Effects of Dietary Starch Source on via the Portal Vein Nutrient and Energy Absorption of Growing Pigs

Four crossbred （Duroc x Landrace x Yorkshire） boars, weighing an average of 22.40 ± 1.08 kg and fitted with permanent catheters in their portal and mesenteric veins as well as their carotid artery,were utilized in a 4 × 4 latin square design experiment in order to investigate the effects of different starch sources （maize ,brown rice, sticky rice, and resistant starch） on the absorption of energy sources through the portal vein. Portal blood flow averaged 30.68, 28.40, 29.99, and 30. 12 mL/min per kg BW for pigs fed the maize, brown rice, sticky rice, and resistant starch diets, respectively, and did not dif- fer （P 〉 0.05） between treatments. The absorptions of glucose, plasma ammonia, and total amino acids were significantly lower （P 〈 0.05 ） in pigs fed the resistant starch diet than pigs fed the other starch sources. In contrast, significantly （ P 〈 0.05 ） higher amounts of propionate and total volatile fatty acids were absorbed from the portal vein of pigs fed resistant starch than pigs fed diets based on maize, brown rice, or sticky rice. In addition, significantly （P 〈 0.05） more lactic acid was absorbed from the portal vein by pigs fed the sticky rice diet than pigs fed the other three diets. The energy absorbed from the portal vein in the form of glucose and amino-N as well as the total energy absorbed was significantly （P 〈 0.05） lower in pigs fed the resistant starch diet than pigs fed the other three starch sources. In contrast, the amount of energy absorbed in the form of volatile fatty acids was significantly （P 〈 0.05 ） higher in pigs fed resistance starch than pigs fed the other three starch sources. The total energy absorbed through the portal vein as a percentage of the gross energy and digestible energy consumed in pigs fed maize were 50.8% and 54.6%, respectively, which were significantly （P 〈 0.05 ） higher than the values in pigs fed resistant starch （41.5% and 46.6% respectively）. The results indicate that energy is absorbed in different forms and with different utilization efficiencies in the digestive tract of pigs as a result of feeding different starch sources. Starch sources supplying most of their energy in the form of glucose had higher energy utilization efficiencies, while starch sources supplying most of their energy in the form of volatile fatty acids or lactic acid had lower energy utilization efficiencies.     

Effects of Dietary Starch Source on Nutrient and Energy Absorption via the Portal Vein of Growing Pigs

Four crossbred(Duroc×Landrace×Yorkshire)boars,weighing an average of 22.40 ± 1.08 kg and fitted with permanent catheters in their portal and mesenteric veins as well as their carotid artery,were utilized in a 4 × 4 latin square design experiment in order to investigate the effects of different starch sources(maize,brown rice,sticky rice,and resistant starch)on the absorption of energy sources through the portal vein.Portal blood flow averaged 30.68,28.40,29.99,and 30.12 mL/min per kg BW for pigs fed the maize,brown rice,sticky rice,and resistant starch diets,respectively,and did not differ(P0.05)between treatments.The absorptions of glucose,plasma ammonia,and total amino acids were significantly lower(P0.05)in pigs fed the resistant starch diet than pigs fed the other starch sources.In contrast,significantly(P0.05)higher amounts of propionate and total volatile fatty acids were absorbed from the portal vein of pigs fed resistant starch than pigs fed diets based on maize,brown rice,or sticky rice.In addition,significantly(P0.05)more lactic acid was absorbed from the portal vein by pigs fed the sticky rice diet than pigs fed the other three diets.The energy absorbed from the portal vein in the form of glucose and amino-N as well as the total energy absorbed was significantly(P0.05)lower in pigs fed the resistant starch diet than pigs fed the other three starch sources.In contrast,the amount of energy absorbed in the form of volatile fatty acids was significantly(P0.05)higher in pigs fed resistance starch than pigs fed the other three starch sources.The total energy absorbed through the portal vein as a percentage of the gross energy and digestible energy consumed in pigs fed maize were 50.8% and 54.6%,respectively,which were significantly(P0.05)higher than the values in pigs fed resistant starch(41.5% and 46.6% respectively).The results indicate that energy is absorbed in different forms and with different utilization efficiencies in the digestive tract of pigs as a result of feeding different starch sources.Starch sources supplying most of their energy in the form of glucose had higher energy utilization efficiencies,while starch sources supplying most of their energy in the form of volatile fatty acids or lactic acid had lower energy utilization efficiencies.     

Effects of altitude and variety on nutrient levels and epiphytes of oats北大核心CSCD

Oat crops are a major animal feed source in the Qinghai-Tibetan plateau and nearby areas. Typically，the crops are used for making silage rather than hay because of frequent rain at harvest in autumn. However，there is little data on how the yield，forage quality and levels of epiphytes that may affect silage quality of different oat varieties are affected by altitude. Therefore，four oat varieties（Longyan No. 3，Longyan No. 5，Baiyan No. 2 and Bayou No. 3） were planted in 8 localities forming an altitude gradient： Huangzhong （2295 m），Tianzhu （2797 m），Shandan （2860 m），Hezuo （2957 m），Haiyan （3052 m），Maqu （3474 m），Maqin （3765 m）and Chengduo （4217 m）. Measurements included crop yield and dry matter （DM），water soluble carbohydrate （WSC），crude protein （CP），neutral detergent fiber （NDF）and acid detergent fiber （ADF）contents，and counts of lactic acid bacteria （LAB），molds，yeasts and aerobic bacteria. It was found that there were significant altitude and variety effects on fresh yield，nutritional quality and microbial epiphyte counts. With increase in altitude，fresh yield，WSC，NDF and LAB counts increased（P<0.05），as much as 284. 00%，15. 49%，10.81% and 11.60% increment were observed at Chengduo site than that at Huangzhong，respectively；meanwhile DM，CP and yeast and mold counts were reduced by 15. 67%，36.27%，23.53% and 7.75% at Chengduo compared with Huangzhong site，respectively. Among the four tested varieties，Longyan No. 5 had the highest fresh yield （75605 kg·ha−1），WSC （201.4 g·kg-1 DM） and NDF （604. 2 g·kg-1 DM） at the Chengduo site，followed by Longyan No. 3. The highest CP （119.7 g· kg-1 DM） and mold counts （4.12 lg cfu·g-1 FM） were observed in Baiyan No. 2 at the Huangzhong site. Bayou No. 3 produced the highest LAB and yeast counts at Maqin and Chengduo sites. In general，Longyan No. 3 and Longyan No. 5 gave better performance at sites above 3000 m altitude；for sites below 3000 m，the four tested varieties were all found to be suitable for silage production. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Screening of antifreeze-thawed lactic acid bacteria and their effects on oat silage fermentation quality and aerobic stability北大核心CSCD

The effects of freeze-thaw conditions on the fermentation quality and aerobic stability of oat silage were investigated. Four strains of freeze-thaw-resistant lactic acid bacteria（LAB）with rapid growth and efficient acid production were screened from 437 strains,which had been isolated from the Qinghai-Tibetan Plateau. Based on physiological and biochemical characteristics and 16S rRNA gene sequence alignment,the four strains were identified as Lactobacillus plantarum 157（LP157）,L. plantarum 160（LP160）,Lactobacillus brevis 248（LB248）,and Lactobacillus pentosus 260（LPE260）. In order to investigate their effects on the fermentation quality,nutrient composition,microbial counts and aerobic stability of oat silage under freeze-thaw conditions,seven treatments were tested as follows：1）LP157;2）LP160;3）LB248;4）LPE260;5）LP160+Lactobacillus rhamnosus 753 mixture （MIX）;6）A commercial bacterial silage additive（COM）;7）The same amount of sterilized distilled water（CK）. All treatments were ensiled for 60 days at a constant temperature of 20 ℃ and under a 20 ℃/-5 ℃ regime alternating every 12 h（freeze-thaw）. LP inoculation improved silage quality：The pH and dry matter loss in silages inoculated with LP157,LP160,LB248 and LPE260 were significantly lower than CK（P<0. 05）and lactic acid and acetic acid contents were significantly higher than CK（P<0. 05）,and the growth of spoilage micro-organisms such as coliform bacteria,yeast and mold were inhibited,both with fermentation at constant 20 ℃ and under freeze-thaw conditions. After aerobic exposure for 5 days,the pH and NH3-N of silages treated with LP157,LP160,LB248 and LPE260 were significantly（P<0. 05） lower than CK,MIX and COM. The aerobic stability of oat silage was improved,especially when inoculated with LP160（70 h vs. CK 11 h）. The results show that the four screened strains can be used as effective LAB inoculants for silage preparation in the freeze-thaw environment of the Qinghai-Tibetan Plateau. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Evaluation of adaptability of naked oat varieties in the alpine region of North China based on the AMMI model and GGE Biplot北大核心CSCD

In order to comprehensively evaluate the productivity, stability and adaptability of varieties of naked oats, as well as the discriminative power and representativeness of testing sites in the alpine region of North China, data for six naked oat varieties and six testing sites in 2019 were analyzed and evaluated using the AMMI （additive main effects and multiplicative interaction） model and GGE （genotype main effect plus genotype-environment interaction） biplot. It was found that analyses of naked oats regional trial results using the two methods together reduced the statistical error and increased the ability to declare variety means significantly different, compared to traditional ANOVA methods. It was found that genotype, environment, and genotype×environment interaction effects all contributed to differences in grain yield. Variety 200910-28-4-3（G2） showed the best performance in both grain yield and stability of yield across sites, followed by varieties 200910-5-2（G3） and 200910-22-1（G4）. In terms of the selection of regional adaptability test sites for varieties, Ulanqab pilot in Inner Mongolia had both good representativeness and strong discriminability, and was the most ideal test site. Chongli Shizigou Seed Farm and Zhangbei Base were also comparatively good test sites. This study provided a scientific evaluation of methodology for performance testing of naked oat varieties in the alpine region of north China and the results basis will assist future breeding and promotion. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Herbaceous Cultivation Test of Mulberry in Sichuan Sericultural Area

With Guiteyou 2 as the test mulberry variety, mulberry herbaceous cultivation field was established at the planting densities of 60 000,90 000 and 120 000 plants/hm~2, respectively. Hybrid mulberry herbaceous cultivation test was conducted, with Tongxiangqing mulberry field of mid-fist-form at conventional planting density of 4 995 plants/hm~2 as the control. The results showed that the leaf yield of herbaceous cultivation mulberry was closely related to the planting density. With the increasing planting density, the leaf yield per plant was decreasing, but the leaf yield per unit area of mulberry field was increasing. The annual leaf yield per unit area in the mulberry field with the average planting density of 120 000 plants/hm~2 was 37 560 kg/hm~2, 2.14 times of that of the control field. The moisture content of mulberry leaf in herbaceous cultivation field was 4.74% higher than the control; the contents of crude protein, crude fat, crude fiber and crude ash were 1.264%, 0.014%, 0.744% and 0.002%lower than the control, respectively. Comparison of leaf rearing with herbaceous cultivation mulberry and control mulberry showed that there was no significant difference in growth status of silkworm. The cocoon weight, cocoon shell weight, cocoon yield per 10 000 larvae, cocoon filament length and non-broken filament length of Chuanshan × Shushui were 12.81%, 14.29%, 13.85%, 5.95% and 7.68% lower than the control, respectively; but the percentage of common cocoons was 0.16% higher than the control; the cleanness and neatness were 0.2 and 1.25 points higher than the control;the filament size was 0.196 dtex lower than the control. The cocoon weight, cocoon shell weight, cocoon yield per 10 000 larvae, cocoon filament length and non-broken filament length of Jingsong × Haoyue were 11.06%, 10.20%, 11.53%, 9.46% and 9.03% lower than the control, respectively;but the percentage of common cocoons was 1.77% higher than the control; the cleanness and neatness were 0.12 and 2.50 points higher the control;and the filament size was 0.196 dtex lower than the control.     

Effects of dietary neutral detergent fiber on muscle fiber type composition and meat quality characteristics of black Tibetan sheep北大核心CSCD

The effects of different neutral detergent fiber （NDF） diets on body size indexes，muscle fiber type and meat quality of Qinghai black Tibetan sheep were investigated. Forty healthy 2-month-old black Tibetan sheep with similar body weights ［（10.28±0.43 kg］ were randomly divided into 2 groups with 20 rams per group. They were fed diets with differing neutral detergent fiber （NDF） levels of 26.33% （group L） and 46.14% （group H）. Using enzyme-linked immunosorbent assay， ATPase histochemical stain and real-time PCR， the muscle fiber characteristics，gene expression of myosin heavy chains （MyHCs） and meat quality in Black Tibetan sheep were evaluated. Results were as follows：1） The tagma indexes in group H were significantly lower than those in group L （P<0.05）. 2） The number of type II a muscle fibers in group H was significantly more than in group L （P< 0.05），and the areas of type I and type II a muscle fibers in group H were also greater than in group L （P< 0.05）. 3） The mRNA expression levels of MyHC I and MyHC IIa in group L were lower than those in group H （P<0.05），but the mRNA expression levels of MyHC IIb and MyHC IIx exhibited an opposite movement （P< 0.05）. 4） Compared with group L，superoxide dismutase，glutathione peroxidase，catalase and total antioxidant capacity contents increased （P>0.05） in group H，while the malondialdehyde （MDA） content was significantly decreased with in group L. 5） The muscle shear force in Group L was higher than that in Group H （P<0.05），while the redness （a*） was lower than that in Group H （P>0.05）. In conclusion，compared with a low-NDF diet，the high-NDF diet effectively reduced the proportion of glycolic muscle fiber and also enhanced antioxidant capacity，improving the muscle quality of black Tibetan sheep. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

The community structure of Methanomassiliicoccales in the rumen of Chinese goats and its response to a high-grain diet

Background: The newly proposed methanogenic order ‘Methanomassiliicoccales' is the second largest archaeal population in the rumen, second only to the Methanobrevibacter population. However, information is limited regarding the community of this new order in the rumen.Methods: This study used real-time PCR and 454 pyrosequencing to explore the abundance and community composition of Methanomassiliicoccales in the rumen of Chinese goats fed a hay(0% grain, n = 5) or a high grain(65% grain, n = 5) diet.Results: Real-time PCR analysis showed that the relative abundance of Methanomassili coccales(% of total archaea) in the goat rumen was significantly lower in the high-grain-diet group(0.5% ± 0.2%) than that in the hay-diet group(8.2% ± 1.1%, P 0.05). The pyrosequencing results showed that a total of 208 operational taxonomic units(OTUs) were formed from ten samples at 99% sequence identity. All the sequences were identified as Methanomassiliicoccaceae at the family level, and most of the sequences(96.82% ± 1.64%) were further classified as Group 8, 9, and 10 at the Methanomassiliicoccales genus level in each sample based on the RIM-DB database. No significant differences were observed in the number of OTUs or Chao1's, Shannon's or Pielou's evenness indexes between the hay-and high-grain-diet groups(P ≥ 0.05). PCoA analysis showed that diet altered the community of Methanomassiliicoccales.At the genus level, the relative abundances of Group 10(67.25 ± 12.76 vs. 38.13 ± 15.66, P = 0.012) and Group 4(2.07 ± 1.30 vs. 0.27 ± 0.30, P = 0.035) were significantly higher in the high-grain-diet group, while the relative abundance of Group9 was significantly higher in the hay-diet group(18.82 ± 6.20 vs. 47.14 ± 17.72, P = 0.020). At the species level, the relative abundance of Group 10 sp.(67.25 ± 12.76 vs. 38.13 ± 15.66, P = 0.012) and Group 4 sp. MpT 1(2.07 ± 1.30 vs. 0.27 ± 0.30,P = 0.035) were significantly higher in the high-grain-diet group, while the relative abundance of Group 9 sp. ISO4-G1 was significantly higher in the hay-diet group(12.83 ± 3.87 vs. 42.44 ± 18.47, P = 0.022).Conclusions: Only a few highly abundant phylogenetic groups dominated within the Methanomassiliicoccales community in the rumens of Chinese goats, and these were easily depressed by high-grain-diet feeding. The relatively low abundance suggests a small contribution on the part of Methanomassiliicoccales to the rumen methanogenesis of Chinese goats.     

Effects of Soybean Meal Replaced by Fermented Plant Protein Compound on Growth,Immune, Antioxidant and Intestinal Microflora Structure of Black Carp (Mylopharyngodon piceus)北大核心CSCD

This experiment was conducted to study the effects of soybean meal replaced by fermented plant protein compound on growth, immune, antioxidant and intestinal microflora structure of black carp (Mylopharyn-godon piceus). The different proportions (1∶1 and 2∶1) of fermented cottonseed meal and fermented rapeseed meal were used to replace 0 (control group), 50% and 75% soybean meal in the basic diet, respectively, 5 kinds of isonitrogenous and isoenergetic experimental diets were prepared, and the black carp with initial weight of (6. 04 ± 0. 18) g were fed for 8 weeks. The results showed that there were no significant differences on growth performance, morphological indicators and body composition among all group (P>0.05). There were no significant differences on serum complement 3, malondialdehyde, albumin contents and lysozyme activity among all group (P>0.05). The serum complement 4 content in 50% replacement group was significantly higher than that in other groups (P<0.05), and the serum immunoglobulin M content in 75% replacement group was significantly higher than that in the control group (P<0.05). There were no significant differences on hepatopancreas superoxide dismutase, catalase, alkaline phosphatase activities and total antioxidant capacity and total cholesterol content among all group (P>0.05). There were no significant differences on intestinal α-amylase and lipase activities among all group (P>0.05), and the intestinal pepsin activity in fermented cottonseed meal and fermented rapeseed meal replacing 75% soybean meal with 1 ∶ 1 proportion group was significantly higher than that in the control group (P<0.05). The dominant microflora in intestine of black carp at the phylum level were Proteobacteria, Firmicutes, Fusobacteria and Planctomycotes, and the dominant bacteria at the genus level were Aeromonas, Cetobacterium, Ralstonia and Plesiomonas. There were no significant differences on the relative abundances of intestinal main microflora among all group (P>0.05). To sum up, under the experimental conditions, the high proportion (75%) of fermented plant protein replacing soybean meal do not cause hepatopancreas damage and intestinal microflora structure change of black carp, and even improve the activities of some immune indicators in serum and intestinal protease activity, and the compound proportion of fermented cottonseed meal and fermented rapeseed meal have no significant effects on growth performance, morphological indicators, body composition, hepatopancreas antioxidant indexes and intestinal microflora structure of black carp. © 2023 Chinese Journal of Urology. All rights reserved.     

Comparison of Genetic Diversity and Growth Performance between the Selected Population and Hybridized Population of Litopenaeus vannamei at Low Temperature

[Objective] This study was conducted to compare the genetic diversity and growth performance of two Litopenaeus vannamei populations at low temperature. [Method] One population(selected population, SP) was produced through inbreeding and 3 years of selection from seven popula-tions of L. vannamei introduced from the United States and Singapore. The other population(hybridized population, HP) was the F1 generation of the crosses between Population SP and some excellent populations introduced from South Korea and Singapore. The growth performance of the two populations at low temperature was compared, and the genetic diversity and genetic differentiation between the two populations were assessed using13 microsatellite loci. [Result] The shrimps of population HP had better growth performance than those of population SP. The average body weight(BW) for population HP, which was(13.18 ±3.65) g/ind., was significantly higher than that of population SP, which was(12.20 ±3.14) g/ind. The coefficient of variation in body weight for population SP was 25.74%, and that for population HP was 27.69%. The other growth indices of popula-tion HP were all higher than those of population SP. One-way analysis of variance(ANOVA) indicated that there were highly significant differences in both BW and width of third abdominal segment(WTAS) between HP and SP( P0.001). The specific growth rate(SGR) and absolute growth rate(AGR) for population HP were(5.09±0.61) %/d and(0.26±0.60) g/d, respectively, while the SGR and AGR for population SP were(4.94 ±0.57) %/d and(0.24±0.63) g/d., both significantly lower than those of population HP(P0.001). Genetic diversity analysis revealed that the number of alleles(Na) of population HP(Na=7.9) was slightly higher than that of population SP(Na=7.6). The average polymorphic information content(PIC) of HP and SP populations was similar 0.63 and 0.62, both indicating high level of genetic diversity. The average observed heterozygosity( Ho) of HP and SP was0.492 and 0.483, and the expected heterozygosity(He) was 0.675 and 0.663, respectively. Both Hoand Heof population HP were higher than those of population SP, suggesting that HP had higher genetic diversity than population SP. Moreover, the mean of Fs Tvalues at the 13 microsatellite loci between HP and SP was 0.155 6, suggesting there was a significant genetic differentiation between the two populations. [Conclusion] Our results provide a theoretical basis for the breeding of new L. vannamei strains that are resistant to low temperature.     

高寒地区不同燕麦品系抗倒伏相关性状分析

为明确影响燕麦抗倒伏性的关键性状，选用高寒地区一组抗倒伏能力较强的燕麦资源（QYJ301、QYJ386、QYJ322、QYJ986、QYJ211）与另一组较易倒伏的燕麦资源（QYJ272、QYJ224、QYJ288、QYJ320、QYJ280、QYJ055）对与抗倒伏相关的25个性状进行方差分析。结果表明，抗倒伏组品系与易倒伏组品系的株高（抗倒伏组：103.00~117.40 cm；易倒伏组：125.80~144.18 cm）、穗长（抗倒伏组：17.82~21.94 cm；易倒伏组：23.82~27.10 cm）、重心高度（抗倒伏组：50.24~56.34 cm；易倒伏组：56.70~59.24 cm）、穗位高（抗倒伏组：84.54~95.46 cm；易倒伏组：98.80~117.08 cm）、基部节长、茎粗、茎粗系数、倒伏指数与茎基部力学性状均存在显著（P<0.05）或极显著（P<0.01）差异，且不同倒伏性能的燕麦资源在抗倒伏相关性状上表现不同。利用上述存在显著差异的22个相关性状进行聚类分析，以相对距离10作为划分，将11个燕麦资源聚成两类，即抗倒伏组与易倒伏组。进一步通过相关性分析发现，株高、穗长、重心高度、穗位高、茎粗系数、茎基部力学性状均与倒伏指数存在显著（P<0.05）或极显著（P<0.01）相关关系，均可作为评价燕麦抗倒伏性能的重要指标，这些性状综合影响燕麦的抗倒伏能力。     

半干旱区燕麦品种茎秆理化特性及其与抗倒性的关系研究

本研究以抗倒性不同的4个燕麦（Avena sativa L.）品种为材料,分析了乳熟期茎秆基部理化物质含量差异,探讨了茎秆理化特性与燕麦抗倒伏的关系。结果表明：4个燕麦品种田间倒伏分级和实际倒伏率差异显著（P<0.05）,抗倒伏品种与易倒伏品种在茎秆理化物质含量上差异显著（P<0.05）。抗倒伏品种茎秆基部第1节、第2节氮和镁低于易倒伏品种,而茎秆基部第1节、第2节钾、钙和硅高于易倒伏品种。另外,抗倒伏品种茎秆基部第1节、第2节木质素、纤维素和可溶性糖及C/N显著（P<0.05）高于易倒伏品种。4个燕麦品种茎秆基部理化物质与倒伏指数及其构成要素、茎秆基部形态特征间均存在显著（P<0.05）或极显著（P<0.01）相关关系,茎秆基部第1节与第2节钾、钙和硅,可溶性糖、木质素及纤维素含量的高低与燕麦抗倒伏关系密切。     

机播深度、播种量和施肥量对苦荞倒伏及产量的影响

为探明小型机械在丘陵山区播种苦荞的农机农技配套技术，以酉荞5号（中抗倒伏苦荞品种）为试验材料，于2016和2017年秋季，利用播种深度2（A₁）、3（A₂）和4 cm（A₃），播种量16.8（B₁）、33.6（B₂）和50.4 kg·hm^-2（B₃），施肥量150（C₁）、300（C₂）和450 kg·hm^-2（C₃）三因素三水平设计L₉3⁴正交试验，研究9个处理水平对苦荞倒伏和产量的影响。结果表明：对苦荞倒伏影响表现为播种深度>播种量>施肥量，随播种深度的增加，倒伏时期后移，3 cm播种深度苦荞倒伏级别和倒伏率最小；随播种量、施肥量的增加倒伏级别和倒伏率都增大。茎秆基部第二节间长度、茎粗、鲜重和抗折力从盛花期到成熟期逐渐增加，对茎秆基部第二节间茎粗、鲜重和抗折力的影响表现为播种量>播种深度>施肥量，随播种量的增加，第二节间茎粗、鲜重和抗折力逐渐减小，第二节间长度先减后增；播深对茎秆第二节间长度影响大于播量和施肥量，随播深的增加，第二节间茎粗、鲜重和抗折力先增后减，第二节间长度先减后增；随施肥量的增加，第二节间长度、直径、鲜重和抗折力逐渐增加。从盛花期到成熟期茎秆基部第二节间4-香豆酸辅酶A连接酶（4-coumarate：CoA ligase， 4CL）、苯丙氨酸解氨酶（phenylalanine ammonia-lyase，PAL）、肉桂醇脱氢酶（cinnamyl alcohol dehydrogenase，CAD）活性先升后降，木质素含量逐渐增加，对木质素含量、4CL、PAL、CAD酶活性的影响表现为播种量>播种深度>施肥量。对产量、单株粒数和总株数的影响表现为播种量>播种深度>施肥量，对千粒重的影响表现为播种量>施肥量>播种深度。随播种量的增加，总株数增加，单株粒数和千粒重减少，产量先增后减；随播种深度的增加，产量、单株粒数和总株数先升后降，千粒重先减后增；随施肥量的增加，总株数和产量差异不显著，单株粒数和千粒重显著增加。本试验条件下，丘陵山区苦荞小型机械播种A₂B₂C₃处理（3 cm播种深度、33.6 kg·hm^-2播种量和450 kg·hm^-2施肥量）最佳。     

不同燕麦品种茎秆形态特征与抗倒伏性的关系

以20个燕麦品种为材料,研究茎秆形态特征与抗倒伏性的关系,明确影响燕麦抗倒伏性的关键形态特征,为燕麦抗倒伏育种及栽培提供参考。结果表明：供试燕麦品种田间倒伏分级年际间变化不大,不同燕麦品种茎秆形态特征差异显著（P<0.05）,均与茎秆倒伏指数具有显著的相关性（P<0.05）。筛选出对燕麦倒伏起关键作用的6类主要形态因子,第2节粗度与壁厚、重量、节间充实度,机械强度、单茎（株）重、穗下节长是衡量和鉴定燕麦品种抗倒伏性强弱的关键形态指标。茎秆质量可划分为特优型、优质型、中间型和劣质型四种类型,其优劣程度间接反应抗倒伏能力,不同类型间茎秆倒伏指数和第2节机械强度差异显著（P<0.05）。     

高寒区不同燕麦品种(系)表型性状和茎秆力学特征与抗倒伏性的关系研究

为明确不同燕麦品种(系)间抗倒伏能力差异及其原因,在青藏高原高寒地区对选育的I-D品系及父本(青海甜燕麦)、母本(青海444),以抗倒伏较强的林纳和抗倒伏较弱的青引1号燕麦为对照,在开花期和乳熟期开展了表型性状、器官鲜重和茎秆力学特征等指标与抗倒伏性间的相关关系研究,找出影响燕麦倒伏的主要性状,探明燕麦抗倒伏评价的主要指标,为今后抗倒伏型燕麦品种选育及相关研究提供理论依据。结果表明,5个燕麦品种(系)乳熟期抗倒性强弱依次为林纳>I-D品系>青海甜燕麦>青海444>青引1号。相关分析表明,倒伏指数、表观倒伏率与穗长、穗位高、株高、重心高度、各器官鲜重、节间长呈正相关,与茎粗、秆壁厚间呈显著或极显著负相关,与茎秆力学特性间呈显著或极显著负相关关系。燕麦第二茎节对抗倒伏性的影响大于第三茎节。茎粗、秆壁厚、穿刺强度、茎秆折断力、折断弯矩、弯曲力矩和弯曲性能可作为燕麦抗倒性评价指标。株高对燕麦品种倒伏性的影响大于穗部特征,秆壁厚和茎粗对燕麦的抗倒性影响最大,穿刺强度最能反映燕麦品种抗倒伏能力,提高茎秆厚度和折断性能是提高燕麦抗倒伏能力的重要途径。选育的I-D品系燕麦株高适中,茎粗、秆壁厚、节间长及茎秆力学特性等方面优于亲本,其抗倒性显著优于亲本。     

追氮时期对饲用燕麦茎秆理化特性和抗倒性的影响

为了明确不同追氮时期对燕麦茎秆形态学特征、理化物质构成的影响及其与倒伏性的关系,本研究以2个饲用燕麦（Avena sativa L.）品种为材料,在大田条件下设置不同追氮时期处理,测定燕麦植株形态学、茎秆理化特性、抗倒性和产量指标。结果表明：随追氮时期后移,2个品种株高、基部节间和穗下节间长度、重心高度和倒伏率呈降低趋势,植株茎粗、茎秆鲜重、机械强度、茎秆中钾、硅、木质素含量在孕穗期追氮达到最高,可溶性糖含量在抽穗期追氮达到最高。与不施氮处理比较,孕穗期追氮处理‘蒙燕1号’和‘蒙特’品种的植株茎秆机械强度提高62.29%和42.72%,茎秆抗倒指数分别提高59.18%和45.58%,干草产量分别提高40.85%和19.22%（P<0.05）。综上,茎秆钾和硅元素、木质素及可溶性糖含量与燕麦抗倒伏性密切相关,在孕穗期追施氮肥有利于提高燕麦抗倒性能并获得较高饲草和种子产量。     

外源硒对燕麦茎部特征及其抗倒伏性的影响

为探讨喷施亚硒酸钠对燕麦（Avena sativa L.）茎部形态特征及其抗倒伏能力的影响,本研究以‘坝莜18号’为试验材料,在抽穗期对大田燕麦喷施不同浓度亚硒酸钠（0,16.44,21.92,54.8,65.76,98.64 g·hm^-2）,分析在喷硒后10,20,30,48 d燕麦茎部的形态特征、力学特征及抗倒伏性能的变化。结果表明：叶面喷施亚硒酸钠会影响燕麦茎秆的形态特征和抗倒伏能力。随着施硒量的增加,燕麦茎秆抗倒伏能力先升高后降低,并在施硒浓度为54.8 g·hm^-2水平下达到最大值。抗倒伏指数与株高、重心高度、茎秆基部第2节间茎粗、壁厚、节间充实度、惯性矩、抗弯刚度和机械强度之间存在极显著正相关关系（P<0.01）,与弹性模量呈显著正相关关系（P<0.05）。外源硒通过影响燕麦茎部形态特征和茎秆基部第二节间的强度,进而影响燕麦的抗倒伏能力。在燕麦抽穗期喷施浓度为54.8 g·hm^-2的亚硒酸钠,其抗倒伏性最强。     

全生育期干旱胁迫对‘青燕1号’燕麦叶绿素荧光参数的影响

干旱是限制燕麦生长的关键因素之一，为探究干旱胁迫对燕麦光合系统的影响，选用青海省推广品种‘青燕1号’为材料，设置4个水分梯度，即正常供水（CK，75%FWC）、轻度胁迫（60%FWC）、中度胁迫（45%FWC）和重度胁迫（30%FWC）。生育期干旱胁迫分为4类，即苗期-拔节期干旱（SJ）、苗期-抽穗期干旱（SH）、苗期-开花期干旱（SF）和苗期-乳熟期干旱（SM），并设置全生育期正常供水作为对照处理（CK）。探讨不同生育期燕麦叶绿素荧光参数对干旱胁迫的响应，以期为青藏高原燕麦抗旱育种和节水高产栽培提供理论指导。结果表明：1） 不同胁迫程度整体影响大小为：30%FWC>45%FWC>60%FWC；2） 不同生育时期胁迫整体影响大小为：SM>SF>SH>SJ；3） 胁迫程度与胁迫时期互作（Sd×Sp）对燕麦叶绿素参数影响最为显著。在30%FWC和SM时期时，叶绿素荧光参数受到的影响最大，此时光合作用的主要限制因素是非气孔限制，主要表现为PSⅡ反应中心失活，光合电子传递受阻；在60%FWC和SJ时，其受到的影响最小，此时影响光合作用的主要因素是气孔限制； 4） 在45%FWC、SH和SF时期，燕麦可通过叶片的气孔导度调节蒸腾作用和碳同化之间的关系，从而适应干旱胁迫；5） 叶绿素荧光参数的变化，间接反映了受到干旱胁迫时，燕麦光合作用能力的变化。Y（NO）、NPQ、Y（NPQ）和β与CK相比增加了85.52%、65.21%、33.76%和26.60%，F_v、F_m、ΦPSⅡ、ETR、F_m′、F_s、F₀′、qP、F₀、α和F_v/F_m分别降低了84.86%、75.41%、75.03%、75.00%、70.89%、61.38%、57.73%、57.06%、48.86%、45.61%和38.50%。     

不同燕麦资源生物量构成和茎秆特征与倒伏间的相关性研究

为探讨高寒区不同燕麦（Avena sativa L.）资源抗倒伏能力差异及其原因,本研究选择抗倒性不同的6份燕麦材料,比较其乳熟期生物量构成和茎秆特征与倒伏的关系,为燕麦抗倒伏研究提供科学依据。结果表明：6份燕麦材料茎基部的第二茎节茎粗、茎粗系数、节间长显著高于第一茎节,第一茎节杆壁厚和茎部力学特性显著高于第二茎节。燕麦表观倒伏率与茎、穗和单株鲜、干重间呈显著负相关;与重心高度间呈极显著正相关;与茎基部第一、二茎节茎粗、杆壁厚和茎粗系数间呈显著负相关,与茎节长间呈显著正相关;与茎秆力学特征间呈显著的负相关。地上生物量、重心高度、茎秆基部的茎粗、杆壁厚和茎秆力学特性可作为高寒区燕麦抗倒伏评价的重要参考指标。     

山西省大同市早播饲用燕麦叶部真菌病害病原鉴定及影响因素分析

山西省大同市是我国饲用燕麦的主产区之一，叶部真菌病害已成为限制其生产的主要因素，但目前尚不清楚病害种类及病原。此外，早播燕麦罹患病害产生的侵染源可能增加复种植物病害流行风险，阻碍燕麦可持续生产，迫切需要明确影响早播燕麦病害发生程度的主要因素，有针对性地制定防治措施。鉴于此，利用形态学特征和致病性测定对大同市天镇县的早播饲用燕麦种植田发现的叶部真菌病害进行鉴定，并且分析了收获期病情指数和病害影响因素之间的关系。结果表明：早播饲用燕麦共发现3种由真菌引致的叶部病害，分别为禾谷炭疽菌（Colletotrichum cereale）引致的叶枯病，燕麦内脐孺孢（Drechslera avenacea）引致的条斑病和禾柄锈菌燕麦转化型（Puccinia graminis f. sp. avenae）引致的秆锈病。不同种植和管理方式下，饲用燕麦叶枯病、条斑病和秆锈病均有不同程度发生，病情指数均值分别在1.9~5.6，1.0~6.2和0~0.9。相关性分析表明：喷灌是导致条斑病发病严重的主要因素，豆禾混播能降低饲用燕麦叶枯病的发生程度。此外，土壤速效N和速效K含量也能影响叶枯病和秆锈病的发生。建议牧草种植者在生产饲用燕麦时，采用合理的灌溉和施肥模式，推广牧草混播等种植技术，使用低毒高效杀菌剂对早播饲用燕麦进行病害防治，保证饲用燕麦产业的可持续发展。