不同光强和缺镁胁迫对黄瓜叶片叶绿素荧光特性和活性氧产生的影响

不同光强和镁离子浓度对黄瓜叶片叶绿素荧光特性和活性氧产生的影响研究发现 ,在强光和缺镁胁迫下 ,黄瓜叶片发生了明显的光抑制 ,主要表现为Pn下降 ,叶绿素荧光参数Fv/Fm、Fv/Fo、qP和 qN降低 ;活性氧超氧阴离子产生速率和H2O2以及膜脂过氧化产物MDA增加。这些结果表明 ,缺镁黄瓜叶片在强光下qP和 qN的降低使叶片吸收的过剩光能通过光化学反应途径和非辐射能量途径耗散受阻 ,从而增加了过剩光能所激发的电子用来生成活性氧的比例 ,这在一定程度上可缓解光抑制 ;但其不能被及时清除掉时 ,会加剧光抑制 ,甚至引起光氧化对光合机构造成破坏 ,最终导致叶片的失绿坏死。适当遮荫有利于提高PSII的光化学效率 ,减轻光抑制。     

转基因棉花早代材料细胞学变异研究

农杆菌介导转基因棉花早代 ( T0 )材料 ,花粉母细胞的染色体构型变异很大 ,只有部分二价体 ( 7～ 1 6个 ) ,多数是单价体 ,没有更高的价体。二价体位于赤道面 ,但多形成染色体桥。单价体多散布在两极。减数分裂后形成 1～ 8个分体的多分体 ,其中四分体虽然比例很高 ,多为畸形。染色体数目的减少、PMC染色体构型变异等 ,是这类材料高度败育的直接原因     

Parameter Design for Machining Quenched Internal Helical Gears by EDM

Aiming at the problem of machining quenched internal helical gears, a method and its equipment are discussed and designed, which is used for machining quenched internal helical gears by EDM. Its characteristic and principle are proposed. The modifying design of the electrode gear and the calculating method of its modification coefficients is presented. Analyzing for the error of the machining equipment is done. The results show that this problem can be solved by EDM, the electrode gear is the modification gear of machined gear and the machining accuracy can be improved by controlling errors.     

信息技术在农业学科课程教学中的应用现状与思考

作为教育信息化基石的信息技术给农业学科课程教与学带来活力和契机,将信息技术应用于农业学科教学就是将现代信息技术作为手段和工具渗透到农业学科教学之中。结合信息技术在甘肃农业大学部分涉农专业专业基础课和专业课教学中的应用现状进行成果整合,并对存在的主要问题提出解决措施。     

Granular computing model for conflict resolution in product design

The conflicts of product design are difficult to be resolved using the model of distributed constraint satisfaction problem for the characteristics of hierarchy, distribution and dynamic of product design’s constraints. Product design is translated into a granular world in quotient space, and a multi-level hierarchical model of granular computing for conflict resolution in product design is constructed. The conflicts of product design can be resolved hierarchically and progressively through granulation and division of product design’s constraints and combination between quotient mapping and granularity synthesis which can achieve the mapping and backdate between different design domains. The method resolves the problem in a hierarchical coarse-to-fine and layer by layer manner. By the granular computing for conflict resolution, the distributed constraint satisfaction problems can be simplified and the computing complexity of the problem solving can be decreased, and it has the characteristics of systematicity, integrity and hierarchy.     

丝素/纳米SiO2凝胶共混膜的制备及性能测试

为了改善丝素膜作为医用材料的物理性能,以丝素和纳米SiO2为基材,乙醇为溶剂,制备不同质量比的丝素/纳米SiO2凝胶共混膜。对丝素/纳米SiO2凝胶共混膜的微观形态与结构进行表征:共混膜表面呈凹凸状,横截面为多层次的网络状结构,丝素蛋白分子主要为β-折叠结构。对不同质量比丝素/纳米SiO2凝胶共混膜的物理性能进行测试:当丝素与纳米SiO2共混质量比为80∶5时,共混膜的断裂强度最大,为94.86 MPa;当共混质量比为80∶3时,共混膜的断裂伸长率最大,为55.20%;共混膜的溶胀度和热水溶失率与纳米SiO2含量成反比,而透气性随着纳米SiO2含量的增加呈先上升后下降的趋势。测试结果表明,在天然高分子材料丝素溶液中加入具有补强增韧功能的纳米SiO2制备的共混膜,更接近优良人工皮肤材料的物理性能特征,丝素与纳米SiO2的共混质量比以80∶3和80∶5为宜。     

Effects of curcumin analogue B50 on proliferation and apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance

AIM: To compare the effects of B50, a mono-carbonyl analogue of curcumin, on the proliferation and apoptosis between homologous nasopharyngeal carcinoma cells CNE-2R and CNE-2 with different radioresistance.METHODS: The effects of B50 on cell viability and cell growth were detected by MTT assay and colony-forming experiment, respectively. The changes of cell cycle, apoptosis and mitochondrial membrane potential (MMP) were determined by flow cytometry.RESULTS: B50 inhibited the cell viability of CNE-2R cells in a time-and dose-dependent manner with the IC₅₀ of (8.06±0.14) μmol/L (24 h), (2.49±0.02)μmol/L (48 h) and (1.42±0.02) μmol/L (72 h), which was more effective than that in CNE-2 cells . The inhibitory effect of B50 on CNE-2R cell growth was more effective than that on CNE-2 cells . After treated with B50 for 48 h, the proportion of CNE-2R cells in G₂/M stage was increased from 7.1% to 34.9%, which was better than that of CNE-2 cells (from 12.4% to 35.7%). After treated with B50 for 24 h, the early apoptotic rate in CNE-2R cells was increased from 3.7% to 19.5%, which was better than that in CNE-2 cells (from 4.4% to 14.8%), and the MMP in CNE-2R cells was decreased by (43.17±3.11)%, which was better than that in CNE-2 cells .CONCLUSION: B50 is more effective on inhibiting the cell viability and cell growth, blocking the cell cycle at G₂/M stage, inducing apoptosis and decreasing MMP in CNE-2R cells than those in CNE-2 cells, indicating that B50 may enhance the radio-sensitivity of CNE-2R cells by blocking the cell cycle and inducing apoptosis through mitochondrial pathway.     

厚皮甜瓜新品种苏甜1号的选育

苏甜1号是以M-123为母本,以M-12-4为父本配制而成的厚皮甜瓜一代杂种。中早熟,果实发育期35 d（天）左右。植株长势稳健,田间调查对白粉病和蔓枯病的抗性强于对照西薄洛托,耐低温,易坐果。果实圆球形,果皮乳白色,光滑无网纹,果肉白色,肉厚3.5～4.0 cm,肉质软而多汁,香味浓郁,可溶性固形物含量15.0%～17.0%,单瓜质量1.5～1.8 kg,每667 m2产量1 900～2 100 kg,适于华东地区及气候相似地区春季保护地栽培。     

观赏羽衣甘蓝抗寒性评价

在5~-15℃不同低温处理下对观赏特征不同的5个羽衣甘蓝品系叶片的细胞膜透性、MDA含量、CAT、POD、SOD活性进行了研究。结果表明:各品系的细胞膜在-10℃时开始受到损伤;过氧化氢酶和过氧化物酶在整个处理范围内总体活性上升,尤其在-10℃时增加明显;超氧化物歧化酶在-10~-15℃变化不明显。综合各生理指标的结果,温度低于-10℃,羽衣甘蓝自身抗寒调节能力开始逐渐丧失。     

不同类型吊兰光合特性研究

运用便携式光合作用测定系统,进行全绿吊兰、银心吊兰、银边吊兰3种不同类型吊兰的光合特性比较分析.结果表明:全绿吊兰的净光合速率和胞间CO2浓度均显著高于银心吊兰和银边吊兰;而蒸腾速率以及气孔导度显著低于其它2种吊兰.而银心吊兰和银边吊兰之间相比,以上4个光合指标差别不显著.