玉米赤霉烯酮在冬小麦短日春化中的作用

应用酶联免疫技术,研究了冬小麦品种燕大１８１７ 在不同光周期条件下,体内内源玉米赤霉烯酮（ＺＥＮ） 和ＡＢＡ 含量的变化。结果表明,冬小麦品种燕大１８１７ 具有短日春化性,苗期经４ 周ＳＤ 处理后转到ＬＤ 下能正常抽穗。ＳＤ 诱导春化的幼苗茎尖和叶片中ＺＥＮ 含量高于未经诱导的ＬＤ 幼苗,而在两种光周期条件下生长的幼苗中ＡＢＡ 含量变化趋势并无明显差异。马拉硫磷（ ＭＡＬ） 抑制ＳＤ 幼苗体内ＺＥＮ 含量高峰的出现,也部分抑制抽穗;外源ＺＥＮ 可部分抵消ＭＡＬ对植株的影响,降低茎尖内源ＡＢＡ 含量,并有促进小麦拔节的作用。说明在冬小麦短日春化过程中,ＺＥＮ 具有促进作用,而ＡＢＡ 没有直接影响。     

Levels of Growth Regulating Substances during Vernalization of Winter Wheat

Seeds of winter wheat (Triticum vulgare L.) cultivars Fema and Ferto, were vernalized at 3°C in the dark. Samples were taken 9, 18, 27, 36 and 45 days after the start of vernalization, and extracts were analysed for auxins, gibberellins and growth inhibiting substances. As vernalization progressed the levels of auxins and gibberellins increased whereas the levels of growth inhibitors decreased. The pattern of growth regulator changes was almost similar in both the cultivars. Vernalization seemingly controls the balance between growth promoting and growth inhibiting substances in winter wheat.     

冬小麦春化过程中低温诱导的与花芽分化相关的mRNA和蛋白质的合成

应用SDS电泳及高分辨双向电泳技术,分析了冬小麦经春化、脱春化及超期春化处理后茎类蛋白质组分的变化。发现52.5,38kD和16.2kD蛋白质与冬小麦开花诱导密切相关。mRNA体外翻译结果表明,春化作用中低温诱导与开花紧密相关的mRNA的出现有一定的顺序性。因此推测:春化诱导开花是低温导致某些特定基因表达的结果,而表达的调节主要发生在转录水平上。     

黄淮南片冬麦区主导品种春化基因及冬春性分析

以1950～2007年黄淮南片冬麦区的127个主导小麦品种为材料,利用第5同源群的春化基因分子标记对其进行了春化基因检测,并分析了小麦品种的春化基因与其冬春性的对应关系及黄淮南片冬麦区8次品种更换中春化基因与品种冬春性的演变规律.结果表明,参试品种中没有品种携带显性Vrn-A1基因,7个品种含有Vrn-B1基因(5.5%),2个品种含有Vrn-B1+Vrn-D1基因(1.6%),56个品种含有Vrn-D1基因(44.1%).春化基因类型与品种冬春特性基本相符,春化基因控制着小麦品种的冬春特性.主导品种含春化显性基因频率的变化趋势与冬春性变化规律存在较大差异,与传统方法相比,仅用春化基因来确定品种冬春性存在一定的不完善之处.采用春化基因分子标记与传统的冬春性鉴定方法相结合来认识品种冬春性、预测品种的抗寒性对黄淮南片冬麦区的小麦品种利用更具有指导意义.     

小麦春化发育的分子调控机理研究进展

春化发育特性是小麦品种的重要性状,直接影响着小麦品种的种植范围和利用效率.本文就小麦春化相关基因的发现,以及对春化相关基因VRN1、VRN2和VRN3的克隆、表达特性以及春化发育分子调控机理方面的研究进展进行了综述.     

Expression of Vernalization Genes in Near-lsogenic Wheat Lines: Duration of Vernalization Period

Vernalization periods ranging from 0 to 11 weeks at 4 °Cwere used to study the reproductive development of four near-isogeniclines of wheat (Triticum aestivum L. em. Thell). From the resultsfor days to anthesis two types of gene action were identified,a threshold (all-or-nothing) response (vrn3 and/or vrn4) anda cumulative (graded) response (vrn1). The action of anothergene (vrn2) intensified these two responses. Based on the actionof genes, a model relating days to anthesis to genotype wasderived. Final leaf number and days to anthesis were shown tobe closely related after adjusting for differences due to theduration of vernalization treatment. No relationship betweendays to anthesis and spikelet number was observed. This studyemphasises the need to understand vernalization at the levelof the gene in terms of responses and interactions. Such knowledgeshould enable the plant breeder to predict and more preciselycontrol reproductive development. Triticum aestivum L., wheat, vernalization, gene action, isogenic lines     

The Effect of Restricted Germination during Vernalization on First Leaf Length of Winter Rye

Winter rye grain was vernalized, using the restricted moisturetechnique, at various temperatures and moisture levels and therelation between first-leaf blade length and the degree of vernalizationanalysed. There was an inverse relation between these two factors,but leaf length was influenced by both temperature and moisturelevel in a manner quite different from the effect on the vernalizationtemperatures and the major requirement for short-leaf productionproved to be the period of restricted germination normally imposedduring vernalization. Cell counts of the epidermis of the firstleaf blade showed that the reduction in length was due to inhibitionof the earliest phase of leaf extension growth. It is suggested that some growth-promoting substance in theembryo, possibly IAA, is broken down during the restricted germinationperiod. When grain is sown this shortage impedes early leafextension until the level is restored by synthesis or translocation.     

Temperature Response of Vernalization in Wheat: Modelling the Effect on the Final Number of Mainstem Leaves

This paper outlines a modelling approach which predicts theeffect of both continuous and intermittent low temperature regimeson the final number of leaves in winter wheat. The model takesaccount of the balance between the concurrent processes of leafprimordium initiation and rate of saturation of vernalization,and their response to temperature. The inverse of the time tosaturation of vernalization, at which stage final leaf numberis set, is modelled as a linear function of vernalizing temperature,between 0 and 17 °C. The rate of leaf primordium initiationis modelled using the established linear relationship betweenrate and temperature above 0 °C. Final leaf number is hencethe product of the number of leaf primordia initiated once vernalizationis saturated. In the model, genotypes are characterized by (1)the slope and intercept of the linear response of the rate ofsaturation of vernalization to temperature in the vernalizingrange, and (2) by a development rate towards floral transitionat on-vernalizing temperatures (above 17 °C). The modelis tested against data from experiments where six cultivarsof winter wheat plants of different ages were exposed to a rangeof low temperature regimes, including continuous and intermittentvernalizing temperatures. Overall, the model predicted, withr ²values of 70–90%, the final leaf number across a rangeof six to 21 leaves. Prediction of final leaf number for somecultivars was better in continuous than in intermittent vernalizingregimes. This modelling approach can explain the often-conflictingreports of the effectiveness of different temperatures for vernalization,and the interaction of plant age and vernalization effectiveness. Triticum aestivum L.; wheat; vernalization; rate; temperature; leaf number; modelling; phenology; flowering     

Effect of Photoperiod on the Regulation of Wheat Vernalization Genes VRN1 and VRN2

Wheat is usually classified as a long day (LD) plant because most varieties flower earlier when exposed to longer days. In addition to LD, winter wheats require a long exposure to low temperatures (vernalization) to become competent for flowering. Here we show that in some genotypes this vernalization requirement can be replaced by interrupting the LD treatment by 6 weeks of short day (SD), and that this replacement is associated with the SD down-regulation of the VRN2 flowering repressor. In addition, we found that SD down-regulation of VRN2 at room temperature is not followed by the up-regulation of the meristem identity gene VRN1 until plants are transferred to LD. This result contrasts with the VRN1 up-regulation observed after the VRN2 down-regulation by vernalization, suggesting the existence of a second VRN1 repressor. Analysis of natural VRN1 mutants indicated that a CArG-box located in the VRN1 promoter is the most likely regulatory site for the interaction with this second repressor. Up-regulation of VRN1 under SD in accessions carrying mutations in the CArG-box resulted in an earlier initiation of spike development, compared to other genotypes. However, even the genotypes with CArG box mutations required LD for a normal and timely spike development. The SD acceleration of flowering was observed in photoperiod sensitive winter varieties. Since vernalization requirement and photoperiod sensitivity are ancestral traits in Triticeae species we suggest that wheat was initially a SD–LD plant and that strong selection pressures during domestication and breeding resulted in the modification of this dual regulation. The down-regulation of the VRN2 repressor by SD is likely part of the mechanism associated with the SD–LD regulation of flowering in photoperiod sensitive winter wheat. These authors contributed equally to this work     

春化处理控制冬小麦的小穗发育

春化作用是决定冬性及二年草本植物成花和穗化的一个关键生理过程,通过用不同时间的前期低温处理,观察对冬小麦（Triticum aestivum L.)后期形态建成中穗分化启动,小花发育及结实率的影响,发现前期低温处理对穗启动分化的早晚具有决定作用,春化时间越长,穗分化启动越早,较长时间低温有利于促进穗分化,在实验室低温处理条件下,促进小花分化和提高结实率的最佳春化处理时间是45d左右,实验观察表明,春化处理促进小麦生长锥分化启动时间和分化速率,减少小穗退化,这一结果表明了春化处理不仅是冬小麦开花启动过程所必需的,而且是花序正常发育过程和顶部与基部小穗完全结实所不可缺少的。     

Vernalization,a Switch in Initiation of Flowering,Promotes Differentiation and Development of Spikelet in Winter Wheat

Vernalization is a decisive physiological process for heading, flowering and graining of biennial plants. Variable duration of low-temperature treatment has effects on lateral morphogenesis, such as spike initiation, floral development and graining rate in winter wheat ( Triticum aestivum L.). The investigation data showed that the duration of vernalization treatment was a decisive factor for the initiation of spike relevant to the time of initiation; the longer the duration at low temperature, the earlier the spike initiation in winter wheat. In the process of the spike differentiation, relatively lower temperature and longer differential time benefited for spike differentiation. Under laboratory condition, a low-temperature treatment for 45 d was optial for flower differentiation and graining in winter wheat. It is novelly recognized that vernalization treatment is essential for development of both spikes and spikelets, besides for promoting initiation of differentiation in winter wheat.     

FLC基因表达在植物春化过程中的作用

在对以往有关不同开花途径研究简要总结的基础上综述了FLC基因在春化过程中的作用。近期以拟南芥不同生态型和突变体为模式的研究结果表明基因FLC可能是春化反应的关键基因。研究发现 ,FLC的表达水平与植株低温处理的时间呈数量关系 ,低温处理时间越长 ,FLC的表达越弱 ,去甲基化也可能对FLC起负调控的作用。同时FLC也存在于自主开花途径中 ,与其他基因共同作用以调节植株开花时间。而FLC的表达对开花起抑制作用。一系列研究表明 ,春化的低温作用可能在于相关基因的去甲基化 ,消除了FLC对开花的抑制作用 ,从而解除赤霉素合成途径的封锁最终导致植株在一定时期开花。     

FLC基因表达在植物春化过程中的作用

在对以往有关不同开花途径研究简要总结的基础上综述了FLC基因在春化过程中 的作用。近期以拟南芥不同生态型和突变体为模式的研究结果表明基因FLC可能是春化反应的关键基因。研究发现,FLC的表达水平与植株低温处理的时间呈数量关系,低温处理时间越长,FLC的表达越弱,去甲基化也可能对FLC起负调控的作用。同时FLC也存在于自主开花途径中,与其他基因共同作用以调节植株开花时间。而FLC的表达对开花起抑制作用。一系列研究表明,春化的低温作用可能在于相关基因的去甲基化,消除了FLC对开花的抑制作用,从而解除赤霉素合成途径的封锁最终导致植株在一定时期开花。     

Influence of Vernalization and Photoperiod on Supernumerary Spikelet Expression in Wheat

Two tetraploid (Triticum turgidum L.emend gr. turgidum and gr.durum) and five hexaploid wheats (Triticum x aestivum L. emendgr. aestivum) with reported tendencies for ‘branched heads’(supernurnerary spikelets) exhibited variation in its expressionunder different vernalization photoperiod and temperature regimes. Two main types of supernumerary spikelets were identified, multiplesessile spikelets (MSS) with two or more complete spikeletsat a rachis node and indeterminate rachilla spikelets (IRS)with two to 13 spikelets on an extended rachilla. The degree of supernumerary spikelet expression in wheats withvernalization response differed from those without. Short photoperiods(9–14 h) both outdoors and in a glasshouse environment,were more conducive to supernumerary spikelet expression than24 h photoperiod in both environments. The 24 h photoperiodglasshouse environment (higher mean temperatures) was leastconducive to its expression except in lines with a strong vernalizationresponse. The high stability of supernumerary spikelet expression in certaingenotypes in the different environments indicated the feasibilityof incorporating this character in breeding and selecting commercialwheats to increase grain number per head. Triticum, wheat, ear-branching, supernumerary spikelets, vernalization, photoperiod, temperature     

The Effects of Vernalization on the Growth of the Wheat Shoot Apex

he effect of vernalization on the growth of the wheat shootapex was examined by comparing three genetic lines of ChineseSpring (CS) wheat having strong [CS (Hope 5D)], medium (CS Euploid),or no [CS (Hope 5A)] vernalization requirement. The mean volumeof the apical dome increased gradually in all lines, and thenthe apical dome enlarged rapidly as its relative growth rate(RGR) increased prior to double ridge formation. Phytomer volumeat initiation remained constant, so that the ratio of phytomerto apical dome at primordium initiation decreased in successiveplastochrons. In CS Euploid and in unvernalized CS (Hope 5D),the RGR of the apical dome tended to decrease at least untilinitiation of the collar primordium. The rate of primordiuminitiation at double ridge formation increased in proportionto the RGR of the apex at that time; i.e. it increased greatlyin CS (Hope 5A) and vernalized CS (Hope 5D), less so in CS Euploid,but no increase was observed in unvernalized CS (Hope 5D). Thetime of formation of double ridges seemed to be independentof the growth rate or size of the apical dome. The number oftillers present at ear emergence was inversely proportionalto vernalization requirement and was reduced by vernalization.Vernalization resulted in a decrease in the RGR of the newly-initiatedleaf primordia in relation to the RGR of the apical dome andthe axial part of the phytomer. Transfer of plants from longto short days at various times during growth showed that vernalizationincreased the number of labile primordia which could developinto either leaf, collar or spikelet. Vernalization thereforeseems to alter the ability of the apex to respond to subsequentphotoperiod rather than to affect its growth directly. Triticum aeslivum, wheat, chromosome substitution lines, shoot apex growth, vernalization     

Reanalysis of Vernalization Data of Wheat and Carrot

Vernalization is an important determinant of the growth, development,and yield of biennial and perennial crops. Accurate simulationof its response to temperature is thus an important componentof successful crop systems modelling. Vernalization has a lowoptimum temperature compared to other temperature responsesof plants, and thus may be difficult to treat using expressionsthat are appropriate for other plant processes. This paper examinesthe application of a simple equation that has been used forother processes. It reads as v=V_max(T_max-T_{Tmax- Topt} ) (T_Topt)^{T_optTmax-T_opt}, where v is thedaily rate of vernalization progress at temperature T, T_optandT_maxare the optimum and maximum temperatures for vernalization,respectively, andV_max is the maximum daily rate of vernalization(the inverse of the minimum number of days required to completevernalization), which occurs at T_opt. The model was appliedto published vernalization data for wheat and carrot. The fitsto data were good (adjusted R²for wheat of 0.94, for carrot0.98), with estimatedT_opt and T_maxbeing 5.7±0.5 and 21.3±1.4°C, respectively, for wheat ‘Norin 27’ and 6.6±0.2and 14.1±0.3 °C for carrot ‘ Chantenay RedCored’. The estimated parameters, in particular the highT_maxfor wheat, were close to those reported using differentanalytical approaches. It was suggested that the function wouldbe useful for summarizing vernalization data, and that its usewould avoid the abrupt changes that are inevitable when differentlinear relationships are used for part of the overall response.It was also suggested the high T_maxshould be taken into accountwhen interpreting data obtained with wheat grown under warmconditions. Copyright 1999 Annals of Botany Company Plant, vernalization, temperature response, modelling, wheat (Triticum aestivum L.), carrot (Daucus carota L.).     

Zearalenone-Like Substance in Winter Plants and Its Relation to Vernalization

It was found that there is a zearalenone-like substance in the growing points of vernalized wheat seedlings and carrot plants. The content of this substance synchronously increased with the depth of vernalization. It was separated by thin layer chromatography. Its UV spectrum was similar to that of zearalenone. It is believed that this substance may be one of the important endogenous substances which control the vernalization of winter plants.     

Genotype Differences in Photoperiodic Sensitivity and Vernalization Response in Wheat

The regression of final leaf number on leaf number at transferfrom an 8 h to an 18 h photoperiod was used to compare the photoperiodicresponse of eight locally-adapted lines of wheat. Comparisonsof such regressions in the vernalized and univernalized conditionsenabled detection of the presence or absence of a significantcultivar vernalization response and comparisons of differingresponses between cultivars. Prior vernalization generally did not significantly alter the‘rate’ of photoperiodic response, as the slope ofthe LNT/FLN regression, indicating a certain physiological independenceof vernalization and photoperiodic responses in wheat. Differences, both in photoperiodic and vernalization responseof the eight wheats studied have been discussed in terms ofadaptability and breeding for maturity alteration in wheat.Evidence has been produced for the possible existence of a thirdfactor influencing developmental processes associated with floweringin wheat.     

Changes of Soluble Protein Components in Winter Wheat (Triticum aestivum L.) Shoots During Vernalization and its Relation to Morphogenesis

Winter wheat “Nong Da 139” and spring wheat “Zhong 8022” were used for this experiment. The effect of low temperature treatment at different periods on protein content and composition of the seedling shoots as well as subsequent development was studied. The main results are as follows: 1. More than 40 days of vernalizing treatment were required for a rapid and uniform earing by winter wheat “Nong Da 139”. After 14–21 days vernalization, the winter wheat is possible to ear in summer, but in an irregular manner. The results indicate that during the whole vernalization process, the effect of low temperature on earing development varies with the duration of treatment. At the earlier stage, it is likely that the Iow temperature induces a change in physiological process, and in the later stage, it only accelerates the development. It is there- fore, suggested that there are two distinct processes existing during vernalization. The transformation from the former to the latter state appears to occur at the middle period of vernalization process. 2. The protein metabolic inhibitors, such as ethionine and p-fluorophenylalanine, interfere with the vernalizing process of winter wheat also at its middle period. 3. With low temperature treatment for different periods, the soluble protein content and composition are found to be changed in winter wheat shoots. At the middle-stage of vernalization (after 14 days low temperature treatment), not only is the content of protein increased twice as compared with the control, but new proteins (on electrophorestic gel) are also produced. On the contrary, there was no difference in protein bands for spring wheat. Spring wheat not to be treated by low temperature, has already possessed the proteins that appeared in vernalized winter wheat shoots. These results demonstrated that the days of 14–21 are the critical time for the vernalization of the winter wheat. The new proteins synthesized at this stage might be the factor of the determination whether or not the plants will transform from vegetative stage into reproductive phase.     

Temperature Response of Vernalization in Wheat: A Developmental Analysis

The vernalization response of wheat ( Triticum aestivum L.)was reinterpreted from a developmental perspective, using currentconcepts of the developmental regulation of wheat morphologyand phenology. At temperatures above 0 °C, the effects ofthe process of vernalization per se in wheat are confoundedby the effects of concurrent vegetative development. These effectsare manifested by differences in the number of leaves initiatedby the shoot apex prior to floral initiation, which in turnaffects the subsequent rate of development to ear emergenceand anthesis. Leaf primordia development during vernalizationand total leaf number at flowering were used to develop criteriato define both the progress and the point of saturation of thevernalization response. These criteria were then used to reinterpretthe results of Chujo ( Proceedings of the Crop Science Societyof Japan 35 : 177–186, 1966), and derive the temperatureresponse of vernalization per se for plants grown under saturatinglong day conditions. The rate of vernalization increased linearlywith temperature between 1 and 11 °C, such that the timetaken to saturate the vernalization response decreased from70 d at 1 °C to 40 d at 11 °C. The rate declined againat temperatures above 11 °C, and 18 °C was apparentlyineffective for vernalization. Total leaf number at saturation,however, increased consistently with temperature, as a resultof the balance between the concurrent processes of leaf primordiuminitiation and vernalization. Total leaf number at saturationincreased from 6 at 1 °C to 13.3 at 15 °C, which inturn influenced the time taken to reach ear emergence. The advantagesof using this developmental interpretation of vernalizationas the basis for a mechanistic model of the vernalization responsein wheat are discussed. Triticum aestivum L.; wheat; vernalization; rate; temperature; primordia; leaf number; flowering