茶叶中总硒含量及其影响因素的研究

茶叶中硒素总量测定结果表明：土壤含硒量的高低是直接影响茶叶中硒的总量。茶树根、茎、叶、果中均有硒元素,叶片是茶硒积累的主要器官,尤其是老叶,其含量是嫩叶的几倍．茶树品种间含量的差异显著,最大差异达10倍以上．毛茶加工的成品茶含硒量受加工技术措施影响较大,其不同等级的含硒量与级别没有线性关系．     

彩色多普勒超声对盆腔瘀血综合征的诊断价值及与临床因素的相关性研究

目的:探讨盆腔瘀血综合征患者彩色多普勒超声的影像学特征及与临床因素的相关性。方法:对112例盆腔瘀血综合征患者行彩色多普勒超声检查,按超声诊断分级Ⅰ级、Ⅱ级、Ⅲ级分为62例、27例、23例,观察彩色多普勒超声的影像学特征,分析静脉内径与病程的相关性,并分析超声诊断分级与临床症状积分、体质量指数(BMI)、妊娠次数、既往工作站立时间的相关性。结果:不同超声诊断分级患者的静脉内径、静脉丛范围和静脉流速差异具有统计学意义(P<0.05)。静脉内径与病程呈正相关(P<0.05),超声诊断分级与临床症状积分、妊娠次数、既往工作站立时间呈显著正相关(P<0.05),与BMI呈负相关(P<0.05)。结论:彩色多普勒超声对盆腔瘀血综合征具有特异性的诊断价值,超声诊断分级、静脉内径与临床因素存在一定的的关联性。     

次生栎林蒸腾强度与生态因子的关系

采用多元回归分析和灰色关联分析方法,探讨下蜀次生栎林蒸腾强度与生态因子的相关关系。研究认为用二次工咕次多项式回归方程和指数回归方程拟合更能反映各生态因子在整个生长季中与蒸腾强度关系的性质。影响蒸腾强度的主要生态因子是温度和净辐射;其次是空气相对湿度和土壤热流通量;风速和土壤含水率的影响很小。灰色关联分析与多元回归分析的结论一致。研究结果为进一步阐明次生栎林的结构和功能提供了理论基础。     

固沙树种梭梭在不同水分梯度下的光合生理特征

对不同水分梯度下梭梭光合作用的研究发现,地下水位、土壤含水量、灌水量对梭梭的光合具有明显的影响。在1．4m、2．4m、3．4m地下水位下,梭梭的光合速率、呼吸作用、量子效率随水位的降低而降低,光补偿点随水位的降低而增大;在滴灌供水时,梭梭的光合速率较对照明显提高,且灌水量越大,梭梭的光合速率越高;半流动沙丘、丘间低地、粘土沙障固定沙丘退化梭梭的光合作用的强弱同其林地土壤水分的高低基本一致。7月,不同水分梯度下的梭梭光合作用均表现出午休现象,9月只有立地条件较差的梭梭发生光合午休,而且9月光合作用要强于7月,说明9月环境条件更有利于梭梭生长。     

灰翅麦茎蜂蛹的发育分级研究

室内饲养了灰翅麦茎蜂Cephus fumipennis Eyersmann,对该种蛹的发育进行了研究.结果表明,灰翅麦茎蜂蛹期(30±2.08)d,根据蛹体色的显著变化分为5级(Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ),其历期依次为:(6.5±0.55)d、(3.9±0.48)d、(4.4±0.5)d、(4.6±0.49)d和(10.5±...     

曼地亚红豆杉蒸腾速率日变化及因子分析

应用LI-1600 稳态气孔计对曼地亚红豆杉(Taxus media cv.Hicksii)叶片的蒸腾速率、气孔阻力和几个生态因子的日变化同步进行了测定。并采用多元回归分析和灰色关联度分析的方法探讨了曼地亚红豆杉叶片蒸腾速率与影响因子的关系, 结果表明:影响曼地亚红豆杉蒸腾速率的主要因子是叶温、气温;其次是光量子通量密度、空气相对湿度、气孔阻力。灰色关联度分析与多元回归分析结论基本一致。对曼地亚红豆杉叶片蒸腾速率与气孔阻力的相关关系分析表明:蒸腾速率和气孔阻力间属非线性关系, 其方程为:Tr=12.789-13.419 lg Rs(R²=0.971 7)     

呼伦贝尔草甸草原不同土壤水分梯度下羊草的光合特性

为探索气候变化引起的干旱可能对呼伦贝尔草甸草原生产力造成的影响,利用Li-6400便携式光合测定系统对呼伦贝尔草原4个土壤水分梯度下羊草的光合生理指标进行测定.结果表明:羊草叶片净光合速率的日变化在土壤质量含水量为(40±1)%、(20±1)%及(10±1)%的条件下呈双峰曲线,峰值分别出现在8:00和16:00,有明显的光合午休现象,在干旱胁迫(土壤质量含水量为(5±1)%)条件下变化趋势平缓,曲线双峰特征不明显,净光合速率大幅下降;叶片蒸腾速率和气孔导度的日变化趋势均呈双峰曲线;不同土壤水分梯度下羊草叶片胞间CO2浓度的日变化与净光合速率日变化趋势相反.通过光响应的研究表明,土壤水分胁迫使最大净光合速率、光饱和点、表观量子效率以及水分利用效率降低,而光补偿点升高.干旱胁迫降低了呼伦贝尔草甸草原植被的光合生产能力,从而可能导致草地生产力大幅下降.     

The Relation of Storage Protein to Vigor and Its Mobilization Pattern in Germinating Peanut Seeds

The peanut (Arachis hypogaea L.) seeds harvested at the last stage of maturation were divided into five grades by size. The content of total protein, salt-soluble protein, arachin, conarachin I and 2s globulin in these seeds were measured. No obvious differences in germination percentage and the length of radicle and hypocotyl within 3d germination in dark were observed among the five grades of seeds. But there were significant differences in the seedling growth after two weeks of germination in light. There was a very close correlation between the storage protein in cotyledons and the seedling growth. When seeds germinated in light, the efficiency of mobilization of the salt-soluble protein in the cotyledons was higher than that in the cotyledons of the seeds germinating in dark. All of the salt-soluble protein in cotyledons was used up after 14d seedling growth in light. SDS-PAGE of salt-soluble protein showed that 23.5, 38.5 and 41 kD subunits of arachin were first mobilized during germination. The 18 kD subunits of arachin were not mobilized until the above-mentioned subunits were used up. The 60.5 kD subunit of conarachin I and 2s globulin were degradated within 2 to 3 days during germination.     

放牧对五台山高山、亚高山草甸植被-土壤系统耦合的影响

以野外样地调查和室内分析的数据为基础,研究了放牧压力下五台山高山、亚高山草甸植被、土壤的变化特征,并利用灰色系统分析法,从群落和物种两个尺度探讨了放牧对五台山植被-土壤系统耦合的影响。结果表明:随着放牧压力的加大,土壤pH、有机质和全氮含量呈先下降后上升的非线性变化,在极度退化草甸下达到最大值;灰色关联分析表明土壤有机质和全氮与群落地上生物量、物种多样性、群落总盖度的关联度较高,土壤有机质、全氮对群落特征变化有一定影响;在受到强度干扰时,植物群落优势物种由原生种向退化种发生替代变化。系统耦合度的定量研究表明,现有的放牧强度已经使五台山山地草甸的植被-土壤系统的耦合水平降低。草甸的退化不仅仅是植被与土壤的衰退,也导致两个子系统耦合关系的减弱,使系统表现出相悖的发展趋势。     

Bee pollination improves crop quality,shelf life and commercial value

Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar–acid–ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11%. This is accounting for 0.32 billion US$ of the 1.44 billion US$ provided by bee pollination to the total value of 2.90 billion US$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.