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为了明确线虫角质层胶原蛋白基因(Col)与根结线虫病害的关系,利用从线虫基因组中预测的Col设计特异引物,克隆了南方根结线虫Meloidogyne incognitacol基因MiCol.该基因完整编码区长903bp,编码300个氨基酸.克隆的MiCol与预测的MiCol基因序列一致性高达99.67%,氨基酸序列一致性高达100%.利用病毒介导的基因沉默技术,将其导入番茄植株并接种南方根结线虫,60 d后,沉默载体pTV-MiColi处理番茄植株的根结数比空载体对照及清水对照分别减少49.4%和49.2%,表明MiCol基因沉默显著降低了南方根结线虫的侵染数量. 相似文献
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为探讨菌根真菌的互作效应,筛选协同互作模式组合,对从野生兜兰新鲜营养根中分离、筛选出的3种菌根真菌(PF02、PF06和PF07),采用单菌接种、双菌混合接种和三菌混合菌种等7种接种方式,开展菌−苗共生培养,筛选出优势菌株PF02和PF07,揭示在实验室环境下接菌方式与接种效应之间的相互联系,分析菌根真菌互作对带叶兜兰植株生长和生理的影响。结果表明:显示菌根真菌互作对宿主植株的生物量、保护酶活性及叶绿素总量具有较好的正向效应。3种双菌混合接种方式PF02−PF06、PF02−PF07及PF06−PF07均能有效促进带叶兜兰生物量增长,尤其是PF02−PF06接种方式,抗氧化酶POD、超氧化物歧化酶SOD、过氧化氢酶CAT活性及叶绿素总量提高显著。选择优化的接种方式,以及能够协同促进、达到共生平衡的最佳接种方式组合,最大限度发挥菌根对宿主植物的益生作用。 相似文献
96.
土地资源利用现状的区域差异及可持续利用研究——以南京市为例 总被引:2,自引:0,他引:2
在科学确定大城市市域土地资源利用现状区域差异指标评价体系的基础上,通过动态聚类方法,以乡(镇)为单位,对南京市郊区和郊县的土地利用现状进行分区,并分析了不同土地利用现状区土地利用特征,提出了不同区域土地资源可持续利用的政策取向 相似文献
97.
The invasion of Ambrosia artemisiifolia and Ambrosia trifida from their native range to occupy large areas in China has raised considerable concern. Using the maximum entropy (Maxent) method, we developed models for each Ambrosia species, based on occurrence records from both native ranges (North America) and their invaded ranges (e.g. northern and south‐western Europe) to predict the availability and distribution of suitable habitats for these two species in China. For each species, we also assessed potential shifts in habitat suitability for the year 2050, using three general circulation models (GCMs) and two emission scenarios. Elevation and average mean precipitation in October contributed most to model development for both species. Potential distribution projections under future climatic change scenarios suggested an averaged percentage of suitable area (2.21%) and habitat gain (1.49%) in A. artemisiifolia distribution, with further expansion to environmentally favourable locations in south‐east coastal regions, northern Taiwan and the Beijing–Tianjin–Tangshan area in northern China. Future predicted percentage of suitable area for A. trifida was 0.03% with a very limited suitable habitat gain of <1% although this species had the potential to continue to spread in northern China. Our findings suggest that management priorities should be focused on A. artemisiifolia, whilst effective control strategies for A. trifida may be optimised by concentrating efforts on those relatively fewer regions of China where the species is currently abundant. 相似文献
98.
拉美斑潜蝇(L.huidobrensis)属双翅目、潜蝇科,是一种重要的杂食性害虫,主要在温室或温暖地区为害蔬菜、花卉、装饰植物和杂草。因发现较晚,其生物学特征还不十分清楚。但它作为斑潜蝇的一个种,有其共性,如卵和幼虫都在叶肉内为害,幼虫发育期短,成虫小而灵活,这种共性给化学防治带来了很大困难。因为化学药剂可能杀死其天敌,而它却接受了一个不致死的农药剂量,刺激了它的生长,也促进了它对农药产生抗药性。但它也有个性,如为害特点、生命周期、对寄主植物的偏食性及对药剂的敏感性等,这些因素使适合其它种的综合治理策略不完全适合于它。如Macdonald 1991年比较三叶草斑潜蝇和拉美斑潜蝇对几类药剂敏感性时,发现适合防治三叶草斑潜蝇的综合治理策略要作适当修改才能适合于防治拉美斑潜蝇。因此,为了制定适合于拉美斑潜蝇的综合治理策略, 相似文献
99.
Dong Ruan Qiuli Fan Ahmed Mohamed Fouad Yunyun Sun Shengshu Huang Aiji Wu Chuxiao Lin Zhixiang Kuang Chang Zhang Shouqun Jiang 《Journal of animal science》2021,99(2)
Essential oils are plant-derived aromatic volatile oils, and they contain bioactive compounds that have been shown to improve poultry nutrition. In this study, we investigated the effects of oregano essential oil (OEO) on intestinal antioxidative capacity, immunity, and gut microbiota of young yellow-feathered chickens. A total of nine hundred and sixty 1-d-old female Qingyuan partridge chickens were randomly allocated to four treatment groups with six replicates of 40 birds each, and the feeding trial was lasted for 30 d. The controls were fed on a basal diet without in-feed antibiotics; the birds in the antibiotic group were fed the basal diet supplemented with 20 mg/kg virginiamycin; the remaining birds were fed the basal diet containing 150 or 300 mg/kg OEO, respectively. Dietary supplementation with 150 or 300 mg/kg OEO increased average daily feed intake (P = 0.057) and average daily gain (P < 0.05). The activities of glutathione peroxidase and total antioxidative capacity in plasma, jejuna, and ileal mucosa were increased by OEO supplementation (P < 0.05), with a trend of lower jejunal content of malonaldehyde (P = 0.062). Moreover, dietary OEO increased the content of secretory immunoglobulin A (P = 0.078) and the relative expression of Claudin 1, Mucin 2, and Avain beta-defensin 1 in ileum (P < 0.05). Sequencing data of 16S rRNA indicated that dietary OEO increased the relative abundance of Firmicutes phylum, and Clostridium and Lactobacillus genera, and decreasing that of Romboutsia. Functional analyses indicated that microbial amino sugar and nucleotide sugar metabolism, replication, and repair systems were higher in OEO groups than those of controls and antibiotic treatment. In conclusion, dietary supplementation with OEO enhanced growth performance, alleviated local oxidative stress in intestine, improved production of natural antibodies, and favorably modulated intestinal microbiota composition. 相似文献
100.
Chengquan Tan Yongcheng Ji Xichen Zhao Zhongquan Xin Jiaying Li Shuangbo Huang Zhiying Cui Lijun Wen Caihua Liu Sung Woo Kim Jinping Deng Yulong Yin 《动物营养(英文)》2021,7(1):111
Increased metabolic burdens in breeding sows, which are induced by elevated systemic oxidative stress, could increase the need for nucleotides to repair lymphocyte DNA damage; however, de novo synthesis of nucleotides may be insufficient to cover this increased need. This study investigated the effects of dietary nucleotides on milk composition, oxidative stress status, and the reproductive and lactational performance of sows. Forty multiparous sows were assigned to 2 dietary treatments (Control group, and 1 g/kg Nucleotides group) based on a randomized complete block design using their BW at 85 d of gestation as a block. Sows from 2 groups were fed a restricted diet during gestation and ad libitum during lactation. The experiment lasted from 85 d of gestation to 21 d of lactation. The reproductive performance of sows and the growth performance of suckling piglets were measured. Oxidative stress parameters and milk components were also analysed. Data were analyzed using contrasts in the MIXED procedure of SAS. Sows in the Nucleotides group consumed more feed during the first week (P < 0.01) and from 1 to 21 d (P < 0.05) of lactation than those in Control group. Correspondingly, the litter weight gain of piglets showed a tendency to increase from cross-fostering to 9 d (P = 0.09) and from cross-fostering to 20 d (P = 0.10) in the Nucleotides group relative to the Control group. Additionally, the Nucleotides group was higher (P < 0.01) than the Control group in the concentrations of uridine 5''monophosphate, guanosine 5''monophosphate, inosine 5''monophosphate, adenosine 5''monophosphate and total nucleotides in milk. Furthermore, the Nucleotides group was higher (P < 0.01) than the Control group in the serum levels of total antioxidant capacity (P < 0.01) for sows at 109 d of gestation and glutathione peroxidase for weaning piglets, but lower at the levels of thiobarbituric acid-reactive substances (P < 0.05) in serum of weaning piglets. This study indicated that maternal dietary nucleotides could promote piglet growth, probably due to the higher lactational feed intake and higher concentration of nucleotides in the milk of sows, and lower oxidative stress for both sows and piglets. 相似文献