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61.
Traditional NIR calibration methods rely on assembling a calibration set of samples and using procedures such as multiple linear regression or partial least squares to develop the calibration. The problem with this methodology is to assemble a calibration set which maximises the diversity of samples represented whilst minimising the intercorrelations between constituents, particularly total protein content and moisture content. The application of NIR measurements of grain has moved beyond simply measuring protein and moisture content. There is now considerable interest in using NIR to measure a range of quality parameters such as Extensograph extensibility and maximum resistance. These parameters are not themselves represented in the NIR spectrum, but are a direct result of the protein composition of the sample. Consequently, a method for predicting the protein composition would be useful. In this paper, we present the results of a comparison of a curve fitting methodology and the more usual partial least squares curve fitting of the component protein spectra, using samples obtained from a wheat breeders» trial. Gliadin and glutenin contents were measured by SE-HPLC and used to develop a partial least squares calibration and the results compared with a curve-fitting methodology. For the situation examined here, the curve fitting methodology did not perform as well as partial least squares calibration. For glutenin, SEP=0·65 for the curve fitting compared to SECV=0·38 for a traditional PLS calibration. However, the results from the curve-fitting are independent of the total protein content and show sufficient discrimination for potential use in sample protein ranking.  相似文献   
62.
A computer simulation model, SWAP93, was used to simulate the soil water balance of sugarcane (Saccharum officinarum L.) over a period of 6 years, in order to develop an efficient irrigation scheduling scheme for Sindh, Pakistan. Given the limitations and inflexibility of the existing warabandi irrigation system, which does not allow on-demand irrigation, only irrigation depth and irrigation interval were varied in order to assess the best irrigation depth/interval combination for sugarcane production. Twelve irrigation treatments were simulated. These treatments were four irrigation amounts (900, 1200, 1650 and 1800 mm) and three irrigation frequencies (7, 10 and 15 days). Three seasons with rainfall totaling less than 20 mm were compared with three seasons of over 200 mm rainfall. Two approaches were used in assessing the irrigation schemes: yield parameters and water management response indicators. Treatment parameters (e.g. irrigation amounts, weather conditions, soil characteristics, etc.) served as input for SWAP93, actual transpiration was calculated and then used in a crop water production function to predict yield and water use efficiency. Additionally, water management response indicators were derived from model outputs, and used to assess the impact of the schemes on soil salinity and water logging. Both these indicators and the yield and water use efficiency indicated that a seasonal total of 1650 mm, applied at a 15-day interval was the best irrigation scheme for the region.  相似文献   
63.
《农业科学学报》2023,22(8):2509-2520
Phosphorus (P) is a finite natural resource and is increasingly considered to be a challenge for global sustainability. Agriculture in China plays a key role in global sustainable P management. Rhizosphere and soil-based P management are necessary for improving P-use efficiency and crop productivity in intensive agriculture in China. A previous study has shown that the future demand for phosphate fertilizer by China estimated by the LePA model (legacy phosphorus assessment model) can be greatly reduced by soil-based P management (the building-up and maintenance approach). The present study used the LePA model to predict the phosphate demand by China through combined rhizosphere and soil-based P management at county scale under four P fertilizer scenarios: (1) same P application rate as in 2012; (2) rate maintained same as 2012 in low-P counties or no P fertilizer applied in high-P counties until targeted soil Olsen-P (TPOlsen) level is reached, and then rate was the same as P-removed at harvest; (3) rate in each county decreased to 1–7 kg ha–1 yr–1 after TPOlsen is reached in low-P counties, then increased by 0.1–9 kg ha–1 yr–1 until equal to P-removal; (4) rate maintained same as 2012 in low-P counties until TPOlsen is reached and then equaled to P-removal, while the rate in high-P counties is decreased to 1–7 kg ha–1 yr–1 until TPOlsen is reached and then increased by 0.1–9 kg ha–1 yr–1 until equal to P-removal. Our predictions showed that the total demand for P fertilizer by whole China was 693 Mt P2O5 and according to scenario 4, P fertilizer could be reduced by 57.5% compared with farmer current practice, during the period 2013–2080. The model showed that rhizosphere P management led to a further 8.0% decrease in P fertilizer use compared with soil-based P management. The average soil Olsen-P level in China only needs to be maintained at 17 mg kg–1 to achieve high crop yields. Our results provide a firm basis for government to issue-relevant policies for sustainable P management in China.  相似文献   
64.
铁蛋白为机体内贮存铁的可溶性蛋白,人血清铁蛋白是机体含铁量的间接标记物,用于诊断缺铁性贫血。铁蛋白重链1(FHC)是铁蛋白的一种亚基,在氧化应激、病毒性肝炎、肿瘤细胞、视网膜的保护、少突胶质细胞的成熟、猪蓝耳病等方面具有重要调控作用。本文就FHC基因表达调控及生物学功能进行综述,以期为该基因作为动物抗病育种的遗传标记奠定基础,为免疫治疗、癌症预防与监控等研究提供参考。  相似文献   
65.
Tree peony (Paeonia suffruticosa Andr.), considered by many to be the national flower of China, is famous for its ornamental, medicinal and culinary attributes. In this study, a total of 8,663 Simple Sequence Repeats (SSRs) were detected by means of a microsatellite search of unigene sequences identified from the de novo assembly of sequence data from different genotypes of tree peony from the Zhongyuan group. Among 100 randomly selected SSR markers, 25 were successfully amplified and showed polymorphism in 31 tree peony accessions. The number of polymorphic alleles ranged from 3 to 11 for each locus and the polymorphism information content value (PIC) ranged from 0.58 to 0.85, with a mean of 0.73, indicating a high level of discriminative capability. To analyse the genetic diversity, a phylogenetic tree was constructed, which demonstrated that tree peonies of similar flower colour were clustered together. The large number of tree peony SSR markers identified in this study will be valuable in studies in genetic diversity and linkage map construction, in gene localisation and cloning and in molecular-marker-assisted breeding in tree peony.  相似文献   
66.
67.
为了明确土壤细菌群落对小麦产量的影响,以河南省济源市冬小麦种植户田块为研究对象,通过采集扬花期麦田土壤样品,利用Illumina高通量测序技术测定细菌16S rRNA V3+V4区序列,分析冬小麦不同产量水平土壤的细菌群落差异。结果表明,高产组土壤铵态氮含量显著高于低产组(P<0.05),土壤有机质含量、速效钾含量、有效磷含量、硝态氮含量、pH值在组间均无显著差异,土壤酸性磷酸酶、碱性磷酸酶、脲酶和过氧化氢酶活性在组间也均无显著差异。酸杆菌门(Acidobacteria)和变形菌门(Proteobacteria)是土壤细菌群落的主导菌门。门水平上,小麦产量与芽单胞菌门(Gemmatimonadetes)、装甲菌门(Armatimonadetes)、纤维杆菌门(Fibrobacteres)、Latescibacteria、Dadabacteria相对丰度显著相关。属水平上,Bryobacter、黄杆菌属(Flavisolibacter)、芽单胞菌属(Gemmatimonas)、丰佑菌属(Opitutus)、黏液杆菌属(Mucilaginibacter)、Dongia、Chryseo...  相似文献   
68.
钟明智  朱凌威  吉红  武文一  苟妮娜 《水产学报》2023,47(4):049612-049612
为探究多鳞白甲鱼幼鱼日粮中最佳碳水化合物添加类型,以葡萄糖、麦芽糖、糊精、玉米淀粉及纤维素5种碳水化合物为糖源,分别配制5种日粮,对多鳞白甲鱼幼鱼进行了为期56 d的养殖实验。结果显示,(1)生长及饲料利用率方面,麦芽糖组的终末体重、特定生长率、饵料系数以及蛋白质效率等指标最佳,纤维素组最差。(2)体成分方面,纤维素组全鱼粗脂肪水平最低,粗灰分水平显著高于麦芽糖组,麦芽糖组及纤维素组肌糖原含量最低,糊精组肝糖原含量最低。(3)主成分分析表明,C16:0、SFA、MUFA和PUFA比例对肝胰脏脂肪酸比例产生主要影响,其中,C16:0和SFA比例在麦芽糖组显著提高,MUFA比例在糊精组显著提高,而PUFA在纤维素组显著提高;C18:1n-9和MUFA比例对肌肉和脂肪组织总体脂肪酸组成产生主要影响,二者比例在麦芽糖组显著提高。(4)血清生化指标方面,麦芽糖组及纤维素组谷丙转氨酶活性、麦芽糖组谷草转氨酶活性显著较高,葡萄糖组及纤维素组碱性磷酸酶活性、球蛋白含量较高,而血糖含量反之。(5)抗氧化能力方面,麦芽糖组肝胰脏过氧化氢酶、总超氧化物歧化酶、谷胱甘肽过氧化物酶活性最高,纤维素组丙二醛含量最...  相似文献   
69.
Strain BC79, isolated from primeval forest soil in Qinling, Mountains, China, was identified as Bacillus methylotrophicus based on morphological, biochemical, physiological and chemotaxonomic analyses as well as phylogenetic 16S rDNA sequencing data. This strain was able to suppress mycelial growth and conidial germination of numerous plant pathogenic fungi in dual cultures on solid media. For exploring potential biocontrol activity, we assessed fermentation conditions for studying B. meth1ylotrophicus BC79. The active substance of BC79, phenaminomethylacetic acid, was extracted by TLC and HPLC, and identified as the strongest inhibitory substance described in B. methylotrophicus. Experiments in a greenhouse showed that application of BC79 culture filtrates 24 h before inoculation of Magnaporthe oryzae, the causal agent of rice blast, had 89.87% biocontrol efficiency. B. methylotrophicus BC79 colonized rice plant tissues and at 10 days after filtrate application, its population in leaves (1.65 × 108 CFU/g) was much larger than in stems (6.78 × 107 CFU/g) or roots (3.56 × 107 CFU/g). Field trials indicated that BC79 culture filtrate (4000 g/667 m2) showed the highest efficiency for M. oryzae, with 84.8% biocontrol effect, followed by of 15% phenaminomethylacetic acid extract (75.5%) and 20% tricyclazole (76.1%). Seedling and post-transplant stages were the best periods to apply BC79 for control of rice blast. The B. methylotrophicus BC79 strain hence has enormous potential as an agricultural agent for biocontrol of rice blast.  相似文献   
70.
The purpose of this study was to determine the optimal time for ovulation induction and artificial insemination (AI) based on the relationship between estrous behavior and ovulation in jennies. Thirty-two jennies were teased by one jackass for 1 hour per day during 46 days and estrous behaviors were recorded, while the follicular development and ovulation was examined by ultrasound. Furthermore, another 31 jennies were teased by one jackass as the teasing group (group T), which were injected with Deslorelin at 2 and 4 days after the onset of estrus, and AI was performed at 8 hours after each injection. Moreover, Ultrasound was performed on the follicle development of 23 jennies as the ultrasonography group (group U). Injection with Deslorelin when the follicle diameter ≥ 30 mm, and AI was performed at 8 hours later. The results showed that mouth clapping was the specific estrous behavior of jennies and indicated the beginning of estrus. The mean time for jennies to develop dominant follicles (≥30 mm) after the onset of estrus was 3.5 ± 1.3 days, and the mean time between the onset of estrus and ovulation was 5.1 ± 1.5 days. Estrous behaviors ended 0.5 ± 1.2 days after ovulation. After AI, there were no significant differences in ovulation (96.8% vs. 91.3%) and conception rates (40.0% vs. 38.1%) between group T and U. The optimal breeding time of jennies can be determined by jackass teasing and hastening ovulation by Deslorelin injection.  相似文献   
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