京西稻的百年传承与发展

京西稻是清康熙、雍正、乾隆等亲自选育的优良品种,在与紫禁城并重的“三山五园”政治中心内外种植,具有多重价值属性,属于皇家御稻。从2000年起,基于北京水资源匮乏等原因,京西稻种植面积大幅度降至134 hm²左右,处于濒危状态。在保护传承过程中,京西稻入选中国重要农业文化遗产目录。在新修订的《北京历史文化名城保护条例》中,又将京西稻列入遗产保护目录。在海淀区,京西稻已经深入公园、学校、社区、酒店等地,在教育文化中发挥着农业以外的作用。     

茶树花青素形成分子机理的研究进展

花青素是由类黄酮合成途径产生的次生代谢产物,含量高时会使茶树新梢呈现红色或紫色。同时,花青素相比儿茶素等具有更明显的抗氧化、预防肿瘤等药理保健作用。文章就茶树花青素合成途径、转录及转录后调控等方面进行综述,以期更好地为高花青素茶树的育种研究提供理论依据。     

Replacement of fish oil in plant‐based diets for Pacific white shrimp,Litopenaeus vannamei,by stearine fish oil and palm oil

Stearine fish oil (SFO) and palm oil (PO) have emerged as promising alternatives for the replacement of fish oil (FO) in aquafeeds. This study evaluated the replacement of FO with alternative oils in practical diets for Litopenaeus vannamei. In a clear brackish water study (14.1 g/L) utilizing shrimp (0.29 ± 0.02 g, initial weight), FO was replaced by SFO at inclusion ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 (FO:SFO) and PO as 90% of FO. After 55 days, no significant differences (p < 0.05) in final weight, growth, or survival of shrimp were observed. A second trial (8 weeks) in low‐salinity water (2.1 g/L) with shrimp (0.92 ± 0.02 g, initial weight) evaluated diets with 100% FO, 100% SFO, 90% PO, 90% soybean oil (SO), or 90% flaxseed oil (FXO) as a replacement for FO and four commercially produced diets with 2% of FO, SO, PO, or FXO. One treatment received half rations of the commercial FO diet, and one treatment was based entirely on natural productivity. Results show that the fatty acid profiles of the tail muscle conformed to the lipids of the feed, and highly unsaturated fatty acids (HUFAs) were preserved. Following 8 weeks of culture, there were no significant differences in production performance.     

全球植物科学领域发展态势分析

基于农业科技创新的发展需求,为农业科技资源的有效配置提供支撑,从文献计量角度对全球植物科学领域研究现状及态势进行分析。利用定性、定量相结合的方法构建检索策略,基于Web of Science数据库及文献计量分析工具,对文献发表量、文献主要贡献国家、机构、期刊及发文量较高的作者H指数进行统计分析。结果表明,1995—2018年植物科学领域的文章发表量整体上呈现稳定增长趋势,学科呈现蓬勃发展的整体势头。美国和中国是文献主要贡献国家,文献量和总被引频次显著高于其他国家,但美国及欧洲国家的篇均被引数量高于中国。从全球来看,中国科研机构在发文数量占有绝对优势,而德国马克思普朗克的文章篇均被引数量高,达到10以上。对2016—2018年的高被引文献(Top10)进行内容分析,并通过高频词共现主题聚类可视化分析。从论文影响力及主题词规模2个维度表征领域内研究方向。结果表明,“植物应对生物及非生物胁迫”、“基因编辑技术”、“基因组学分析”、“植物生殖发育调控”是近年来植物科学的高关注度研究方向,主题内容与前期的需求调研相符,初步预测这些研究方向将对农业创新发展起到重要推动作用。     

Do cover crops change the lability of phosphorus in a clayey subtropical soil under different phosphate fertilizers?

Plants have developed different mechanisms to absorb and solubilize phosphorus (P) in the soil, especially in environments with low P availability. This study evaluated the effects of different winter cover crops on soil P availability in a clayey subtropical (Hapludox) soil receiving soluble P fertilizer and a rock phosphate applied to the summer crop, under no‐tillage. The experiment was carried out over 3 yrs (2009–2011) with five different cover crop species: common vetch, fodder radish, ryegrass, black oat, white clover and fallow as control. The soil was sampled after the third year of cover crop cultivation and analysed for inorganic and organic P forms according to the well‐established Hedley fractionation procedure. Phosphate fertilizers promoted accumulation of both labile and nonlabile P pools in soil in the near surface layer, especially under rock phosphate. Fertilizer applications were not able to change P fractions in deeper layers, emphasizing that the Brazilian clayey soils are a sink of P from fertilizer and its mobility is almost nil. Although the cover crops recycled a great amount of P in tissue, in a short‐term evaluation (3 yrs) they only changed the content of moderately labile P in soil, indicating that long‐term studies are needed for more conclusive results.     

含刚性沉水植物明渠水流结构的试验研究

【目的】得到含刚性沉水植物明渠的水流结构。【方法】采用粒子图像测速仪(PIV),用有机玻璃棒模拟刚性植物,在不同来水流量、植物密度条件下对明渠水流结构进行了试验研究。【结果】无植物时平均流速沿垂向呈对数分布规律,有植物时则呈现明显的分区分布特性。无植物时紊动强度值沿垂向变化不大,有植物时在植物顶端位置处紊动最剧烈。流量或植物密度越大,植物顶端位置的流速梯度就越大,植物层上方的流速最大值也越大。植物密度越大,植物顶端位置的紊动强度越大,植物密度对水流紊动强度由最大值减小到最小值的区域影响很大。【结论】刚性沉水植物的存在会改变水流结构,增强紊动掺混,增强流体质点交换和能量传递,且上述影响会随着流量或植物密度的增大而增强。     

Impact of soil water content on maize responses to the plant growth-promoting rhizobacterium Azospirillum lipoferum CRT1

Members of the bacterial genus Azospirillum are root-associated bacteria that increase yield in cereals by promoting growth and alleviating drought stress. How plants integrate the many bacterium-derived growth-promoting stimuli with other environmental factors to generate a coordinated response remains unresolved. Using a commercial Azospirillum strain, A. lipoferum CRT1 and two host maize cultivars, it was observed that bacterization reduced the drought-induced increase in lateral root growth and enhanced the flood-induced increase in lateral root growth in the more drought- and flood-sensitive cultivar. In the other one, A. lipoferum CRT1 only elicited a moderate root growth response under low soil water potential. The photosynthetic potential and activity were increased in the earlier cultivar and decreased in the later one, irrespective of the soil water content. No impact of the bacterium was seen on the growth of the leaves of both cultivars under both stresses until the third leaf stage, therefore suggesting that it is a consequence of multiple primary adaptations to biotic and abiotic stresses. It is suggested that host–bacteria recognition leads to a stress-specific modulation of the root response and a differential stress-independent effect on photosynthesis. This is the first report of the impact of Azospirillum under flood conditions.     

Preparation and characterization of gluten-free sheeted doughs and noodles with zein and rice flour containing different amylose contents

This study aimed to explore the feasibility of zein as a gluten alternative in preparing sheeted doughs with rice flours containing different amylose contents (12, 19, and 26%) that were successfully slit into noodle strands. Rice-zein mixtures with lower amylose contents exhibited lower pasting parameters and the high amylose paste samples possessed more elastic properties. Higher water absorption was observed in the low amylose rice-zein mixture whereas the use of zein were effective in increasing the stability of rice dough regardless of amylose content. In case of thermal conductivity, the noodle doughs prepared with high amylose rice-zein mixture had low thermal conductivity, probably implying a long cooking time. The structure of the rice-zein noodles had a tendency to become firmer with increasing levels of amylose by showing greater breaking stress and resistance to extension that could be correlated to reduced cooking loss.     

MYB转录因子参与植物非生物胁迫响应与植物激素应答的研究进展

基因的时空表达受转录因子的精确调控。植物在面对不利环境因素比如高温、低温、干旱、盐碱等胁迫时其细胞生理生化会迅速地从“舒适”状态转变进入“胁迫响应”状态。这种快速响应的状态转变依赖于植物对胁迫信号的感知及传递、激素通路(脱落酸、茉莉酸等)的激发、转录因子的活化等复杂的过程;最终植物通过胁迫相关基因的表达、次生代谢转变、抗氧化物质的积累等实现胁迫条件下细胞内环境的再平衡从而获得生存。植物MYB(v-MYB avian myeloblastosis viral oncogene homolog)转录因子就是上述转变中的重要参与者。本文介绍了植物MYB转录因子的结构特征、分类,综述了近些年来MYB转录因子与非生物胁迫,以及植物激素应答过程相关的研究进展。