不同浓度大豆卵磷脂替代蛋黄对东佛里生奶绵羊精液冷冻保存效果的影响

本试验皆在研究添加不同浓度大豆卵磷脂（SL）冷冻保存东佛里生奶绵羊精液的效果。我们在Tris基础稀释液中,添加18%蛋黄为对照组,添加0.5%、1%、1.5%、2%、2.5%SL设为试验组,检测冷冻精液解冻后的精子活率和顶体完整率。结果显示,添加0.5%、2.5% SL冷冻稀释液稀释的精液,解冻后精子活率和顶体完整率与其他组之间存在显著差异（P<0.05）;添加18%蛋黄和1%～2% SL冷冻稀释液稀释的精液,冷冻解冻后精子活率和顶体完整率之间无显著差异（P>0.05）;添加18%蛋黄和1.0%～1.5% SL冷冻稀释液稀释后的精液,进行人工授精后母羊的妊娠率与对照组无显著差异（P>0.05）。因此,大豆卵磷脂可以作为冷冻保护剂用于东佛里生奶绵羊精液的冷冻保存,其最佳添加浓度为1～2%（g／L）。     

Genetics of grains per spike in durum wheat under normal and late planting conditions

Parental, F₁, F₂, BC₁, BC₂, BC₁₁, BC₁₂, BC₂₁, BC₂₂, BC₁ self and BC₂ selfed generations of three crosses involving six cultivars of durum wheat (Triticum durum Desf.) were studied for grains per spike under normal and late sown environments to analyze the nature of gene effects. A 10-parameter model did not fully account for the differences among the generation means. In two cases more complex interactions or linkage were involved in the inheritance of grains per spike in durum. Both digenic and trigenic epistatic interactions had a role in controlling the inheritance of grains per spike, however, trigenic interactions contributed more than digenic interactions. Non-fixable gene effects were many times higher than fixable ones in all three crosses and in both sowing environments indicating a major role of non-additive gene effects in the inheritance of this trait. Duplicate epistasis between sets of three genes under both environments was recorded for the cross Raj 911 × DWL 5002. Epistatic interactions, particularly the trigenic ones, contributed the maximum significant heterosis. Epistatic interactions involving dominance in the F₂ generations caused significant inbreeding depression. Selective diallel mating and/or biparental mating could be used for amelioration of grains per spike in durum wheat.     

两种玉米温敏不育系的育性相关性状的比较及不育基因的初步定位

本研究通过形态学、生态学、遗传学及基因定位研究表明,玉米温敏不育系琼6Qms和琼68S是两种完全不同的玉米温敏不育系,琼6Qms的育性主要表现为颖壳不开裂,育性转换主要受温度影响,该性状由两对隐性重叠不育基因控制,分别位于第3和第5染色体上。琼68S为花药败育型,其育性转换受温度控制,不育性由一对隐性基因控制,该基因位于第2染色体上。     

Powdery mildew resistance gene (<Emphasis Type="Italic">Pm</Emphasis>-<Emphasis Type="Italic">AN</Emphasis>) located in a segregation distortion region of melon LGV

Powdery mildew is one of the most important melon pathogens all over the world. So far, many genes conferring resistance to powdery mildew of melon have been described, but few of these have been finely mapped or cloned. Two F₂ populations derived from Ano2 × Hami413 and Ano2 × Queen were used to map the powdery mildew resistance gene by methods of Bulked Segregation Analysis (BSA), comparative genomics and Resistance Gene Analogues (RGA) mapping. It was found that the resistance to powdery mildew in Ano2 was conferred by a dominant gene, and the gene was named Pm-AN. The genetic analysis revealed that Pm-AN located between two codominant markers RPW and MRGH63B in linkage groupV. The genetic distances between Pm-AN and these two markers were 1.4–1.8 and 1.6–2 cM. No recombination was found between Pm-AN and markers ME/E1, SRAP23. Pm-AN was located in a RGA-rich region and cosegregated with the RGA marker MRGH5 and the resistance gene Vat. Synteny analysis showed that markers in this region were collinear between melon and cucumber. Segregation distortion was found in this region using both Ano2 × Hami413 and Ano2 × Queen F₂ populations, and the distortion was more distinct in Ano2 × Hami413 F₂ population. The center of segregation distortion was located in the RGA rich region harboring Pm-AN.     

Identification of RAPD markers linked to the rust (<Emphasis Type="Italic">Uromyces fabae</Emphasis>) resistance gene in pea (<Emphasis Type="Italic">Pisum sativum</Emphasis>)

Summary Two RAPD markers linked to gene for resistance (assayed as pustule number cm⁻² leaf area) to rust [Uromyces fabae (Pers.) de Bary] in pea (Pisum sativum L.) were identified using a mapping population of 31 BC₁F₁ [HUVP 1 (HUVP 1 × FC 1] plants, FC 1 being the resistant parent. The analysis of genetics of rust resistance was based on the parents, F₁, F₂, BC₁F₁ and BC₁F₂ generations. Rust resistance in pea is of non-hypersensitive type; it appeared to be governed by a single partially dominant gene for which symbol Ruf is proposed. Further, this trait seems to be affected by some polygenes in addition to the proposed oligogene Ruf. A total of 614 decamer primers were used to survey the parental polymorphism with regard to DNA amplification by polymerase chain reaction. The primers that amplified polymorphic bands present in the resistant parent (FC 1) were used for bulked segregant analysis. Those markers that amplified consistently and differentially in the resistant and susceptible bulks were separately tested with the 31 BC₁F₁ individuals. Two RAPD makers, viz., SC10-82₃₆₀ (primer, GCCGTGAAGT), and SCRI-71₁₀₀₀ (primer, GTGGCGTAGT), flanking the rust resistance gene (Ruf) with a distance of 10.8 cM (0.097 rF and LOD of 5.05) and 24.5 cM (0.194 rF and a LOD of 2.72), respectively, were identified. These RAPD markers were not close enough to Ruf to allow a dependable maker-assisted selection for rust resistance. However, if the two makers flanking Ruf were used together, the effectiveness of MAS would be improved considerably.     

Remote sensing and in situ-based estimates of evapotranspiration for subirrigated meadow,dry valley,and upland dune ecosystems in the semi-arid sand hills of Nebraska,USA

Water consumed through evapotranspiration (ET) impacts local and regional hydrologic regimes on various spatial and temporal scales. Estimating ET in the Great Plains is a prerequisite for effective regional water resource management of the Ogallala (High Plains) Aquifer, which supplies vital water resources in the form of irrigation for extensive agricultural production. The Sand Hills region of Nebraska is one of the largest grass-stabilized eolian (windblown) sand dune formations in the world, with an area of roughly 50,000–60,000 km² that supports a system of five major land cover types: (1) lakes, (2) wetlands (with lakes, ~5%), (3) subirrigated meadows (water table is within ~1 m of surface; ~10%), (4) dry valleys (water table is 1–10 m below surface; ~20%), and (5) upland dunes (water table is more than 10 m below surface; ~65%). Fully understanding the hydrologic regime of these different ecosystems is a fundamental challenge in regional water resource assessment. The surface energy and water balances were analyzed using Bowen Ratio Energy Balance Systems (BREBS) at three locations: (1) a meadow, (2) a valley, and (3) an upland dune. Measurement of the energy budget by BREBS, in concert with Landsat remote sensing image processing for 2004 reveals strong spatial gradients between sites in latent heat flux that are associated with undulating topographic relief. We find that daily estimates of ET from BREBS measurements and remote sensing agree well, with an uncertainty within 1 mm, which is encouraging when applying remote sensing results across such a broad spatial scale and undulating topography.     

Elevated CO<Subscript>2</Subscript> alters the abundance but not the structure of diazotrophic community in the rhizosphere of soybean grown in a Mollisol

The effect of elevated CO₂ (eCO₂) on rhizospheric diazotrophic community in cropland has little been studied, although eCO₂ facilitates nodulation and N₂ fixation in legumes. In this study, four soybean cultivars (Xiaohuangjin, Suinong 8, Suinong 14, and Heinong 45) were grown in Mollisols for 65 days under ambient CO₂ (aCO₂) (390 ppm) or eCO₂ (550 ppm). Quantitative PCR and Illumina MiSeq sequencing targeting the nifH gene that reflects the composition of diazotrophic community were determined. Elevated CO₂ significantly increased the abundance of nifH gene copies in the rhizospheres of the Suinong 8 and Heinong 45 cultivars, but not in the Suinong 14 and Xiaohuangjin cultivars. The nifH abundance correlated negatively with nodule density (p?≤?0.01) but positively with nodule size (p?≤?0.01). Elevated CO₂ did not significantly alter the composition of diazotrophic community, nor shift dominant bacterial operational taxonomic units (OTUs). These results indicated that eCO₂ stimulated the growth but did not alter the community composition of diazotrophs in the rhizosphere of soybean, which depended on cultivar and might contribute to nodulation responses to eCO₂.     

Biological P cycling is influenced by the form of P fertilizer in an Oxisol

Phosphate rock (PR) is an alternative fertilizer to increase the P content of P-deficient weathered soils. We evaluated the effects of fertilizer form on indicators of biological cycling of P using an on-farm trial on a Rhodic Kandiudox in western Kenya. Treatment plots were sampled after 13 cropping seasons of P applications as Minjingu phosphate rock (PR) or as triple super phosphate (?TSP) (50 kg P ha^?1 season^?1), as well as a P-unfertilized control (0 kg P ha^?1 season^?1). Soils (0–15 and 15–30 cm) were analyzed for microbial biomass P (P_mic), activities of acid phosphomonoesterase, alkaline phosphomonoesterase, and phosphodiesterase, and sequentially extractable P fractions. P additions as Minjingu PR yielded 299% greater P_mic than TSP at 0–15-cm depth despite similar labile P concentrations in the two P fertilization treatments and stimulated activities of acid phosphomonoesterase (+39%). When added in the soluble form of TSP, a greater percentage of total soil P was present in mineral-bound forms (+33% Fe- and Al-associated P). Higher soil pH under Minjingu PR (pH 5.35) versus TSP (pH 5.02) and the P-unfertilized treatment (pH 4.69) at 0–15-cm depth reflected a liming effect of Minjingu PR. The form of P fertilizer can influence biological P cycling in weathered soils, potentially improving P availability under Minjingu PR relative to TSP via enhanced microbial biomass P and enzymatic drivers of P cycling.     

Steam explosion pretreatment used to remove hemicellulose to enhance the production of a eucalyptus organosolv dissolving pulp

The steam explosion (SE) pretreatment associated with the organosolv process was investigated to produce dissolving pulp from eucalyptus. Prehydrolysis Kraft (PHK) pulping was also done to produce viscose and acetate grade pulps as reference. The organosolv pulps were delignified in two steps with sodium chlorite. Viscose and acetate grade PHK pulps were bleached by OD₀(EH)D₁P and OD₀(EP)D₁PCCE sequences, respectively. Dilute acid-catalyzed (with acid addition) SE pretreatment dissolved more xylan than auto-catalyzed (no acid addition) SE pretreatment. Steam-exploded unbleached organosolv pulps showed lower residual lignin content and screened yield than unbleached organosolv pulps without SE pretreatment. Steam explosion pretreatment helped to decrease lignin content and damaged fiber length of unbleached organosolv pulps. The 1.0% H₂SO₄ organosolv pulp (organosolv dissolving pulp at bioconversion conditions) showed the highest reactivity. Even showing low viscosity for some applications, in general, the organosolv dissolving pulps produced in this study can be used for making lyocell fibers.     

Effects of density and resin content on the physical and mechanical properties of scrimber manufactured from mulberry branches

The silk industry in China produces a large amount of mulberry branches as by-product every year. Mulberry branches have high longitudinal toughness and good overall mechanical properties. However, these branches are incinerated because their utility in other industries is limited by their small size. This study determines the feasibility of manufacturing scrimber from mulberry branches by using cold pressing method, followed by thermo-curing with different densities and resin contents. Results show that density [ranging from (0.81–1.24) g/cm³] exerts a greater effect on the shear strength, modulus of rupture (MOR), and modulus of elasticity (MOE) than resin content (changing from 8 to 20 %). The increase rate slows down when the density exceeds 1.1 g/cm³ and the resin content reaches more than 12 %. The strength-to-weight ratio analysis shows that the MOR/density and MOE/density maximum at 1.02–1.10 g/cm³. The density and resin contents of mulberry scrimber with cold compress and heat setting can be set to 1.0–1.1 g/cm³ and at approximately 12 %, respectively. The mechanical properties of the product meet the maximum requirement indicated in the Chinese national standard for construction. Mulberry scrimber can be a very promising supplement for wood because of its good performance, abundant supply, and renewability.