The Early-Morning Flowering Trait of Rice Reduces Spikelet Sterility under Windy and Elevated Temperature Conditions at Anthesis

Abstract

We previously demonstrated that heat-induced spikelet sterility at anthesis could be mitigated by using an early-morning flowering (EMF) line of Oryza sativa L. cv. Koshihikari crossed with wild rice, O. officinalis. Another microclimate factor, high wind velocity, is known to increase the sterility induced by heat. In this study, we evaluated whether EMF rice could mitigate sterility under the combined stresses of heat and wind. Rice plants were exposed to three levels of wind velocity (1.1, 2.2, 3.4 m s^?1) from early-morning until 1500 in a glasshouse, where air temperature reached 30°C at 0800, 34°C at 1000 and 38°C around noon. Under these conditions, sterility steadily increased in Koshihikari, ranging from 28.4 to 86.9% as wind velocity increased. However, in the EMF line, low levels of sterility were observed since most spikelets flowered before 1000 when air temperature reached 35°C, the critical value for causing sterility. These results indicated that the increase in heat-induced spikelet sterility by wind can be potentially mitigated by using EMF rice.     

频繁开花高产小桐子组织培养的初步研究

为了奠定频繁开花型高产小桐子的快繁及转基因基础,通过对小桐子茎段腋芽培养、叶片和叶柄愈伤诱导及不定芽分化的不同激素组合培养进行研究。结果表明：适合该高产品种的茎段培养的最佳培养基为MS＋6-BA 0.5 mg/L＋IBA 0.1 mg/L,叶片愈伤诱导及不定芽分化培养基为MS＋6-BA 2.5 mg/L＋IBA 0.5 mg/L,叶柄愈伤诱导及不定芽分化培养基为MS＋6-BA 1.0 mg/L＋IBA 0.2 mg/L,生根培养以1/2MS＋IBA 0.5 mg/L＋AC 0.1%较为适宜。引起小桐子组培苗玻璃化现象的主要原因之一是BA浓度过高;在不定芽的分化培养中,愈伤过多会严重影响不定芽的数量及质量。     

γ-氨基丁酸促进拟南芥开花的机理研究

为了探讨γ-氨基丁酸(GABA)对拟南芥植物开花的影响机制,以3种不同浓度（1 mmol/L,5 mmol/L和10 mmol/L）的GABA采用隔天喷施的方法,处理7天龄的拟南芥幼苗至4周龄,以双蒸水作为对照,观察拟南芥的开花时间的变化。结果表明,在长日照（16 h光照/8 h黑暗）和短日照（8 h光照/16 h黑暗）条件下,GABA能不同程度地促进拟南芥早开花2~5天。运用荧光定量PCR技术,对开花途径的开花抑制因子基因Flowering Locusc C（FLC）、自主开花途径基因FCA(FLOWERING TIME CONTROL PROTEIN FCA)和花序分生组织特征基因LEAFY（LFY）的表达进行研究。与对照相比,GABA处理下调FLC的表达2~5倍,而促进FCA（1.5~6倍）和花序分生基因LFY（3~11倍）的表达。初步的实验结果表明,GABA对拟南芥开花的促进作用有可能通过上调FCA的表达,抑制FLC从而促进LFY的表达而最终促进植物提早开花。     

紫花苜蓿高迁移率族蛋白基因MsHMG-Y调控花期的功能分析

【目的】开花是植物营养生长转向生殖生长的重要标志,对植物的生物量有重要的影响。紫花苜蓿作为世界上最重要的饲草作物之一,其产量和品质与开花时间密切相关。紫花苜蓿的最佳刈割时期是初花期,此时产量和品质最佳。前期获得一个与花期相关的编码基因HMG-Y,通过分析其结构及表达模式,探究其在开花调控途径中的功能,为揭示开花调节机制提供理论基础。【方法】同源克隆MsHMG-Y,并对其进行多序列比对和进化树分析。利用qRT-PCR检测不同组织和不同开花时期该基因的表达水平;分析MsHMG-Y受光照、赤霉素（GA3）、水杨酸（SA）、茉莉酸甲酯（MeJA）诱导后的表达模式;观察过表达MsHMG-Y紫花苜蓿的表型,并分析开花促进因子与抑制因子的表达水平。【结果】MsHMG-Y与蒺藜苜蓿MtHMG-Y相似性最高,亲缘关系最近。组织特异性分析显示,MsHMG-Y在花、茎、叶中均有表达,其中,在父本和母本中均为花中表达量最高,叶中表达量最低;在早花表型父本的初花期表达量最高,在晚花表型母本的花芽分化期相对表达量最高。光周期分析表明,延长光照到16 h后,MsHMG-Y表达水平下调,延长光照到28 h后,MsHMG-Y表达水平持续低于对照组,说明该基因受光诱导后下调表达。外施50 μmol·L^-1 GA3、100 μmol·L^-1 SA、100 μmol·L^-1 MeJA后,与对照组相比,MsHMG-Y表达水平均上调,其中,GA3诱导1 h时表达量最高,为对照的3.5倍;SA诱导6 h时表达量最高,为对照的24倍;MeJA诱导3 h时表达量最高,为对照的11倍,说明该基因受3种激素诱导。表型观察发现,与对照相比,过表达MsHMG-Y紫花苜蓿开花较晚,促进开花相关基因的表达水平均下调,抑制开花相关基因的表达水平均上调,其中,表达量变化显著的有促进开花基因MsPHYA、MsGI和MsFTa1,分别降低了4.9、3.9和2.8倍,抑制开花基因MsTEM1和MsSVP的表达量分别提高了2.5和1.9倍。【结论】MsHMG-Y受光周期及外源激素GA3、SA和MeJA的诱导表达。MsHMG-Y对延迟苜蓿开花的调控机制有重要作用。     

植物配子体自交不亲和机制研究进展

结合国内外最新的研究进展对配子体自交不亲和性的细胞学机制和分子生物学机制进行了综述,包括与S-核酸酶(S-RNase)、花粉管胞质自由钙离子以及其他因子相关的信号转导机制。并根据目前的研究现状提出了植物配子体自交不亲和机制研究中存在的问题及今后研究的重点,旨在为其深入研究提供参考。     

Heritability of oil content and the onset of flowering in a population of Dimorphotheca pluvialis

To develop efficient breeding strategies for the improvement of oil content and onset of flowering in Dimorphotheca pluvialis, narrow-sense heritabilities of these characters were estimated. Forty plant progenies were tested in 2 years and heritabilities were estimated from parent-offspring regression as well as from half-sib family variance components analyses. For oil content, the heritabilities estimated by means of parent-offspring regression were 0.36 and 0.33 for 1993 and 1994, respectively. The heritabilities obtained from the variance components analyses were 0.41 and 0.23 for the two years. Heritability estimates for onset of flowering showed more variation. From parent-offspring regression, the heritabilities were 0.72 and 0.37, and from variance component analysis the estimates were 0.53 and 0.19 for 1993 and 1994, respectively. The obtained heritability values and realized responses suggest that particularly in early selection generations, even with mass selection, considerable progress can be expected. Since correlation studies revealed neither phenotypic nor genotypic correlation between oil content and onset of flowering, selection for both characters can be undertaken independently.     

西南杂交水稻抽穗开花期耐热性筛选

利用人工气候室,以相对受精率为耐热能力评价指标,对西南地区生产上大面积使用的62个杂交水稻品种进行抽穗开花期耐高温特性鉴定。筛选出相对受精率≥60%的品种9个,并通过聚类分析将62个杂交水稻品种分为耐热能力不同的3类,为水稻生产布局提供科学依据。     

石榴花期西花蓟马的防治试验初报

通过采用色板、性诱剂诱杀和药剂防治的方法,对石榴花期西花蓟马的防治试验表明:蓝色粘板的诱杀效果最好,其次是黄色粘板,白色粘板效果最差;辅助挂置蓟马性信息素诱芯能增加粘板的诱集量;48%乐斯本乳油和3%汗马啶虫脒乳油在施药后7天的防效分别达到70.0%、75.2%,可以作为西花蓟马的应急防治药剂。     

水稻光温敏核不育系的开花习性研究

以蜀光582S、GD-8S、徐选S、GD-7S、02—142、208S、W9593S、YW-2S、Y3和S25共10个我国新近育成的光温敏核不育水稻为材料,以培矮64S和农垦58S为对照,观察了开花习性。结果表明：开花习性因不育系不同而有很大差异,大致分为4类：1）蜀光582S、Y3、02—142与培矮64S（CK）,花期集中、花时较早,盛花期出现在穗后2～5d,午前花率在60％以上,柱头活力强,但开颖时间短;2）徐选S、GD-7S、W9593S,花期分散、花时较迟。柱头外露率一般,对“920”敏感;3）GD-8S、208S、YW-2S,花期集中,但花时分散,柱头外露率一般,表面积较小;4）粳型不育系S25和农垦58S,主要特点是花时集中,但花时高峰迟,柱头外露率低。     

花铃期棉花黄萎病抗病与感病品种对土壤细菌群落结构的影响

【目的】研究花铃期棉花黄萎病抗/感品种土壤细菌群落结构,了解抗/感品种土壤细菌群落结构与土壤理化性质之间的关系,为棉花黄萎病的监测与绿色生态防控打下理论基础。【方法】通过田间小区试验,以感病品种(鄂荆1号,EJ)和抗病品种(冀863,J863)为试验材料,采用实时荧光定量PCR(real-time PCR)和高通量测序(Illumina MiSeq)技术分别测定花铃期不同阶段(盛花期、开花后期和结铃期)土壤中大丽轮枝菌(Verticillium dahliae)数量和土壤细菌群落结构,结合冗余分析(RDA)明确细菌群落结构与土壤理化性质的相关性。【结果】棉花黄萎病的发生与土壤中大丽轮枝菌ITS基因拷贝数量存在不同程度的相关性,其中感病品种EJ的发病率和病情指数与土壤中病原菌数量呈正相关,而抗病品种J863的发病率和病情指数与病原菌数量相关性不大。除盛花期外,棉花开花后期和结铃期抗病品种J863土壤中的病原菌数量低于感病品种EJ。高通量测序分析表明,除开花后期,抗病品种J863在盛花期和结铃期的细菌丰富度Chao1和ACE指数均高于感病品种EJ。主成分分析表明,抗/感品种之间及其在花铃期...