花生高效再生体系的建立初报

为了建立花生高效再生体系,选用外引及自选共8个花生品种(系)胚小叶作外植体,研究愈伤组织诱导率和不定芽分化率。结果表明:品种间愈伤组织诱导率和不定芽分化率均差异显著。品种冀花4号愈伤组织诱导率最高,为98%;太空1号、唐油4号、豫花9626、花育20较高,泉花646、阜花13次之;品系452-2最低,为43%。不定芽分化率为5%~73%,其中冀花4号最高,为73%;太空1号68%较高;豫花9626次之,为35%;花育20、泉花646和452-2较低,分别为13%、11%和10%;阜花13、唐油4号最低,均为5%。     

东北红豆杉配子形成与胚胎发育解剖观察1）

利用显微技术观察了东北红豆杉雌、雄配子形成和胚胎发育过程。结果表明：直生胚珠3月份恢复发育,5月中旬大孢子母细胞形成,下旬减数分裂,6月中、下旬雌配子体形成。3月中旬花粉母细胞减数分裂,经过1个月左右发育为成熟的单核花粉,4月底至5月初散粉。传粉后约2个月受精,受精后的原胚经历球形胚、卵形胚、柳叶形胚、棒槌形胚,进而发育成具有胚芽、胚根、胚轴和子叶的胚体。     

摘花序、打顶对商洛桔梗生长的影响

研究了摘花序、打顶对2年生桔梗的生长性状及根部有效成分的影响,结果表明:摘花序、打顶后的植株生长健壮、干物质积累多、根部产量高、有效成分积累量大,明显优于2种处理方法的单独使用。     

对绿色证书培训的思考

介绍绿色证书培训的形成与发展,阐述绿色证书培训的重要性,提出推进绿色证书培训的措施,以为农业现代化提供强有力的人才保障。     

含蜡原油管道胶凝形成机理研究进展

介绍了国内外献中对含蜡原油胶凝形成机理的研究成果。研究结果表明，在含蜡原油管道中，当油温低于浊点时，易在管壁处形成一层类似固体的凝胶物质。含蜡原油管道胶凝的形成主要受热历史和剪切历史的影响，胶凝湿度随冷却速度的减小而降低，随剪切应力的增大而降低，而浊点与冷却速度和剪切应力无关。在环境湿度高于油温的情况下， 即便油温低于浊点湿度，含蜡原油也不会形成胶凝。由于胶凝具有类似固体的机械特性，因此冷却速率越快，石蜡晶体越小，越多，屈服应力也越大，胶凝屈服应力取决于蜡晶的大小和数目。     

Progress and Yield Bottleneck of Aerobic Rice in the North China Plain: A Case Study of Varieties Handao 297 and Handao 502

Aerobic rice has been considered a promising rice cultivation system as water scarcity is increasing in the world. This article summarizes the advances in aerobic rice management researches in the North China Plain, focusing on yield formation and its bottleneck. High-yielding and good-quality aerobic rice varieties adapted to aerobic soil conditions have been released officially and adopted by farmers in North China. The varieties Handao 502 and Handao 297 have been recognized as the most promising varieties reaching a yield level ranging 3.5-5.0 t ha-1 with 450-650 mm water input. Compared with lowland rice, water input in aerobic rice was more than 50% lower, and water productivity was 60% higher. Researches on responses of rice cultivars to nitrate nitrogen （N） and ammonium N supplied at early growth stages provided the first evidence for a preference of aerobic rice HD297 for nitrate N supply, compared with the lowland rice variety. Zinc uptake studies demonstrated that introduction of aerobic rice system on calcareous soils may increase zinc deficiency problems. Sink size was identified as the limitation of aerobic rice yield, because its spikelet number m-2 was too low （20000-24 000） compared with the lowland rice. For future research, more attention is suggested to be paid to yield formation focusing on effects of water regimes on tiller dynamics. Understanding of nutrient uptake and response to fertilization effects are also urgently required to establish optimized crop management technology. Additionally, alternative cropping systems based on aerobic rice should be established, and key sustainability and environmental impact issues in the systems need to be identified.     

农业高校产学研结合难点及其成因探讨

农业高校产学研结合的制约因素较多,就其难点来看,既有科研过程本身的问题:主要包括不规范的项目运作,游离于市场需求之外的科研模式以及科研浮躁等;又有科研成果的质量问题:主要包括有效成果较少、技术缺乏创新和配套技术不完善等。     

Vegetative propagation of Beta vulgaris by leaf cuttings

Summary Leaf cuttings without axillary buds were made from young vegetative beet plants. Roots were formed at the petiole end. Adventitious bud formation occurred at a very low frequency and could not be stimulated by application of growth regulators. Leaf cuttings with axillary buds formed plants at a higher frequency but development of buds into shoots was slow and irregular. As no vascular connections were found between petiole and axillary bud, the slow growth of the buds was attributed to insufficient supply of assimilates from the leaves. Axillary buds rapidly developed into shoots when petiole explants with buds were placed on culture media. Nearly all cultures, however, were contaminated with bacteria that originated from the inner tissue of the explants.     

The floral system of tomato

The tomato floral system is distinguished from that of Arabidopsis and Antirrhinum in several ways. The shoot is a sympodium, the first flower of the inflorescence is apical and no bracts are formed. We discuss the possible function of genes affecting growth habit and inflorescence development and analyze in detail the unique developmental alterations caused by inhibition or ectopic expression of tomato-specific MADS-box genes. Preliminary analysis of transgenic tomato plants expressing an alien homeotic gene and several different chimeric genes of the MADS-box family is also reported.