砒砂岩与沙混合比例及作物种植季数对复配土壤性质和作物产量的影响

【目的】探讨砒砂岩与沙不同混合比例及作物种植季数对复配土壤理化性状和作物产量的影响,为促进毛乌素沙地土地的可持续利用提供理论依据。【方法】2010-2011年,在陕西省富平县采用二因素随机试验设计,将砒砂岩与沙按不同体积比(1∶1,1∶2,1∶5)混合后,分别于第1季作物(玉米、大豆、马铃薯)和第2季作物(小麦、马铃薯)收获后,对土壤质地、水稳性团聚体含量、有机质含量及作物产量进行测定,分析砒砂岩与沙不同混合比例及作物种植季数对测定指标的影响。【结果】1)随拌沙比例和作物种植季数的增加,复配土壤耕层砂粒比例增加粉粒和黏粒比例减少;随作物种植季数的增加,复配土壤耕层质地趋于砂质化,粉粒和黏粒向土壤下层运移;2)砒砂岩与沙1∶1复配土壤的水稳性团聚体含量明显高于砒砂岩与沙1∶2和1∶5复配土壤;随着作物种植季数的增加土壤有机质含量呈增大趋势,而砒砂岩与沙混合比例对土壤有机质含量的影响不明显;3)砒砂岩与沙混合比例和作物种类对复配土壤作物产量影响明显,总体上表现为1∶2和1∶5复配土壤的作物产量较高。【结论】复配土壤耕层质地随作物种植季数的增加趋于砂质化;砒砂岩与沙1∶1复配土壤具有较高的水稳性团聚体和有机质含量,且随作物种植季数的增加而增大;玉米、大豆和冬小麦适宜在砒砂岩与沙1∶2复配土壤上种植,马铃薯适宜在砒砂岩与沙1∶5复配土壤上种植。     

岚皋魔芋软腐病病原细菌生物多样性研究

【目的】研究岚皋魔芋软腐病病原细菌生物多样性。【方法】采用组织分离法分离纯化魔芋软腐病球茎及叶柄中的致病菌,通过魔芋球茎、胡萝卜及马铃薯块的侵染试验初步确定其致病性,再利用魔芋球茎侵染致病及盆栽致病性试验确认其致病性;经菌落与细胞形态、生理生化特性及16SrRNA序列测定确定病原菌的类型。【结果】从魔芋软腐病球茎及叶柄中共分离获得16株细菌,侵染试验表明,其中CDS1-B1、CDS1-B2、CDS2-B1、CDS2-B2、CZS-B4和CZS-B6共6株细菌可使魔芋球茎表现软腐症状,并导致盆栽魔芋发病;6株细菌的菌落与细胞形态均存在差异;在魔芋、胡萝卜及马铃薯块上的侵染能力不同;16SrRNA序列分析表明,菌株CDS1-B1、CDS1-B2、CDS2-B1及CDS2-B2均与菊欧氏杆菌(Erwinia chrysanthemi)亲缘关系最近,菌株CZS-B4与菊欧文氏菌(Dickeya dadantii)亲缘关系最近,相似度为98.8%,菌株CZS-B6与菊果胶杆菌(Pectobacterium chrysanthemi)的相似度达99.9%。【结论】导致岚皋县魔芋软腐病的致病细菌存在生物多样性,其致病性也存在差异,其中新发现的魔芋软腐病原菌菊果胶杆菌(Pecto-bacterium chrysanthemi)致病性最强,菊欧氏杆菌(Erwinia chrysanthemi)和菊欧文氏菌(Dickeya dadantii)致病性较弱。     

新疆红肉苹果杂交后代绵/脆肉株系果实质地差异相关酶活性的初步研究

 以‘富士’× 新疆红肉苹果杂交F₁群体中的2个绵肉株系‘绵肉1号’、‘绵肉2号’和2个脆肉株系‘脆肉1号’、‘脆肉2号’不同发育时期的果实为试材,测定其果实硬度、脆度、乙烯释放量和细胞壁降解酶活性,分析探讨它们之间的相关性。结果表明：①2个脆肉株系各个时期的果实硬度和脆度均显著高于2个绵肉株系;②在幼果期和果实膨大期的乙烯释放量均小,绵肉株系与脆肉株系间差异不明显,在花后130 d的成熟期,2个绵肉株系的乙烯释放量是2个脆肉株系的10倍;③2个绵肉株系果实的果胶酶和β–半乳糖苷酶活性绝大部分发育时期高于2个脆肉株系,而α-L–阿拉伯呋喃糖苷酶、β–木糖苷酶、淀粉酶和脂氧合酶的活性在发育前期差异较小,到发育后期2个绵肉株系显著高于2个脆肉株系;④相关分析显示,绵肉脆肉特性与多聚半乳糖醛酸酶、α-L–阿拉伯呋喃糖苷酶及淀粉酶活性密切相关。     

履齿高度对集矿机牵引性能的影响及参数确定

为研究履齿高度对集矿机在多金属结核矿区稀软底质上的牵引性能的影响,并确定履齿高度,以优化集矿机的行走机构。该文基于稀软底质的剪切位移和应力模型,构建了单履带板、齿与稀软底质的驱动力模型和集矿机的附着力模型,研究了履齿高度参数对集矿机在稀软底质上的牵引性能的影响。结果表明,履齿高度能提高集矿机在稀软底质上的牵引性能:集矿机在稀软底上产生的驱动力随履齿高度增加而快速增加;附着力在齿高小于15cm时随齿高增加快速增加,齿高大于15cm后趋缓。集矿机的齿高应不大于15cm。     

基于晶闸管软起动的三相异步电动机的研究

文章论述了利用改变晶闸管的触发角来调节异步电动机定子两端电压,进而改变电机的转速和定子电流的软起动的原理。这种软起动方式结构简单,性能好,调试容易,对于要求不高的风机、泵类负载非常适用。     

Bioactive eunicellin-based diterpenoids from the soft coral Cladiella krempfi

Four new eunicellin-based diterpenoids, krempfielins A-D (1-4), along with two known compounds (5 and 6) have been isolated from a soft coral Cladiella krempfi. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and by comparison with spectroscopic data of related known compounds. Compounds 5 and 6 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. Furthermore, compounds 2, 3, 5 and 6 were shown to exert significant in vitro anti-inflammatory activity against LPS-stimulated RAW264.7 macrophage cells.     

Capilloquinol: a novel farnesyl quinol from the Dongsha atoll soft coral Sinularia capillosa

Capilloquinol (1), possessing an unprecedented farnesyl quinoid skeleton, was isolated from the Dongsha Atoll soft coral Sinularia capillosa. The structure of capilloquinol was elucidated by extensive analysis of spectroscopic data. The cytotoxicity and antiviral activity against human cytomegalovirus of 1 was evaluated in vitro.     

nardosinane-type sesquiterpenoids from the formosan soft coral Paralemnalia thyrsoides

Five new nardosinane-type sesquiterpenoids, paralemnolins Q-U (1-5), along with three known compounds (6-8), were isolated from the Formosan soft coral Paralemnalia thyrsoides. The structures of new metabolites were elucidated on the basis of extensive spectroscopic methods, and the absolute configuration of 1 was determined by the application of Mosher's method on 1. Among these metabolites, 1 and 3 are rarely found nardosinane-type sesquiterpenoids, possessing novel polycyclic structures. Compounds 1, 3, 6 and 7 were found to possess neuroprotective activity.     

The resistance of potato plants toErwinia carotovora subsp.atroseptica in relation to their calcium and magnesium content

Summary The effect of adding gypsum (CaSO₄) to growing media on the resistance toErwinia carotovora subsp.atroseptica (van Hall) Dye of potato (Solanum tuberosum L.) stems and mother and daughter tubers was examined in field and glasshouse experiments. The decayin situ of inoculated mother tubers from field plots treated before planting with gypsum was significantly delayed compared with tubers sampled from non-amended plots. Blackleg development was also significantly delayed in the gypsum-amended plots; however, for both mother tubers and stems the increased resistance associated with the application of gypsum later disappeared. Stem resistance tended to be related to tissue calcium and magnesium concentrations which were higher in plots treated with gypsum than in untreated plots. Daughter tubers produced in plots amended with gypsum generally contained a higher concentration of calcium in their cortex and were more resistant to decay byE. carotovora subsp.atroseptica but the effect was not consistent.     

沙棘资源开发符合循环经济的基本原则

本文在砒砂岩区沙棘植物＂柔性坝＂试验研究和周章义提出＂把沙棘作为‘农作物’和沙棘开发的基础上,论证了沙棘资源开发符合循环经济的基本原则,给出了沙棘生态工业链状开发框架模式和防止土壤侵蚀的生态环境功能。提出建立小流域支毛沟沟头沙棘生态园,有序进行沙棘开发,把建立黄土高原基岩产沙区沙棘生态工业园开发,作为21世纪该区一场新...