土壤低温对嫁接黄瓜生理生化特性的影响

黄瓜嫁接及自根植株在结果初期经１１～１３℃土壤低温处理１周后,根系中酶的活性降低,根系生长受到抑制,伤流速率降低,伤流液中矿质元素含量明显减少,地上部生长也受到抑制,叶绿素含量减少,叶片水势降低,气孔阻力和细胞间隙ＣＯ２浓度增大,光合速率和蒸腾速率降低。嫁接植株各项测定指标均优于自根植株。由此得出,土壤低温通过根系对整个植株产生了不良影响;嫁接能够增强根系抗土壤低温的能力。     

妊娠后期梅花鹿母鹿精料营养成分分析及营养物质表观消化率测定

本研究采用化学分析和部分粪便收集法,对大连森林动物园妊娠后期梅花鹿精料营养成分及主要营养物质的表观消化率进行测定。结果表明:大连其精料中干物质(DM)含量为95.71%,粗蛋白(CP)为22.88%,粗脂肪(EE)为5.37%,粗纤维(CF)为4.16%,无氮浸出物(NFE)为56.21%,粗灰分(Ash)为7.09%,Ca为1.57%,总能(GE)含量为17.74mJ/kg;母鹿日干物质摄入量为1.26kg,DM、CP、CF、Ca和GE表观消化率分别为74.26%,74.26%,82.74%,69.38%,79.41%和78.25%。精料中主要营养成分、干物质日摄入量及营养物质消化率均较高,能满足妊娠后期梅花鹿母鹿在动物园这种特殊环境下的营养需要。     

新型发酵豆粕在断奶仔猪日粮中应用效果

旨在研究新型发酵豆粕对断奶仔猪生产性能、血液生化指标和肠道发育的影响.根据胎次、体质量相近原则,选择90头26日龄体质量为(4.75±0.38)kg的杜枫姜断奶仔猪,分为对照组、试验Ⅰ组(饲粮中添加17.5%发酵豆粕)和试验Ⅱ组(饲粮中添加35%发酵豆粕),每组3个重复,每重复10头.结果表明:试验Ⅰ组、Ⅱ组仔猪日增体质量显著高于对照组,分别增加13.90%(P<0.05)、50.55%(P<0.01),料重比较对照组分别降低19.47%(P<0.05)和4.21%(P>0.05).试验Ⅱ组(P<0.01)、试验Ⅰ组(P<0.05)仔猪腹泻率均显著低于对照组.试验Ⅱ组和试验Ⅰ组血清尿素氮(BUN)含量分别比对照组低5.23%(P<0.05)、4.13%(P<0.05).两试验组总蛋白(TP)和白蛋白(ALB)含量均有不同程度升高,血糖(GLU)均显著高于对照组(P<0.05).试验Ⅱ组的肠绒毛高度和绒毛高度/隐窝深度比值显著高于对照组(P<0.05),隐窝深度和肠壁厚度显著降低.新型发酵豆粕可改善断奶仔猪生长性能,显著降低腹泻率,提高饲料利用率,且可促进仔猪胃肠道发育.     

酸雨胁迫下La(Ⅲ)对水稻种子萌发及POD活性影响

为揭示酸雨影响种子萌发机理及减轻酸雨抑制种子萌发的途径,以pH2.0、2.5、3.0、3.5、4.0、4.5、5.0模拟酸雨溶液和稀土La(Ⅲ)复合处理水稻种子,探讨La(Ⅲ)对酸雨胁迫下水稻种子萌发、过氧化物酶(POD)活性和可溶性蛋白含量的影响.结果表明,高强度酸雨(pH≤2.5)胁迫下,经La(Ⅲ)处理和单一酸雨处理的水稻种子萌发均受到不可逆转性伤害:发芽率、发芽势、发芽指数、活力指数皆为零,部分种子异状发芽,POD活性及可溶性蛋白含量显著下降,La(Ⅲ)对种子的防护作用不明显.酸雨强度在pH≥3.0时,经La(Ⅲ)处理种子各项指标均高于单一酸雨处理种子,且指标变化曲线的拐点向酸度加大的地方推进,加强了种子对pH的耐受限度,说明La(Ⅲ)在缓解酸雨对水稻种子的伤害过程中具有重要意义.     

新合院生活的景观体验——黄骅新城家园景观设计

文章从分析现状入手,依据建筑规划所形成的空间提出了新合院的景观设计理念,并通过对道路系统、出入口、水系、植物、老年儿童活动空间等景观空间的精心组织,形成小区一心、二街、三轴、四院的景观骨架,再结合对景、框景等造园手法来打造一个简洁朴实又不失特色的小区景观。     

Biochemical properties,molecular characterizations,functions, and application perspectives of phytases

As a kind of enzyme widely existing in eukaryotic species, especially in grains and oil seeds, phytases play an important role in the degradation of some phosphates containing organic molecules. So far, phytases derived from various species have been successfully used as animal feed additives. It has also been experimentally verified that phytases have a potential use in generating crop germplasm with high phosphorus use efficiency, based on their biochemical role in releasing Pi from the phytate and its derivatives. In this paper, the biochemical properties, molecular characterizations, functions and the potential application perspective of phytases are reviewed and commented on, aiming at the further exploration of the biochemical and molecular characterizations, and promotion of the application of phytases, a kind of important enzyme possessing potential use in animal feeding and creation of high P use crop cultivars, in the future.     

离散数学中的研究标准

离散率过去是应用于不合格数据的研究。在物理学中离散率是应用于实验室的实验标准与本底的离散。这个与本底的离散就是实验数据的离散率研究标准。研究标准在生产实践中得出,被称作误差范围。制定这个给定的范围,应该从实验数据,经验数据,以及实际应用范围出发制定。     

Multi‐channel visual evoked potential as an ancillary tool to diagnose intraorbital optic nerve lesions

Multi‐channel visual evoked potential (MVEP) recording method was used to assist in diagnosing a 4‐month‐old Chinese Albino rabbit with an intraorbital mass. Subcutaneous MVEP of its both eyes were recorded simultaneously using 16 electrodes (4 × 4) multi‐channel array. Analysis of the cortical potential landscapes (CPL) showed that the conduction function of right eye was remarkably impaired in terms of decreased amplitudes and prolonged latencies. Specific side‐dominant distribution asymmetry of the decreased MVEP amplitudes indicated that the temporal side of the optic nerve (ON) was severely involved. Overall prolonged latencies of the CPL without side differences suggested that the functional impairment could have been caused by the mechanical compression exerted by an intraorbital mass. Surgical removal procedures confirmed that the mass was located temporally to the ON. Pathological examination provided a final diagnosis of a giant polycystic mucocele. Beyond its significance as a standard tool to assess functional changes of the visual pathway, MVEP recordings might assist locating intraorbital lesions that involve the ON by careful analysis of abnormal CPLs.     

Genetic Analysis and Molecular Mapping of a Stripe Rust Resistance Gene YrH9014 in Wheat Line H9014-14-4-6-1

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most widespread and destructive wheat diseases in many wheat-growing regions of the world. The winter wheat translocation line H9014-14-4-6-1 has all stage resistance. To identify stripe rust resistance genes, the segregating populations were developed from the cross between H9014-14-4-6-1 and Mingxian 169 (a wheat cultivar susceptible to all Pst races identified in China). The seedlings of the parents and F 1 plants, F2 , F3 and BC 1 generations were tested with Pst races under controlled greenhouse conditions. Two genes for resistance to stripe rust were identified, one dominant gene conferred resistance to SUN11-4, temporarily designated YrH9014 and the other recessive gene conferred resistance to CYR33. The bulked segregant analysis and simple sequence repeat (SSR) markers were used to identify polymorphic markers associated with YrH9014. Seven polymorphic SSR markers were used to genotype the F2 population inoculated with SUN11-4. A linkage map was constructed according to the genotypes of seven SSR markers and resistance gene. The molecular map spanned 24.3 cM, and the genetic distance of the two closest markers Xbarc13 and Xbarc55 to gene locus was 1.4 and 3.6 cM, respectively. Based on the position of SSR marker, the resistance gene YrH9014 was located on chromosome arm 2BS. Amplification of a set of nulli-tetrasomic Chinese Spring lines with SSR marker Xbarc13 indicated that YrH9014 was located on chromosome 2B. Based on chromosomal location, the reaction patterns and pedigree analysis, YrH9014 should be a novel resistance gene to stripe rust. This new gene and flanking markers got from this study should be useful for marker-assisted selection (MAS) in breeding programs for stripe rust.     

Legume–grass species influence plant productivity and soil nitrogen during grassland succession in the eastern Tibet Plateau

In recent years, numerous studies have evaluated the effect of plant function diversity on ecosystem functions such as productivity and soil nutrient status. We performed a redundancy analysis (RDA) to examine the relationship between plant functional diversity, productivity and soil nitrogen in a chronosequence of abandoned fields in sub-alpine meadow in the eastern part of the Tibet Plateau, China. We found that along the secondary succession sequence, legume richness and aboveground biomass significantly increased and both were positively correlated with total species richness (S) and aboveground biomass (T-bio). This pattern suggests that legume richness increases community productivity. In addition, we found that total aboveground biomass, legume and grass richness were positively correlated with soil microbial nitrogen (MBN), the ratio of microbial nitrogen to soil total nitrogen (MBN/TN) and the ratio of soil organic carbon and soil total nitrogen (C/N), whereas they were negatively correlated with soil total nitrogen (TN), organic carbon (C_org), and microbial carbon (MBC). Contrary to our predictions grasses such as Stipa grandis, Scirpus tripueter, Koeleria cristata were more closely associated with MBN, MBN/TN than legumes such as Oxytropis ochrocephala, Thermopsis lanceolate and Astragalus polycladus. The late-successional grass Kobresio humilis had a stronger positive correlation with NH₄-N as compared to the legumes and NO₃-N was not associated with any legume species. This suggests that the grasses and legumes have a synergetic positive influence on the ecosystem properties, especially nitrogen. Therefore, in this N-limited, plant community diversity of both legumes and grasses has a strong influence on ecosystem changes during succession.