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71.
Sun  Meng  Gao  Jian  Ali  Tariq  Yu  Dan  Zhang  Shiyao  Khan  Saeed U.  Fanning  Séamus  Han  Bo 《Tropical animal health and production》2017,49(4):843-849
Tropical Animal Health and Production - Aerococcus viridians (A. viridans), an environmental Gram-positive bacterium, has been documented to be associated with bovine mastitis. However, its exact...  相似文献   
72.
Influence of different phosphorus (P) sources on growth, yield and oil quality of linola was evaluated when randomized in complete block design using three replications. Treatments were control (No P), hydropriming, soil phosphorus (50 kg ha?1), seed inoculation with phosphate solubilizing bacteria (PSB, Bacillus spp.) and seed priming with single super phosphate (2%) alone and combined with reduced soil phosphorus (25 kg P ha?1). Among treatments, hydropriming and seed inoculation reduced seedling 50% and mean emergence time with highest emergence index, seedling fresh and dry weights and chlorophyll contents. Seed inoculation with soil P (25 kg ha?1) produced highest seeds per capsule, 100-seed weight, seed and biological yield, harvest index. Maximum oil percentage, low protein contents and high cost benefit ratio with net economic returns were also found for seed inoculation combined with soil phosphorus. Nonetheless, soil phosphorus application can be reduced when seed inoculation with PSB is employed.  相似文献   
73.
Aim of the present research is to investigate the effect of nitrogen (N) and phosphorus (P) on soil food webs (microbes, nematodes and microarthropods) trophic interactions in agriculture ecosystems. A complete randomized block design experiment of N and P fertilization was initiated in 2010 with four treatments: (1) P-addition, (2) N-addition, (3) NP-addition and (4) control. After 4 years of fertilization, compared with control, N-addition had a negative effect on microarthropods and clarify indirectly by significantly (< 0.05) increasing soil total nitrogen (0.37 g kg?1) and available nitrogen (20.03 mg kg?1). The reduction in microarthropods resulted significant (< 0.05) increase in bacterivores and fungivores feeding on bacteria and fungi, an example of top-down control. P-addition had indirect negative effects on microarthropods by means of significantly (< 0.05) increasing soil total phosphorus (0.62 g kg?1) and available phosphorus (24.17 mg kg?1), aggravated fungivores feeding on fungi and strengthened top-down control. NP-addition significantly (< 0.05) increased total microbial biomass, nematodes and microarthropods and resulted in bottom-up control. These results suggested that top-down effects were the dominant force in N- or P-addition treatments. NP-addition strengthened bottom-up control by enriching food resource. Unbalance fertilization could pose adverse on agricultural soil ecosystem and yield potential of crops.  相似文献   
74.
【目的】从陆地棉中克隆GhNAC7,分析其结构和功能,研究其在棉花不同组织中以及叶片不同发育时期的表达量。并转入拟南芥进一步探究其在棉花叶片衰老过程中的作用。【方法】利用中国农业科学院棉花研究所棉花生物学国家重点实验室建立的棉花衰老叶片cDNA文库中的序列,获得1个含有NAM结构域的EST,使用Oligo6.71设计引物,重新在陆地棉叶片cDNA中进行克隆。使用Gene Structure Display Server软件分析GhNAC7结构,使用在线工具Plant CARE分析启动子序列,利用在线工具Gen Scan进行氨基酸序列翻译。同时,利用拟南芥基因组数据库(TAIR)进行序列比对,选取得分较高的NAC家族基因,使用MEGA 6.06软件和Gene Doc软件进行进化树分析和氨基酸比对。以XbaⅠ和SacⅠ为酶切位点构建35S::GhNAC7-GFP融合表达载体,分析其在洋葱表皮细胞中的瞬时表达,进行亚细胞定位。利用实时荧光定量PCR技术分析GhNAC7在棉花不同组织、不同叶片发育时期以及在200μmol·L~(-1) ABA调控下的表达量。通过构建p GhNAC7-GUS融合表达载体并转拟南芥,分析其启动子特异性。以Eco RⅠ和SalⅠ为酶切位点,利用p BI101和p BI121载体,分别构建融合表达载体并转拟南芥进行过表达分析。【结果】从陆地棉中成功克隆GhNAC7,其全长为1 064 bp,包含3个外显子,2个内含子。生物信息学分析结果表明,GhNAC7开放阅读框为834 bp,可编码277个氨基酸,其蛋白质分子量为31.35 k D,等电点为9.22。结构域分析表明其属于NAC转录因子的NAM亚家族,进化树分析显示GhNAC7与ANAC041、ANAC083同源性最高,其中,GhNAC7与ANAC083结构域位置均为17—58 aa。其启动子核心元件包含一系列与衰老、激素、胁迫相关的顺式作用元件。亚细胞定位表明其蛋白为核蛋白。组织特异性表明GhNAC7在真叶、子叶、花、花药和衰老真叶中均明显表达,其中在衰老的真叶中表达量最高。启动子特异性分析表明,其GUS活性在衰老的叶片中最强。在拟南芥中过表达该基因,转基因植株比野生型表现出明显的衰老症状。荧光定量PCR分析表明,ABA处理后6 h GhNAC7明显上调表达,并在48 h表达量达到最高,这表明ABA可调控GhNAC7表达从而调节棉花叶片衰老。【结论】GhNAC7可以促进棉花叶片衰老并受ABA的调控。  相似文献   
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77.
In a 1-year study, quantification of nitrous oxide (N2O) emission was made from a flood-irrigated cotton field fertilized with urea at 100kg N ha−1 a−1. Measurements were made during the cotton-growing season (May–November) and the fallow period (December–April). Of the total 95 sampling dates, 77 showed positive N2O fluxes (range, 0.1 to 33.3g N ha−1 d−1), whereas negative fluxes (i.e., N2O sink activity) were recorded on 18 occasions (range, −0.1 to −2.2g N ha−1 d−1). Nitrous oxide sink activity was more frequently observed during the growing season (15 out of 57 sampling dates) as compared to the fallow period (3 out of 38 sampling dates). During the growing season, contribution of N2O to the denitrification gaseous N products was much less (average, 4%) as compared to that during the fallow period (average, 21%). Nitrous oxide emission integrated over the 6-month growing period amounted 324g N ha−1, whereas the corresponding figure for the 6-month fallow period was 648g N ha−1. Subtracting the N2O sink activity (30.3g N ha−1 and 3.8g N ha−1 during the growing season and fallow period, respectively), the net N2O emission amounted 938g N ha−1 a−1. Results suggested that high soil moisture and temperature prevailing under flood-irrigated cotton in the Central Punjab region of Pakistan though favor high denitrification rates, but are also conducive to N2O reduction thus leading to relatively low N2O emission.  相似文献   
78.
In Indian mustard (Brassica juncea L. Czern & Coss), a major oilseed brassica crop, oil yield is the ultimate trait of economic value, which is determined by seed yield (SY) and oil content (OC). SY, the end product of many complex biological processes, is influenced by many traits, such as plant height (PH), branch number, siliqua number, seed weight, seed size and pod length. It is difficult to accurately select for high-yielding genotypes based exclusively on SY, neglecting other yield-determining traits in commercial breeding programs. Therefore, it is desirable for breeders to simultaneously improve several traits of economic importance, most of which are quantitative in nature. The purpose of the present study was to develop selection indices for simultaneous selection of multiple quantitative traits to enhance selection efficiency of the mustard breeding program of Punjab Agricultural University (PAU) located in Abohar, Punjab. A set of 487 diverse mustard genotypes, comprising germplasm accessions of Indian and European origin, advanced breeding lines, landraces, and cultivars, was evaluated using an alpha lattice design for 2 years (2015–16 and 2016–17) at the Regional Research Station of PAU, Abohar, District Fazilka (the major mustard-growing region of the Punjab state). Data on PH, main shoot length (MSL), number of primary branches (NPB), number of secondary branches (NSB), number of siliquae on main shoot (NSMS), siliqua length (SL), number of seeds per pod (NSP), 1000-seed weight (TSW), SY on a plot basis and OC were recorded. To compute selection indices, economic weights, as determined via path coefficient analysis, were assigned to major yield-determining traits. Out of eight recorded agronomic traits, four traits, viz., NSMS, TSW, NSB and NPB, had larger direct effects on SY than other traits, and hence were assigned relative economic weights of 0.60, 0.20, 0.12 and 0.08, respectively. Selection indices were computed using different combinations of traits via Kang_SASPath computer program. When seven traits were used in a selection index (PH, NPB, NSB, NSMS, SY, TSW and MSL; or PH, NPB, NSB, NSMS, SY, TSW and OC), expected genetic advance (GA)at 5% selection intensity was about the same (9.55; selection efficiency or SE = 163% compared with selection based on SY alone).The GA was 9.46 (SE = 161%)for five traits, viz., NPB, NSB, NSMS, SY and TSW; and 9.30 (SE = 159%)for four traits, viz., NPB, NSB, NSMS, and TSW. These GAs were compared with the GA for SY only, which was 5.90 (benchmark; SE = 100%). We concluded that simultaneous selection based on multiple traits was always more efficient than selection based on SY alone. As there was only a small difference between the GA based on four traits (SE = 161%) and GA based on seven traits (SE = 163%), we suggest that mustard breeders use the parsimonious combination of four traits, viz., NPB, NSB, NSMS, and SY, to enhance SY and, consequently, oil yield in mustard.  相似文献   
79.
Inhibition of nitrification as a mitigation tool to abate nitrogen (N) losses and improve N use efficiency (NUE) is a promising technology. Nitrification inhibitor (dicyandiamide, DCD) was evaluated in two consecutive wheat-maize rotations (2015–2017), with two different N fertilizer levels applied in wheat (160, 220 kg N ha?1) and maize (180, 280 kg N ha?1). More NH4+-N contents (101% and 102% in wheat and 74% and 73% in maize) and less NO3-N contents (37% and 43% in wheat and 46% and 57% in maize) were observed at both N levels treated with DCD compared to without DCD. Higher pH, lower EC and reduced NO3-N accumulation were the other benefits of DCD. The NO3-N accumulation within the 0–200 cm soil profile was significantly less at both N levels with DCD (66 mg kg?1 and 121 mg kg?1) compared to without DCD (96 mg kg?1 and 169 mg kg?1). Application of DCD also improved the growth and yield in both crops. Increase in NUE from 38% to 49% in wheat and 27% to 33% in maize with DCD at higher N level was also observed. Overall, the effectiveness of DCD in retarding the nitrification process was higher in wheat than maize.  相似文献   
80.
Citrus family especially Grapefruit, has attained considerable attention due to the presence of a number of essential components that have cardiovascular and anti-hypertensive properties. The juice and essential oil extracted from eight recently released grapefruit cultivars were used to study physicochemical and antioxidant properties. The total soluble solids (TSS), titratable acidity (TA) and pH of juice samples extracted from various grapefruit varieties differed significantly. The refractive index, specific gravity and optical rotation values for the oil varied from 1.473 to 1.396, 0.863 to 0.847 and +93 to +86, respectively. The percent 2,2-diphenyl-1-picrylhydrazyl radical activity (% DPPH activity) and ferric reducing antioxidant power (FRAP) values for grapefruit juice and peel oil varied from 24.06 to 18.79, 2.91 to 1.44 mmol g–1 and 84.87 to 74.73, 7.76 to 5.73 mmol g–1, respectively. There were significant differences in physicochemical, antioxidant properties and volatile profiles of extracted juice and oil. The oil exhibited higher DPPH and FRAP values than the juice. Among different components identified which accounted for over 99% of the volatile fraction, limonene, myrcene, and benzopyran were major components in all oil samples.  相似文献   
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