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排序方式: 共有1074条查询结果,搜索用时 31 毫秒
991.
为改善农民的生存环境,搞好农村新型清洁能源的开发利用,减缓全社会能源紧张局面,沼气作为优质可再生能源,具有不可比拟的优点,必须重视起来。 相似文献
992.
Pollination dynamics in a Douglas-fir seed orchard as revealed by pedigree reconstruction 总被引:1,自引:0,他引:1
Ben Sk Lai Tomas Funda Cherdsak Liewlaksaneeyanawin Jaroslav Klápště Annette Van Niejenhuis Cathy Cook Michael U. Stoehr Jack Woods Yousry A. El-Kassaby 《Annals of Forest Science》2010,67(8):808-808
- ? Pollination dynamics was studied in a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard using 8 nuclear microsatellite markers and pedigree reconstruction.
- ? The seed orchard consisted of 49 parents (clones). Cone-crop management included bloom delay and supplemental mass pollination (SMP) using 12 internal and 4 external pollen donors.
- ? A random sample of 801 bulk seeds was genotyped for both haploid megagametophyte and corresponding diploid embryo.
- ? Using the parental population’s multilocus genotypes, full pedigree reconstruction generated all the information needed to estimate the maternal, paternal, and parental reproductive success, selfing, pollen contamination, and pollination success of the 4 external pollen donors.
- ? Maternal, paternal, and parental reproductive success varied with 80% of gametes being produced by 23, 45, and 37% of the orchard’s parents, respectively, resulting in a drastically reduced effective population size as compared to the census number (14 vs. 53).
- ? Selfing, pollen contamination, and aggregate SMP success (internal and external) were estimated to be 15.2, 10.4, and 15.0%, respectively.
- ? Full pedigree reconstruction was effective in unraveling the orchard’s pollination dynamics and both female and male reproductive success.
993.
运用形态计量学方法对31头牦牛肉阜间区子宫腺的相关组织学数据进行了测定,并进行统计分析。研究发现,除了妊娠151~180 d,牦牛肉阜间区子宫腺上皮高度随着妊娠时间的增长极显著降低(P0.01);妊娠期子宫腺管周长和面积非常明显增大(P0.01);不同妊娠阶段之间体积密度差异极显著(P0.01),先增加后下降,而表面密度无显著差异(P0.05);除了妊娠151~180 d,扭曲腺管和管状腺管的比例随着妊娠时间的增长分别非常显著地增大或减小(P0.01);分泌腺管的比例在妊娠期间有明显变化(P0.05),牦牛肉阜间区还存在嵌套腺管。结果显示,妊娠期牦牛肉阜间区子宫腺形态结构有明显的变化,子宫腺变的更大、更长,形状更加扭曲。 相似文献
994.
Imen Mahjoub Mohamed M. Masmoudi Jean P. Lhomme Netij Ben Mechlia 《Annals of Forest Science》2009,66(6):608-608
995.
Zeineb Ghrabi-Gammar David R. George Amina Daoud-Bouattour Imtinne Ben Haj Jilani Samia Ben Saad-Limam Olivier A.E. Sparagano 《Industrial Crops and Products》2009,30(3):441-443
A laboratory experiment was conducted with the poultry red mite Dermanysuss gallinae (De Geer) to assess the toxicity of a range of essential oils obtained from wild-growing plants in Tunisia to this pest. Details of the percentage essential oil yield from these plants were also recorded. For comparison, commercially sourced essential oil from Thymus vulgaris (L.) was also tested against D. gallinae after work elsewhere found this product to be acaricidal. Recently fed adult female D. gallinae were exposed to the essential oils at 0.1 mg oil/cm2 in Petri-dishes at 22 °C over a period of 24 h.Results showed that the yield of essential oil varied considerably depending upon the source plant. Whilst maximum yields of 0.5% were achieved, three of the seven wild plants selected provided yields of less than 0.1%. Similar variability was recorded with respect to the toxicity of the essential oils to D. gallinae. Three of the essential oils tested did not cause significant D. gallinae mortality (in comparison to the control). However, all other selected oils provided mortality levels statistically similar to the 90% mortality achieved with commercial T. vulgaris essential oil, with the oil from Pelargonium graveolens (L’Hér.) killing 100% of D. gallinae exposed to it. Essential oil from P. graveolens in particular may be suitable for further development as a D. gallinae acaricide alongside or in place of commercial thyme essential oil. 相似文献
996.
Ben Vosman Wendy P. C. van’t Westende Betty Henken Henriëtte D. L. M. van Eekelen Ric C. H. de Vos Roeland E. Voorrips 《Euphytica》2018,214(3):46
Wild relatives of tomato possess effective means to deal with several pests, among which are a variety of insects. Here we studied the presence of resistance components against Trialeurodes vaporariorum, Myzus persicae, Frankliniella occidentalis, and Spodoptera exigua in the Lycopersicon group of Solanum section Lycopersicon by means of bioassays and comprehensive metabolite profiling. Broad spectrum resistance was found in Solanum galapagense and a few accessions of S. pimpinellifolium. Resistance to the sap sucking insects may be based on the same mechanism, but different from the caterpillar resistance. Large and highly significant differences in the leaf metabolomes were found between S. galapagense, containing type IV trichomes, and its closest relative S. cheesmaniae, which lacks type IV trichomes. The most evident differences were the relatively high levels of different methylated forms of the flavonoid myricetin and many acyl sucrose structures in S. galapagense. Possible candidate genes regulating the production of these compounds were identified in the Wf-1 QTL region of S. galapagense, which was previously shown to confer resistance to the whitefly B. tabaci. The broad spectrum insect resistance identified in S. galapagense will be very useful to increase resistance in cultivated tomato. 相似文献
997.
998.
Khlil Z. Ben Khnissi S. Rekik M. Lassoued N. 《Tropical animal health and production》2017,49(3):607-612
Tropical Animal Health and Production - To test the efficacy on reproductive performance of nutritional supplementation in an out-of-season mating system, 66 adult prolific Barbarine ewes were... 相似文献
999.
1000.