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11.
以嘉氏羊蹄甲(Bauhinia galpinii)种子为材料,开展了不同浸种催芽处理对比试验。结果表 明,相比不浸种处理,3 个浸种处理明显提高嘉氏羊蹄甲的种子发芽势和发芽率,平均苗高也明显高于不 浸种组,其中,温水(60 ℃ ) 浸种6 h 组嘉氏羊蹄甲种子发芽率最高,达74.7%,苗高生长最快。  相似文献   
12.
旋耕机刀片的耐磨性研究   总被引:1,自引:0,他引:1  
结合旋耕机刀片的工况条件,运用摩擦学的研究成果,揭示了旋耕刀的磨损机理,并建立了冲蚀磨损模型。经试验验证,提出了影响旋耕刀耐磨性的因素,指出低碳高合金钢作为旋耕刀材料具有比高碳钢65Mn更好的抗磨损机能。  相似文献   
13.
Human commensal species take advantage of anthropogenic conditions that are less likely to be challenged by the selective pressures of natural environments. Their morphological and physiological phenotypes can therefore dissociate from habitat characteristics. Understanding how these species adjust their morphological and physiological traits across latitudinal gradients is fundamental to uncovering the eco-physiological strategies underlying coping mechanisms. Here, we studied morphological traits in breeding Eurasian tree sparrows (ETSs; Passer montanus) among low-latitude (Yunnan and Hunan) and middle-latitude (Hebei) localities in China. We then compared body mass; lengths of bill, tarsometatarsus, wing, total body, and tail feather; and baseline and capture stress-induced levels of plasma corticosterone (CORT) and the metabolites including glucose (Glu), total triglyceride (TG), free fatty acid (FFA), total protein, and uric acid (UA). None of the measured morphological parameters varied with latitude except in the Hunan population, which demonstrated longer bills than those in other populations. Stress-induced CORT levels significantly exceeded baseline levels and decreased with increasing latitude, but total integrated CORT levels did not vary with latitude. Capture stress-induced significantly increased Glu levels and decreased TG levels, independent of site. However, the Hunan population had significantly higher baseline CORT, baseline and stress-induced FFA levels, but lower UA levels, which differed from other populations. Our results suggest that rather than morphological adjustments, physiological adjustments are mainly involved in coping mechanisms for middle-latitude adaptation in ETSs. It is worth investigating whether other avian species also exhibit such dissociation from external morphological designs while depending on physiological adjustments.  相似文献   
14.
This paper discuss the effects of automatic plug mills in small seamless tube mills. Far from traditional ideas,the auther comes rp with mew ideas, which adot the mew process of replacing rolling by piercing,a huge sum of economical interests and great social benefits will be gained.  相似文献   
15.
论农业文化遗产保护与美丽乡村建设——以云南为例   总被引:1,自引:1,他引:0  
曹茂  莫力  杨玲 《农学学报》2020,10(8):89-94
党的十九大提出了乡村振兴战略,美丽乡村是农业文明的重要体现,是中华民族的文化根脉和精神家园。云南有着丰厚的农业文化遗产,本文从农业文化遗产地村落景观保护、特有农作物品种保护和加大农业文化遗产宣传保护等层面,提出了挖掘云南农业文化遗产及建设云南美丽乡村的对策建议。  相似文献   
16.
Salinity tolerance of 47 wild barley genotypes and six barley cultivars was evaluated under control and salinity stress (300 mM NaCl) conditions. Shoot and root dry weight (DW), plant height, membrane stability index (MSI), relative water content, survival rate, leaf malondialdehyde (MDA) and proline contents, root and leaf Na, K, Ca and K/Na ratio, and chlorophyll a fluorescence were measured. Salinity stress caused significant increase in the MDA, proline content, Na and Ca concentrations of the roots and leaves, but resulted in a decrease in the other traits. H. spontaneum genotypes were considerably less affected by the salinity than the genotypes of H. vulgare. Plant survivability was negatively correlated with the Na concentration (r =−.66) but positively correlated with the leaf K/Na ratio (r = .67) and MSI (r = .68). Tolerance mechanisms such as ion exclusion (Na) were likely to be present in the wild barley causing K/Na homeostasis as well as the much lower root and shoot Na, resulting in the higher survival rate.  相似文献   
17.
防治红火蚁触杀型药剂的筛选   总被引:8,自引:1,他引:7  
测定了9种杀虫剂的触杀活性和其中8种药剂对红火蚁工蚁的致死中浓度,触杀活性测试表明,48%毒死蜱对工蚁的击倒速度和致死率均高,药后0.5 h工蚁死亡率达100%;氨基甲酸酯类药剂药后8 h工蚁的被击倒率达100%;5%氟虫腈10 000倍和10%溴虫腈10 000倍药液处理后工蚁的被击倒速度低,但药后24 h工蚁死亡率达100%;高效氯氰菊酯和杀虫双对工蚁的毒性是可恢复的。毒力测试表明,98%杀螟丹对红火蚁毒力最强,其次是10%溴虫腈和48%毒死蜱,而有机磷类的敌敌畏和氨基甲酸酯类的丁硫克百威毒力表现较差,拟除虫菊酯类的高效氯氰菊酯表现一般。试验结果表明,氟虫腈、溴虫腈、毒死蜱、杀螟丹等药剂可被推荐用于野外红火蚁的灌巢防治。  相似文献   
18.
采用多元回归分析预测广西2010年和2015年桑园面积和鲜茧产量。预测结果:2010年广西桑园面积可发展到10.3万hm2,鲜茧产量16.3万吨;2011年后桑园面积不再增加,宜控制在10.3万hm2,2015年鲜茧产量可发展到19.7万吨。通过比较分析,提出了此期间广西蚕桑发展规划布局。  相似文献   
19.
Abalones were reared in a laboratory to determine the percentage response rate, response time, average crawling speed and the time taken to recover an upright posture under nine light‐emitting diode light quality treatments (red, orange, yellow, green, cyan, blue, purple, white and grey) and a dark environment. Animals were placed in the centre of an experimental device, and the tropism of each animal was continuously monitored by video. The highest percentage response rate (80% in dark adapted abalones, 60% in light adapted abalones) was observed in the dark environment, followed by red and orange light (27% and 30% in dark adapted abalones, respectively, 22% and 24% in light adapted abalones). Two induction materials (substrate and brown algae Laminaria japonica) were used to assess the effect of light quality on the tropism of abalones, with the highest percentage response rate (76% in the L. japonica treatment, 22% in the substrate treatment) also observed in the dark environment, followed by red and orange light (both 25% in the L. japonica treatment, and 26% and 32%, respectively, in the substrate treatment). The tropism order of the abalones under dark, red, orange and yellow light was as follows: dark > orange > red, yellow, but fewer abalones chose to stay in blue, green, cyan and purple light. The response time (about 700 s) in the dark environment was significantly longer than for the other light quality treatments. Compared with the average crawling speed in the other light quality treatments, abalones were relatively slower (about 3.8 mm s?1) in red and orange light, and the dark environment. The mean time required for the recovery of an upright posture in red light and the dark environment was longer than in the other light quality treatments, with the average recovery time reaching a maximum of 60 s in the dark environment. The results demonstrate the phototaxis and locomotion behaviour of abalones, as well as confirming the necessity of a dark, orange or red environment for their management and aquaculture.  相似文献   
20.
吉富罗非鱼生长过程中氮收支变化的研究   总被引:2,自引:0,他引:2  
王振华  刘晃  宿墨  吴凡 《南方水产》2013,9(3):85-89
为充实有关鱼类研究数据,提供实际生产理论依据,研究了吉富品系尼罗罗非鱼(Oreochromis niloticus)从鱼种(18 g)生长至成鱼(180 g)过程中氮收支变化。试验为期73 d,每日饱食投喂并收集鱼粪,溶解氧质量浓度为8.0-6.0 mg·L-1,pH为 7.5-6.5,水温为24-30 ℃。在鱼均质量达到50 g、100 g和180 g时测定并计算当前生长阶段氮收支。结果表明,生长氮比例在养殖初期最高(64%),养殖中期最低(47%);粪氮比例在养殖中期最高(9%),养殖初期和末期分别为5%和4%;排泄氮比例随鱼的生长而逐渐增加。此外,试验期间水中总氮增加速度在养殖中期减慢,养殖末期再次加快。  相似文献   
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