小麦品系M8003-5抗条锈病基因遗传分析和分子作图

为了利用小麦抗条锈病品系M8003-5中的抗病基因,用当前7个流行的条锈菌生理小种对小麦品系M8003-5的抗条锈性进行了鉴定,发现该品种对当前的各优势小种均有良好抗性。在温室内以病菌小种Su11-4对M8003-5在进行苗期抗条锈性鉴定和遗传分析,初步确定M8003-5对Su11-4的抗性由1对显性基因控制,位于7DS上的SSR标记Xbarc5、Xwmc463、Xwmc405、Xbarc126、Xgwm295、Xgwm44、Xwmc702、Xwmc438、Xwmc121、Xgwm111和Xbarc121与该基因连锁,最近的为Xwmc702和Xwmc438,遗传距离分别为3.5 cM和4.3 cM。分子标记及其相关分析表明,此基因可能来自黑麦,与已定位于7D染色体上的抗病基因不同,暂命名为YrM8003。利用与其紧密连锁的标记Xwmc702和Xwmc438测黄淮麦区43个主栽品种,结果显示,有20%的品种具有与YrM8003基因相同的标记位点。这一结果有助于YrM8003在抗条锈病育种的应用。     

聚酰胺-UV法检测蜂花粉总黄酮的研究

黄酮类成分因其具有多样生物活性成为目前天然产物研究的热点。本实验探讨了聚酰胺-UV法作为蜂花粉总黄酮测定方法的可行性。结果表明以芦丁为标准品，以360nm为检测波长，用聚酰胺-UV法检测蜂花粉总黄酮在0．005-0．025mg／mL范围内，浓度与吸光度呈良好的线性关系，相关系数R2为0．9998，回收率、稳定性、精密度和重现性均理想，其RSD分别为2．48％（n=3），2，12％（n=3），0．49％（n=3）、0．88％（n=5）。该法检测油菜蜂花粉中总黄酮含量为1．54％。     

谈实行森林生态效益补偿的必要性

从4个方面论述了实行森林生态效益补偿的必要性。     

北京市樱桃沟流域小气候探析

对北京市门头沟区樱桃沟流域进行气候观测研究结果表明 ,该区樱桃沟流域具有一定的气候资源优势 ,符合大樱桃种植的气候要求 ,适宜种植发展大樱桃     

Energy metabolic enzyme responses of <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> to thermal stress: a comparative study in freshwater and seawater conditions

To investigate the effect of hypothermal (22?→?16 °C) and hyperthermal (22?→?28 °C) stress on the energy regulation of Litopenaeus vannamei cultured in long-term freshwater, the activities of hexokinase (HK), pyruvate kinase (PK), lactic dehydrogenase (LDH), and succinate dehydrogenase (SDH) were determined and compared with those kept in seawater. Results showed that at the early stage of thermal stress, HK, PK, and LDH activities increased and then decreased. At the end of the trial (48 h), all enzyme activities except PK and LDH activities in shrimps cultured in freshwater returned to the pre-experiment level. Following temperature stress, SDH activity of shrimps cultured in freshwater and seawater all decreased first and then increased, and finally reached the pre-experiment level, while SDH activity in gills of shrimps cultured in seawater was significantly lower than that before. At a constant temperature of 22 °C, compared with shrimps cultured in seawater, those cultured in freshwater had a lower level in HK, PK, and SDH activities, but a higher level in LDH activity. In summary, shrimps cultured in freshwater might rely more on anaerobic metabolism, while the opposite was true for glycolysis and aerobic metabolism. Because shrimps cultured in freshwater had a higher sensitivity to thermal stress, noticeable temperature variation especially when temperature decrease should be avoided in the freshwater intensive culture of L. vannamei.     

A fatty acid glycoside from a marine-derived fungus isolated from mangrove plant Scyphiphora hydrophyllacea

To study the antimicrobial components from the endophytic fungus A1 of mangrove plant Scyphiphora hydrophyllacea Gaertn. F., a new fatty acid glucoside was isolated by column chromatography from the broth of A1, and its structure was identified as R-3-hydroxyundecanoic acid methylester-3-O-α-l-rhamnopyranoside (1) by spectroscopic methods including 1D and 2D NMR (HMQC, (1)H-(1)H COSY and HMBC) and chemical methods. Antimicrobial assay showed compound 1 possessed modest inhibitory effect on Saphylococcus aureus and methicillin-resistant S. aureus (MRSA) using the filter paper disc agar diffusion method.     

不同降雨年型下种植密度对旱作马铃薯生长、水分利用效率及产量的影响

为探索宁南半干旱偏旱区覆膜垄作马铃薯合理的种植密度, 于2015和2016年设置37 500、45 000、52 500、60 000、67 500株 hm ^-2 5个种植密度, 以当地传统种植密度37 500株 hm ^-2为对照, 研究不同种植密度对土壤水分、马铃薯生长、水分利用效率及产量的影响。结果表明, 不同种植密度可显著影响马铃薯生育前期和中期0~100 cm层土壤水分状况, 以45 000和52 500株 hm ^-2处理土壤贮水量最高, 均显著高于37 500和67 500株 hm ^-2处理。45 000和52 500株 hm ^-2处理较其他处理均显著提高马铃薯出苗率, 促进马铃薯生育前期和中期的生长, 而在马铃薯生育后期各处理间差异不显著。马铃薯产量和商品率均随种植密度的增加呈先增加后下降的变化趋势, 45 000和52 500株 hm ^-2处理两年平均降水利用效率分别较37 500株 hm ^-2处理显著提高15.3%和17.6%, 作物水分利用效率分别提高11.1%和15.0%。通过两年数据拟合函数发现, 在宁南半干旱偏旱区2015年平水年和2016年枯水年, 旱作覆膜垄作马铃薯种植密度为51 187~51 302株 hm ^-2时, 其水分利用效率和块茎产量最高。     

竹焦油对植物病原真菌抑制活性初探

以竹炭生产副产物竹焦油为活性成分,采用菌落生长速率法测定了竹焦油对12种植物病原真菌的抑菌活性。室内盆栽药效试验表明．体积分数50％竹焦油乳油在质量浓度为2000mg·L^-1对黄瓜白粉病Sphaerotheca fuliginea的预防效果达到79．13％．治疗效果达到78．36％;对黄瓜灰霉病Botrytiscinerea的预防效果和治疗效果分别为42.38％和46．98％,其防效与对照药剂200mg·L^-1三唑酮没有显著差异。竹焦油具有较好的抑菌活性。