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61.
光质对烤烟生长发育、主要经济性状和品质特征的影响   总被引:1,自引:0,他引:1  
陈伟  蒋卫  梁贵林  邱雪柏  潘文杰 《生态环境》2011,20(12):1860-1866
以烤烟(Nicotiana tabacum)云烟87为材料,在烤烟团棵期和打顶期用透光率相近的有色薄膜分别对其进行遮光处理直到采收结束,研究光质对烤烟生长发育、主要经济性状和品质特征的影响。结果表明:蓝光有促进烟株生殖生长和延缓烟叶成熟的作用,红光、黄光和白光对烟株的生育进程无明显影响,打顶期遮光有延长烟株大田生育期的趋势。光质对叶片生长发育影响最大,红光和蓝光的影响效应主要表现在烟叶生育前期,黄光和白光的影响效应主要体现在烟叶生育后期。自然光和红膜下烟株的农艺性状综合表现最好,红光有促进烟茎生长和叶片发育的作用,蓝光和黄光则抑制茎干生长和降低叶面积。烟株生长前期增加红光比例有助于初烤烟叶主要经济性状的改善,后期蓝光的作用逐渐凸显。烟株不同生长时期红光和黄光的适当组合在改善烟叶品质中起着重要作用,烟株生长前期增加红光比例有利于降低初烤烟叶烟碱和蛋白质含量,提高糖类物质含量和评吸质量,但对氧化钾含量作负效应贡献;烟株生长后期提高黄光比例可使初烤烟叶的化学成分更为协调,对吸食品质有较好的提升作用。  相似文献   
62.
Abstract:  For successful conservation of species it is important to identify traits that predispose species to the risk of extinction. By identifying such traits conservation efforts can be directed toward species that are most at risk of becoming threatened. We used data derived from the literature to determine ecological traits that affect distribution, distribution change, and the risk of extinction in Finnish noctuid moths (Lepidoptera, Noctuidae). The ecological traits we examined included body size, larval specificity, length of the flight period, and overwintering stage. In addition, in monophagous species we examined the effects of resource distribution. Larval specificity, length of the flight period, and the overwintering stage each had an independent effect on the risk of extinction when the effects of other traits were controlled by entering all traits into the same regression model. Not a single trait predicted the risk of extinction when analysis was conducted without controlling for the other traits. This discrepancy among the results suggests that a single trait may not be enough to allow prediction of the risk of extinction. Instead, it seems that for successful, predictive conservation science data on several ecological characteristics are needed.  相似文献   
63.
为研究儿童对不同形状字体警示语标识的视觉注意特征,将字体形状为单一变量的警示语标识图片作为视觉刺激材料,利用Eye-Link Ⅱ型眼动仪记录了30名小学生观看这些图片时的注视点个数和首次注视时间等试验数据,用SPSS分析了注视点个数和首次注视时间,基于视觉注意理论结合主观调查问卷结果表明:1)被试者对黑体字体注意程度最大;2)儿童对不同形状字体警示语标识的注意程度由大到小为黑体、隶书、宋体(楷体)、幼圆.  相似文献   
64.
纳米二氧化钛(nano-Ti O2)应用领域广泛,由于其对有机物或生物分子有吸附作用,二者相互反应,对各种细胞可能产生与nano-Ti O2单独作用时不同的毒性作用。为探讨双酚A(BPA)对nano-Ti O2理化性质的影响,以及BPA和nano-Ti O2联合暴露对人胚肝L-02细胞的DNA损伤效应。用不同缓冲液,测定不同浓度的BPA(0、0.1、1、10 mol·L-1)对不同浓度nano-Ti O2(0、0.1、1、10 mg·L-1)的粒径、表面电位和吸附能力的影响;然后测定不同浓度BPA和nano-Ti O2联合暴露对人胚肝L-02细胞DNA双链断裂、DNA损伤关键修复酶h Msh2基因(h Msh2)、O6-甲基鸟嘌呤甲基转移酶(MGMT)和DNA依赖蛋白激酶复合物催化亚基(DNA-PKcs)的m RNA表达水平表达的影响。结果表明在不同缓冲液中,随着BPA浓度的增加,nano-Ti O2粒径增加,表面电位上升,在细胞培养液DMEM中这一变化趋势最为明显;但在不同缓冲液中nano-Ti O2对BPA的吸附能力无明显差异。单独nano-Ti O2暴露不引起DNA双链断裂,对DNA损伤修复关键酶的表达也无明显影响,但nano-Ti O2可加重BPA的DNA双链断裂效应。与相应剂量的BPA单独染毒组比较,nano-Ti O2与BPA混合染毒组的细胞DNA双链断裂损伤加重(P0.05),h Msh2、MGMT和DNA-PKcs的基因表达水平明显上升(P0.05)。上述研究结果显示BPA可促进nano-Ti O2团聚,但团聚的nano-Ti O2仍可吸附BPA。单独nano-Ti O2暴露无DNA损伤作用,但nano-Ti O2可加重BPA的DNA双链断裂效应。其中h MSH2、MGMT和DNA-PKcs都参与2种污染物联合暴露所致的DNA损伤修复。  相似文献   
65.
淡竹森林公园地处括苍山脉中部,保存有括苍山脉最好、最完整的常绿阔叶林,是浙中和浙东沿海区域原生性最强的原始次生森林。在系统调查的基础上,分析得出淡竹森林公园旅游资源的6大特点——风景资源品味较高,天然常绿阔叶林景观较典型,水体景观多姿多彩,山体和岩体景观奇妙,森林环境优异,山区风情较淳厚;提出了淡竹森林公园旅游开发的5条基本思路,即依法开发、保护为先,体现特色与周边景区互补相结合,突出重点与循序发展相结合,旅游产品应以自然性休闲型为主导,塑造主题旅游形象,强化宣传促销。  相似文献   
66.
Endocrine disrupting chemical (EDC) effects during early life have the potential to modulate population structure, either directly through increased mortality or by causing inappropriate aggregation events, thus affecting the number of young that will reach adulthood. An alteration in the dispersal and recruitment patterns can also impair the connectivity among geographically distant populations. However, the detection of EDC-induced effects occurring after egg hatch, when newborns increase their chances of contacting with environmentally dispersed contaminants, is not a simple process as effects might be masked by the large natural mortality rates that usually occur during fish early life.Since there is a lack of information regarding the impact of EDCs on fish early life dispersal patterns, particularly on vertical migrations patterns, the effects of environmentally relevant concentrations of EE2 on the vertical distribution of newborn fish was assessed through an ex situ exposure experiment. Syngnathus abaster newborns were exposed to EE2 (nominal concentrations of 8, 12 and 36 ng L−1) and the dynamics of their vertical distribution was monitored for up to 40 d. No significant differences in overall mortality were observed between treatments or in the dynamics of the registered death curves. Nevertheless, an alteration in the distribution patterns was observed. The commonly benthic newborn tended to shift their vertical distribution towards the surface, in a dose-dependent manner. Curiously, a follow up of the exposed pipefish confirmed that EE2 effects were also noticeable upon sexual maturity, namely by the alteration of several primary and secondary sexual characters. The observation that vertical distributional patterns, at least in pipefish, are clearly altered at environmentally relevant EE2 concentrations indicates that EDC’s impact in fish larvae behaviour should be considered when addressing the effects of contaminants, given the obvious implications on population connectivity, stability and persistence.  相似文献   
67.
高莲凤  张振国 《资源开发与市场》2007,23(12):1151-1152,1150,F0004
山西省地质旅游资源丰富,不同地域分布着各具特征的地质景观。地质旅游资源特征明显、种类繁多,蕴藏着巨大的旅游潜力。在认真探讨各类地质景观分布特征的基础上,针对这些资源的开发现状和保护程度,提出了该省地质旅游线路规划、资源开发规划及地质旅游区的环境治理和保护规划方案。  相似文献   
68.
针对设备检修中伤亡事故的多发问题,根据有关冶金企业伤亡事故统计情况,对设备检修中主要的危险危害因素及伤害特征进行了分析,在此基础上,就如何防止检修中的伤亡事故提出了防范措施。  相似文献   
69.
Long-term dynamics of the numbers of complete (normal) veins, venation anomalies, and linear wing parameters were analyzed in male Calopteryx splendens Harr. damselflies from neighboring population groups. Correlation analysis showed that some anomalies may appear additionally to complete veins, whereas other anomalies are formed instead of them. The damselflies from the generations of even years proved to have significantly greater numbers of anomalies. A probable cause of this phenomenon was a sharp increase in the background radiation level in the summer of 1986, after the Chernobyl accident, which could lead to serious hereditary disturbances manifested in a series of generations. The results of the study show that the formation of wing venation anomalies in damselflies is a stochastic process, which is enhanced under the effect of both environmental and genetic stress. These anomalies may be regarded as markers characterizing the degree of stability of ontogenetic processes in the population, which essentially reflect specific genotypic traits of individual organisms. Analysis of wing venation anomalies appears to be a more precise instrument for assessing developmental stability than estimation of the levels of fluctuating asymmetry and general phenotypic variance.  相似文献   
70.
Summary Examination of three populations of the field cricket Teleogryllus oceanicus revealed the presence of an acoustically-orienting parasitoid fly, Ormia ochracea (Tachinidae), in the population of crickets that has been introduced to the Hawaiian Islands. The cricket is native to Australia and the Pacific, and the fly is native to North America but has also been introduced to Hawaii. Up to 27% of males and 7% of females in Hawaii were infested with fly larvae. Song structure in the parasitized Hawaiian population was distinct from that of the other two groups, with the Hawaiian crickets showing several reduced song parameters. In addition, onset and cessation of calling at dusk and dawn were more abrupt in the Hawaiian population. These results are consistent with selective pressure from the phonotactic flies to decrease risky calling. Silent males were present in all three populations, suggesting that these noncallers may not represent a unique adaptation to the parasitoid. Correspondence to: M. Zuk  相似文献   
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