Paraffin section observation of flower bud differentiation of Chimonanthus praecox in Kunming and comparison of the differentiation processes in different regions,China

Chimonanthus praecox is an important ornamental plant and cut flower material in China.It blooms in the freezing winter and its flower emits charming fragrance.However,in different region the flowering time is variable.In order to understand the flowering mechanism of Ch.praecox in the winter,we studied the flower bud differentiation in Spring City-Kunming using paraffin sectioning method in the present study.Meanwhile we compared the differentiation process difference from different regions.It was found that the temperature is the key factor for its flower bud differentiation and blossom of Ch.praecox.In the process of bud differentiation,the temperature 20℃was the optimum for inducing changes from vegetative axillary buds to reproductive buds and subsequent morphological differentiation in Ch.praecox.Furthermore in the first three differentiation periods—tepal primordial stage,staminal primordial stage and pistil primordial stage,Kunming took the shortest time to finish the process due to very rapid temperature rise to 20℃,whereas,in Zhengzhou the time for these differentiations was the longest,which may be caused by the slow temperature rise.After May,the high temperature stress forced the flower buds into the first long dormant period in all regions except Kunming.In Kunming,the average temperature was only 20–25℃,so the flower bud continued to differentiate.In all regions,Kunming is the first to complete whole flower bud differentiation even on the early August,and started the second dormancy very early but very long.In the other regions,the plants went through a shorter dormancy and the low temperature broke the dormancy rapidly.Contrarily the plants of Kunming spent a longer period for the low temperature.Thus,the low temperature less than 10℃is a key factor to breaking the second dormancy.Surely the regular effects of temperature on flower bud differentiation and blossom is very helpful for florescence regulation of Ch.praecox.

Changes in Nutritive Materials in Off-season Mango in Flower Bud Differentiation Stage

Under off-season production mode, change laws of nutritive materials in leaves of fruiting mother branches of mango in flowering process induced by dif- ferent agents were investigated. The results showed that the flowering time of manga trees in the potassium nitrate treatment was earlier than the ethephon treatment by 7 d, and changes trends of materials in leaves of the potassium nitrate and ethephon treatments were substantially the same. The nutritive materials in leaves showed trends of increasing at first and decreasing then. In early flower bud differentiation stage, soluble sugar and starch in leaves increased rapidly, and content of soluble protein also increased rapidly and showed its their peak values, thereby providing energy substances and structural substances demanded by flower bud formation. With flower bud differentiation going on, soluble sugar, starch and soluble protein decreased gradually. It was indicated that the accumulation of soluble sugar, starch and soluble protein is beneficial to flower bud differentiation.

Expression of AP1 Gene During Off-season Flower Bud Differentiation of Mango

This study was conducted to investigate changes in the expression of AP1 gene in flowering process. Potassium nitrate and ethephon were sprayed on 7- year-old Guifei trees out of season. The results showed that AP1 gene had a higher expression level in terminal buds, and especially, the expression level increased significantly in late stage of flower bud differentiation. Potassium nitrate and ethephon promoted flower bud differentiation, and the expression level of AP1 gene in- creased in flowering process remarkably. Expression ofAP1 gene of the potassium nitrate treatment was significantly greater than that of the ethephon treatment and the CK.

Effect of Shoot Control on Flower Bud Differentiation,Flowering,and Fruit Setting in Zanthoxylum armatum DC.

In this study,newly sprouted shoots of Zanthoxylum armatum(Z.armatum),which were collected after the harvesting period,were used as the primary experimental specimens.A randomized block design and paraffin sectioning method were used to investigate the flower bud differentiation process and the quantity and vitality of buds.Furthermore,the study examined the response of flowering and fruiting to cultivation methods for shoot growth,including layering and plant growth regulator application.The results showed that(a)layering and application of plant growth regulators for Z.armatum accelerated the process of flower bud differentiation by approximately 20 days compared to the control group.Additionally,both shoot control methods generated more and larger bud primordia and perianth primordia during the same differentiation phase.(b)The application of plant growth regulators resulted in well-developed buds,exhibiting higher levels of flower bud differentiation than the layering method.The quality of flower bud formation for both shoot control methods was superior to that of the control group.(c)The flowering phenological period was relatively consistent between the two cultivation methods,but the fruit maturity phase for shoot-controlled trees occurred 20 days earlier than the control group.(d)Both layering and the application of plant growth regulators significantly decreased the rates of unfertilized flower shedding and fruit shedding.However,no significant difference was noted in fruit setting per inflorescence and per flower between the two methods and the control.The effect of altitude for both methods on the fruit setting was not significant.Under both shoot control methods,the Z.armatum exhibited earlier morphological differentiation of flower buds,faster differentiation process,improved flower bud quality,and significantly decreased rates of flower and fruit shedding.Thus,these cultivation methods demonstrated the potential to promote flowering,improve fruit setting,and reduce fruit shedding in Z.armatum.

Observation on Flower Bud Differentiation of Crape Myrtle in Red Soil Environment

Flower bud differentiation is a key component of plant blooming biology and understanding how it works is vital for flowering regulation and plant genetic breeding,increasing the number and quality of flowering.Red soil is the most widely covered soil type in the world,and it is also the most suitable soil type for crape myrtle planting.The flower buds of crape myrtle(Lagerstroemia indica)planted in red soil were employed as experimental materials in this study,and the distinct periods of differentiation were identified using stereomicroscopy and paraffin sectioning.We optimized the steps of dehydration,transparency,embedding,sectioning and staining when employing paraffin sections.When seen under a microscope,this optimization can make the cell structure of paraffin sections obvious,the tissue structure complete,and the staining clear and natural.The flower bud differentiation process is divided into 7 periods based on anatomical observations of the external morphology and internal structure during flower bud differentiation:undifferentiated period,start of differentiation period,inflorescence differentiation period,calyx differentiation period,petal differentiation period,stamen differentiation period,and pistil differentiation period.The differentiation time is concentrated from the end of May to mid-June.Crape myrtle flower bud differentiation is a complicated process,and the specific regulatory mechanism and affecting elements need to be investigated further.

Research Progress of Flower Bud Differentiation of Apple

Flowering is a prerequisite for apple fruiting,and apple flower buds are mixed buds,that is,the vegetative organs and flower structure exist in the same terminal bud simultaneously,which are formed in the year before flowering and fruiting,mainly including spur terminal buds and axillary buds.The infrequent formation of flower buds during its growth and biennial bearing are closely related to flower bud differentiation.Therefore,this paper reviews the research progress of flower bud differentiation of apple from the morphological differentiation,plant hormones and flowering-related genes,in order to provide a theoretical reference for efficient cultivation and stable yield of apple.

Endogenous phytohormones and the expression of flowering genes synergistically induce flowering in loquat

Flowering is an important process for the reproduction of higher plants.Up to this point,the studies on flowering have mostly focused on the model plant Arabidopsis thaliana,and the flowering mechanism of fruit trees remains mostly unknown.The diversity of the flowering time of loquat(Eriobotrya japonica Lindl.)makes it an ideal material to study the regulation of flowering.In this study,we first observed the inflorescence bud differentiation in two varieties of loquat that had different blooming times(cv.Dawuxing(E.japonica),that blooms in the fall and cv.Chunhua(E.japonica×Eriobotrya bengalensis Hook.f.)that blooms in the spring)and found that the starting time of inflorescence bud differentiation and the speed of inflorescence development were responsible for the difference in blooming times.The determination of endogenous phytohormones by high performance liquid chromatography(HPLC)indicated that abscisic acid(ABA),zeatin(ZT),and gibberellin(GA3)promoted flowering in loquat,while indole-3-acetic acid(IAA)was mainly involved in inflorescence bud differentiation in Chunhua.A transcription level analysis illustrated that multiple flowering-related genes could respond to different signals,integrate to the TFL1,AP1 and FT genes,and then synergistically regulate flowering in loquat.Thus,this study provides a new insight into flowering regulation mechanisms in loquat.

Differences in Carbon Nutrition between On-season and Off-season Longan during the Flowering Process

Flower-bud differentiation is the most critical stage of fruit yield formation, as well as a complicated carbon transfer process. To understand the changes of carbon during the flower bud differentiation process of longan, it is very important to adopt suitable planting measures and control flowering time. This study fo- cused on the changes of sugar and starch content of on-season and off-season longan during the flowering process. The results showed that the accumulation and transformation of carben differed between on-season and off-season longan during flower-bud differentiation process ; to be specific, sugar and starch content in tissues differentiated from apical buds of on-season longan were reduced at the late flower-bud physiological differentiation stage except in leaf buds ; on the contrary, sugar and starch content in off-season longan increased at the late flower-bud physiological differentiation stage： specifically, total sugar content increased from 15.43 （ - 7 d） to 31.38 mg/g （7 d） ; starch content increased from 5.42 to 8.31 mg/g during this time, which may be relevant to the external environment or tree original metabolism damaged by potassium chlorate.

天红2号苹果花芽分化期枝条和叶片碳水化合物含量和C/N变化

以天红2号苹果为试材,研究不同砧木短枝和中枝在花芽分化期间叶片和枝条中碳水化合物含量和C/N变化情况。结果表明,稳产期天红2号苹果成花率不受砧木影响。整个花芽分化期,无论嫁接在SH40中间砧还是八棱海棠乔砧上,在同一枝类中,天红2号苹果叶片可溶性糖、蔗糖、果糖和氮含量高于枝条,淀粉含量和C/N低于枝条。嫁接在SH40中间砧上的天红2号苹果成花率高的短枝叶片淀粉和果糖含量低于成花率低的中枝叶片,可溶性糖、蔗糖含量和C/N于花芽分化初期至花瓣原基分化期高于中枝叶片,短枝枝条可溶性糖、果糖含量和C/N低于中枝枝条,短枝枝条淀粉含量于花瓣原基分化期前高于中枝枝条;嫁接在八棱海棠乔砧上的天红2号苹果成花率高的短枝叶片可溶性糖、淀粉、果糖含量和C/N低于成花率低的中枝叶片,短枝枝条可溶性糖、果糖含量和C/N低于中枝枝条,短枝枝条淀粉含量于转化期低于中枝枝条。说明碳水化合物含量和C/N的高低对苹果成花不起决定性作用。在整个花芽分化期,叶片中可溶性糖含量呈上升趋势,枝条中淀粉含量和C/N呈波动性上升趋势,说明天红2号苹果花芽形态分化需要碳水化合物和C/N的积累。

不同心皮数量棉花心皮发育特征、基因表达及相关性状比较

【目的】探究棉花心皮发育特征,不同心皮数量的差异表达基因与植物激素含量,以及心皮数量与棉铃发育的关系。【方法】以3心皮(C3)、4心皮(C4)、5心皮(C5)棉花材料为研究对象,观察棉花心皮发育过程,统计不同杂交组配后代的心皮数量。花芽发育5 d、10 d和开花当天分别进行转录组测序及激素含量测定,并在不同发育时期测定棉铃的表型。【结果】花蕾长度为2~3 mm时,心皮原基发育起始;花蕾长度为4~5 mm时,心皮融合形成合生心皮。心皮原基的发育早于雌蕊器官。C3、C4、C5两两杂交F1的平均心皮数量介于双亲之间。C3、C4和C5中差异表达基因主要富集于生物学过程。花芽发育5 d、10 d和开花当天,富集通路中心皮发育相关基因AP1、AGL6、WUS、MYB21和ARF6在C5中的表达量高于C4,且显著高于C3。花芽发育5 d、10 d,C5的茉莉酸含量显著高于C3、C4,吲哚乙酸含量显著低于C3、C4;C4的脱落酸含量显著低于C3、C5。开花后20 d、35 d和60 d,C5的棉铃直径、棉铃鲜物质质量、棉瓣厚度以及纤维和胚珠鲜物质质量显著高于C3、C4。【结论】3、4、5心皮棉花亲本的杂交组配后代中,心皮数量介于双亲之间。多个心皮发育相关基因在C5中的表达量更高。开花前,C5中茉莉酸含量最高,吲哚乙酸含量最低。心皮数量增多利于增加棉铃直径、鲜物质质量,同时增加纤维和胚珠鲜物质质量。

3个蓝莓品种花芽分化特性比较研究

为探讨云南省蓝莓多次花芽分化的形态变化、花芽分化规律和品种间的差异,对蓝丰、双丰及夏普蓝的物候期进行调查,利用改良的石蜡切片方法对其花芽分化过程进行观察和分析,并采用MRM方法测定了夏普蓝3次花芽分化过程中5种内源激素含量。结果表明,蓝丰一年现蕾和开花结果1次;双丰一年现蕾和开花结果2次,分别表示为双丰第1次、双丰第2次;夏普蓝一年现蕾和开花结果3次,分别表示为夏普蓝第1次、夏普蓝第2次、夏普蓝第3次。双丰第1次的果熟末期与双丰第2次的现蕾期之间的时间间隔比较明显;从现蕾到果熟期,夏普蓝第1次与夏普蓝第2次具有重合的生育期,夏普蓝第2次与夏普蓝第3次也具有重合的生育期。3个蓝莓品种的花芽分化主要阶段有6个,依次为开始分化期、花序原基分化期、萼片原基分化期、花瓣原基分化期、雄蕊原基分化期、心皮原基分化期。3个蓝莓品种完成花芽分化的时间不同,蓝丰完成花芽分化的时间最长,需53 d,其次是双丰,双丰2次花芽分化完成的时间均比夏普蓝3次花芽分化完成的时间长。不同于蓝丰和双丰,夏普蓝在云南省不需要低温诱导,春季自剪之后立刻进入花芽分化。蓝莓花芽孕育期需要的IAA、CKs、GAs含量均较低,但需要的ABA、ACC含量均较高,要想对花器官后期的花芽分化有利,应保持IAA、CKs、GAs含量为平衡状态。

不同日照时长对韭菜抽薹的影响

为明确不同日照时长对韭菜抽薹的影响,筛选适宜抑制韭菜抽薹的日照时间,以深休眠韭菜品种海韭6号为试验材料,设置自然光照(CK)、9 h、10 h、11 h和12 h 5个日照时长,研究不同日照时长对韭菜抽薹的影响。结果表明,适当缩短日照时长可显著抑制韭菜抽薹,其中10 h和11 h日照下韭菜抽薹率最低,分别为0.66%、0.34%;9 h和12 h日照下韭菜抽薹率分别为8.47%、3.31%;花芽分化解剖学观察结果也表明,适当缩短日照时间可有效抑制韭菜花芽分化。本研究结果可为提高河北张家口等高海拔冷凉地区夏季韭菜产量和品质提供参考。

不同节位修剪对‘夏黑’葡萄二次花芽分化及果实品质的影响

为研究‘促早+避雨’栽培模式下,不同节位修剪对葡萄二次成花及二次果果实品质的影响,以7 a生‘夏黑’葡萄为材料,分析留5芽、留7芽和留9芽(简称5芽、7芽、9芽)修剪对葡萄萌芽率、成花率、单果质量、穗重、可溶性固形物含量等指标的影响。结果表明:3种不同修剪方式对葡萄二次萌芽率和成花率均产生了一定影响。其中,5芽修剪萌芽率和成花率最高,9芽修剪则较低。在单果质量和穗重方面,5芽修剪二次果穗重最大,但不同节位修剪并未对单果质量和果形指数产生显著影响。5芽和7芽修剪二次果可溶性固形物含量显著高于9芽修剪,5芽修剪二次果可滴定酸含量则显著低于9芽修剪,5芽修剪二次果葡萄糖和果糖含量均显著高于9芽修剪,但不同节位修剪均未对蔗糖和花色苷含量产生较大影响。综上所述,3种修剪方法中留5芽修剪最适宜于‘夏黑’葡萄一年两熟栽培,其次为留7芽修剪,留9芽修剪则不太适宜。

四季花金花茶花芽分化进程及叶片内源激素变化

四季花金花茶(Camellia perpetua)为山茶属中唯一几乎全年开花的珍稀濒危植物。为探究其花芽分化进程及不同花发育时期和年生长周期叶片内源激素变化,该研究通过石蜡切片,观察四季花金花茶花芽分化进程,采用酶联免疫吸附法测定不同花发育时期叶片及年生长周期内有花芽和无花芽叶片的脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA3)和玉米素核苷(ZR)含量的变化规律。结果表明:(1)四季花金花茶花芽分化顺序由外向内进行,分为6个时期,共历时35 d,从花芽分化至开花约2个月。(2)花芽形态分化期叶片ABA、GA3的含量及GA3/ABA、(IAA+GA3)/ZR的比值较高,IAA、ZR的含量及IAA/ABA、ZR/ABA的比值较低。(3)年生长周期内有花芽叶片ABA、IAA、ZR的含量整体上高于无花芽叶片;IAA/ZR及(IAA+GA3)/ZR的比值整体上低于无花芽叶片。综上表明,四季花金花茶花芽分化至开花时间较短;高水平的ABA、GA3及低水平的IAA、ZR有利于花芽分化;较高水平的ABA、IAA及ZR有利于花芽发育。该研究为该物种持续开花机理的阐明提供了参考依据。

秋季剪梢对温室蓝莓芽分化及内源激素的影响

花芽分化是蓝莓开花结实的基础,秋季剪梢是温室蓝莓栽培管理中的重要措施之一,可有效调节其花芽分化。为探明秋季剪梢对温室蓝莓花芽分化及期间芽中内源激素变化的影响,于秋季对日光温室内5年生北高丛‘M7’蓝莓树体上的健旺直立枝条进行剪梢处理,以未剪梢为对照。在明确2种处理下新梢腋芽花芽分化差异的基础上,分析未剪新梢上、中部腋芽与剪梢后的新梢上部腋芽中赤霉素(gibberellin A_(3),GA_(3))、生长素(indoleacetic acid,IAA)、脱落酸(abscisic acid,ABA)和玉米素(zeatin,ZT)含量以及IAA/ABA、ABA/ZT的比值变化。结果表明,与未剪梢相比,剪梢处理明显加快了温室蓝莓花芽分化的进程,花芽数量和花芽率分别显著提高4和7倍,花芽直径显著提高78.26%;剪梢处理上部芽中的GA_(3)含量在其成花诱导期较未剪梢显著降低32.74%,而后花器官原基形成时期又持续升高,且显著高于未剪新梢上、中部芽内GA_(3)含量;剪梢处理上部芽内的IAA含量在其成花诱导期显著高于未剪梢中部芽,却显著低于未剪梢上部芽,在其花器官原基形成期显著低于未剪梢中部腋芽。在剪梢后留存新梢的上部腋芽成花诱导过程中,ABA与IAA呈极显著正相关关系,且ABA/ZT值先大幅升高,且显著高于未剪梢中部芽;而在剪梢上部芽的花器官原基形成过程中,IAA/ABA的值均高于未剪枝中部芽。即秋季剪梢处理通过先大幅降低芽内GA_(3)和ZT的含量、升高IAA含量并提升ABA/ZT的比值来诱导温室蓝莓花芽分化并加快其花芽分化进程,而后通过提高GA_(3)含量、降低IAA含量,并维持较高的IAA/ABA值来促进温室蓝莓花器官原基的发育。以上结果为探讨秋季剪梢对蓝莓花芽分化的作用机理及温室蓝莓花芽分化的调控提供理论依据和技术支撑。

西番莲花芽分化过程观察及花生长模型的拟合

【目的】明确我国南方生态区主栽西番莲品种的花芽分化过程,建立西番莲花芽形态分化的花生长模型,为西番莲促花保花提供参考。【方法】以紫果类主栽品种‘台农1号’(TN)和黄果类广西主推新品种‘壮蜜05’(同‘壮乡蜜宝’,MB)为试验材料,通过扫描电镜和石蜡切片解剖观察两品种花芽分化过程,观察茎顶端分生组织以下各节位分化进程,并测量各节位花芽的第一苞片长、叶片长、卷须长;通过将茎顶端分生组织以下第7节记为初始标记节位,此时花芽为第一苞片分化期,跟踪调查标记后0—16 d花芽分化进程及标记后至开花的第一苞片长、花蕾长等5个花形态指标的动态变化,构建花生长模型。【结果】供试的两个西番莲品种花芽分化的主要过程包括第一苞片形成期、额外苞片形成期、萼片形成期、花瓣形成期、雄蕊形成期、雌蕊形成期和副花冠形成期等,其中第一苞片形成到雌蕊形成历时10—12 d,TN较MB进程快1—2 d,雌蕊形成是西番莲花芽发育成功的重要标志,此时花芽第一苞片长度为3—4 mm,第一苞片形成到开花历时36—44 d,TN较MB进程快3—4 d。茎顶端分生组织以下第4—5节位可见卷须分化,第6节位花原基分化,着生于卷须旁侧,第7节位可见第一苞片分化,第9节位出现腋生营养分生组织,单独位于卷须和花芽内侧,第10—11节位可见腋芽形成,第14—15节位雌蕊原基分化。利用Origin软件对MB和TN的第一苞片长度、第一苞片宽度、花梗长、花蕾长、花梗和花蕾总长共5个花形态指标和标记后天数进行Logistic模型的非线性回归拟合,决定系数R2为0.9524—0.9988,标准化均方根误差(n RMSE)为8.54%—19.62%,模型方程的拟合效果较好。根据模型参数和实际观察,苞片的长度在标记后即第一苞片形成期后11—12 d进入快速增长期,标记后24—26 d进入缓慢增长期后趋于稳定;之后花梗和萼片迅速生长,萼片长度超过苞片,花蕾和花梗总长在标记后24—25 d进入快速增长期,标记后41—42 d进入缓慢增长期到最大值后开花。【结论】西番莲的花芽与卷须紧靠,而与营养芽分开独立;西番莲花芽分化和形态分化可分为3个阶段,第一苞片形成期到雌蕊形成期,历时10—12 d;苞片生长期,历时12—14 d;花梗和花蕾生长期,历时15—17 d。在西番莲实际生产中,可通过花生长模型预测开花时间,通过苞片长度等形态指标判断花芽分化进程,为促花保花方案提供参考依据。

干旱胁迫对西克刺桐花芽分化的生理特性影响

为了研究干旱胁迫诱导西克刺桐Erythrina sykesii花芽分化的生理特性,以其8年生植株为材料,测定干旱胁迫下叶片光合色素、可溶性糖、丙二醛、内源激素含量和超氧化物歧化酶、过氧化物酶活性等生理指标,分析西克刺桐对干旱胁迫的生理响应及其成花诱导特性。结果表明,随着干旱胁迫程度增加,西克刺桐叶片光合色素、抗氧化酶活性和内源激素含量均呈先增后降的变化趋势;轻度干旱胁迫时叶片叶绿素和类胡萝卜素、淀粉、可溶性糖、IAA、GA3和ZR含量达到最大值;中度干旱胁迫时SOD、POD和CAT活性,可溶性蛋白含量达到最大值;丙二醛、ABA含量和碳氮比均随着干旱胁迫程度增加而显著增加。以上生理指标变化表明,干旱胁迫下西克刺桐枝条成花率显著提高,其中中度胁迫效果最明显。西克刺桐在中度干旱胁迫下提高ABA含量和抗氧化酶活性,缓解植株的细胞损伤;同时提高可溶性蛋白合成和碳氮比,促进植株花芽分化,提高枝条成花率。

温度对大蒜花形态建成和花粉活力的影响

为探究温度对大蒜不育机制的影响,本研究以2个薹蒜品种成县汉中蒜及荷兰大蒜NL-3为试验材料,利用压片法和亚历山大染色法,比较常温(平均温度23℃)和低温(平均温度17℃)下2个大蒜品种花芽分化过程、花粉母细胞减数分裂过程中染色体变异和花粉活力的差异。结果表明,低温处理下,2个大蒜品种的花芽分化进程比常温处理延长9~10 d。不同温度下,2个大蒜品种花粉母细胞减数分裂过程中染色体行为异常比例和成熟花粉活力存在较大差异;低温下,NL-3花粉母细胞减数分裂过程中染色体行为正常的比例和成熟花粉的活力分别由常温下的5.47%和4.01%提升为29.65%和26.17%,差异显著;而低温处理不能显著提升成县汉中蒜花粉母细胞减数分裂过程中染色体行为正常的比例和成熟花粉的活力。总之,不同大蒜品种雄配子体对温度的响应具有显著差异,荷兰大蒜NL-3雄配子体对温度更为敏感,是育性保持和恢复的潜力品种。

胡桃科植物花发育研究进展

胡桃科植物作为重要的木本油料作物和坚果,具有雌雄同株异花特性。其中核桃属和山核桃属果实具有较高的经济价值,但在实际生产中树体雌、雄花比例失衡,雄花过多,雌花太少,严重制约了果实产量,影响其经济效益。总结了胡桃科植物雌、雄花发育的形态特征,对内源激素、营养物质、矿质元素和位置效应对花芽分化的影响及成花诱导、花发育模型相关基因功能研究进行了综述,以期对胡桃科植物雌、雄花分化机制和果实优质高产栽培研究提供参考。

‘红地球’葡萄VvARF18功能分析

【目的】生长素响应因子ARF是生长素信号转导途径中的重要调控因子,在植物生长发育和各类生理过程中发挥着重要作用。分析‘红地球’葡萄VvARF18启动子、异源表达、内源激素含量及其对激素响应的表达,以探究VvARF18在‘红地球’葡萄生长素(IAA)信号转导途径及花芽分化进程中的作用机理。【方法】以设施‘红地球’葡萄花芽为试验材料,通过同源克隆获得VvARF18序列,利用在线数据库PLACE分析启动子的顺式作用元件。以pCAMBIAI2300植物表达载体为基础,通过双酶切和同源重组法构建植物超表达载体pC2300-VvARF18。采用电击法将重组载体pC2300-VvARF18转化至根癌农杆菌GV3101菌株中,以本氏烟草叶片为外植体,通过农杆菌介导的愈伤组织转化法转入烟草中,经PCR检测获得阳性转基因幼苗。利用实时荧光定量PCR(qRT-PCR)对转VvARF18烟草株系表达水平进行分析,筛选出高表达量的转基因株系培养至T_(3)代,并分别进行IAA和GA_(3)处理,以分析VvARF18的表达情况。通过酶联免疫法测定转基因烟草花芽和叶片中的IAA、GA、ABA、CTK含量。【结果】‘红地球’葡萄VvARF18位于第13条染色体,含有3个外显子和2个内含子。VvARF18启动子区域存在多种光响应、植物激素响应和逆境响应的顺式作用元件。表型分析发现,转基因烟草的花芽分化进程快于野生型烟草。qRT-PCR结果显示,VvARF18在转基因烟草花芽发育的4个时期中呈先上升后下降的表达趋势,且S3时期表达量达到最高。转基因烟草植株花芽和叶片中IAA、CTK、GA和ABA测定结果表明,转基因烟草花芽和叶片中4种植物激素的含量均高于野生型植株,其中GA/IAA在转基因烟草花芽发育的4个时期中变化趋势与VvARF18表达趋势相一致。转基因烟草植株经IAA和GA_(3)处理后,VvARF18的表达量随IAA处理浓度的增高而降低,也随GA_(3)处理时间的延长而降低。【结论】葡萄Vv ARF18负调控生长素参与植物花芽分化进程,可能与赤霉素信号转导途径中的关键因子相互作用协同调控植物花芽中的激素水平,对植物花芽分化具有促进作用。