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991.
Stalk related traits, comprising plant height (PH), ear height (EH), internode number (IN), average internode length (AIL), stalk diameter (SD), and ear height coefficient (EHC), are significantly correlated with yield, density tolerance, and lodging resistance in maize. To investigate the genetic basis for stalk related traits, a doubled haploid (DH) population derived from a cross between NX531 and NX110 were evauluated under two densities over 2 yr. The additive quantitative trait loci (QTLs), epistatic QTLs were detected using inclusive composite interval mapping and QTL-by-environment interaction were detected using mixed linear model. Differences between the two densities were significant for the six traits in the DH population. A linkage map that covered 1 721.19 cM with an average interval of 10.50 cM was constructed with 164 simple sequence repeat (SSR). Two, two, seven, six, two, and eight additive QTLs for PH, IN, AIL, EH, SD, and EHC, respectively. The extend of their contribution to penotypic variation ranged from 10.10 to 31.93%. Seven QTLs were indentified simultaneously under both densities. One pair, two pairs and one pair of epistatic effects were detected for AIL, SD and EHC, respectively. No epistatic effects were detected for PH, EH, and IN. Nineteen QTLs with environment interactions were detected and their contribution to phenotypic variation ranged from 0.43 to 1.89%. Some QTLs were stably detected under different environments or genetic backgrounds comparing with previous studies. These QTLs could be useful for genetic improvement of stalk related traits in maize breeding.  相似文献   
992.
Summary

Nitric oxide (NO) is an active molecule involved in many physiological functions in plants. To characterise the roles of NO in the tolerance of eggplant (Solanum melongena L.) to salt stress, the protective effects of exogenous sodium nitroprusside (SNP), a donor of NO, applied at different concentrations (0, 0.05, 0.1, or 0.2 mM), on plant biomass, photosynthesis, and anti-oxidant capacity were evaluated. The application of SNP alleviated the suppression of growth in eggplant under salt stress, as reflected by a higher accumulation of biomass. In parallel with growth, the application of SNP to salt-stressed plants resulted in enhanced photosynthetic parameters such as the net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), and intercellular CO2 concentration (Ci), as well as an increased quantum efficiency of PSII (Fv/Fm), efficiency of excitation capture of open PSII centres (Fv’/Fm’), quantum yield of PSII ( psii) and photochemical quenching coefficient (qP). Furthermore, exogenous SNP also reduced significantly the rate of production of O2? – radicals and the concentrations of malondialdehyde (MDA) and H2O2. It also increased the activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in eggplant leaves grown under salt stress. The results indicated that the protective effects of NO against salt stress in eggplant seedlings were most likely mediated through improvements in photosynthetic performance and the stimulation of anti-oxidant capacity.  相似文献   
993.
奇楠沉香为极具收藏及药用价值的上品沉香,其鉴定目前以化学方法为主,但其种苗从苗期至采香之间则难以用传统分类和化学方法进行鉴定,DNA条形码的发展为这一产业难题的解决提供了新的思路。本研究在明确白木香良种‘热科2号’可产奇楠沉香的基础上,采用11对植物DNA条形码通用引物对‘热科2号’和普通白木香两个沉香品种进行分子鉴定探索,发现改良的CTAB法更适合白木香叶片样本的DNA提取,继而发现ITS、ITS2和源自叶绿体的8个DNA条形码在两个品种均无变异,而ITS1序列的第159个碱基在‘热科2号’中为T,在普通白木香中为A,多样本实验证明该变异位点可以作为‘热科2号’和普通白木香种苗鉴定的分子标记。本研究结果为白木香良种‘热科2号’及其幼苗的鉴定提供分子水平的技术支持,也为白木香良种的溯源提供新的思路。  相似文献   
994.
Hesperidin is a flavanone glycoside widely available for dietary intake in citrus fruits or citrus fruit derived products; however, exhaustive and reliable data are scarcely available for biological activity when it exerts protective health effects in humans. The principal intent of this work is to check binding domain and structural changes of human serum albumin (HSA), the primary carrier of flavonoids, in blood plasma association with hesperidin by employing molecular modeling, steady state and time-resolved fluorescence, and circular dichroism (CD) methods. From molecular modeling simulations, subdomains IIA and IIIA, which correspond to Sudlow's sites I and II, respectively, were earmarked to possess affinity for hesperidin, but the affinity of site I with flavanone is greater than that of site II. This corroborates the site-specific probe and hydrophobic 8-anilino-1-naphthalenesulfonic acid (ANS) displacement results placing the hesperidin at warfarin-azapropazone and indole-benzodiazepine sites. Steady state and time-resolved fluorescence manifested that static type, due to HSA-hesperidin complex formation (1.941 × 10(4) M(-1)), is the operative mechanism for the diminution in the tryptophan (Trp)-214 fluorescence. Moreover, via alterations in three-dimensional fluorescence and CD spectral properties, we can securely draw the conclusion that the polypeptide chain of HSA is partially destabilized after conjugation with hesperidin. We anticipate that this study can provide better knowledge of bioavailability such as absorption, biodistribution, and elimination, of hesperidin in vivo, to facilitate the comprehension of the biological responses to physiologically relevant flavanones.  相似文献   
995.
为改变木材加工企业圆木旋切工艺现状、提高旋切设备自动化水平、拓宽加工范围、提高企业竞争力。运用集成制造系统的设计理论,提出了一种木材产品在线旋切系统的总体设计方案。在分析了在线旋切系统软、硬件组成和工作方式的基础上,剖析了无卡轴旋切机的结构特点,提出了新的旋切公式,建立了驱动辊变速进给的数学模型,设计了以PLC为控制核心的变频调速控制系统,为在线旋切系统的设计生产提供了指导方向与理论基础。进行了系统的在线生产测试,测试结果表明:可加工范围为厚度0.3~3.7mm的单板,圆木利用率达95%以上,出板线速度达27m/min,单板误差厚度小于0.03mm。在满足加工精度前提下,能够提高旋切速度,与上下游设备协调良好,满足木材加工企业现场的生产需要。  相似文献   
996.
基于图像频谱特征的稻飞虱识别方法   总被引:2,自引:2,他引:0  
为准确、快速的识别稻飞虱种类,采用自行设计的野外环境昆虫图像采集装置获取稻飞虱背部图像,通过对背景与目标像素的统计,选取140为阈值,对稻飞虱图像的蓝色通道进行二值化,将背景与目标分割开,采用形态学滤波以及开运算,与灰度图像进行与操作,获取单个稻飞虱虫体背部区域的灰度图像。然后对灰度图像进行二维傅里叶变换,获得虫体背部图像的二维傅里叶频谱。最后以ll(l=1,2,…,6)的二维频谱窗口数据作为稻飞虱特征参数,建立Fisher判别函数。训练集和验证集的试验结果表明,选用33二维傅里叶频谱窗口数据建立的判别模型,稻飞虱正确识别率可达到90%以上。该方法可以实现田间稻飞虱的自动识别。  相似文献   
997.
肉桂油/海藻酸钠薄膜物理特性和抗菌性能分析   总被引:6,自引:3,他引:3  
为了研究开发新型可降解抗菌包装材料,该文以添加不同体积肉桂油到海藻酸钠膜液中制成的肉桂油/海藻酸钠抗菌薄膜为研究对象,比较分析肉桂油添加量对肉桂油/海藻酸钠薄膜厚度、透光率、色泽和水蒸气透过率等物理特性的影响,同时,考察其对薄膜的抗菌性能的影响。膜液中肉桂油体积分数在0~1.0%时,薄膜厚度无明显变化,体积分数为1.2%时,薄膜厚度显著增加。随着肉桂油体积分数的增加,薄膜的透光率显著降低,薄膜水蒸气透过系数增大。肉桂油对薄膜色泽影响显著,随着肉桂油添加量的增加,薄膜色泽值a和b呈显著增加趋势。膜液中肉桂油体积分数为0.8%时,薄膜抗菌能力显著增强。研究结果表明,当膜液中肉桂油体积分数为0.8%时,薄膜具有较好的抗菌效果和物理性能。该研究可为肉桂油/海藻酸钠可降解抗菌薄膜生产工艺参数的进一步优化提供参考。  相似文献   
998.

Purpose

A field experiment with a reclamation chronosequence under rice?Cbarley cropping was conducted to investigate soil enzyme activities and microbiology in a coastal saline soil. The aim of this study was to test whether changes in enzyme activity and microbial community structure are directly impacted by changes in soil pH, electrical conductivity (EC), and organic carbon (SOC) due to reclamation.

Materials and methods

The research area is located in south-eastern China. Four experimental sites were reclaimed in 1976, 1984, 1996, and 2006, respectively, and each site was divided into three plots, each of which was 22?m?×?10?m. Each year, the plots were planted with rice (cv Xiushui) in summer and barley (cv Yanmai) in winter. Soil pH and EC were determined in an aqueous suspension with a 1:5 ratio of soil and water. Soil organic carbon content was measured by dichromate oxidation with heating. Measured soil enzyme activities included catalase, urease, and protease. Soil microbial community structures were assessed using denaturing gradient gel electrophoresis.

Results and discussion

Reclamation under rice?Cbarley cropping reduced EC and pH, but increased SOC, the activities of catalase, urease and protease, and the cell numbers of bacteria, actinomycetes, and fungi, resulting in an increase in the bacterial community diversity. The enzyme activities and bacterial community diversity were significantly positively correlated with SOC, and negatively correlated with pH and EC. Five bacterial groups related to Gaetbulibacter, Sporosarcina, Flavobacterium, Aequorivita, and Gillisia, which have been associated with saline waters, did not appear in the soils that had been reclaimed prior to 1996.

Conclusions

Results of this field study suggest that soil properties which affect microbial activity such as EC, pH, and SOC significantly influence the activities of catalase, urease, and protease, and microbial community composition. More than 10?years after reclamation under rice?Cbarley cropping, EC had decreased and bacteria typically found in marine and saline environments had disappeared from the soil.  相似文献   
999.

Purpose

The aim of this study was to understand the effect of nitrogen fertilization on soil respiration and native soil organic carbon (SOC) decomposition and to identify the key factor affecting soil respiration in a cultivated black soil.

Materials and methods

A field experiment was conducted at the Harbin State Key Agroecological Experimental Station, China. The study consisted of four treatments: unplanted and N-unfertilized soil (U0), unplanted soil treated with 225?kg?N?ha?1 (UN), maize planted and N-unfertilized soil (P0), and planted soil fertilized with 225?kg?N?ha?1 (PN). Soil CO2 and N2O fluxes were measured using the static closed chamber method.

Results and discussion

Cumulative CO2 emissions during the maize growing season with the U0, UN, P0, and PN treatments were 1.29, 1.04, 2.30 and 2.27?Mg?C?ha?1, respectively, indicating that N fertilization significantly reduced the decomposition of native SOC. However, no marked effect on soil respiration in planted soil was observed because the increase of rhizosphere respiration caused by N addition was counteracted by the reduction of native SOC decomposition. Soil CO2 fluxes were significantly affected by soil temperature but not by soil moisture. The temperature sensitivity (Q 10) of soil respiration was 2.16?C2.47 for unplanted soil but increased to 3.16?C3.44 in planted soil. N addition reduced the Q 10 of native SOC decomposition possibly due to low labile organic C but increased the Q 10 of soil respiration due to the stimulation of maize growth. The estimated annual CO2 emission in N-fertilized soil was 1.28?Mg?C?ha?1 and was replenished by the residual stubble, roots, and exudates. In contrast, the lost C (1.53?Mg?C?ha?1) in N-unfertilized soil was not completely supplemented by maize residues, resulting in a reduction of SOC. Although N fertilization significantly increased N2O emissions, the global warming potential of N2O and CO2 emissions in N-fertilized soil was significantly lower than in N-unfertilized soil.

Conclusions

The stimulatory or inhibitory effect of N fertilization on soil respiration and basal respiration may depend on labile organic C concentration in soil. The inhibitory effect of N fertilization on native SOC decomposition was mainly associated with low labile organic C in tested black soil. N application could reduce the global warming potential of CO2 and N2O emissions in black soil.  相似文献   
1000.
针对农业生产过程中信息监测点相对分散和数据有线传输方式的局限性,设计和开发了一种基于无线传感器网络的农田土壤含水率监测系统,系统由3个土壤含水率监测终端节点、1个路由节点和1个网关节点组成。传感器采用蓄电池供电,终端节点和路由节点采用干电池供电,各节点间通信遵循Zigbee通信协议。同时,开发了数据采集、无线通信等程序,能够以任意时间间隔采集监测点土壤含水率数据,实现数据的处理、传输和存储等功能。实验结果表明,系统能实现数据的稳定传输,适合农田土壤含水率实时监测。  相似文献   
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