A model describing the flowering of single plants, and the heritability of flowering traits of Dimorphotheca pluvialis

In the development of new crops such as Dimorphoteca pluvialis (L.) Moench, improvement of flowering synchronisation is an important breeding objective. The flowering of single plants of Dimorphotheca pluvialis could be described by a logistic curve obtained by the regression of cumulative number of open flowers on time. The curve is characterised by three parameters, corresponding with the total number of flowers produced by the plant, the rate of flowering development and the day at which peak bloom is reached. From these parameters two other characteristics were derived, i.e., onset of flowering and duration of flowering. The use of the flowering model for selection for improved flowering synchronisation is discussed. Heritabilities of flowering traits were estimated using parent-offspring regression and variance components analyses. Onset of flowering and date of peak bloom showed high (>0.69), and total number of flowers moderate to high (0.30–0.90) heritability values, indicating that for these traits considerable progress may be expected from mass selection, particularly in the early selection generations. Duration of flowering showed low to moderate values (0.25–0.45), and methods other than mass selection (e.g. family selection) should be considered. Determination of phenotypic and genetic correlations revealed only an additive genetic correlation between date of peak bloom and duration of flowering (r _A = 0.80 and 0.69 for 1993 and 1994, respectively), suggesting the possibility of indirect selection for curtailed duration of flowering by means of selection against late date of peak bloom. Duration of flowering, total number of flowers and onset of flowering were not correlated. This revised version was published online in August 2006 with corrections to the Cover Date.     

NAA和IBA对菊花生长发育和花期的影响

通过对３个秋菊品种用长日照、ＮＡＡ、ＮＡＡ＋ＩＢＡ组合和自然短日照处理试验,发现长日照处理是秋冬季菊花栽培延迟开花提高品质的最佳途径．ＮＡＡ和ＮＡＡ＋ＩＢＡ组合喷施叶面,可显著延迟秋菊开花,随浓度的提高,延迟开花时间越长．不同的品种株高、叶数、开花直径对生长调节剂反应不一样,短日照迟感型品种使用ＮＡＡ或ＮＡＡ＋ＩＢＡ组合处理比短日照敏感型品种在生长质量与延迟开花方面可获得更好的效果．ＮＡＡ＋ＩＢＡ组合处理效果比ＮＡＡ单独喷施效果好．     

油梨开花物候的研究

研究结果表明,油梨嫁接苗在定植后第三、四年可在海南正常生长并开花,开花期一般在２月上中旬至４月上中旬;油梨小花开放两开两合,第１次开放雌蕊成熟,第２次开放雄蕊成熟,整个过程历时约２４￣３６ｈ;油梨异常花比例高,在２０％以上;有限花序仅在部分油梨品种中出现,比例很低,一般在３％以下。根据部分油梨品种的开花物候特点,确定了部分油梨授粉品种的搭配。     

苗期遮光对易抽薹型大白菜抽薹开花的影响

以易抽薹型大白菜自交不亲和系８７１５８为试材，探讨了苗期遮光对其抽薹开花的影响。结果表明：４叶１心和６叶１心的幼苗的花芽已分化，２叶１心开始遮光处理以每天处理６小时的效果最好，比对照延迟花芽分化７天。遮光处理对易抽薹型大白菜延迟现蕾和抽薹开花有一定的作用，在本试验范围内，开始遮光处理的时间越早，每天遮光处理的时间越长，遮光处理的天数越多，效果越明显     

白蜡属植物的开花特性和动态观察

研究花器官形态结构和开花特性,为白蜡授粉受精提供理论依据。本研究选取了3个白蜡品种（‘鲁蜡2号’、‘鲁蜡5号’和‘金箭’）,对其开花特性、花器官构造进行观察。结果表明,白蜡品种雄株花期为11～13天,开花时间比雌株早13～15天;雌株‘鲁蜡2号’的花期为5～6天。3个白蜡品种的小花密集,开花后苞片2裂,花萼钟状4深裂,无花冠。雄花开花后露出舟形花药,花丝极短。雌花苞片开裂后露出雌蕊,柱头成熟时两裂,呈粉红色,花柱极短。扫描电镜下的3个白蜡品种苞片和花萼表面均有盾毛分布,不同品种间盾毛的形态有差异;‘金箭’、‘鲁蜡5号’的花药与花粉结构无显著差异;‘鲁蜡2号’整个雌蕊表面都有不规则褶皱分布。本研究可为进一步开展白蜡属植物的育种和种质资源创新利用研究提供参考。     

澳洲坚果开花与座果习性的调查

对澳洲坚果开花及座果习性的调查研究结果表明∶澳洲坚果花日开放率与开花进程呈极显著直线正相关关系;品种间花序的开放天数差异显著,花序花朵数差异极显著;澳洲坚果座果率与开花进程呈极显著直线的负相关关系;澳洲坚果落果量最大的是花后20~50d,落果占总座果数的76%;其次是花后60~100d,落果占总座果数的14.5%。     

基于去趋势分析的中国温带旱柳开花始期对气候变暖的响应

为了更准确地揭示植物在物候水平上对气温变化的响应与适应机制,在去气温和物候时间序列趋势的基础上,建立日尺度的气温?物候回归模型,分析中国温带地区40个站点1986-2011年旱柳开花始期对气温变化的响应与适应机理。结果表明：中国温带地区77.5%的站点旱柳开花始期呈提前趋势,相应的敏感时段春季气温则呈上升趋势（0.8±0.5℃·10a-1）。其中,75%的站点物候期或气温时间序列存在显著变化趋势。进行去趋势处理后,17.5%的站点相关性发生变化,去趋势前其相关性较低,去趋势后,表现为显著负相关;模拟的均方根误差（RMSE）从去趋势前的5.5d降至去趋势后的4.9d,说明去趋势方法能提高气温-物候响应关系诊断的精确度。基于去时间序列线性趋势的气温－物候回归模型,得到92.5%的站点旱柳开花期与敏感时段春季气温呈显著负相关关系,即随着气温的升高,旱柳开花期呈提前趋势,其线性响应速率为-2.5±2.1d·℃-1。     

初花后短日照诱导对小豆叶片内源激素含量变化的影响

以中熟品种‘冀红9218’和晚熟品种‘唐山红小豆’为试材,在初花-初荚(EF-EP)、初荚-初粒(EP-ES)和初花-初粒(EF-ES)期进行短日照诱导,通过酶联免疫技术来研究初花后小豆叶片的内源激素含量以及之间的动态平衡。结果表明,初花后短日照诱导使小豆的株高降低,花期提前,且‘唐山红小豆’更为明显;2个品种的GA_(1+3)和ABA含量较对照呈现降低趋势,IAA含量的变化不同,‘冀红9218’在开花期、结荚期和鼓粒期的波动不大,但各个处理较对照降低,而‘唐山红小豆’在开花期和结荚期较对照降低,鼓粒期却升高,2个品种的ZR含量较对照呈现升高趋势,但‘唐山红小豆’却稍有差异,开花期降低,而在结荚期和鼓粒期较对照都升高,鼓粒期升高显著,激素含量的变化会影激素之间的动态平衡,与对照相比,2个品种的GA_(1+3)/ABA和IAA/ABA比值降低,而ZR/ABA和(ZR+GA_(1+3))/ABA比值呈现升高趋势,由激素含量及其比值之间的变化可以看出,初花后短日照诱导使ZR含量升高,促使小豆植株细胞分裂旺盛,生长迅速,营养物质快速转移至果荚中,提前成熟,但较初花前作用减弱。     

Influence of fungicides on gas exchange of pecan foliage

There are several fungicide chemistries used for disease control on pecan (Carya illinoinensis), but there is little or no knowledge of subtle short‐ or long‐term side effects of these chemistries on host physiological processes, including net photosynthesis (P_n). This study quantifies the impact of several fungicides used to control scab on P_n and other gas exchange characteristics of pecan foliage and provides much‐needed insight to ensure proper usage in commercial pecan operations. Multiple field experiments found that certain fungicide chemistries have the potential to reduce P_n, stomatal conductance (C_s), transpiration rate (T_r) and water use efficiency (E_w; P_n/T_r), whereas others are benign. For example, neither triphenyltin hydroxide nor the triazoles tested had a negative impact on gas exchange characteristics, regardless of when measurements were taken or the number of spray applications. However, dodine, phosphorous acid, ziram and certain strobilurins were capable of suppressing gas exchange, especially P_n, up to several weeks after a single treatment. Suppression of P_n by some fungicides was relatively short term, but was long term or permanent for other fungicides. In certain cases, leaf P_n was suppressed by as much as 50–80% for at least several weeks after a single exposure. These studies suggest that use of fungicides in commercial pecan orchards might result in negative side effects that need to be taken into consideration when determining how best to use these fungicides in pecan disease management.     

利用CRISPR/Cas9技术编辑粒长基因GS3改善粳稻花时

【目的】花时不遇是影响杂交水稻制种产量的直接因素之一,已有研究表明水稻粒型差异对花时有影响。本研究采用GS3功能缺失突变来研究粳稻花时差异,以期为粒型影响花时提供佐证。【方法】利用CRISPR/Cas9技术来定向编辑控制粒长基因GS3,获得13对粒型差异的近等基因系粳稻,小区种植,采用目测法来调查花时。【结果】获得转基因T0植株并对其T1植株测序分析,发现长白25、吉粳102、浙粳88、武运粳27和J42均发生单碱基插入移码突变,垦鉴稻6号、空育131、浙粳22、扬粳4227、南粳9108、J5933、J6167和J5938均发生部分碱基缺失突变。对T1植株粒型考查表明,gs3突变体的粒长均显著长于野生型。对稳定的后代花时统计分析发现,粒型变长的突变体均比野生型花时有所提前,且吉粳102、空育131、浙粳88、武运粳27、扬粳4227这5个材料的gs3突变体花时均显著早于野生型,其余材料开花也提早,但不显著。【结论】长粒型粳稻GS3突变体的花时早于短粒粳稻野生型,这一研究可为粳稻粒型育种提供参考,加速长粒粳稻亲本选育,有望推动杂交粳稻发展。