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991.
【目的】探讨化肥减量配施增效剂对广东省惠州地区蔬菜地土壤理化性质及菜心产量、品质的影 响,为蔬菜地化肥减量提供理论依据和技术支持。【方法】以华南地区代表性的蔬菜作物菜心为研究对象,采 用田间小区试验,设置当地施肥(T1,CK)、当地施肥 + 增效剂(T2)、减肥 20%(T3)、减肥 20%+ 增效剂 (T4)4 个处理,比较不同处理下土壤的理化性质、微生物量、酸性磷酸酶活性以及菜心产量、品质等指标。【结 果】与 T1(CK)相比,T3 处理菜地土壤毛管持水量、田间持水量、非毛管孔隙度和总孔隙度分别提高 13.3%、 43.1%、29.4% 和 9.2%,T4 处理菜地土壤非毛管孔隙度和总孔隙度分别提高 42.1% 和 13.0%;与 T1(CK)相比, T3 处理菜地土壤 pH 值提高 15.9%,其他土壤肥力指标均无显著变化,T4 处理菜地土壤 pH 值提高 13.4%、碱解 氮和速效钾含量分别显著提高 33.3% 和 15.8%;与 T1(CK)相比,T3 处理菜地土壤微生物量碳、氮和酸性磷酸 酶活性分别提高 35.6%、43.1% 和 15.5%,T4 处理土壤微生物量碳、氮、磷和酸性磷酸酶活性分别提高 78.1%、 111.2%、49.1% 和 24.3%; 与 T1(CK)相比,T3 处理菜心氮、磷、钾养分吸收量分别提高 22.1%、11.3%、 17.9%,T4 处理菜心氮、磷、钾养分吸收量分别显著提高 33.0%、28.5% 和 30.0%;与 T1(CK)相比,T3 处理 菜心产量提高 19.4%、硝酸盐含量下降 13.6%、Vc 含量提高 2.2%,T4 处理菜心产量显著增加 28.1%、硝酸盐含 量下降 12.1%、Vc 含量提高 4.2%。【结论】化肥减量配施增效剂可以提升土壤肥力、提高土壤的微生物量和酸 性磷酸酶活性、提高菜心的产量和改善品质。  相似文献   
992.
Rapeseed (Brassica napus L.) harvesting method is critical since it significantly determines the seed yield, oil quality, and industrial efficiency. This study investigated the influences of harvesting methods on the quality of cold-pressed rapeseed oil of two varieties. Oil color, peroxide value (POV), tocopherol content, fatty acid composition, and polarity of total polyphenols (PTP) contents of two rapeseed varieties in Huanggang and Xiangyang were compared through artificially simulated combined harvesting and two-stage harvesting. Results showed significant differences in the quality of rapeseed oil between the two harvesting methods. The red value (R-value), POV, total tocopherol contents, linoleic and linolenic acid content, and PTP content of the pressed rapeseed oil prepared by the combined harvesting method were about 27.6, 5.7, 15.8, 2.0, 0.5, and 28.6% lower than those of the oil produced from the two-stage harvesting method, respectively. Xiangyang and Huayouza62 performed better in the two regions and two varieties, respectively. To sum up, the rapeseed oil obtained 41–44 days after final flowering of combined harvesting, 35 days after final flowering, and six days of post-ripening of the two-stage harvesting had the best quality.  相似文献   
993.
Mixing or regrouping of calves from different pens is a common animal management practice on the farm, which frequently occurs after weaning and has a negative effect on calve welfare.  Social integration before regrouping may relieve stresses, but more evidences are needed to verify this hypothesis.  The present study aimed to investigate acute physiological and behavioral variations of individually- or group-housed calves after being introduced into a mixed group.  A total of 132 postnatal calves were randomly divided into groups of 1, 3, 6 and 12 animals (S, G3, G6, and G12; 6 replicates in each group) until 59 days of age.  At 60 days of age, every two replicates from different groups (S, G3, G6 and G12) were introduced in a larger pen which containing 44 of the aboved experimental calves.  Before and after regrouping, physiological parameters of stress, including heart rate (HR), saliva cortisol (S-CORT), saliva secretory immunoglobulin A (SIgA), interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) levels, and behavioral responses were recorded.  After regrouping, HR and S-CORT increased immediately (P<0.05), and higher (P<0.05) levels of such molecules were found in S calves compared to those in group-housed calves.  Levels of SIgA and IL-2 were decreased (P<0.05), and the lowest (P<0.05) IL-2 values were found in S calves compared to those in group-housed calves.  In addition, the introduced calves displayed a distinct behavior, including altered active and rest time, which was associated with negative emotions triggered by the novel surroundings.  Allogrooming, play, exploration behaviors and lying time were increased significantly (P<0.05) in group-housed calves than those in S calves.  Conversely, self-grooming, aggressive behaviors, standing and walking time were increased (P<0.05) in S calves than those in group-housed calves.  These findings suggest that individually-housed calves may be more susceptible to stressors arising from regrouping than group-housed calves, which consequently negatively affected behavioral and neuroendocrine responses.  Furthermore, moving calves with previous social experience may help mitigate regrouping stress.  相似文献   
994.
995.
为减少果园用工费,提高果园经济效益,在渭北旱塬以常规修剪苹果园为对照,监测量化修剪对疏花疏果用工费、果实品质和果园经济效益等的影响;在陕北丘陵沟壑区以苹果套袋(纸袋)为对照,监测喷施苹果面膜(腐殖酸型苹果免套袋膜剂)替代果实套袋对果园用工费、果实品质和果园经济效益等的影响。结果表明,量化修剪在冬季修剪时较常规修剪多支付用工费4500元/hm2,疏花可减少11250元/hm2,疏果可减少2250元/hm2;量化修剪的苹果单果重大,品质高,产值提高13.73%;经济效益提高34860元/hm2。喷施苹果面膜较果实套袋和去袋可减少用工费22850元/hm2,材料费减少8250元/hm2;喷施苹果面膜提高了苹果的外观商品价值和贮藏运输性能,产值提高50.01%;果园经济效益提高192900元/hm2。量化修剪和喷施苹果面膜降低了果园用工费,提高了果园经济效益,果园管理过程中应积极开展量化修剪和喷施苹果面膜。  相似文献   
996.
In order to study the influence of dicyandiamide added into the insulation paper on the oil-paper insulation during the aging process.The insulation paper containing dicyandiamide and the insulation paper without any stabilizer are prepared. They are immersed in transformer oil separately and placed in the aging chamber with predefined temperature of 130℃ for 31 days to perform thermal aging experiment of oil-paper insulation. The specimens are periodically sampled and some parameters are measured like the degree of polymerization(DP), the breakdown voltage, the nitrogen content, the acidity of insulation oil, and UV-Vis spectrum. The results show that the insulation paper added with dicyandiamide has a distinct anti-aging and anti-breakdown effect and the DP is 58% higher than that of blank sample at the later stage of aging. In the aging process, decline of the nitrogen content of insulation paper is not serious. The oil-paper sample containing dicyandiamide has a far lower value of acidity than that of blank sample, besides the oil color is deeper. Dicyandiamide in the insulation paper improves not only the anti-aging and anti-breakdown properties, but also the performance of oil in the aging process.  相似文献   
997.
细胞周期蛋白(cyclin)对细胞生长繁殖起到关键的调节作用。该研究采用高通量测序技术,构建了三角帆蚌(Hyriopsis cumingii)转录组文库,进行了cyclins基因筛选与生物信息分析,通过qRT-PCR技术,探讨其在不同组织(闭壳肌、内脏团、外套膜、斧足、心脏、血液、鳃、性腺)与性别中的表达特征。转录组测序共得到257 457条unigene(N50为1 796 bp),注释率为86.7%;通过分析,cyclin Acyclin D2、cyclin E被筛选出,且cyclin A、cyclin D2与cyclin E蛋白的氨基酸序列均与美洲牡蛎(Crassostrea virginica)、太平洋牡蛎(Crassostrea gigas)具有较高相似性。实时荧光定量分析结果表明,cyclin Acyclin D2、cyclin E在三角帆蚌各组织中均有表达,且存在显著的组织差异:cyclin Acyclin E基因在性腺中表达量显著高于其他组织(P<0.05),在斧足中表达量最低;cyclin D2基因在鳃中表达量最高(P<0.05),在血液中表达量最低。在同一组织的不同性别之间:cyclin A基因在性腺、闭壳肌、心脏、血液中表达存在显著性别差异(P<0.05);cyclin D2在外套膜、心脏、性腺中的表达具有显著(P<0.05)的性别差异;cyclin E在性腺、斧足、鳃、心脏中的表达具有显著(P<0.05)的性别差异;cyclin Acyclin E基因在雌性心脏和性腺中表达量显著(P<0.05)高于雄性,而cyclin D2反之(P<0.05),cyclin D2基因在雌性外套膜表达量显著高于雄性(P<0.05),暗示cyclin Acyclin E与性腺发育关系密切,cyclin D2可能与鳃损伤修复有关。本研究初步探究了三角帆蚌cyclin Acyclin D2、cyclin E基因的功能,为建立三角帆蚌细胞系提供了分子基础。  相似文献   
998.
土传病害的发生与土壤环境,特别是微生物群落结构变化密切相关,田间自然发病条件下探讨土传病害发生、发展过程中土壤环境因子的变化特征,可更加科学地评价病害发生与土壤环境因子变化的关系,为进一步了解土传病害发生机理提供必要科学依据。选择云南烟草黑胫病危害较为严重的3个植烟区(石林板桥、保山耇街、保山珠街)统一种植高感黑胫病烤烟品种红花大金元,调查定点田块病害发生情况并根据病害调查标准将发病烟株划分不同程度(正常烟株、轻度发病烟株、中度发病烟株、重度发病烟株)。同时在保山耇街试验点采集不同发病程度烟株根际土壤,分析比较其土壤酶活性及细菌群落的差异。研究结果表明:各调查点不同发病程度烟株根际土壤与脲酶、蔗糖酶、酸性磷酸酶、过氧化氢酶活性随发病程度增加均呈下降趋势;土壤16S rRNA高通量测序及多样性分析表明,与土壤细菌门类水平优势群落组成相似,并且随发病程度放线菌门相对丰度呈下降趋势,而酸杆菌门呈上升趋势;不同发病程度根际土壤细菌群落属水平上相对丰度差异较大,其中甾体杆菌属(Steroidobacter)、阿达尔杆菌属(Adhaeribacter)、根瘤菌属(Mesorhizobium)、杜氏杆菌属(Tumebacillus)随发病程度呈先下降后上升的趋势;细菌群落α多样性指数均不同程度低于健康根际土壤,且均表现为轻度发病烟株根际土壤α多样性指数最低,其中shannon和simpson指数轻度发病烟株显著低于健康烟株;PCoA主成分分析表明,根际土壤细菌群落结构随发病程度发生了明显分离,且沿第二主成分坐标轴上细菌群落结构分离随发病程度呈逐渐增大趋势。综上所述,不同发病程度烟株根际主要环境因子存在较大差异,土壤酶活性受到不同程度抑制,细菌群落组成发生趋向性变化,群落结构发生趋向性改变,土壤微生物多样性降低。  相似文献   
999.
探讨除草剂减施对麦田杂草的防治效果,以及对小麦生长过程中叶绿素SPAD值变化的影响。结果表明,药后45 d,10%苯磺隆WP 9.00 g/hm~2处理(减施60.00%)、10%苯磺隆WP 9.00 g/hm~2+5%(唑啉草酯+炔草酯)EC 30.00 g/hm~2处理(减施60.00%)、7%双氟·炔草酯OD 63.00 g/hm~2处理(减施25.00%)和28%唑草·苯磺隆WP 16.80 g/hm~2处理(减施33.33%)对麦田阔叶杂草的鲜质量防效分别为98.64%、98.99%、98.54%和98.68%,表明除草剂减量施用对麦田杂草仍具有较好的防效。施用除草剂后,小麦叶片叶绿素SPAD值呈现先下降再上升的趋势。药后3 d、5 d、7 d,28%唑草·苯磺隆WP 33.60 g/hm~2处理(增施33.33%)小麦叶片叶绿素SPAD值显著低于7%双氟·炔草酯OD 63.00 g/hm~2处理(减施25.00%)、10%苯磺隆WP 9.00 g/hm~2处理(减施60.00%)和空白对照(CK)的叶绿素SPAD值,低于其他处理的叶绿素SPAD值。  相似文献   
1000.
种植密度是影响青稞抗倒伏和秸秆饲用特性的重要因子。以抗倒伏品种昆仑14号和倒伏品种门源亮蓝为试验材料,比较研究种植密度对这2个品种生长发育、抗倒伏特性和秸秆饲用特性的影响。结果表明,种植密度对2个品种的抗倒伏和秸秆饲用特性的影响存在差异。随着种植密度的增加,昆仑14号根长、根体积、根数和根干重先增后降,茎粗和壁厚依次下降;门源亮蓝根系和茎秆相关指标则随种植密度增大而下降。昆仑14号抗倒伏相关指标先增后降,但整个生育期未发生倒伏;门源亮蓝各指标均显著降低,诱发倒伏现象提前发生,致使倒伏率增大、倒伏程度加剧。昆仑14号茎秆中性洗涤纤维、酸性洗涤纤维、半纤维素、纤维素和木质素等化学成分含量随密度增加先增后降,门源亮蓝各成分含量呈下降趋势,相对饲喂价值随密度增加呈现增高的趋势。综合抗倒伏特性与秸秆饲用特性,昆仑14号最佳种植密度为375×104株hm~(-2),门源亮蓝粮饲兼用时适宜密度为300×104~375×104株hm~(-2)。  相似文献   
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