Biolistic mediated site-specific integration in rice

Cre-lox mediated site-specific integration in tobacco or Arabidopsis used polyethylene glycol or Agrobacterium, respectively, to deliver the integrating DNA. The polyethylene glycol method is inconvenient since it requires the use of protoplasts. The Agrobacterium method is inefficient as the single-stranded T-DNA is not a substrate for Cre-lox recombination. In this study, we tested the biolistic method for the site-specific insertion of DNA into the rice genome. Two target callus lines, each harboring a single genomic lox target, were generated by Agrobacterium-mediated transformation. The target callus lines were subjected to a second round of transformation by particle bombardment with a construct designed to excise the plasmid backbone from the integrating DNA, followed by the recombination of the integrating DNA into the genomic lox target. Site-specific integration was obtained from both target callus lines. Three integrant plants were regenerated from one target line and were found to have a precise copy of the integrating DNA at the target site, although only one plant has the integrating DNA as the sole copy in the genome. Site-specific integration through the biolistic delivery of DNA can be considered for other plants that are transformable via particle bombardment.     

Annexin-mediated secretory vesicle aggregation in plants

The mechanism by which membranes fuse during vesicle-mediated secretion is of considerable importance for plant cell growth, but remains unknown. We have identified Ca²⁺-dependent phospholipid-binding proteins (annexins) from maize ( Zea mays ), that may play a part in this process. An assay for Ca²⁺-dependent binding of annexins to liposomes, revealed that the maize proteins (p23, p33 and p35) and annexins from bovine lung, bind over a similar range of Ca²⁺ concentrations. Turbidity assays further revealed that both maize and bovine annexins induced liposome aggregation and that the plant annexins were also effective at aggregating plant secretory vesicles. This aggregation occurred at levels of free Ca²⁺ similar to that required for the binding of annexins p33 and p35. We discuss the significance of these results for the plant secretory apparatus.     

Transformation of Orychophragmus violaceus Using Agrobacterium tumefaciens And Regeneration of Transgenic Plants

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突触囊泡蛋白在ALS转基因鼠海马的表达变化

目的为了为揭示肌萎缩脊髓侧索硬化症（amyotrophic lateral sclerosis,ALS）认知功能障碍的机制提供依据,观察不同年龄ALS转基因小鼠海马中突触囊泡蛋白（synaptophysin,Syp）的表达情况。方法取95d、108d和122dALS转基因鼠海马,应用免疫荧光、Westernblot、RT-PCR技术检测Syp在海马中的表达变化。结果与同窝野生型鼠比较,Syp蛋白和mRNA表达水平在95d龄ALS转基因鼠海马中无明显变化,在108d与122d龄ALS转基因鼠海马中明显降低。结论Syp在ALS转基因鼠海马中表达减少表明,突触可塑性降低是ALS学习记忆能力下降的重要病理学基础。     

北方冬小麦/夏玉米轮作体系土壤氨挥发的原位测定

采用通气法测定了北方冬小麦／夏玉米轮作体系田间土壤的原位氨挥发。结果表明,与冬小麦施用基肥相比,夏玉米追肥后土壤的氨挥发速率很快升高,但军发高峰期持续时间较短,最大氨挥发速率亦低于冬小麦,冬小麦拨节期追肥,氨挥发速率低且呈波动变化,未出现高峰值,从整个生长季节来看,冬小麦不施氮和每公顷施氮120、240、360kg时的累计挥发量分别为4．4、6．9、13．0、38．4kgN/hm^2,夏玉米为8．4、15．1、20．0、26．1kgN/hm^2。按我国北方冬小麦／夏玉米播种面积1864．4万hm^2计,每年由氨挥发向大气排放的氨素达23．8－120．2万t,其中17．2－96．4万t来自氮肥,相当于氮肥投入的2．1％－9．5％。     

干旱条件下夏玉米地-气温差的影响因素及其模拟

地-气温差指标表征作物水分亏缺状况已经被广泛研究,但地-气温差随作物生育进程的变化特征及其影响因子的观测研究仍较少,制约着地-气温差的准确模拟.基于夏玉米2014年三叶期和2015年拔节期的5个灌溉水分控制试验资料的研究表明: 随着夏玉米生育进程的推进,土壤水分的变化显著影响了夏玉米农田的地-气温差,土壤水分亏缺越严重,地-气温差越高.在整个水分处理期间,归一化植被指数是地-气温差的主要影响因子且两者呈显著的线性关系,但不同生育期地-气温差还受其他因子的影响:三叶期后受冠层吸收光合有效辐射比影响且呈显著的线性关系,三叶期至拔节期则受土壤相对湿度和空气相对湿度的影响且呈显著的线性关系.在此基础上,基于2014年试验资料建立了夏玉米全生育期地-气温差模拟模型、营养生长期地-气温差模拟模型和生殖生长期地-气温差模拟模型,并利用2015年夏玉米拔节期5个灌溉水分控制试验资料进行了模型验证,结果表明,夏玉米全生育期地-气温差模型可以解释2015年地-气温差变异的63%,但地-气温差分生育期模拟模型,即营养生长期地-气温差模拟模型和生殖生长期地-气温差模拟模型综合的模拟结果则可解释2015年地-气温差变异的79%.研究结果为基于地-气温差的作物干旱指标定量评估作物干旱提供了依据.     

History and evolution of the International Association for Plant Biotechnology (IAPB): 1963–2008

The International Association for Plant Biotechnology (IAPB) was founded in 1963 at the first truly international conference on plant tissue culture, which was organized by Philip R. White. White was a devoted internationalist and was strongly committed to global scientific cooperation. He felt that the time had come for the international tissue culture community to organize so that it could meet regularly and provide a forum to its members for the exchange of ideas and information of mutual interest and use. The various activities of the IAPB since its founding—the publication of its newsletter, its journal, and the proceedings of its quadrennial congresses—faithfully document the remarkable advances in plant biotechnology that were made possible by the successful integration of tissue culture and molecular biology. In particular, the congress proceedings serve as time capsules, providing a wealth of information about the best of science and the most prominent scientists of the time. The history of the IAPB is indeed the history of plant biotechnology.     

玉米秸秆还田对石灰性土壤Zn形态及其有效性的影响

采用尼龙网袋田间填埋的方法,研究了玉米秸秆还田对石灰性土壤Zn形态及其生物有效性的影响.结果表明：与施用Zn肥相比,秸秆还田对提高土壤全Zn含量贡献较小;施Zn肥和添加秸秆处理均显著增加土壤有效Zn(DTPA-Zn)含量,且施Zn肥处理增加的幅度更大;高锌秸秆还田后释放的Zn更易转化为土壤DTPA-Zn,转化率达49.0%,秸秆还田后土壤DTPA-Zn转化率呈先减小后增大的趋势,而施Zn肥处理的变化不大.土壤交换态Zn(Ex-Zn)、碳酸盐结合态Zn(Carb-Zn)、氧化锰结合态Zn(OxMn-Zn)、紧结有机态Zn(Sbo-Zn)和残渣态Zn(Min-Zn)含量在各处理中差异不大,施Zn肥处理的土壤松结有机态Zn(Wbo-Zn)含量显著大于对照和只添加秸秆处理.尽管玉米秸秆的含Zn量较低,但秸秆Zn释放后更易转化为DTPA-Zn,秸秆还田同时施用Zn肥是提高石灰性土壤供Zn能力的有效方法.     

Enhanced evapotranspiration was observed during extreme drought from Miscanthus,opposite of other crops

The impact of extreme drought and heat stress that occurred in the Midwestern U.S. in 2012 on evapotranspiration (ET), net ecosystem productivity (NEP), and water‐use efficiency (WUE) of three perennial ecosystems (switchgrass, miscanthus, prairie) and a maize/soybean agroecosystem was studied as part of a long‐term experiment. Miscanthus had a slower initial response but an eventually drastic ET as drought intensified, which resulted in the largest water deficit among the crops. The substantially higher ET at peak drought was likely supplied by access to deep soil water, but suggests that stomatal conductance of miscanthus during the drought may respond differently than the other ecosystems, consistent with an anisohydric strategy. While there was a discrepancy in the water consumption of maize and switchgrass/prairie in the early time of drought, all these ecosystems followed a water‐saving strategy when drought intensified. The gross primary production (GPP) of miscanthus dropped, but was reversible, when temperature reached 40 °C and still provided the largest total GPP among the ecosystems. Increased ET for miscanthus during 2012 resulted a large decline in ecosystem WUE compared to what was observed in other years. The biophysical responses of miscanthus measured during an extreme, historic drought suggest that this species can maintain high productivity longer than other ecosystems during a drought at the expense of water use. While miscanthus maintained productivity during drought, recovery lagged associated with depleted soil moisture. The enhanced ET of miscanthus may intensify droughts through increase supply of deep soil moisture to the atmosphere.     

施磷对间套作玉米叶面积指数、干物质积累分配及磷肥利用效率的影响

通过2011、2012年连续两年田间试验, 研究了“小麦/玉米/大豆”间套作体系中不同施磷处理（小麦0、45、90、135、180 kg P₂O₅·hm^-2, 记为WP₀、WP₁、WP₂、WP₃、WP₄; 玉米0、37.5、75、112.5、150 kg P₂O₅·hm^-2, 记为MP₀、MP₁、MP₂、MP₃、MP₄）对玉米叶面积指数、干物质积累动态和磷肥利用效率的影响.结果表明: 在玉米与小麦共生期, 施磷明显增加了玉米叶面积指数（LAI）和群体光合势（LAD）, 促进了茎、叶干物质的积累（DMA）; 玉米拔节以后LAI、LAD、生长率（CGR）和DMA均随磷肥施用量的增加呈先增加后减少的趋势, 最大值都出现在MP₂或MP₃处理; 玉米生殖生长期营养器官的干物质输出随着磷肥施用量的增加而增加.玉米籽粒产量和体系总产量均随磷肥施用量的增加先增大后减少,都以P₃处理为最高,分别为6588和11955 kg·hm^-2.玉米磷肥表观利用率（PARE）以MP₂处理最高（26.3%）,分别比MP₁（14.4%）、MP₃（19.0%）、MP₄（10.4%）处理高82.6%、38.4%和152.9%.综上,在麦/玉/豆间套作体系中,适量施用磷肥可促进玉米的生长、减轻小麦对玉米的影响,同时可提高玉米当季磷肥利用率,玉米的磷肥施用量在75～112.5 kg P₂O₅·hm^-2为宜.