomitant development of follicular cysts.  相似文献   
44.
The study was conducted to assess early-expressed reproductive traits of Boran cattle and their crosses with Jersey and Holstein Friesian (HF). The traits studied were age at first services (AFS), number of services for first conception, age at first calving (AFC), first dry period (FDP), first calving interval (FCI), and first service period (FSP). Genetic group and period of birth/calving had a significant (p?<?0.05) effect on reproductive traits. The Boran cattle were inferior to HF or Jersey crosses. First crosses (F 1) for Jersey and Boran (50 % Jersey: 50 % Boran) showed a significantly (p?<?0.05) younger AFS (by 7.25 months) and AFC (by 10.75 months), had shorter FCI (by 63.27 days), FDP (by 61.13 days), and FSP (by 60.3 days), and needed less (by 0.35) numbers of services per first conception as compared to the Boran cattle. The F 1 for Jersey and Boran (50 % Jersey: 50 % Boran) crosses showed better performance than the F 1 for HF and Boran (50 % HF: 50 % Boran). Heritability values for AFS and AFC were the highest and were estimated at 0.51?±?0.10 and 0.49?±?0.13, respectively, and lowest heritability was recorded for FDP (0.02?±?020) and FSP (0.10?±?0.29). The genetic correlation was highest (0.10?±?0.20) between AFS and AFC and was lowest (?0.01?±?0.66) between FCI and FSP. The breed additive for Jersey was only significant (p?<?0.01) for AFS and AFC. The crossing of HF with Boran cattle has desirably reduced 9.16?±?2.88 months in AFS; the corresponding reduction in AFS was 3.49?±?3.59 months by crossing with Jersey. The performance comparisons and genetic and crossbreeding parameters indicated that crossbreeding of Boran with HF or Jersey can improve reproductive performance.  相似文献   
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