Effect and Functional Mechanism of the Action of Exogenous Gibberellin on Flowering of Peach

This study was conducted to assess the effect of gibberellin and its possible mechanism of action on peach flower formation. At flower induction, 100 mg L^-1 of gibberellic acid 3 （GA3） was sprayed on the leaves of peach [Prunus persica （L.） Batsch.] cv. Bayuecui. Using anatomy, immunohistochemistry, and semi-quantitation, the in situ distribution of GAs and the expression of the key genes involved in peach flower formation in the apical meristem were studied during flowering differentiation. The results showed that induction of flowering in the Bayuecui peach occurred prior to 10 July in Beijing, China. Flower induction and further differentiation of the peach flower organs were significantly inhibited by leaf-spraying of GA3 at a concentration of 100 mg L^-1 during the induction stage. The flowering rate was only 11.67% after treatment. The distribution of GA1 in the apical meristem varied during the process of flower bud differentiation. From 13 June to 25 July, the GA1 signal from control plants was detected mainly in the vascular bundles at the base of the flower buds. No GA1 signal was detected in the apical meristem. After treatment with GA3, the distribution was similar to that of the control from 13 June to 3 July. On 13 July, a GA1 signal was detected in the apical meristem accompanied by an increase in the GA1 signal in the vascular bundles at the base of the flower buds. The GA1 signal weakened significantly in both the vascular bundles and the apical meristem on 25 July. The expression of the genes PpLEAFY and MADS6 in flower buds could be detected only on 10 October in the GA3-treated plants. The critical period for flower induction of Bayuecui peach in Beijing was in early July, during which time, leaf-spraying with 100 mg L-1 GA3 could effectively inhibit flower induction and further differentiation of the flower buds. GA1 in the gibberellin family was the suppressor for flower induction in peach. Its action was affected by the stage of flower bud differentiation. Expression of the key gen     

Regulation of Development and Endogenous Polyamine Level in Chinese Cabbage (B. Campestris ssp. Pekinensis)

The endogenous polyamine levels were tested at every developmental stage in different ecotypes of the Chinese cabbage. The results showed that polyamincs (PAs) were decreased in the process of flower bud initiation and fornfation, but the floral stem formation and elongation were accompied by PAs increase. The level of Spm was related to the bolting date of Chinese cabbage. During the inducing of flower bud initiation and elongation of floral stem, and the changes of Spm were reversed between early bolting date and late bolting cultivars, but they have the same requirment for Spd for the starting of flower bud initiation and the starting of bolting. The level of Spd changed little during entire developmental stage for early bolting cultivars, but a lot for late bolting cultivars. The time that the highest level of Put appeared is related to the bolting date of Chinese cabbage.     

Effects of paclobutrazol on biomass production in relation to resistance to lodging and pod shattering in Brassica napus L.

Paclobutrazol was sprayed at 0,150,and 300 mg L~(-1) during the closed canopy stage and the early bud stage with two high-yielding cultivars of rapeseed,Yangguang 2009 and Fengyou 520.The impact of paclobutrazol on the accumulation and distribution of biomass and its relationship with yield,resistance to lodging and pod shattering were determined.All the treatments increased the resistance as well as yield.The maximum yield was obtained when paclobutrazol was applied during the closed canopy stage at 150 mg L~(–1).The plant’s resistance to both lodging and pod shattering was the maximum when paclobutrazol was applied during the early bud stage at 300 mg L~(–1).Paclobutrazol also delayed senescence,with the higher concentration or later spraying leading to more obvious effects;improved the net assimilation rate before the early bud stage;and promoted the relative growth rate of the main growth organ at each stage of growth and maximized the rate and quantities of biomass accumulation.However,at the higher concentration and later spraying,the increments were smaller.The spraying also increased the rates of biomass allocation to roots,leaves,and pods,but the rate of allocation to stems decreased as the plants grew shorter.The higher allocation to roots and the lower allocation to stems favoured resistance to both lodging and pod shattering whereas higher allocation to leaves and pods favoured yield.The higher concentration or late spraying led to excessive biomass being allocated to roots,which decreased leaf biomass during the bud stage,leading to greater resistance but lower yields.     

Correlation Between Endogenous Hormones of Stem Apices and Fruit Locule Numbers in Tomatoes During Floral Bud Differentiation Stages

The study was designed to elucidate the changes in the endogenous hormones of stem apices in tomatoes and the function of correlative endogenous hormones in tomatoes during floral bud differentiation stages. The tomato parents were crossed and reverse crossed by using two inbred lines of multi-locule （MLK1） and few-locule （FL1） with significant difference, and the relationship between endogenous hormones GA3, IAA, and ABA levels and ovary locule numbers of parents and progeny during floral bud differentiation initial stage, floral bud differentiation stage, sepal petal formation stage, carpel formation initial stage, and ovary locule complete formation stage was studied. GA3 levels in P1, P2, F1, and RF1 were consistent with locule numbers, and IAA and ABA levels were reverse to ovary locule numbers during the key stage. The correlation showed that, during sepal petal formation stage, the ovary locule numbers were positively correlated with GA3, GA3/IAA, and GA3/ABA, and were negatively correlated with IAA and ABA. It was speculated that increasing GA3 levels or decreasing IAA and ABA levels of stem apices in tomato might be able to enhance ovary locule numbers. The sepal petal formation stage was an important stage which regulated endogenous hormones in the ovary locule formation.     

Effects of Mg on C and N Metabolism of Soybean at Different Nitrogen Supplying Levels

A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen rate on N content, soluble protein, soluble sugar contents were not alike at different growth stage, although nodule dry weights raised, the yield and protein content of seeds decreased, however, the oil content was improved. The application of magnesium at medium and high nitrogen supplying levels promoted the uptake of N effectively, increased the soluble protein and soluble sugar contents, but the nodule dry weights of application magnesium at medium nitrogen supplying level decreased and the yield increased only a little despite the improved quality. Application of magnesium at high nitrogen supplying level raised nodule dry weights and soybean yield significantly, the quality of seeds was also improved.     

Physiological Changes and Cold Tolerance of Three Camphor Species During Natural Winter Temperature Fluctuations

The dynamic changes in the malondialdehyde（MDA）, superoxide dismutase（SOD）, soluble sugar, proline, and soluble protein contents, as well as the relative electrolyte conductivity and the corresponding cold resistance, of Cinnamomum bodinieri Level., C. camphora L., and C. caudiferum Kisterm were investigated during the winter months of October 2009 to April 2010. During the short period of temperature decline that lasted until mid-December, the changes in the relative electrolyte conductivity and MDA content with temperature were insignificant. In January, SOD activity continued to increase and then peaked as a result of rapid increases in soluble sugar, proline, soluble protein, as well as the inhibition of the relative electrolyte conductivity and decrease in MDA content. These physiological changes protected the camphor trees from cold damage during winter. From February to March, SOD activity and the soluble protein and proline contents increased with the increase in temperature. However, the relative electrolyte conductivity and MDA content decreased, indicating that the cell membrane damaged by low temperature was gradually being repaired. The cold dip in April led to slight increases in the relative electrolyte conductivity and MDA content. Using a fuzzy mathematics method, the cold resistance adaptability of the camphor trees was divided into three periods namely, the enhancement setting stage, the vigorous stage, and the reducing stage. The cold tolerance abilities were ranked as the following order： C. bodinieri Level〉C. camphora L.〉C. caudiferum Kisterm.     

QTLs for Sugar Content of Stalk in Sweet Sorghum （Sorghum bicolor L.Moench）

High sugar content of sorghum stalk is an important factor in the sorghum silage production. To identify the genomic regions controlling sugar content and to develop molecular markers linked to sugar content in sweet sorghum, we used an F2：3 segregating population consisting of 207 individuals derived from a cross between a high sugar content inbred line, Early Folger, and a normal inbred line, N32B, for genetic linkage mapping and quantitative trait locus （QTL） analysis. We constructed a genetic linkage map spanning 983.5 cM based on a total of 327 markers comprising 31 restriction fragment length polymorphism （RFLP） markers, 254 amplified fragment length polymorphism （AFLP） markers, and 42 simple sequence repeat （SSR） markers. In the 20 linkage groups detected, 98.2% of markers aligned to the 10 linkage groups of sorghum. Variations in sugar content at different growth stages and among internodes suggested that the sugar content of middle internodes is stable and suitable for measuring at early dough stage. The broad sense heritability （hB0 of sugar content was 0.64 and 0.62 estimated from the data of F3 families and each parent in 2003 and 2004. We identified one and two QTLs accounting for 22.2 to 25.0% of phenotypic variance using simple interval mapping method in 2003 and 2004, respectively. These two QTLs showed a negative additive effect, and over-dominance effect. A QTL on LG-D was detected in both two years. Above results will be help us to understand the genetic mechanism of sugar content in sorghum and the QTL detected in this study might be useful in the improvement of sugar content by marker-assisted selection.     

Effect of Alkali Stress on Soluble Sugar, Antioxidant Enzymes and Yield of Oat

Alkali stress can cause severe crop damage and reduce production. However, physiological processes involved in alkali stress in oat seedlings are not well understood. In this study, physiological responses and yield of oat to alkali stress were studied using the alkali-tolerant oat genotype Vao-9 and the alkali-sensitive oat genotype Baiyan 5. The results were: (i) low concentrations of alkali stress (25 and 50 mmol L-1) significantly reduced the yield and grain weight while increased the oat grain number per spike. A negative correlation between yield and malondialdehyde (MDA) content at the jointing and grain filling stages and positive correlations between yield on one hand and superoxide dismutase (SOD), and peroxidase (POD) activities on the other at the jointing stage were observed. There was a positive correlation between MDA and soluble sugar at the grain filling stage; (ii) soluble sugar content was increased at the jointing and grain filling stages and decreased at the heading stage by alkali stress; (iii) alkali stress increased the SOD activity during the heading and grain filling stages, and increased the POD activity at the heading stage. As compared to the control, the increase of MDA contents in alkali-treated oat was observed, during the jointing, heading and grain filling stages; (iv) under alkali stress, the oat genotype Vao-9 showed higher antioxidant enzyme activity and lower soluble sugar contents during the heading stage, and lower MDA contents than those in the oat genotype Baiyan 5 under alkali stress. The result suggested that the high ROS scavenging capacity and soluble sugar levels might play roles in oat response to alkali stress.     

寒地早粳花培培养基中铁的效应(英文)

In this study, through vitro culturing anthers of 7 F1 progenies of early Japonica rice in cold region on medium with different Fe2+ contents, it was found that Fe2+ content generated greater impacts on the induction rate and green plantlet differentiation. The result demonstrated that if Fe2+ increased from 32 to 40 mg/kg, the induction rate of early Japonica rice anther culture in N6 culture media was more then 1.4 times higher than that in N6 culture media containing 5.6 mg/kg Fe2+. In this concentration range, the induction rate increased with the increase of Fe2+ content, while if the concentration was over this concentration range, the induction rate decreased with the increase of Fe2+, showing single peak distribution. When the Fe2+ was 40 mg/kg in differentiation medium, the differentiation rate decreased dramatically. The green plantlet differentiations of callus which were induced on culture media containing 32-40 mg/kg Fe2+ were different, when they were cultured on MS culture media, and 85.7% materials could increase green plantlet productivity to about 7.8%. Therefore, increasing Fe2+in induction media properly could increase anther culture efficiency of early Japonica rice in cold region.     

Application of brassinolide alleviates cold stress at the booting stage of rice

The objective of the study was to determine the physiological mechanisms of plants in response to brassinolide(BR) alleviating cold water stress on rice. In this study, physiological responses of rice to exogenous BR and cold water submergence were investigated using the chilling-tolerant cultivar Kongyu 131(KY131) and the chilling-sensitive cultivar Kenjiandao 6(KJD6). A total of 2 mg L~(–1) BR increased activities of superoxide dismutase(SOD) and peroxidase(POD) and the contents of soluble sugar, soluble protein, and chlorophyll, but decreased the malondialdehyde(MDA) content in KY131 and KJD6 under cold water stress. The observed decreases in SOD and POD activities and MDA content recovered quickly after plants were returned to irrigation with water at temperatures of about 23.0°C in 2014. Additionally, the contents of nitrogen(N), phosphorous(P), and potassium(K) were increased by BR treatment under cold water stress. Exposure to BR also raised the percentage of high effective leaf area and leaf area index at the heading stage. Furthermore, it promoted soluble sugar synthesis, increased the rate of dry matter accumulation, and enhanced the export and translocation rates of the stem-sheath. The yield in KJD6 was significantly(P≤0.01 and P≤0.05) higher than that of the control in 2013 and 2014, respectively. The effect of BR treatment on rice leaf SOD and POD activities, MDA, chlorophyll, P, and stem-sheath K contents were more significant in KJD6 than in KY131. In conclusion, exogenous BR effectively reduced the physiological and metabolic damage in rice due to cold stress at the booting stage, promoted functional recovery in plants that received irrigation with water at a normal temperature following cold stress, and mitigated the effects of cold water stress on yield.The two varieties exhibited differential responses to BR; the weaker cold-resistant variety was more sensitive to BR and displayed stronger responses to exogenous BR.     

贵州草海耕地土壤与农作物中DDTs和HCHs残留及污染特征

采集草海流域周边成熟期整株农作物及土壤样品,分析测试其中DDTs和HCHs的含量,对比研究了土壤和作物中DDTs和HCHs污染水平及其在作物中富集能力。结果表明:研究区域土壤中HCHs和DDTs残留检出率均为100%,残留范围分别为0.06~16.66μg·kg-1和0.08~39.77μg·kg-1,土壤中HCHs和DDTs的残留量均小于国家土壤环境质量一级标准;三种农作物中DDTs、HCHs及Σ(DDTs,HCHs)残留量差异显著,HCHs含量最高的是玉米,DDTs和Σ(DDTs,HCHs)最高的是马铃薯;三种农作物中HCHs和DDTs残留的风险系数均为1.1,属于低度风险,农作物中DDTs、HCHs及Σ(DDTs,HCHs)的安全指数IFSC均小于1,DDTs和HCHs残留量对三种农作物安全影响的风险是可以接受的。     

1999和2000年安徽省汛期旱涝分析及可能性预报

1999与2000年安徽省汛期出现了2种截然不同的气候模态。1999年雨带位于长江流域,安徽出现南涝北旱,而2000年雨带位于淮河流域,安徽出现北涝南旱。通过环流对比分析认为1999年南涝北旱主要是6～7月鄂海阻塞高压的形成和维持及8月大陆异常的高压所致;2000年副高较1999年长期显著偏弱偏东、脊线位置偏北是形成雨带偏北的主要原因之一,因此是由于副高的影响机制不同而导致雨带位置的偏差。统计分析表明,副高对拉尼娜的响应滞后6～18个月最为显著,2000年副高的变化是对拉尼娜的响应,而1999年副高的变化可能是受厄尔尼诺的影响。另外,通过对南亚高压的季节性转换与夏季东亚阻塞高压的关系分析认为,南亚高压季节性转换早,夏季东亚易形成阻塞,江淮梅雨显著。     

凤丹与洛阳红根际微生物及其与根皮中丹皮酚含量的关系

用涂布平板法测定牡丹品种凤丹与洛阳红根际微生物种类及数量,用高效液相色谱仪测定其根皮中丹皮酚的含量,研究牡丹根际微生物及其与根皮中丹皮酚含量的关系。结果表明,凤丹根皮中丹皮酚含量(24.688 g/kg)高于洛阳红(13.024 g/kg);凤丹品种根际微生物数量明显低于洛阳红;丹皮酚含量与根际真菌、细菌数量呈负相关。凤丹和洛阳红根际真菌、细菌与放线菌总量均大于非根际;凤丹根际真菌、细菌数量均小于洛阳红,而放线菌数量大于洛阳红。     

巴蜀地区花生青枯病的分布、防治及抗病育种研究

对巴蜀地区(原四川省)花生青枯病的发生、分布及防治对策作了调查研究,发现巴蜀地区有花生青枯病发生。发病面积3万hm^2左右,约占全国发病面积的10％。明确了四川盆地南部的酸性土区是主要病区,其次是江河沿岸的老冲积黄壤和新冲积潮沙土区,尚未发现石灰性紫色土上有花生青枯病。试验证实硫酸铜、西力生、托布津等杀菌剂和2～3年轮作,对花生青枯病无防治作用,而选用抗病品种能有效遏制花生青枯病蔓延为害,并筛选出一批抗病品种用于生产。     

广西暴雨洪涝灾害的暴露度与脆弱性时空特征

在采用灾情数据数理统计方法重建广西壮族自治区2015年暴雨洪涝灾害时空格局的基础上,选取人口密度、GDP、农作物播种面积、受灾人口、直接经济损失、农作物受灾面积等作为暴露度和脆弱性的指标,从时空角度对暴雨洪涝灾害的暴露度与脆弱性进行分析,结果表明:2015年广西壮族自治区暴雨洪涝灾害月际分布不均,夏季最为集中;玉林市的人口暴露度最高;北海市的经济暴露度最高;河池市的人口脆弱性最高;桂林市的经济脆弱性最高;南宁市的农作物暴露度和脆弱性最高。     

我国科研院所研究生培养与科技创新

研究生培养与科技创新相结合是提高研究生培养质量与科技创新水平的关键。文章通过对我国科研院所在研究生培养方面的优势和特点的分析,结合科研院所在研究生科技创新能力培养方面的不足,从导师队伍建设、研究生培养环节、学术氛围、研究平台以及激励机制等五个方面探讨了加强科研院所研究生创新能力培养的途径,为提高我国科研院所研究生培养水平提供参考。     

高校专利保护和管理存在的问题及对策

高校是知识和技术创新的源头,是获得知识产权的重要单位,专利的保护和管理是高校知识产权保护管理的重点内容。文章针对高校专利保护与管理的现状和存在的问题,提出了增强保护意识、完善管理体制、培养管理人才、提高专利质量、减少专利流失等对策,为高校专利管理与保护工作提供参考。     

NAS and APS Meetings: Changes in Moods and in Modes

The National Academy of Sciences (NAS) and the American Physical Society (APS) both met in Washington in the week after Easter. Beyond the coincidence of time and place it is fair to say that the meetings shared a common mood. The truce in Vietnam is generally regarded as the principal cause of a muting of the voices of protest that have been heard at so many scientific meetings in recent years and finally had disturbed the even tenor of the academy's ways. Particularly at APS there seems to be new interest and energy directed to exploring ways to work within the system.     

TAIL-PCR研究进展及其在畜牧兽医中的应用

热不对称交错PCR(TAIL-PCR)是一种以PCR为基础的染色体步移,主要用于分离已知基因的侧翼序列,具有简便、快速、高效、特异性强等特点.文章从TAIL-PCR的原理、优势及局限性、反应体系优化等方面对TAIL-PCR的研究进展进行综述,其中在畜牧兽医中主要用于已知基因侧翼克隆和转基因动物模型外源基因插入位点确定.但由于基因组DNA的庞大和复杂性,使得从基因组中克隆获得目的基因仍存在诸多限制因素,如特异性引物错配和随机引物结合位点不确定,易造成非特异性产物的产生;模板GC含量异常或存在高度重复序列时,即使使用多种简并引物也难以获得阳性产物.因此,应根据实际情况对TAIL-PCR进行灵活调整.当模板较复杂时,可借鉴连接介导PCR原理,给引物加上接头,提高扩增反应的特异性;当模板较简单或序列较清晰时,可根据模板特点(如高GC含量)或已知模板序列设计引物、调整反应条件,增加操作的简便性;还可参考Suppression-PCR原理,选择引物和反应条件,获得较长的扩增片段.此外,TAIL-PCR可与多种技术联合使用,促使其在畜牧兽医中获得更广泛深入的应用.