‘巨峰’葡萄休眠及解除过程糖类物质变化研究

为更好地了解葡萄休眠期糖类物质变化与休眠的关系,以离体1年生‘巨峰’葡萄枝条为试材进行水培,监测葡萄休眠过程糖类物质变化。通过液相色谱等方法进行蔗糖、葡萄糖、果糖、可溶性糖和淀粉、纤维素含量的测定。结果表明,‘巨峰’葡萄在1月6日休眠达到最深,2月5日解除休眠;葡萄糖、果糖、可溶性糖和淀粉含量随休眠加深而升高,解除休眠后葡萄糖、果糖、可溶性糖及蔗糖下降;蔗糖含量随着休眠的加深而下降,在休眠解除过程中升高;纤维素在整个休眠中及解除后变化不明显;果糖与葡萄糖在各器官内呈极显著正相关关系;芽、韧皮部、木质部中的可溶性糖含量呈两两极显著正相关关系。     

植物信号转导对‘夏黑’葡萄冬芽休眠解除的调控

本研究2016年-2017年以生态休眠状态下的‘夏黑’葡萄冬芽为试材,经单芽扦插处理、用转录组方法辅以生理指标测定,探讨了影响葡萄冬芽休眠解除的关键因子。单芽扦插7 d (EB1)和扦插14 d (EB2)后冬芽转录组测序均得到45 Mb以上的Clean Reads,经过滤、拼接、数据库比对均得到25 000以上转录本。从基因表达分析看EB2与EB1相比,1 051个基因上调表达,587个基因下调表达。差异表达基因(DEGs) GO富集分析发现葡萄冬芽自然休眠解除过程中DEGs主要富集在催化活性、结合、代谢过程和单有机体过程,进一步KEGG代谢途径分析发现植物信号转导途径是休眠解除的重要参与环节,尤其赤霉素(gibberellin,GA)和脱落酸(abscisic acid, ABA)代谢与休眠解除关系密切,芽子休眠解除过程中的内源激素变化和信号转导路径上相关基因qRT-PCR也验证了这一点。因此本研究认为内源激素和植物信号转导是调控葡萄冬芽自然休眠解除的重要因子之一。     

牡丹花芽休眠解除进程中碳氮比的变化与低温处理时间的关系

以牡丹‘鲁荷红’花芽为材料,对不同低温处理的牡丹花芽的4种营养物质的含量进行测定,同时测定淀粉水解酶和谷氨酰胺合成酶的活性。目的是探索其变化趋势与牡丹休眠解除的相关性。试验结果表明,在牡丹花芽休眠解除过程中,淀粉、可溶性糖与可溶性蛋白质均有不同程度的增加;但是基本打破休眠时,即低温15天时可溶性蛋白含量有所降低,打破休眠后,又恢复含量;而游离氨基酸的量变化不明显,整个过程趋于稳定。其花芽的总体碳氮比,在未感受低温时,比值较低,感受低温后的花芽其总体的碳氮比持续处于较高的水平,并趋于稳定。在牡丹花芽休眠解除过程中,淀粉水解酶活性持续缓慢升高,可溶性糖含量升高,碳水化合物积累,是碳氮比升高的重要原因。谷氨酰胺合成酶活性呈现先升高后下降的趋势, 在感受低温15天时达到最高值。     

水稻休眼分蘖芽萌发过程中内源激素水平的变化

以2个籼稻品种II优航1号、扬稻6号为材料,研究了齐穗后去除顶穗和保留顶穗对倒2节间叶腋内休眠分蘖芽(倒2芽)的生长动态及倒2芽、倒2芽着生节(倒2节)中内源激素(IAA、Z+ZR、ABA)含量的影响。结果表明,去除顶穗后,倒2芽休眠解除,开始萌发生长。在去除顶穗后1 d内,倒2节中吲哚-3-乙酸(IAA)水平、倒2芽中脱落酸(ABA)水平迅速下降,其后2种激素含量基本保持稳定,而留穗处理这2种激素含量变化不大。去除顶穗后,倒2节和倒2芽中玉米素+玉米素核苷(Z+ZR)含量均持续升高,与留穗处理间的差异不断扩大,其变化动态与倒2芽生长动态相一致。而2个处理间倒2节中ABA水平、倒2芽中IAA水平相差不大。分蘖芽的萌发生长是多种激素共同作用的结果,芽中较低的ABA/(Z+ZR)值、节中较低的IAA/(Z+ZR)值有利于分蘖芽的生长,其值较高抑制分蘖芽生长。     

外源GA3、ABA对种子发芽与亲本穗上发芽内源激素变化影响研究

以外源GA3和ABA处理种子和水稻亲本,研究GA3和ABA对水稻种子萌发及亲本穗上发芽的影响,结果表明,外源GA3处理后引起两者种子内源GA3升高,降低种子内ABA、IAA水平,提高了GA3/ABA比值;外源ABA处理,引起种子内ABA含量升高,降低GA3、IAA水平,GA3/ABA比值减少;种子萌发和穗芽形成过程中GA3含量、GA3/ABA比值对比,发现前者小于后者,而种子萌发率与穗芽率相比,前者远远大于后者,表明穗上穗芽形成是一个更为复杂的生理变化过程.     

水稻休眠分蘖芽萌发过程中内源激素水平的变化

以2个籼稻品种Ⅱ优航1号、扬稻6号为材料,研究了齐穗后去除顶穗和保留顶穗对倒2节间叶腋内休眠分蘖芽(倒2芽)的生长动态及倒2芽、倒2芽着生节(倒2节)中内源激素(IAA、Z+ZR、ABA)含量的影响.结果表明,去除顶穗后,倒2芽休眠解除,开始萌发生长.在去除顶穗后1 d内,倒2节中吲哚-3-乙酸(IAA)水平、倒2芽中脱落酸(ABA)水平迅速下降,其后2种激素含量基本保持稳定,而留穗处理这2种激素含量变化不大.去除顶穗后,倒2节和倒2芽中玉米素+玉米素核苷(z+ZR)含量均持续升高,与留穗处理间的差异不断扩大,其变化动态与倒2芽生长动态相一致.而2个处理间倒2节中ABA水平、倒2芽中IAA水平相差不大.分蘖芽的萌发生长是多种激素共同作用的结果,芽中较低的ABAJ(Z+ZR)值、节中较低的IAM(Z+ZR)值有利于分蘖芽的生长,其值较高抑制分蘖芽生长.     

北乌头种子休眠解除过程中营养物质的代谢变化研究

以北乌头种子为材料,测定其萌发过程不同阶段贮藏物质及相应酶活性的动态变化,为北乌头种子休眠解除提供生理学基础.结果表明,种子在休眠及解除休眠过程中,可溶性糖含量先上升后减少;淀粉、粗脂肪和可溶性蛋白含量一直减少.三种抗氧化酶活性在露白阶段均升高,淀粉酶、蛋白酶和酸性磷酸酶活性持续增加.     

‘木门’百合休眠和花芽分化进程中激素变化

为了探究植物激素变化与百合休眠和花芽分化之间的关系,以‘木门’百合为试材,通过糖类物质变化和显微观测确定了休眠解除和花芽分化时期,并通过HPLC-MS技术进行了激素含量变化分析。结果表明‘木门’百合种球在3℃冷藏条件下56天左右休眠解除,70天左右开始花芽分化,其进程分为花芽分化初期、小花原基分化期和花器官分化期3个时期;休眠解除前GA₃/ABA上升,IAA/ABA、ZR/ABA比值保持低水平,休眠解除后GA₃/ABA保持升高,IAA/ABA、ZR/ABA比值升高;花芽分化初期ZR上升、GA₃下降、ZR/GA₃急剧上升,小花原基分化期ZR下降、GA₃上升、ZR/GA₃急剧下降,花器官分化期ZR和GA₃均上升,ZR/GA₃稳定不变。由此可见,低水平IAA/ABA、ZR/ABA促进休眠维持,持续上升的GA₃/ABA促进休眠解除,ZR/GA₃上升促进花芽分化起始,下降则促进小花原基形成。本研究结果将为‘木门’百合的采后储藏和开花调节提供一定理论参考。     

6-BA处理对马铃薯内源激素含量及StTCP15基因表达的影响

TCP基因家族是参与调控植物内源激素的重要转录因子,马铃薯中StTCP15基因受到细胞分裂素、ABA和GA3的诱导表达,并在块茎休眠打破过程中StTCP15基因表达量变化显著。为探究外源6-BA对马铃薯块茎休眠时间、内源激素含量变化及StTCP15基因表达模式的影响,以马铃薯栽培品种‘鄂薯10号’块茎为试验材料,用液相色谱-质谱(LC-MS/MS)和实时荧光定量PCR (RT-qPCR)技术分别测定了10 mg/L6-BA处理下马铃薯块茎内源GA3、ABA、6-BA、IAA的含量及StTCP15基因表达量变化。结果表明外源6-BA处理与对照相比提前1周打破块茎休眠,块茎内源激素含量短时间与对照差异显著,随着时间延长差异减小;在块茎休眠阶段随着贮藏时间的延长处理组与对照组块茎内源激素ABA、GA3和IAA含量升高,6-BA含量下降;休眠打破后ABA和IAA含量降低,GA3和6-BA含量升高;发芽期间4种内源激素含量均升高。RT-qPCR分析结果表明6-BA处理及对照块茎休眠期间StTCP15基因表达量持续升高,休眠解除后表达量下降。StTCP15基因可能参与ABA信号通路,并在马铃薯休眠...     

滇重楼种子休眠机理研究

探讨滇重楼种子休眠机理,为打破种子休眠促进滇重楼实生育苗提供理论基础。采用重量法、胚率测定、ELISA等方法对种子吸水特性、萌发抑制物及种胚休眠与发育的内源机理进行了研究。结果表明,滇重楼种子休眠属于形态学-生理学休眠类型。滇重楼种胚发育不完全、种子中存在萌发抑制物质是种子休眠的主要原因。种子不存在吸水障碍,与休眠无关。内源激素ABA和GA3在滇重楼种子休眠与萌发过程中起着重要作用,ABA是引起休眠的关键因素,ABA含量的降低是滇重楼种胚发育的始动因子,GA3有助于种子的生理后熟。萌发抑制物的存在可能抑制了种胚发育,而与生理学后熟过程无关。在自然条件下,滇重楼生境中较长的低温时期可能是滇重楼种子具有较长时间休眠的外界原因。     

茶树越冬芽在休眠与萌发时期的物质交流变化及其分子调控

为揭示不同萌发物候型茶树的休眠机制,以特早生茶树品种龙井43和中生茶树品种碧云为材料,利用钙黄素处理茶树茎段,检测越冬芽在休眠与萌发时期与其他器官的物质交流情况。利用同源比对鉴定胼胝质水解相关基因,并分析其序列特征及在冬季不同时期的表达模式。结果表明,越冬芽在茶树生长阶段和休眠阶段都存在着与着生茎段和母叶间的物质交流;从茶树越冬芽休眠形成到解除的不同时期,其物质交流存在"强-弱-强"的变化规律,但龙井43的与碧云相比存在较短的物质交流减弱时期;两种茶树的物质交流变化模式与鉴定到的茶树胼胝质水解正向调控相关基因CsGLU1的表达模式密切相关;启动子序列分析进一步证实CsGLU1启动子区有多个与激素信号以及低温和休眠响应相关转录因子结合的保守序列。茶树越冬芽在休眠和非休眠状态下都存在与茎和母叶之间的物质交流,且物质交流强弱与茶树越冬芽休眠状态改变密切相关。CsGLU1可能是参与胼胝质水解调控,改变茶树越冬芽物质交流水平,进而影响茶树休眠状态的关键基因。这对明确茶树越冬芽休眠状态变化和深入揭示不同萌发物候型茶树休眠机理有重要意义。     

油菜素内酯合成和信号转导基因在马铃薯块茎贮藏期间的表达变化及对萌芽的影响

为探明油菜素内酯BR在块茎萌芽中的作用,建立更有效的种薯催芽调控体系,选择了休眠期不同的3个品种,利用q RT-PCR分析与BR合成、信号转导、调控有关的9个基因在贮藏期间及抑芽处理下的表达模式;同时检测BR类似物24-表油菜素内酯(24-e BL)及其与赤霉素GA3对块茎萌芽的影响。结果表明,涉及BR合成的4个基因表达量均随贮藏时间延长升高,短休眠品种升高的时间点早于中、长休眠品种;信号转导及调控基因中BRI1和CYCD3的变化与合成基因相似,BSK和TCH4的表达量则在中、长休眠期品种中保持恒定。抑芽处理在贮藏前期能刺激这些基因的表达升高,但之后都迅速下降并保持低水平。转录因子BZR1在各品种中以及抑芽处理下均没有明显变化。24-e BL利于块茎解除休眠,但不促进芽的伸长生长,与GA3互配效果更佳,单株块茎增重37.92%~98.41%。结论表明,BR合成和信号转导是块茎从休眠向萌芽转变的必经生理过程,它与GA3互配用于催芽更利于种薯萌芽的整齐、健壮并促进块茎形成。     

The effect of water and nitrogen availability during grain filling on the timing of dormancy release in malting barley crops

Pre-harvest sprouting (PHS) causes immediate loss of seed viability, making barley (Hordeum vulgare L.) grains worthless for malting purposes. Grain dormancy release rate in barley crops is genetically and environmentally controlled. A 2 year experiment was conducted to evaluate the effect of soil nitrogen and water availability during grain filling on the dormancy release pattern (and then on the PHS susceptibility) for five malting barley commercial cultivars. Drought and well-irrigated control treatments were imposed from anthesis onwards, and contrast nitrogen fertilization treatments were applied at tillering. Nitrogen availability showed no effects on dormancy release. Drought during grain filling accelerated dormancy release with respect to well-irrigated control in 2004, but not in 2005 year. Mean temperatures during the last stages of grain filling were much higher (ca. 6°C) in 2005 than in 2004, indicating that high-dormancy loss promoting temperatures had masked drought effects on dormancy release.     

Breeding of white-grained wheats for Japan

The possibility of breeding white-grained wheats tolerant to pre-harvest sprouting under Japanese humid weather conditions is discussed. New genetic dormancy sources, such as, AUS1408, 8019R1 and RyuuMai7, were evaluated for seed dormancy in different weather conditions. Some white-grained dormant wheats showed a strong dormancy similar to that of red-grained dormant wheats in a greenhouse trial, in the field their dormancy expression was much less than the red wheats. Three populations involving crosses with these new sources for winter wheat breeding were examined under repeated selection for seed dormancy. Some dormant white-grained lines, as judged under glasshouse conditions, were developed. Again the level of dormancy in these lines was not sufficient compared to red dormant varieties in field trial. In order to develop truly superior dormant white-grained materials, one population involving crosses with two dormant varieties, AUS1408 and 8019R1, was examined under repeated selection. From these materials we succeeded in breeding lines that had not only a good dormancy but also showed adaptation to Japanese weather conditions, including earliness, scab resistance and good seed appearance. However again the dormancy of these lines in field trial was not sufficient compared to that of red wheats and there was not a clear difference for seed dormancy between breeding lines and their parents. We conclude therefore that more work involving the use of new genetic sources or new breeding techniques, will be necessary for breeding advanced lines that maintain a sufficient tolerance to PHS in humid Japanese weather condition. This revised version was published online in August 2006 with corrections to the Cover Date.     

白皮小麦收获前穗发芽及品种抗性机制探讨

对４８个白皮小麦种质及２个红皮小麦种质连续３年测定结果,品种间收获前穗发芽率,籽粒发芽率及收获后种子休眠特性差异显著。穗发芽敏感性因年份和种子发育时期而异,开花后３５－４０天较敏感,品种间差异大。休眠期长短与穗发芽率间呈极显著负相关。收获后的种子α－淀粉酶活性,降落值,与穗发芽率间分别呈极显著正相关和极显著负相关。     

挥发性抑芽物质对马铃薯块茎萌芽的影响及其作用机制

马铃薯块茎过早萌芽会降低商品价值,本试验比较挥发性物质的抑芽效应,并从转录和蛋白水平分析其作用机制。结果表明,抑芽能力薄荷醇(29)樟脑(29)萘,萌芽受抑降低代谢消耗,薄荷醇处理180 d时的重量损失只有对照损失的36%。樟脑处理萌芽块茎3 d引起表达显著上调(或下调)的基因和蛋白分别有1227 (299)和296 (204)个,主要参与响应刺激、防御反应。贮藏期间,果胶代谢基因PEL、PME、PG,角质合成基因CYP77A6、HPFT、WES,乙烯合成基因ACO以及转录因子编码基因GATA4L的表达量随时间升高。樟脑早期不同程度地刺激这些基因表达,中后期则抑制,49d时只有对照的0.68%～23.35%。薄荷醇使上述基因表达保持低水平,但可提高细胞周期负控基因KRP4的表达,为对照的15.9倍。植物病原菌互作通路中的基因WRKY75、STH-2、RBOH表达受樟脑诱导并在后期高表达。樟脑和薄荷醇均能抑制生长发育基因的表达,造成芽死亡,降低贮藏损耗。前者早期能促进合成保护性物质,萌芽时有更强烈的抗菌反应;后者则阻碍细胞分裂。     

Drought and high temperature increases preharvest sprouting tolerance in a genotype without grain dormancy

Preharvest sprouting is common in cereals, which lack grain dormancy when maturing grain is exposed to rainfall or high moisture conditions. Environmental conditions such as drought and high temperature during grain filling have a large effect on the expression of sprouting tolerance. A dormant (DM 2001) and non-dormant (Cunderdin) hard white spring wheat were exposed to drought or irrigated conditions and either low or high temperature during grain filling. Dormancy and embryo sensitivity to ABA were analysed throughout grain filling. The conclusions from this investigation were as follows; firstly DM 2001 was more dormant than Cunderdin, with a four-fold lower germination index (GI) at maturity. Secondly during grain ripening drought increased dormancy and overrides any increase in dormancy with low temperature. Finally embryo sensitivity can be induced in a non-dormant genotype to the extent where the non-dormant genotype in a hot dry environment can have the same phenotype as a dormant genotype grown in a cool wet environment. In summary drought during grain filling increases dormancy suggesting breeders need to avoid drought when screening for sprouting tolerance in order to maximise the chances of identifying genetic differences in grain dormancy and avoid any maturity by drought interactions.     

QTL mapping of the domestication traits pre-harvest sprouting and dormancy in wheat (<Emphasis Type="BoldItalic">Triticum aestivum L.</Emphasis>)

A set of 75 recombinant inbred lines (RILs) of the ITMI mapping population was grown under field conditions in Gatersleben. The lines were evaluated for the domestication traits pre-harvest sprouting and dormancy (germinability). Main QTLs could be localized for pre-harvest sprouting on chromosome 4AL and dormancy on chromosome 3AL. In addition, 85 Triticum aestivum cv. “Chinese Spring”-Aegilops tauschii introgression lines grown under greenhouse conditions were researched. No QTL could be found for pre-harvest sprouting but a major QTL could be detected for dormancy on chromosome 6DL.     

Genetic analysis of pre-harvest sprouting in a durum wheat cross

Pre-harvest sprouting of durum wheat (Triticum turgidum L. var durum) reduces commercial grade, although the actual effects on processing quality are controversial. Little is known about the genetics of the dormancy component of pre-harvest sprouting resistance in durum. We studied the segregation of dormancy in 98 recombinant inbred lines from a cross of a relatively non-dormant line, CI13102, with a moderately dormant line, Kyle. The lines and parents were grown in field tests over three years, 1996, 1997 and 1998. Spikes were collected at approximately 20% moisture and stored at −23 ∘C. Hand-threshed grain of the lines was germinated, and number of seeds germinated was counted each day. A germination resistance index was calculated to characterize dormancy. Dormancy appeared to be complexly inherited in this cross. Lines were observed that were significantly (P < 0.05) more dormant than the parents. The lines transgressive for dormancy expressed in different combinations of the three environments, indicating an environmental interaction. DNA of lines and parents was tested with simple sequence repeat primers and AFLPs that were used in quantitative trait loci (QTL) analysis of dormancy. Significant QTLs for dormancy were found, with the most notable being on chromosome 1A, where other QTLs for pre-harvest sprouting resistance have been reported in common wheat.