穿龙薯蓣光合蒸腾特性

采用LI－6400便携式光合作用测定系统，测定了穿龙薯蓣与光有关的各项生理生态指标，讨论了光对穿龙薯蓣生长发育的作用及影响。结果表明，穿龙薯蓣对不同光照条件的适应性较强。     

光照强度对烤烟化学成分及物理特性的影响

对不同光照强度下烤后烟的矿质元素、主要化学成分、物理特性进行了分析。结果表明:氮、钾、钙、氯、铜、淀粉、还原糖含量,钾/氯,单叶重,叶质重,叶片厚度受光照强度影响较大;铁、锌、总糖含量,含梗率受光照强度影响次之;而磷、镁、平衡含水率受光照强度影响不显著;≥80%全光照适合优质烟叶的生产。     

树形对油桃幼树光截获能力和结果的影响

【目的】研究设施栽培中树形对幼树光截获能力和生长结果的影响。【方法】以一、二年生油桃沪油004为试材，设计4种树形、在生长季节用不同浓度梯度的多效唑树冠叶面喷施处理的方法。【结果】（1）树形对冠层消光系数(K)的影响表现为主干形＞Y形＞开心形＞十字形，十字形和开心形叶面积指数(LAI)之间无明显差异，但都稍高于主干形而极显著大于Y形;冠层光直接辐射透过系数(Tr)和光散射辐射透过系数(TDP)的大小表现为Y形＞开心形＞十字形＞主干形。（2）多效唑处理后，幼树单株平均果实数和平均单果重均表现为主干形多于Y形，而每667m2平均产量则以主干形较高。【结论】设施栽培中采用主干形，树冠形成早期光截获能力较高。多效唑对不同树形的生长结果均产生一定的影响。     

光对一品红生长的影响

本文介绍了光强、光质和光周期三个因子对一品红生长的影响。其中光周期对一品红的开花有着决定作用。     

发动机尾气射流特性研究

利用高速摄影仪实时拍摄发动机尾气的射流运动过程,通过Im age-Pro6.3专业图像处理软件,选择气体射流顶点为研究对象,根据自由射流理论,得到发动机尾气贯穿距离、射流锥角、射流速度随射流时间变化的规律。结果表明:尾气射流分为两个阶段,射流起始段和射流主体段。当发动机转速一定时,在整个射流过程中,射流贯穿距离随射流时间的增加而增加,射流锥角基本保持不变,射流速度随射流时间的增加而减小;当发动机转速提高时,射流贯穿距离、射流速度均有所减小,而射流锥角增大。在此基础上,确定了射流贯穿距离与射流速度之间的数学模型。     

Effect of spectral composition of artificial light on the attraction of moths

During the last decades, artificial night lighting has increased globally, which largely affected many plant and animal species. So far, current research highlights the importance of artificial light with smaller wavelengths in attracting moths, yet the effect of the spectral composition of artificial light on species richness and abundance of moths has not been studied systematically. Therefore, we tested the hypotheses that (1) higher species richness and higher abundances of moths are attracted to artificial light with smaller wavelengths than to light with larger wavelengths, and (2) this attraction is correlated with morphological characteristics of moths, especially their eye size. We indeed found higher species richness and abundances of moths in traps with lamps that emit light with smaller wavelengths. These lamps attracted moths with on average larger body mass, larger wing dimensions and larger eyes. Cascading effects on biodiversity and ecosystem functioning, e.g. pollination, can be expected when larger moth species are attracted to these lights. Predatory species with a diet of mainly larger moth species and plant species pollinated by larger moth species might then decline. Moreover, our results indicate a size-bias in trapping moths, resulting in an overrepresentation of larger moth species in lamps with small wavelengths. Our study indicates the potential use of lamps with larger wavelengths to effectively reduce the negative effect of light pollution on moth population dynamics and communities where moths play an important role.     

Rhizospheric and heterotrophic respiration of a warm-temperate oak chronosequence in China

Plot trenching and root decomposition experiments were conducted in a warm-temperate oak chronosequence (40-year-old, 48-year-old, 80-year-old, and 143-year-old) in China. We partitioned total soil surface CO₂ efflux (R_S) into heterotrophic (R_H) and rhizospheric (R_R) components across the growing season of 2009. We found that the temporal variation of R_R and R_H can be well explained by soil temperature (T₅) at 5 cm depth using exponential equations for all forests. However, R_R of 40-year-old and 48-year-old forests peaked in September, while their T₅ peaks occurred in August. R_R of 80-year-old and 143-year-old forests showed a similar pattern to T₅. The contribution of R_R to R_S (RC) of 40-year-old and 48-year-old forests presented a second peak in September. Seasonal variation of R_R may be accounted for by the different successional stages. Cumulative R_H and R_R during the growing season varied with forest age. The estimated R_H values for 40-year-old, 48-year-old, 80-year-old and 143-year-old forests averaged 431.72, 452.02, 484.62 and 678.93 g C m⁻², respectively, while the corresponding values of R_R averaged 191.94, 206.51, 321.13 and 153.03 g C m⁻². The estimated RC increased from 30.78% in the 40-year-old forest to 39.85% in the 80-year-old forest and then declined to 18.39% in the 143-year-old forest. We found soil organic carbon (SOC), especially the light fraction organic carbon (LFOC), stock at 0-10 cm soil depth correlated well with R_H. There was no significant relationship between R_R and fine root biomass regardless of stand age. Measured apparent temperature sensitivity (Q₁₀) of R_H (3.93 ± 0.27) was significantly higher than that of R_R (2.78 ± 0.73). Capillary porosity decreased as stand age increased and it was negatively correlated to cumulative R_S. Our results emphasize the importance of partitioning soil respiration in evaluating the stand age effect on soil respiration and its significance to future model construction.     

Addition of Leucaena-KX2 mulch in a shaded coffee agroforestry system increases both stable and labile soil C fractions

Agroforestry systems have the potential to increase sequestration of atmospheric carbon dioxide (CO₂) as soil organic carbon (SOC) because of the increased rates of organic matter addition and retention. However, few studies have characterized the relative stability of sequestered SOC in soil. We characterized SOC storage in aggregate size and chemical stability classes to estimate the relative stability of SOC pools after the addition of Leucaena-KX2 pruning residues (mulch) from 2006 to 2008 in a shaded coffee agroforestry system in Hawaii. Soil samples were separated by microaggregate isolation, density flotation and dispersion, and acid hydrolysis, resulting in five distinct fractions that differed in relative stability: coarse particulate organic matter (POM), fine POM, microaggregate-protected POM, silt + clay hydrolyzable soil organic matter (SOM), and silt + clay non-hydrolyzable SOM. With mulch addition, the fine POM fraction increased. There was also a shift in the proportion of SOC to more stable silt + clay fractions. In the absence of mulch there was no significant change in SOC fractions. Given that the turnover time of SOC in silt + clay fractions is on the order of decades to centuries, the potential benefits of active shade management and mulching compensate for the loss of C sequestration in tree biomass from pollarding.     

Light and scanning electron microscopy studies on the infection process of melon leaves by Colletotrichum lagenarium

Colletotrichum lagenarium is the casual agent of anthracnose disease of melons. Light and scanning electron microscopy were used to observe the infection process of C. lagenarium on the leaves of two melon cultivars differing in susceptibility. On both cultivars conidia began germinating 12 h after inoculation (hai), forming appressoria directly or at the tips of germ-tubes. By 48 hai appressoria had melanised and direct penetration of host tissue had begun. On the susceptible cultivar, infection vesicles formed within 72 hai and developed thick, knotted primary hyphae within epidermal cells. By 96 hai C. lagenarium produced highly branched secondary hyphae that invaded underlying mesophyll cells. After 96 hai, light brown lesions appeared on the leaves, coincident with cell necrosis and invasion by secondary hyphae. While appressoria formed more quickly on the resistant cultivar, fewer germinated to develop biotrophic primary or invasive necrotrophic secondary hyphae than on the susceptible cultivar. These results confirm that C. lagenarium is a hemibiotrophic pathogen, and that resistance in melons restricts colonisation by inhibiting the development of necrotrophic secondary hyphae.     

评价大米储藏品质的炊饭特性指标的研究

提出了评价大米储藏品质的炊饭特性新指标——光透过率差。实验证明，随着大米品质的劣化，光透过率差明显变小。以此指标为主，结合原有的加热吸水率和ｐＨ值，对因生霉和陈化引起的大米储藏品质的变化，都能较好地进行评价。同时对影响这些指标稳定的实验因素也进行了探讨。