摘花处理对大豆花荚发育和产量的影响

为了探究大豆的开花潜力及损失补偿能力,本研究以生育期相近但结荚习性不同的中黄13、邯豆5号和Williams 82为材料,设置短期连续摘花处理(3,5和7 d)和长期连续摘花处理,研究摘花处理对大豆开花动态、结荚和产量的影响。结果表明:(1)同期播种条件下,大豆材料的自然开花动态与结荚习性有关,但其总花数差异不大。其中,有限结荚习性的中黄13日开花数先升后降,开花持续日数较短;而亚有限结荚习性的邯豆5号和Williams 82日开花数相对平稳,开花持续日数较长;(2)长期摘花处理能刺激植株不断催生花芽,以补偿摘花损失,导致开花期明显延长。在长期摘花处理下中黄13和邯豆5号植株总花数分别是对照植株的2.46和3.07倍,新生花朵具备正常的生殖能力。自然条件下长期摘花处理可导致茎秆及叶片持绿、底部节位叶腋出现次生茎叶等类似症青的症状;(3)亚有限结荚习性品种进行短期摘花处理,仅刺激摘花节位不断生成新花朵,但对植株相邻节位的开花数没有影响。邯豆5号和Williams 82表现出短期摘花减产或增产的现象,与新生花数、花荚转化率和粒重的变化幅度差异有关。总之,大豆整株花序发育的潜力巨大,一旦花朵无法完成授粉受精而脱落(摘花处理),植株可以催生新花加以补偿,但植株的生育期将延迟。在北方大豆生产中,植株生育期延迟与秋季低温是难以调和的矛盾。研究结果可为大豆开花期非生物逆境的相关研究提供参考。

大豆SWEET基因在荚粒发育过程中与逆境胁迫下的表达

植物叶片光合作用产生的糖类物质需要经过糖转运蛋白运输到其他器官进而发挥其重要功能。SWEET(sugars will eventually be exported transporters)是一类可实现糖类物质运输的蛋白,对植物生长发育及抵御外界生物和非生物胁迫具有重要意义。为分析大豆SWEET基因在荚粒发育过程中以及逆境胁迫下的表达,利用栽培大豆和野生大豆最新公布基因组数据鉴定SWEET基因,然后利用转录组数据分析基因在荚粒发育和抵抗花叶病毒与低磷逆境中的表达。结果表明,栽培大豆Williams82最新版本基因组(Wm82a4v1)有48个SWEET基因,分布于15条染色体,编码蛋白长度为174~354个氨基酸;野生大豆W05基因组有51个SWEET基因,分布于16条染色体,编码蛋白长度为84~392个氨基酸;系统进化树分析显示,99个栽培大豆和野生大豆SWEET基因分为3个亚组。对不同大豆品种转录组数据分析发现,16个SWEET基因在豆荚表达,其中Glyma.06G122200、Glyma.14G159900和Glyma.14G160100等随不同品种豆荚发育进程表达量增加;12个SWEET基因在籽粒表达,其中Glyma.08G025100、Glyma.13G041300和Glyma.14G120300随不同品种籽粒发育进程表达量增加,表明其在豆荚和籽粒发育中具有重要作用。接种大豆花叶病毒后,不同抗性品种间SWEET基因的表达存在较大差别,其中Glyma.08G009900和Glyma.13G264400在抗病品种叶片接种后诱导表达,而在感病品种接种前后表达量没有变化,说明其可能参与大豆抗病反应。对SWEET基因在低磷胁迫前后的表达分析发现,Glyma.04G198400、Glyma.14G160100和Glyma.15G211800等在大豆根系受低磷胁迫诱导表达,可能参与大豆耐低磷反应。栽培大豆SWEET基因单核苷酸多态性(single nucleotide polymorphism,SNP)等位变异分析发现,有43个SWEET基因含有220个非同义突变SNPs,其中103个位于编码蛋白的保守域,可能影响基因功能。研究结果为大豆豆荚和籽粒产量以及抗病耐逆分子育种提供了基因资源。

用^（15）N－尿素研究油菜角果成熟期荚中氮的运转

盆栽条件下，用^（１５）Ｎ－尿素测定了油菜角果成熟期荚中氮的运转。于开花后三个不同时期，将^（１５）Ｎ－尿素涂布于油菜主轴基部荚的表面，植株成熟后测定不同部位荚的荚壳和籽粒的含Ｎ量和^（１５）Ｎ丰度，计算施用Ｎ的回收率，荚中为７９．１％－８４．３％，其中标记荚为７５．３％－８０．４％。开花后４周施用的Ｎ从标记荚的回收率低于开花后２周和６周施用Ｎ的回收率。吸收的尿素Ｎ大部分运转至籽粒，其分配比例随施用时期的推迟而增加。

花生变异

花生自古叶腋生花,受精后子房柄伸长成细管钻入地下发育成茧形果荚。印度于1986年秋在JL24×奇科（Chico）杂交F4子代中发现一株异变花生。在离地面以下12.7厘米处。

Growth of Verticillium tricorpusmA Saprophytic Fungus and Potential Entomopathogen of Cocoa Pod Borer as Affected by the Medium and Light

Cocoa pod borer （CPB） has endangered Indonesian cocoa. Use of entomopathogen in biocontrol of pests is considered to be environmentally friendly approach. Verticillium tricorpus has been reported to be a potential agent for controlling CPB. The aim of this research was to study the possibility in using alternative, easy and cheap media and also the role of intensity and quality of light for mass production of V. tricorpus. The experiments were laid out in split-plot design as factorial, where every combination treatment was replicated three times. Medium, in form of semi-synthetic and natural, was treated as the main plot, while light as sub-plot. Results of this study showed that for the growth and development of fungus V. tricorpus, the use of alternative natural media in form of a mixture of cocoa pod husk and maize was the best. Use of cocoa dextrose agar （CDA） as semi-synthetic medium was more suitable for the growth and development of V. tricorpus compared to potato dextrose agar （PDA）. The semi-synthetic and natural media consisted of cocoa husk and maize are suitable for cocoa production area in Indonesia, where mostly cocoa is planted in lowland area and mostly is also suitable for corn but not for potato growing. Growth of the fungus colony especially on CDA medium reached its optimum condition when using white light with the intensity of 1,000 lux. This study proved that the requirement for light quality was different between growth and development purposes. Development of V. tricorpus until the production of conidia in optimal condition was reached with the use of yellow light with the intensity of 1,000 lux.