葡萄休眠解除过程中冬芽组织活性氧与抗氧化系统的变化特征

以酿酒葡萄‘赤霞珠’(红)和‘霞多丽’(白)为试材,通过考察其自然休眠过程和打破休眠(单氰胺处理)过程中冬芽组织活性氧及抗氧化系统的变化,探讨葡萄休眠机制。结果表明:(1)在陕西杨陵地区,早熟品种‘霞多丽’在12月20日左右进入深度休眠,第2年1月29日进入休眠解除阶段;晚熟品种‘赤霞珠’在1月9日左右达到深度休眠,2月18日左右进入休眠解除阶段;单氰胺处理可促进葡萄休眠的解除。(2)葡萄休眠过程中,活性氧O2.-和H2O2含量在休眠初期逐渐增加,深度休眠时含量最高,休眠解除过程中含量降低,从而促进休眠的解除;超氧化物歧化酶(SOD)活性在休眠中一直降低,休眠解除后活性上升;过氧化物酶(POD)活性在休眠前期较低,随后活性上升,休眠解除过程中活性又降低;过氧化氢酶(CAT)活性在休眠过程中持续上升,随后维持在较高水平;抗坏血酸-还原态的谷胱甘肽(ASA-GSH)循环在休眠前期较弱,休眠解除过程中逐渐增强。研究发现,葡萄进入休眠后,其冬芽抗氧化能力逐渐降低,至深度休眠时抗氧化能力降至最低,随着低温积累需冷量得到满足,活化了抗氧化系统进而抗氧化能力迅速提高,休眠被解除。     

短时间高温处理下桃树活性氧代谢与桃芽自然休眠解除的关系

以6年生曙光油桃为试验材料,研究40℃、45℃、50℃3个梯度高温短时间处理对桃树花芽和叶芽存活率、萌芽级数、活性氧含量及其相关酶活性的影响,探讨短时间高温处理对桃芽自然休眠解除的调控效应.结果表明:随着短时间高温处理时期的延后以及处理温度的升高和处理持续时间的延长,高温处理对桃芽自然休眠的解除作用增强.11月30日处理中,40℃处理对桃芽自然休眠的解除具有负调控效应,其萌芽级数、·OH和O2·-产生速率、H2O2含量、过氧化物酶(POD)和过氧化氢酶(CAT)活性均低于对照,而超氧化物歧化酶(SOD)活性高于对照;45℃和50℃处理对桃芽自然休眠的解除呈正调控效应,其萌芽级数、·OH和O2·-产生速率、H2O2含量及POD、CAT活性与对照相比明显升高,而SOD活性显著降低.12月10日处理中,40℃处理对桃芽自然休眠解除的调控效应不明显,45℃和50℃处理与11月30日处理相同,但前者对桃芽自然休眠的调控效果优于后者.相关分析表明,活性氧的迅速增加可能是高温解除桃芽自然休眠的原因.     

休眠桃树枝条中碳水化合物的含量变化和外源生长调节剂对破除休眠的效应(简报)

自然休眠期间桃树一年生技条中淀粉和总糖含量变化平缓;休眠结束后糖含量迅速上升,而淀粉则呈现下降态势,花芽中碳水化合物含量亦有相似变化。外源赤霉素和细胞分裂素能显著破除休眠和促进芽萌发,喷施时间晚者效果更明显一些;而生长素类则无效果或起抑制作用。     

珙桐种子休眠解除和萌发过程中主要抗氧化酶活性和代谢产物含量的变化

珙桐(Davidia involucrata Baill.)种子在休眠解除和萌发过程中,主要的抗氧化酶和代谢产物在有效清除活性氧和保证种子活力方面具有重要作用。研究以马边自然保护区采集的珙桐种子为研究对象,对其从休眠解除进入萌发阶段过程中的主要抗氧化酶的活性和代谢产物含量进行测定和分析。结果显示:层积初期,过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化歧化酶(SOD)和谷胱甘肽还原酶(GR)活性均上升,但总抗氧化能力(T-AOC)下降。可溶性蛋白质(Pr)下降而抗坏血酸(Vc)、游离氨基酸(FAA)含量增大;层积中期,SOD活性和T-AOC呈先升高后下降的变化趋势。尽管CAT和GR活性下降,但POD活性保持较高的水平;层积后期,SOD和CAT活性较低,POD、GR活性和T-AOC,FAA和Vc含量整体呈上升趋势;萌发阶段,各抗氧化酶活性均有显著增加(P0.05),Vc和FAA含量显著增加,Pr含量降低。研究结果表明,珙桐种子可以通过各抗氧化酶活性(POD,CAT,SOD和GR)和代谢产物(Pr,FAA和Vc)间的相互作用,在种子休眠解除和萌发过程中先后有效地消除活性氧对细胞结构完整性的影响,并促进珙桐种子的形态和生理后熟,从而保证种子顺利萌发。     

油桃花芽破眠过程中H2O2代谢与Ca2+转运的关系

利用化学测定法分析高温、单氰胺和TDZ 3种破眠处理对"曙光"油桃休眠花芽H2O2代谢的主要影响,利用非损伤微测技术检测H2O2对休眠芽Ca2+转运的影响,研究H2O2在芽休眠解除过程中的调控作用.结果表明:在深休眠时期,高温和单氰胺处理均能诱导芽内H2O2含量升高和过氧化氢酶(CAT)活性降低,并具有显著的破眠作用;TDZ对H2O2含量及CAT、过氧化物酶(POD)活性影响不大,破眠效果较差.休眠花芽原基组织钙通道活跃,对外源Ca2+呈吸收状态.外源H2O2可诱导休眠花芽原基组织Ca2+转运发生变化,低浓度H2O2降低Ca2+吸收速率,高浓度H2O2使组织对Ca2+的转运由吸收转变为释放.这表明休眠芽内H2O2信号和Ca2+信号相关联,通过诱导H2O2积累调控Ca2+信号可能在高温和单氰胺打破休眠的信号转导过程中起重要作用.     

高温和单氰胺对油桃休眠花芽呼吸代谢的影响

以3年生盆栽‘曙光’油桃为材料,研究油桃自然休眠过程中50℃高温和单氰胺对花芽呼吸代谢的影响.结果表明:高温和单氰胺均可以打破油桃的自然休眠,导致休眠花芽呼吸代谢显著下降,其呼吸代谢的衰减可持续数小时.主要呼吸途径三羧酸循环(TCA)和磷酸戊糖途径(PPP)的运行均受到影响.未经破眠处理的花芽TCA和PPP均呈衰减趋势,而高温和单氰胺诱导了早期呼吸衰减结束后PPP的迅速活化.高温还表现出对TCA恢复的诱导,而单氰胺在96 h内未表现出这种作用.在高温和单氰胺打破自然休眠的机制中,呼吸衰减和随后出现的PPP活化可能是重要的组成部分.     

砧木类型对甜樱桃花芽多胺代谢相关基因表达和休眠的影响

为验证砧木类型对甜樱桃多胺代谢和花芽休眠的影响,该研究以嫁接于不同砧木——矮化砧木‘吉塞拉6号’[Gisela 6,(G6)]和乔化砧木‘马扎德’(Mazzard)的甜樱桃品种‘罗亚理’为试材,通过田间观察确定嫁接于两种砧木的‘罗亚理’休眠期和花期,利用生物信息学、基因克隆、实时荧光定量、亚细胞定位和双分子荧光互补等手段,对甜樱桃花芽内多胺代谢中关键基因[多胺氧化酶基因(PavPAOs)和精氨酸脱羧酶基因(PavADC)]进行克隆和功能分析,对可能与PavADC存在互作关系的蛋白进行预测和验证,并利用高效液相色谱法对花芽内游离多胺的含量进行测定。结果表明:(1)‘Mazzard-罗亚理’的休眠期(75 d)长于‘G6-罗亚理’(69 d),且初花期晚于‘G6-罗亚理’。(2)‘G6-罗亚理’花芽内游离多胺含量高于‘Mazzard-罗亚理’,其中Put含量高1.2%~163.4%,Spd含量高8.8%~261.1%,Spm仅在1月和3月的‘G6-罗亚理’花芽中检测到。(3)成功克隆获得甜樱桃多胺代谢关键基因PavPAO2、PavPAO4、PavPAO5和PavADC,其长度分别为1485、1611、1704和2307 bp;系统进化分析表明,甜樱桃PavPAOs和PavADC均与桃、扁桃和苹果等物种的亲缘关系较近;亚细胞定位显示,PavPAO2和PavPAO4定位在细胞膜,而PavPAO5和PavADC则定位在细胞核。(4)qRT-PCR分析显示,休眠期间‘G6-罗亚理’花芽中PavPAO5的表达量低于‘Mazzard-罗亚理’,而PavADC的表达量高于‘Mazzard-罗亚理’;在整个休眠期,PavPAO2和PavPAO4的表达量整体水平远远低于PavPAO5,推测PavPAO5可能是在休眠期起主导作用的家族成员。(5)BiFC验证结果表明,在多胺代谢过程中PavADC与PavSAMDC存在互作关系,推测两者相互作用参与调控花芽内多胺水平。研究认为,甜樱桃砧木类型能够通过影响多胺代谢进程而影响休眠以及开花的进程,关键基因PavPAOs和PavADC的高表达能够影响花芽内多胺水平,PavADC能够使多胺含量升高从而促进休眠解除以及提早开花;多胺代谢过程中关键基因的表达和多胺含量变化能够影响休眠和花期,多胺含量的升高能够促进休眠解除以及提早开花。     

桃花芽自然休眠期间水孔蛋白基因的转录表达

以10年生大田栽培及3年生盆栽曙光油桃花芽为试材,利用荧光定量PCR测定了油桃休眠及休眠解除期间(2009年9月15日-2010年1月15日)曙光油桃水孔蛋白基因δTIP1、PIP1;1的表达量,以及低温胁迫下的转录表达.结果表明:在油桃休眠及休眠解除期间,曙光油桃PIP1;1的转录水平呈现持续增高趋势,且1月的高水平表达使水分通过液泡膜和细胞质膜流出,减少了芽体水分含量,阻止细胞内冰晶的形成,从而抵御冻害;可溶性糖、可溶性蛋白、脯氨酸含量均达到最高,防止细胞的脱水伤害.低温处理2周后高水平表达说明PIP1;1为冷诱导基因.δTIP1的转录水平在休眠期间呈现波动性变化,至休眠解除时大幅度增高,这可能与休眠解除时,其上调表达被休眠解除信号及植物活性的增强所诱导有关.低温处理2周后,其表达没有升高,说明δTIP1并非冷诱导基因.     

南方砂梨返花过程中内源激素含量变化及其与秋季返花的关系

为探讨花芽内源激素含量变化与返花的关系,以砂梨品种‘丰水’、‘翠冠’为材料,研究了砂梨采果后返花过程中花芽内源激素(IAA、GA3、ABA)含量变化,以及早期落叶和秋季返花特征。结果表明:(1)在采果后至返花过程中,两个品种梨花芽中内源激素IAA和GA3含量都呈逐渐缓慢下降趋势;花芽ABA含量的动态变化成升-降-升的"S"曲线。(2)花芽返花受3种激素的动态平衡控制,花芽IAA/ABA、GA3/ABA和(IAA+GA3)/ABA值变化趋势均呈相似的"S"形曲线,IAA/ABA、GA3/ABA和(IAA+GA3)/ABA值增加,花芽返花;比值降低,花芽逐渐步入休眠期。(3)砂梨的落叶率与返花率呈极显著正相关关系,花芽中IAA/ABA比值与砂梨落叶率和返花率相关系数分别为0.805、0.774,相关性均达到显著水平。研究认为,梨返花与早期落叶密切相关,受花芽内源激素IAA、GA3、ABA动态平衡控制;早期落叶降低了花芽中ABA的含量,从而使花芽内生长促进型激素占主导地位,阻止自然休眠的花芽进入休眠或促使进入浅休眠部分花芽解除休眠,所以出现秋季返花现象。     

悬铃木越冬芽在冬季的生理适应

悬铃木越冬芽内可溶性蛋白、酚类含量、{OD活性在10月后逐渐升高,至翌年1月达最高值,此后下降趋势;芽含尜量、O2^-、GSH含量、SOD活性、总抗氧化能力与MDA、脂质过氧化产物等则相反,10月后逐渐下降,翌年1月后又呈升高趋势;GSH含量、SOD活性、总抗氧化能力等的下降幅度远较O2^-含量的下降幅度低。这表明悬铃木越冬芽在冬季可能通过提高芽内可溶性蛋白、酚类等物质含量、POD活性与降低活性氧代谢水平来适应冬季的低温逆境,抗氧化系统对提高越冬芽生理适应能力具有一定作用。     

Changes in ribosome population and in nucleic acids during breaking of dormancy and development of apple flower buds

Changes in ribosome population, RNA species and DNA composition in flower buds of apples ( Malus pumila Mill. cvs Ralls and White winter pearmain) were investigated during breaking of dormancy and development. After bursting of flower buds, total ribosomes increased approximately 4-fold, and the polyribosomal fraction increased from 66% to 94% of total ribosomes. The newly synthesized ribosomes were identified by incorporation of radioactive precursor. The observed decrease in specific radioactivity of the monoribosomes is caused by the recruitment of monoribo-somes into polyribosomes after breaking of dormancy.
In both cultivars, the 25S and 18S rRNA peaks increased to a high level on April 8. The peaks of low molecular weight RNA were apparently increased after initial swelling of the flower buds. The DNA of flower buds was separated into three bands by electrophoresis. The median band is the main band of nuclear DNAs. The ahead band and the slow-moving band are satellite components of nuclear DNAs, and they obviously rose after initial swelling of the flower buds. On April 8, when the flower buds had opened, two other small DNA bands could be detected. These results suggest that the changes in level of different ribosome populations, RNA species and DNA composition are related to dormancy breaking development of apple flower buds.     

低温处理对牡丹春节催花及营养类物质变化的影响

连续观察、测定了牡丹春节催花进程中不同低温天数处理对温室外自然低温解除休眠及温室内培养过程中形态及某些生理生化变化的影响,结果显示：低温处理34d后的11月28日温室外牡丹花芽形态及可溶性糖、淀粉、可溶性蛋白、游离氨基酸含量变化显著,11月28日左右是低温处理期间牡丹花芽代谢变化剧烈的时期;处理41d后的12月5口及以后移入温室的植株能够正常开花。以上结果从形态与营养物质变化的角度说明了11月28日左右牡丹花芽开始逐步解除休眠,12月5日花芽已彻底解除休眠,不同低温对牡丹春节催花过程中花芽的发育有着质的作用。     

Metabolic changes in cherry flower buds associated with breaking of dormancy in early and late blooming cultivars

Changes of metabolic activities during dormancy and breaking of dormancy in the cherry flower buds of early blooming (EB) cultivar ( Prunus avium L. cv. Coeur de Pigeon) and late blooming (LB) cultivar ( Prunus serrulata Lindl. cv. Kwanzan) were determined. The LB buds had higher polyamines, protein and 1-(malonylamino) cyclopropane-1-carboxylic acid (MACC) content than the EB buds. During the dormant state, the DNA, RNA, protein and polyamines in the EB buds were low but increased slowly and steadily, whereas those in the LB buds remained at a consistently higher level. The transition from dormancy to the active state in both cultivars was characterized by a sharp increase in DNA, RNA, protein, polyamines, S-adenosyl-methionine (SAM), 1-aminocyclopropane-1-carboxylic acid (ACC) and MACC. After initial swelling and development of flowers, the levels of all these components decreased. Polyamine and ethylene biosyntheses did not seem to be competing for their common substrate, SAM, during flower bud development.     

Levels and Aggregation of Ribosomes during Dormancy and Dormancy Break of Peach Flower Buds

The level of ribosomes and their aggregation state (monosomes-polysomes) have been investigated in relation to dormancy in peach flower buds (Prunus persica). The ribosomes were analysed by a linear sucrose gradient. The ribosomal content hardly changes in the bud before dormancy and until dormancy breaks; on the other hand after this period there is a remarkable increase in the ribosomal level strictly related to the increase in bud weight. The ribosomal content reaches the highest value at flowering. During dormancy break the largest portion of ribosomes is localized in flower primordia, not in scales. Polysomes, which are always present in buds, remain constant during dormancy (35%), increase at dormancy breaking, reaching the highest level at flowering.     

Seasonal shifts in dormancy status, carbohydrate metabolism, and related gene expression in crown buds of leafy spurge

Crown buds of field-grown leafy spurge (Euphorbia esula L.) were examined to determine relationships between carbohydrate metabolism and gene expression throughout para-, endo-, and eco-dormancy during the transition from summer, autumn, and winter, respectively. The data indicates that endo-dormancy plays a role in preventing new shoot growth during the transition from autumn to winter. Cold temperature was involved in breaking endo-dormancy, inducing flowering competence, and inhibiting shoot growth. An inverse relationship developed between starch and soluble sugar (mainly sucrose) content in buds during the shift from para- to endo-dormancy, which continued through eco-dormancy. Unlike starch content, soluble sugars were lowest in crown buds during para-dormancy but increased over two- to three-fold during the transition to endo-dormancy. Several genes (AGPase, HK, SPS, SuSy, and UGPase) coding for proteins involved in sugar metabolism were differentially regulated in conjunction with well-defined phases of dormancy in crown buds. Marker genes for S-phase progression, cell wall biochemistry, or responsive to auxin were also differentially regulated during transition from para-, endo-, and eco-dormancy. The results were used to develop a model showing potential signalling pathways involved in regulating seasonal dormancy status in leafy spurge crown buds.     

几种化学药剂对‘NJ72’油桃休眠解除的影响

在进行果树温室栽培时,经常遇到萌芽率低,萌芽开花延迟,花器官发育差,座果率低的问题。本试验以‘NU72’油桃为试材,观察了3种药剂对解除芽休眠的影响。结果表明,2％（NH2）2CS能提早花期,但存在药害现象,6％KNO3不能提早花期,并且花期不整齐,5％NH4NO3效果与6％KNO3类似。同时化学药剂处理促进花芽内H2O2的积累,抑制了过氧化氢酶（CAT）活性但促进了过氧化物酶（POD）活性,超氧物岐化酶（SOD）活性变化较小,化学药剂使花芽的呼吸速率增加,其中磷酸戊糖途径（PPP）代谢增加,糖酵解（EMP）降低,而三羧酸循环（TCA）代谢波动较小,葡萄糖－6－磷酸脱氢酶（G6PDH）活性在化学药剂处理时也增加。     

几种化学药剂对‘NJ72’油桃休眠解除的影响

在进行果树温室栽培时,经常遇到萌芽率低、萌芽开花延迟、花器官发育差、座果率低的问题。本试验以‘NJ72’油桃为试材,观察了3种药剂对解除芽休眠的影响。结果表明,2%(NH2)2CS能提早花期,但存在药害现象。6% KNO3不能提早花期,并且花期不整齐,5% NH4NO3效果与6%KNO3类似。同时化学药剂处理促进花芽内H2O2的积累,抑制了过氧化氢酶(CAT)活性但促进了过氧化物酶(POD)活性,超氧物岐化酶(SOD)活性变化较小。化学药剂处理使花芽的呼吸速率增加,其中磷酸戊糖途径(PPP)代谢增加,糖酵解(EMP)降低,而三羧酸循环(TCA)代谢波动较小。葡萄糖_6_磷酸脱氢酶(G6PDH)活性在化学药剂处理时也增加。     

Low temperature influence on flowering in Citrus. The separation of inductive and bud dormancy releasing effects

The flowering response of Owari Satsuma mandarin ( Citrus unshiu Marc) to low temperature treatments has been determined using potted trees and in vitro bud cultures. In potted trees the chilling treatments released bud dormancy and enhanced both sprouting and flowering, but these two responses could not be separated. However, bud cultures showed no dormancy, and a specific effect of low temperature on flower induction was demonstrated. Low temperature appears to have a dual effect, releasing bud dormancy and inducing flowering. Potential flower buds have a deeper dormancy than vegetative buds, and the first stages of flower initiation seem to occur before the winter rest period.     

Stamen development and winter dormancy in apricot (Prunus armeniaca)

Background and Aims

In temperate woody perennials, flower bud development is halted during the winter, when the buds enter dormancy. This dormant period is a prerequisite for adequate flowering, is genetically regulated, and plays a clear role in possibly adapting species and cultivars to climatic areas. However, information on the biological events underpinning dormancy is lacking. Stamen development, with clear differentiated stages, appears as a good framework to put dormancy in a developmental context. Here, stamen developmental changes are characterized in apricot (Prunus armeniaca) and are related to dormancy.

Methods

Stamen development was characterized cytochemically from the end of August to March, over 4 years. Developmental changes were related to dormancy, using the existing empirical information on chilling requirements.

Key Results

Stamen development continued during the autumn, and the flower buds entered dormancy with a fully developed sporogenous tissue. Although no anatomical changes were observed during dormancy, breaking of dormancy occurred following a clear sequence of events. Starch accumulated in particular places, pre-empting further development in those areas. Vascular bundles developed and pollen mother cells underwent meiosis followed by microspore development.

Conclusions

Dormancy appears to mark a boundary between the development of the sporogenous tissue and the occurrence of meiosis for further microspore development. Breaking of dormancy occurs following a clear sequence of events, providing a developmental context in which to study winter dormancy and to evaluate differences in chilling requirements among genotypes.