比格犬胫神经皮层体感诱发电位正常值研究

为了测定比格犬胫神经皮层体感诱发电位(somatosensory evoked potential,SEP)的波形及其潜伏期和波幅的正常值。选用15只健康比格犬,在异氟烷吸入麻醉状态下,使用肌电诱发电位仪电刺激其胫神经,将自制参考电极和记录电极分别放置于头部Fz处和Cz处记录SEP波形。结果表明:15只比格犬刺激左右侧胫神经均可记录到清晰的双向SEP波。刺激左侧胫神经引发的波形潜伏期为P(21.71±1.978)ms、N(32.61±2.568)ms、P-N(10.90±1.338)ms,其变异系数分别为9.11%、7.87%、12.88%;波幅为(2.762±1.230)μV,变异系数为41.47%;刺激右侧胫神经引发的波形潜伏期为P(21.49±1.985)ms、N(32.55±2.359)ms、P-N(11.06±1.153)ms,其变异系数分别为9.24%、7.25%、10.24%;波幅为(2.634±1.092)μV,变异系数为44.55%。潜伏期和波幅左右侧差异均不显著(P0.05)。对正常比格犬胫神经皮层SEP的测定,获得了清晰的SEP波形及各波潜伏期和波幅的正常值,印证了潜伏期的稳定性优于波幅的稳定性,可以为实验室研究犬病理状态下的SEP和宠物临床应用SEP诊断疾病提供参考依据。     

Hesperetin attenuates hypoxia/reoxygenation-induced apoptosis in H9c2 cells via inhibition of calcium overload

AIM: To investigate the effect of hesperetin on hypoxia/reoxygenation (H/R)-induced apoptosis in the H9c2 cells and to clarify the underlying mechanism. METHODS: The H/R model was established and the H9c2 cells were pretreated with hesperetin for 4 h. The cell viability and cell damage were measured by CCK-8 assay and lactate dehydrogenase (LDH) detection. The apoptosis was analyzed by Hoechst 33258 staining and flow cytometry. The intracellular calcium fluorescence intensity was measured by fluorescence microscopy and flow cytometry. The calcium-ATPase activity and the level of adenosine triphosphate (ATP) were measured by ELISA. The mitochondrial membrane potential was measured by JC-1 staining. The protein expression levels of Bcl-2, Bax and cytochrome C (Cyt-C) were determined by Western blot. RESULTS: Hesperetin reduced the apoptosis of the H9c2 cells induced by H/R, decreased intracellular Ca²⁺ fluorescence intensity, elevated Ca²⁺-ATPase activity, inhibited the mitochondrial membrane potential depolarization and increased the level of ATP (P<0.05). In addition, hesperetin significantly reduced the release of Cyt-C protein from mitochondria to cytoplasma and increased the Bcl-2/Bax ratio (P<0.05). After using the calcium ion inhibitor nimodipine, the percentage of the cells with mitochondrial membrane depolarization was decreased, the ATP level was increased and the protein expression of mitochondrion-related apoptosis molecules were decreased (P<0.05). CONCLUSION: Hesperetin reduces the apoptosis of the H9c2 cells induced by H/R, which may be related to inhibition of calcium overload and improvement of mitochondrial function.     

滴灌控制土壤基质势对土壤水分分布和苜蓿生长的影响

采用在滴头正下20 cm深度处埋设负压计,分别设置-15、-25和-35 k Pa的土壤基质势控制滴灌,通过田间试验,研究了不同土壤基质势下土壤水分变化特点和紫花苜蓿的生长特性,分析了蒸发、降雨和灌水与土壤基质势之间的关系。从土壤剖面水分分布来看,整个生育期内-15 k Pa处理下的土壤剖面含水率整体集中在14%~15%,较-25和-35 k Pa处理的更为均匀,水分密集区域距离滴头最近;-15 k Pa处理下苜蓿株高达到41.7 cm,盖度为15.3%,生物量值达到了281.29 g/m~2,在所有处理中均为最高。     

西北干旱区节水灌溉效益及潜力分析——以新疆乌苏市为例

基于西北地区农业灌溉特点,以新疆乌苏市为例,分析当前的节水灌溉措施和效益,指出了其中的不足之处,并通过对该地农业节水途径的分析,定量计算了未来10年该地和新疆以及西北地区的节水潜力,同时提出几点有针对性的建议和改进措施,以求为广大西北地区农业可持续提供发展思路.     

刺蒺藜草在我国的适生区预测

本研究基于MaxEnt模型,依据气候、海拔、人类活动等不同层面的12个环境变量建立刺蒺藜草适生性预测模型,模型AUC值高于0.9,表明模型结果可靠。预测显示：我国刺蒺藜草非适生区占73.66%;低度适生区占18.24%;中度适生区占5.11%;高度适生区占2.99%。其中广东、广西、海南几乎全境,福建、台湾、云南的大部分地区为中、高度适生区,具有最大的传入定殖风险。通过预测模型可以看出,bio＿11（最冷季度平均温度）、hf＿v3geo（人类足迹）、bio＿18（最暖季度降水量）和bio＿04（温度季节性变化标准差）等4个环境变量对刺蒺藜草在某地适生产生重要影响。     

基于MaxEnt模型的检疫性害虫小蔗螟在中国的潜在分布预测

小蔗螟是重要的检疫性害虫,许多国家将其列入检疫性害虫名录,主要危害甘蔗、玉米等作物。本研究基于小蔗螟分布记录,结合环境数据,采用MaxEnt软件对其在中国潜在分布区进行预测。结果表明：小蔗螟在我国的高度和中度适生区主要分布在海南、云南、广东、广西及福建等。影响小蔗螟分布的最主要环境变量是最暖季平均降雨量和温度变化方差。阐明小蔗螟在我国潜在地理分布及限制其分布的环境变量,可为我国的检疫工作提供理论依据。     

藜麦研究进展及发展前景

藜麦(Chenopodium quinoa),苋科藜属植物,原产于南美洲安第斯山脉高原地区,具有大约5000~ 7000年的种植历史,是当地印加人备受推崇的主要粮食作物之一,近些年因为其全面的营养价值和均衡的氨基酸比例以及药用保健价值收到追捧,引起了许多科研工作者的兴趣。为了给科研工作者提供一些研究方向的参考,通过对国内外对藜麦的研究文献进行汇总,归纳了在藜麦的引种栽培、营养成分分析、产品开发利用、遗传谱系研究、抗逆性研究、抗病虫害研究等方面的最新研究进展,提出了一些在研究中尚未解决的问题,如藜麦在低海拔地区产量和品质降低、藜麦的多种药用保健作用、藜麦副产物的利用等,将成为未来研究的重点方向,并分析了藜麦作为一种杂粮作物在中国西北地区的引种栽培以及发展潜力。     

Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes

Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:

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Potatoes

°

After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Fresh tomatoes

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From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Processing tomatoes

°

From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψ_soil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψ_soil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψ_{soil, dry side} = −270 kPa).

The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.