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排序方式: 共有337条查询结果,搜索用时 15 毫秒
1.
旨在研究小麦 TaGRF4基因的生物学功能,利用生物信息学技术分析小麦 TaGRF4基因结构及其与其他作物的进化关系,利用实时定量检测 TaGRF4在不同发育时期叶片和不同区段叶片中的表达丰度,同时检测外源GA处理条件下 TaGRF4的表达情况,最后利用BSMV-VIGS体系使 TaGRF4的3个同源基因同时沉默,研究 TaGRF4沉默对叶片生长发育的影响。结果表明, TaGRF4是玉米 ZmGRF10的同源基因,在幼嫩叶片和叶尖部位的表达量最高,而且对外源GA处理响应迅速; TaGRF4沉默后新生叶片明显伸长,说明 TaGRF4与 ZmGRF10有类似的生物功能,能够抑制叶片的伸长生长。 相似文献
2.
Guillermo Trincado V. Raúl Quezada P. Klaus von Gadow 《Forest Ecology and Management》2003,180(1-3):443-451
The study compares two methods of stand table projection based on data from young Eucalyptus nitens (Maiden) plantations in Chile. The projected diameter distributions were estimated using the methods proposed by Nepal and Somers (1992) [For. Sci. 38 (1992) 120] and Cao and Baldwin (1999) [For. Sci. 45 (1999) 506]. The evaluation compared the observed and estimated diameter distributions for different projection intervals, using the Kolmogorov–Smirnov test and an error index called ‘relative discrepancy’. The evaluation showed that both methods are suitable for application in the Eucalypt plantations. However, the method proposed by Nepal and Somers proved to be more accurate, especially when the projection period extends over 4 years or more. Expected error and bias for the observed and estimated total and merchantable volumes at stand level were also evaluated. The observed error and bias were relatively low for both methods; however, some differences were detected when the volume distributions were analyzed at diameter class level. 相似文献
3.
Andrea?D.?KupferschmidEmail author Peter?Brang Walter?Sch?nenberger Harald?Bugmann 《European Journal of Forest Research》2006,125(2):163-179
A bark beetle (Ips typographus) infestation caused the death of almost all Norway spruce (Picea abies) trees in a mountain forest in the Swiss Alps. We developed a tree regeneration model, ‘RegSnag’ (=REGeneration in a SNAG stand), to project the future amount and height of tree regeneration in these snag stands. The model combines a height-class structured tree module with a microsite-based module of snag decay and ground-vegetation succession. Microsite-specific rates of germination, mortality and height growth were modelled for four tree species (Picea abies, Sorbus aucuparia, Acer pseudoplatanus and Betula pendula) in eight height classes (from seedlings to saplings 5 m tall) and on 26 microsite types (e.g. moss, grass). Model tests with independent field data from 8 years after the Picea die-back demonstrated that microsites had a considerable effect on the development of tree regeneration on both the montane and the subalpine level. With microsite-specific parameters, the height and frequency of Picea in each microsite could be simulated more accurately than without considering microsite effects (e.g. bias of 8 vs. 119 saplings ha−1 on the montane level). Results of simulations 40 years into the future suggest that about 330–930 Picea saplings per ha out of those that germinated in 1994 and 1996 will reach a height of 5 m within 30–35 years after Picea die-back. This is due to differences in seed inflow and browsing intensities. Picea and not Betula or Sorbus trees will replace the current herbaceous vegetation in these snag stands. 相似文献
4.
以企业行为为研究对象,梳理了农业转移人口市民化过程中企业成本的概念、内涵、类型,并构建博弈论模型,分析了农业转移人口市民化过程中的企业承担意愿及行为选择,针对性地提出了促进企业主动参与农业转移人口市民化进程的建议。 相似文献
5.
A method for fractionating sorghum proteins using extraction solvents and techniques designed to obtain polymeric protein structures (especially disulfide linked) was developed. Extraction and separation conditions were optimized in terms of completeness of protein extraction, sample stability, and analytical resolution. After pre-extraction of albumins and globulins, a 3-step sequential procedure involving no reducing agents was applied to ground whole sorghum flour. The three fractions obtained represented proportionally different protein polymer contents and molecular weight distribution as evidenced by comparative size exclusion chromatography. Protein composition also varied among the extracts with differences in kafirin composition and non-kafirin proteins detected in the fractions by RP-HPLC and SDS-PAGE analysis. The ability to quantify and further characterize sorghum polymeric protein complexes will be useful for additional studies linking protein structures with functionality and digestibility and variations for these properties within diverse sorghum germplasm. 相似文献
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7.
花后弱光影响小麦淀粉分子积累和结构形成,进而使面粉的加工品质和食用品质变劣。本研究以非糯小麦轮选987和糯小麦农大糯50206为材料,设置3个花后遮光处理(不遮光、遮光30%和遮光60%),研究了花后不同强度遮光对小麦籽粒中淀粉组分及其理化特性的影响。结果表明,花后弱光胁迫使小麦籽粒中总淀粉含量减少,A-型淀粉粒比例增加,淀粉相对结晶度增大。花后光照强度降低,轮选987淀粉的峰值黏度、谷值黏度、最终黏度、稀澥值和反弹值增大,而农大糯50206淀粉的上述参数则呈减小趋势。轮选987淀粉的起始温度、峰值温度和终止温度随弱光胁迫的增强而降低,而糊化焓呈增加趋势;相反,农大糯50206淀粉的上述热力学特征参数呈降低趋势。相关性分析表明,直链淀粉含量、直/支比、A-型淀粉粒体积比例与相对结晶度、峰值黏度、谷值黏度、稀澥值、糊化时间和糊化焓呈显著负相关,与最终黏度和反弹值存在极显著正相关。可见,小麦花后光照强度降低影响籽粒淀粉组分和粒度分布,从而改变了淀粉的晶体、糊化和热力学特性。 相似文献
8.
内部控制和企业价值之间存在着密切的联系,内部控制是否有效及效率高低影响着企业的价值。内部控制质量高的企业有动机通过自愿性信息披露向市场传递企业价值较高的信号,由于信号传递作用,企业更容易获得较低成本的商业信用和银行信用借款,提升了企业价值,而内部控制质量低的企业没有动机进行内部控制信息披露,从而不得不付出较高的债务融资成本,降低了企业价值。 相似文献
9.
为分析不同粒度黄芩颗粒纤维构成及黄酮含量的差异性,以5种黄芩为研究对象,分别对不同品种、不同粒度的黄芩样品中木质素、半纤维素和纤维素等纤维构成及黄芩甙、汉黄芩甙、黄芩素和汉黄芩素等主要黄酮含量进行了测定。通过方差分析发现,不同粒度黄芩中纤维构成、黄芩甙、黄芩素和总黄酮含量差异显著(P<0.05),汉黄芩甙和汉黄芩素含量无显著性差异(P>0.05)。 相似文献
10.