烤烟主要化学成分与烟叶品质关系研究进展

介绍了烟草的研究现状及烤烟主要化学成分与烟叶的外观质量、物理特性、评吸质量、烟气与焦油的关系.     

沙田柚黄龙病病原16S rDNA片段的克隆与序列分析

采集田间表现斑驳症状的沙田柚叶脉,用CTAB法提取总DNA。根据柑橘黄龙病病原16S rDNA的核苷酸序列设计引物P1/P2,进行PCR扩增,获得1条大小为1 167 bp的片段。酶切分析显示,该片段可被切成大小分别约为640 bp和520 bp的2个片段。扩增产物经纯化,与pM D 18-T V ector连接,转化大肠杆菌(E scherich ia coli)DH 5α,筛选克隆重组子。对PCR产物进行测序及序列分析,结果表明,与柑橘黄龙病病原亚洲种16S rDNA的同源性为99%,与非洲种的同源性为97%,与美洲种的同源性为96%。认为,沙田柚的斑驳症状是由黄龙病病原引致的,称之为沙田柚黄龙病。该沙田柚黄龙病病原属于柑橘黄龙病病原亚洲种(L iberobacter as iaticus)中的一个成员。系统进化树分析显示,沙田柚黄龙病病原与中国柑橘黄龙病病原亲缘关系最近,推测是直接来自中国柑橘黄龙病病原。     

Molecular and sensory studies on the umami taste of Japanese green tea

Aimed at defining the key drivers for the quality-determining umami taste of a high-grade powdered green tea, called mat-cha, a bioactivity-guided fractionation using solvent extraction, solvent precipitation, preparative chromatographic separations, and human psychophysical experiments was applied on freshly prepared mat-cha. Liquid chromatography-tandem mass spectrometry and one-/two-dimensional nuclear magnetic resonance studies on isolated fractions led to the identification of l-theanine, succinic acid, 3,4,5-trihydroxybenzoic acid (gallic acid), and (1R,2R,3R,5S)-5-carboxy-2,3,5-trihydroxycyclohexyl-3,4,5-trihydroxybenzoate (theogallin) as umami-enhancing compounds in the green tea beverage, and it can be shown by sensory studies that these compounds are able to raise the umami intensity of sodium l-glutamate proportionally.     

The influence of barley malt protein modification on beer foam stability and their relationship to the barley dimeric alpha-amylase inhibitor-I (BDAI-I) as a possible foam-promoting protein

The foam stability of beer is one of the important key factors in evaluating the quality of beer. The purpose of this study was to investigate the relationship between the level of malt modification (degradation of protein, starch, and so on) and the beer foam stability. This was achieved by examining foam-promoting proteins using two-dimensional gel electrophoresis (2DE). We found that the foam stability of beer samples brewed from the barley malts of cultivars B and C decreased as the level of malt modification increased; however, the foam stability of cultivar A did not change. To identify the property providing the increased foam stability of cultivar A, we analyzed beer proteins using 2DE. We analyzed three fractions that could contain beer foam-promoting proteins, namely, beer whole proteins, salt-precipitated proteins, and the proteins concentrated from beer foam. As a result, we found that in cultivar A, some protein spots did not change in any of these three protein fractions even when the level of malt modification increased, although the corresponding protein spots in cultivars B and C decreased. We analyzed these protein spots by peptide mass finger printing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. As a result, all of these spots were identified as barley dimeric alpha-amylase inhibitor-I (BDAI-I). These results suggest that BDAI-I is an important contributor to beer foam stability.     

浙江省长柄双花木数量分布与林学特性

长柄双花木为我国特产种 ,产于浙、赣、湘三省 ,属国家二级珍稀濒危保护植物。首次报道了该种在浙江的分布数量 ,共计 3 6 72 0丛 ,数量居三省之首。纠正了前人报道的一些谬误 :①文献认为该种在开化已灭绝 ,经查证分析 ,系前人将分布点龙洞误为龙潭之故 ,本次调查在开化重新找到了该种 ,且发现了大面积分布。②文献记载龙泉分布点海拔为 10 0 0m ,经调查实际为 6 5 0～ 80 0m。③文献记载该种为阴性树种 ,经实地观察 ,认为应属中性树种。调查发现该种在浙江的分布特点与其他两省有所不同 ,一是海拔较低 ,二是生境以沟谷为主。详尽记述了该种在浙江的地理分布、生境特点以及群落学特征 ,分析了群落的演替趋势 ,并就其保护与利用等方面提出了具体建议。参 1 1     

Effects of contact with wood on blood pressure and subjective evaluation

This study examined the effects of contact with wood on the living human body using a physiological index and subjective evaluation. Consecutive blood pressure measurements were used as the physiological index, and sensory evaluation using the semantic differential (SD) method was used for subjective evaluation. Consideration was also given to cases in which materials were cooled and heated as well as kept at room temperature, to eliminate the effects of heat flux due to differences in thermal conductivity between wood and other materials. It was found that contact with wood produced coarse/natural sensations, with no associated increase in systolic blood pressure. Contact with cold wood created subjectively dangerous/uncomfortable but still coarse/natural sensations, also with no associated increase in blood pressure; therefore, there was no correspondence between subjective evaluation and physiological responses. Contact with aluminum kept at room temperature and cold acrylic plastic created flat/artificial and dangerous/uncomfortable sensations, with an associated significant increase in blood pressure; thus, there was a close correlation between subjective evaluation and physiological responses. It was therefore concluded that contact with wood, unlike artificial materials such as aluminum, induces no physiological stress even when kept at room temperature or cooled. Part of this report was presented at the 48th Annual Meeting of the Japan Wood Research Society in Shizuoka, April 1998     

长期施肥模式对双季水稻生理特性与产量的影响

为探明双季稻区不同施肥模式下双季水稻生理特性及产量的变化,本研究依托设置在湖南宁乡的长期大田定位试验,自1986年—至今,共设化肥(MF)、秸秆还田+化肥(RF)、30%有机肥(LOM)、60%有机肥(HOM)和无肥对照(CK)5种施肥处理,于2015—2016年取样,系统分析不同处理双季水稻植株叶片保护性酶活性、光合特性及产量的变化。结果表明,施肥条件下,早、晚稻各生育时期叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性提高,丙二醛(MDA)和脯氨酸(Pro)含量降低,叶片净光合速率(Pn)和蒸腾速率(Tr)大小顺序分别表现为LOMHOMRFMFCK和RFLOMHOMMFCK;叶片气孔导度(Gs)均表现为HOMLOMRF MFCK。2个年份的早稻产量均以LOM和HOM处理为最高,分别比CK处理增加3 582.5~3 650.0kg/hm~2和2 569.5~2 641.5kg/hm~2;晚稻产量均以RF和LOM处理为最高,分别比CK处理增加2 480.0~2 757.5kg/hm~2和2 827.5~3 118.5kg/hm~2。总的来说,有机肥与化肥配合施用有利于提高双季水稻叶片保护性酶活性和光合特性。     

临安山核桃林地土壤磷素状况及其淋失风险分析

以天目山地区临安市岛石镇下塔村和湍口镇湍口村发育于石灰岩的山核桃林地土壤为研究对象,采集林地表层（0～20 cm）土壤样品,用于评估长期施肥对山核桃林地土壤磷素状况的影响及其潜在的淋失风险。土壤分析表明：土壤Olsen\|P存在较大的空间变异,含量低的近于0 mg·kg-1,而最高的含量达 893 mg·kg-1。土壤CaCl2\|P与Olsen\|P相关分析显示,岛石镇和湍口镇土壤Olsen\|P的临界值分别为193和293 mg·kg-1。据此,岛石和湍口两地土壤发生磷淋失的林地分别占调查林地的30%和45%。表明研究区已经有相当数量的山核桃林地因土壤磷素积累而存在淋失风险,需要引起重视。     

白花败酱的家化栽培技术

采用不同栽植密度、不同施肥方式及不同的管理措施,对白花败酱的栽培技术进行研究.结果表明冬春时节搭建大棚有利于白花败酱的生长,提高产量.栽植密度以25株@m-2较适宜.施用复合肥能较大幅度地提高白花败酱产量.白花败酱生态适应性较强,适于人工栽培,露地栽种年产量达39.2t@hm-3.表4参8     

大麦植株干物质分配模型

为给建立大麦产量品质形成预测模型奠定基础,通过定量分析不同品种和氮肥处理大麦干物质分配和转移的变化过程,建立大麦植株干物质分配动态模型.模型采用Richards方程描述大麦干物质分配指数的动态变化,引入叶片潜在分配指数、茎鞘潜在分配指数、籽粒潜在分配指数3个品种遗传参数反映不同品种在器官间的干物质分配差异;采用两段Richards方程来描述大麦茎鞘在灌浆期前后的干物质分配动态,较好地解决了两段方程的衔接问题;运用氮素影响因子来校正不同氮素水平对大麦干物质分配的影响,引入潜在临界含氮量和潜在最小含氮量2个品种遗传参数来表达氮素对不同品种干物质分配影响的差异.利用不同品种、氮肥、播期和种植地域试验数据检验模型.结果表明,大麦干物质在叶片、茎鞘、穗和籽粒间分配模拟值与观测值的绝对预测误差为0.001～0.252 kg·m-4,RMSE为0.007～0.186 kg·m-2,精度良好.模型体现出较好的可靠性.