山东半岛南部沿岸中国对虾放流数量对秋汛产量的影响     

信敬福 《水产科学》1999,18(6):7-9

根据１９８３～１９９８年山东半岛南部沿海对虾放流增殖结果,对秋汛对虾产量与放流数量之间的关系进行了研究。结果表明：秋汛对虾产量随放流数量的增加而增加,二者呈Ｙ＝３６３．７＋１２６．４Ｘ相关关系（ｒ＝０．９１８）。  相似文献   

脊尾白虾不同发育期mtDNA拷贝数变化特征分析          下载免费PDF全文

张培  徐莞媛  李志辉  高焕  张庆起  赖晓芳  陈建华  阎斌伦 《渔业科学进展》2018,39(6):173-179

为了解脊尾白虾(Exopalaemon carinicauda)在不同发育期线粒体基因组(mtDNA)拷贝数的变化特征,本研究共采集其8个时期(受精卵期、溞状幼体Ⅰ期、溞状幼体Ⅱ期、溞状幼体Ⅲ期、溞状幼体Ⅳ期、溞状幼体Ⅴ期、仔虾期和成虾期)的DNA样品,利用TaqMan实时荧光定量PCR技术,对上述各发育期单个细胞中的mtDNA拷贝数进行了测定。检测结果显示,脊尾白虾受精卵期、溞状幼体Ⅰ期、溞状幼体Ⅱ期、溞状幼体Ⅲ期、溞状幼体Ⅳ期、溞状幼体Ⅴ期、仔虾期和成虾期的mtDNA拷贝数的均值分别为2366、2648、2644、2873、3559、9948、6452和8872。进一步统计分析结果显示,mtDNA拷贝数与发育时间存在正相关性,相关系数为0.83。研究表明,随着脊尾白虾不断生长,其单个细胞中mtDNA拷贝数总体呈上升趋势。  相似文献   

Enhanced kernel set promoted by synchronous pollination determines a tradeoff between kernel number and kernel weight in temperate maize hybrids     

Martín Uribelarrea  Jorgelina Cárcova  Lucas Borrás  María E. Otegui 《Field Crops Research》2008

Maize (Zea mays L.) grain yield is strongly related to the number of harvested kernels, where kernel number can be increased by synchronously pollinating silks rather than allowing them to be progressively pollinated as they naturally appear from the husks. However, there is scarce evidence on how this practice affects kernel weight (KW) and plant grain yield (PGY), and no report exists on its effects when combined with treatments aimed to reduce apical dominance, like male sterility and detasseling. Field experiments were conducted in two growing seasons (Exp₁ and Exp₂) using two hybrids, cropped at contrasting stand densities (3 and 9 plants per m²) and including (i) male-fertile and male-sterile versions, (ii) tasseled and detasseled plants, and (iii) natural (NP) and synchronous pollination (SP; pollen added manually to ears bagged 5 days after initial silking) systems. Tassel growth of sterile and fertile versions was also evaluated in a separate experiment (Exp₃). Detasseling increased the number of ears per plant reaching silking (P < 0.001) of NP plants, but this beneficial effect of reduced apical dominance did not improve kernel number per plant (KNP) or PGY. Similarly, the early arrest of anther growth in male-sterile plants had no clear benefit on KNP. In contrast, KNP was enhanced by synchronous pollination (range between −13% and +71%; average of +15.4% in Exp₁ and +3.9% in Exp₂). However, this pollination system promoted a decreased in KW (range between −30% and +4%; average of −11.8% in Exp₁ and −7.8 in Exp₂) such that the treatment had no effect on PGY (range between −19% and +37%; average of +1% in Exp₁ and −4% in Exp₂). Because plant growth rate around flowering was not different between pollination treatments, assimilate availability per kernel was reduced from ovary fertilization onwards in synchronously pollinated plants when compared to open pollinated plants. This explains the reduced KW when increasing KNP by synchronous pollination. In summary, none of the imposed treatments allowed grain yield to be increased at the plant level.  相似文献   

Grain number and grain weight in wheat lines contrasting for stem water soluble carbohydrate concentration   总被引：1，自引：0，他引：1  

M. Fernanda Dreccer  Anthony F. van Herwaarden  Scott C. Chapman 《Field Crops Research》2009

In wheat, the ability to store and remobilise large amounts of stem water soluble carbohydrates (WSC) to grain constitutes a desirable trait to incorporate into germplasm targeted to regions with frequent terminal drought. The main aim of this paper was to examine the relationships between WSC storage, grain number and grain weight across several environments. A small set of recombinant inbred lines (2–4) contrasting in stem WSC were grown in six field trials where water availability, sowing date and/or N level were manipulated, with line yields ranging from 400 to 850 g m⁻² across experiments. Biomass, N and WSC concentration (WSCc, mg g⁻¹ dry weight) and amount (WSCa, g m⁻²) were monitored. A resource-oriented area-based model [Fischer, R.A., 1984. Growth and yield of wheat. In: Smith, W.H., Bante, S.J. (Eds.), Potential Productivity of Field Crops Under Different Environments. International Rice Research Institute, Los Baños, pp. 129–154] and intrinsic rates of organ growth were used to investigate the consequences on grain number of potential competition between spike and stem around flowering.  相似文献   

海南香蕉根颈象甲卵的空间分布型及理论抽样数确定     

卢辉  刘奎  钟义海  赵冬香  尹炯 《热带作物学报》2009,30(7):995-999

香蕉根颈象甲[Cosmopolites sordidus(Gemar)1已在海南香蕉园发生,对香蕉生产造成危害.为了研究香蕉象甲的分布和发生规律、指导田间取样,应用几种聚集度指标的计算公式以及Taylor幂法则、Iwao的m*-m回归分析法,分析和测定了香蕉根颈象甲卵的空间分布格局和田间理论抽样数.结果表明:海南香蕉根颈象甲卵在一定密度下呈聚集分布,空间分布符合负二项分布;聚集度指标,I>0,m*/m>1,C>1,Cα>0;Tavlor幂模型表明香蕉根茎象甲卵在一定密度下的分布为聚集的,而且聚集强度随种群密度的上升而升高:Iwao的m*-m回归模型分析表明,m*和m呈显著相关,香蕉根茎象甲个体间相互吸引,最适抽样数n与卵密度m及相对误差D的关系为:n=1/D2(1.3717/m+0.046 3).  相似文献   

玉米LFY同源基因ZFL1与多叶性状的相关性     

张勇  邓德祥  陈梨辉  柏银传  王艳平 《江苏农业学报》2006,22(4):362-368

LFY基因是控制拟南芥花分生组织特异性的关键基因,该基因的突变会引起延迟开花和叶片形态变化。本试验以相同核背景(Y53)下穗上叶片数14叶和4叶的材料为模板,通过PCR反应,扩增出4条ZFL1基因目的片段。对PCR扩增产物进行回收、纯化和测序,将测序片段进行拼接。通过序列比对,结果表明与Y53(4L)相比较,Y53(14L)在外显子3有一段13 bp的重复序列,造成ORF的改变,进而引起氨基酸序列改变。据此,初步认为多叶玉米ZFL1基因在外显子区域发生突变造成表达产物-转录因子结合靶基因的功能性失活,使玉米营养生长阶段延迟,从而引起玉米穗上叶片数的增加。  相似文献   

两种鲤鲫杂交回交子代染色体核型分析及比较     

闫学春  梁利群  葛彦龙 《鲑鳟渔业》2011,(2):4-8

采用PHA和秋水仙素体内注射制备两种鲤鲫杂交回交子代鱼（鲤鲫杂交♀×德国镜鲤♂;鲤鲫杂交♀×鲤♂）的染色体。结果表明：两种鲤鲫杂交回交子代染色体组由150条染色体组成,按着丝粒位置染色体组型可分为四组,每个染色体小组均由三条同源染色体组成。其中鲤鲫杂交♀×鲤♂回交的染色体数目为3n=150,染色体臂数NF=234,其核型公式为：3n=60m＋24sin＋36st＋30t;鲤鲫杂交♀×德国镜鲤♂回交染色体数目为3n=150,染色体臂数NF=258,其核型公式为：3n=63m＋45sin＋12st＋30t。  相似文献   

CFG桩复合地基承载力模糊能度可靠性分析方法     

曹文贵  谭吉玲  张永杰 《湖南农业大学学报(自然科学版)》2011,38(4):8-13

在分析CFG桩复合地基承载力计算方法的基础上，根据其影响因素的区间性与模糊性特点，提出了采用三角模糊数表示计算参数取值，建立出CFG桩复合地基承载力模糊分析模型.通过探讨三角模糊数构造方法，建立出CFG桩复合地基承载力计算参数三角模糊确定方法，然后，基于给定安全系数与承载力设计构建功能函数，引入截集理论与区间运算规则，建立CFG桩复合地基承载力模糊能度可靠性分析方法.工程实例分析表明了该方法对CFG桩复合地基承载力进行分析计算的合理性与易操作性.在勘察数据与设计资料有限，不能直接采用概率可靠性分析方法的情况下，该方法为CFG桩复合地基承载能力可靠性分析与评价提供了一种精度较高的方法.  相似文献   

Mining Applicable Elite Alleles of Growth Duration,Plant Height and Panicle Number per Plant by Conditional QTL Mapping in Japonica Rice   总被引：1，自引：0，他引：1  

JIANG Jian-hua  ZHAO Qi-bing  LIU Qiang-ming  CHEN Lan  CHEN Fu-long  QIAO Bao-jian  HONG De-lin 《水稻科学》2011,18(3):196-203

Unconditional and conditional QTL mapping were conducted for growth duration (GD), plant height (PH) and effective panicle number per plant (PN) using a recombinant inbred line (RIL) population derived from a cross between two japonica rice varieties Xiushui 79 and C Bao. The RIL population consisted of 254 lines was planted in two environments, Nanjing and Sihong, Jiangsu Province, China. Results showed that additive effects were major in all of QTLs for GD, PH and PN detected by the two methods, and the e...  相似文献   

共同支配地位反垄断法规制“企业因素”界定     

曾晶 《湖南农业大学学报(自然科学版)》2015,(5):150-155

企业间的诸多因素，如企业数量、企业对称性、生产能力、以及结构联系，对它们达成或维持协调行为或一致行动很重要。因此，在判定企业是否具有共同支配地位时，必须充分考虑到这些因素，方能确保判断的准确性。目前我国反垄断执法尚未完全掌握这一考察方法，因而今后应充分借鉴相关国家的成熟经验，尽早探寻出一套契合我国国情的共同支配地位判定方法。  相似文献