Effects of Exogenous 24-epibrassinolide on Photosynthetic Physiology of CottonSeedlings under Low Temperature

[Objective] The objective of this study was to investigate the effects of exogenous 24-epibrassinolide (EBR) on the photosynthetic physiology of cotton seedlings under low temperature and to provide basis for improving the cold tolerance of cotton by using EBR as growth regulator. [Method] Taking CCRI 60, Lumianyan 28 and Simian 3 as materials, a field experiment was carried out in Institute of Cotton Research of CAAS(Anyang county, Henan province). Before the first low temperature treatment, the cotton seedlings were sprayed with distilled water (Control) and different concentrations of EBR (0.1 mg·L^－1 and 0.2 mg·L^－1), respectively. After 3 days, the relative electrical conductivity, chlorophyll content, rapid chlorophyll fluorescence induction kinetic curve (OJIP) and fluorescence parameters were measured. [Result] Under low temperature, the relative conductivity of CCRI 60, Lumianyan 28 and Simian 3 spraying with EBR decreased by 17.7%～32.8% compared with control, and there was no significant difference between CCRI 60 and Lumianyan 28 in different concentrations of EBR treatments, butthe relative conductivity of Simian 3 treating with 0.2 mg·L^－1 EBR was significantly lower than those treatments with 0.1 mg·L^－1 EBR . The chl a and chl b contents increased by 9.7%～32.6% and 15.0%～18.9%, respectively. The maximum photochemical efficiency of photosystemⅡ (F_v/F_M) and photosynthetic performance index on absorption basis(PI_ABS) increased significantly. PI_ABS of CCRI 60 increase the maximum by 75.6% using 0.1 mg·L^－1 EBR. Lumianyan 28 and Simian 3 increased the maximum by 101.1% and 265.6% using 0.2 mg·L^－1 EBR, respectively; Absorbed photon flux per cross section (ABS/CSm), electron transport flux (further than QA) per active reactive center (ETo/RC) and probability for electron transport (φEo) are significantly increased. [Conclusion] Exogenous EBR can enhance the ability of low temperature tolerance of cotton seedlings and alleviate the inhibition of photosynthesis in cotton at low temperature. The study showed that 0.1 mg·L^－1 EBR performs well in CCRI 60 and 0.2 mg·L^－1 in Lumianyan 28 and Simian 3.     

糜子愈伤诱导及再分化最适条件研究

研究旨在应用组织培养技术探究愈伤诱导及再分化的最适条件,以期为糜子建立遗传转化体系奠定基础。采用5个糜子品种研究愈伤诱导及再分化的最适条件。利用植物激素2,4-二氯苯氧乙酸(2,4-D)诱导茎尖愈伤组织,筛选出发芽率高、愈伤组织诱导率高、染菌率低的品种,并对诱导愈伤最适激素浓度及配比进行了鉴定。结果显示,‘冀黍2号’出芽率高、愈伤组织诱导率高、染菌率低,适宜进行组织培养;2,4-D对‘冀黍2号’愈伤诱导效果最好,最适浓度为2.5 mg/L,诱导率达86.67%,淡黄色块状,结构紧密,质地较硬,继代培养后形成的胚性愈伤组织状态更好。再分化过程中,2.5 mg/L 2,4-D+3.5 mg/L TDZ时,出现明显的嫩芽。该试验获得‘冀黍2号’愈伤诱导及再分化的最适条件,可为糜子再生体系的构建提供参考。     

基于电磁感应技术的区域三维土壤盐分空间变异研究

以孔雀河流域典型地带为研究区域,利用电磁感应式大地电导率快速测定技术探测获得表观土壤电导率数据,构建了基于电磁感应技术的区域尺度剖面分层土壤盐分精确解译模型,精准解译出研究区剖面土壤盐分含量信息,并以此为数据源采用三维普通克里格法解析并评估了研究区土壤盐分三维空间分布特征。研究表明,不同测量位数据的综合应用能够表征剖面土壤盐分信息,构建出的剖面分层土壤盐分解译模型具有较好的精度;研究区不同区位土壤盐分三维分布呈现明显差异;研究区土壤主体属中度以上盐渍化,局部地带属于重度以上盐渍化土壤,需采取有效治理措施对土壤盐渍化进行可靠防控。     

An improved rotor side control strategy of double fedwind turbine generation system

Based on a on site wind turbine’s output active power vs. generator speed curve, the shortage of conventional power control strategies of doubly fed wind turbine generation system are analyzed. Considering the generator speed restriction and active power fast track control requirement, the power decoupling control strategy in the rotor side converter and variable pitch control strategy are improved, that is, an output mechanical torque of wind turbine and the generator speed of DFIG are used in the rotor side active power control loop in order to achieve an accurate optimal speed control, as well as a direct active power control method is also adopted in the variable pitch control strategy. Finally, the overall operational performances of DFIG wind turbine generation system using the proposed control strategies are simulated, and also compared with the conventional control strategies. The results show that the improved control strategy is more valid and correct.     

IWSF-FA模袋混凝土抗压强度、孔隙结构和物质组成

为优化模袋混凝土衬砌性能,合理利用当地粉煤灰和废弃硅粉代替部分水泥制备模袋混凝土衬砌.通过抗压强度试验、固体紫外试验、核磁共振和热重试验研究双掺粉煤灰-工业废弃硅粉替代适量水泥后对模袋混凝土抗压特性、内部孔隙结构和水化物质组成的影响.结果表明：合理双掺工业废弃硅粉和粉煤灰(如FA15S4)可以提高模袋混凝土的抗压强度;紫外吸收光谱表明其水化产物C-S-H和CH组成优于其他组别;核磁共振T₂谱分布呈现“三峰结构”,左峰信号幅度最高,双掺工业废弃硅粉-粉煤灰有利于改善其内部孔隙结构.并且双掺工业废弃硅粉和粉煤灰后,热学性质良好.建立了基于BP神经网络理论的模袋混凝土早期抗压强度预测模型,预测结果与试验测试值的最大相对误差为2.7%.研究结果可为工业废弃硅粉和粉煤灰混凝土在水工衬砌工程中的应用提供参考依据.     

天蓝苜蓿花药愈伤组织诱导及再生体系的建立

为获得天蓝苜蓿单倍体再生植株,本研究以野生天蓝苜蓿花药为外植体,采用正交设计L16(44)筛选适宜天蓝苜蓿愈伤组织诱导培养基,比较不同基本培养基及生长调节剂组合筛选适宜的分化培养基,并用1/3MS、1/2MS和MS添加不同浓度的NAA研究不定生根.结果表明:天蓝苜蓿现蕾15～25 d的花药其愈伤组织诱导效果最好,高达6...     

暗适应叶光诱导期间出现的光声瞬态研究初报

(1吉首大学城乡资源与规划学院,湖南张家界 427000; 2中国科学院植物研究所数量植被生态学重点实验室,北京 100083)     

铁皮石斛原球茎诱导与增殖研究

以铁皮石斛嫩茎为外植体,采用幼嫩茎段→原球茎诱导→原球茎增殖途径,通过单因子、双因子以及正交试验诱导原球茎。研究结果表明,外植体灭菌条件为：70%酒精浸泡3s后,0.1%升汞溶液中浸泡8min,诱导铁皮石斛原球茎最佳培养基为MS＋6-BA0.5mg/L+NAA0.5mg/L+ 2,4-D1.0 mg/L,原球茎增殖最佳培养基为MS＋6-BA3.0mg/L+NAA0.3mg/L。     

Flower induction in seedlings of Aster novi-belgii and selection before and after vegetative propagation

Bolting and flowering of Aster novi-belgii seedlings as well as correlations between characteristics within seedling populations and between seedlings and their vegetatively propagated offspring were investigated in order to improve breeding efficiency. In seedlings of A. novi-belgii, flower induction was observed without vernalization. Seedlings initially formed a rosette, but bolting was a prerequisite for development of a normal flowering shoot. Bolting was promoted by long photoperiods as compared to short days. The shortest time from sowing to anthesis was recorded when plants were grown under long photoperiods until the main stem was at least 5 cm long, and then moved to short photoperiods. A large variation in time to anthesis, plant height, branching ability, and flower size and color was found among the seedlings within all crosses. Magnitude and significance of correlations between some characteristics varied among crosses. The more consistent correlations seem mainly to be due to natural courses of plant growth and development. High correlations between seedling characteristics and their vegetatively propagated offspring were only found for flower hue. Lower, but significant correlations were found for flower color intensity, plant height and branching ability. There were no significant correlations for the time-to-anthesis between the two groups of plants. This revised version was published online in July 2006 with corrections to the Cover Date.