Barley FASCIATED EAR genes determine inflorescence meristem size and yield traits

In flowering plants,the inflorescence meristem(IM)provides founder cells to form successive floral meristems,which are precursors of fruits and seeds.The activity and developmental progression of IM are thus critical for yield production in seed crops.In some cereals,such as rice(Oryza sativa)and maize(Zea mays),the size of undifferentiated IM,which is located at the inflorescence apex,is positively associated with yield traits such as spikelet number.However,the relationship between IM size and yieldrelated spike traits remains unknown in the Triticeae tribe.Here we report that IM size has a negative correlation with yield traits in barley(Hordeum vulgare).Three FASCIATED EAR(FEA)orthologs,HvFEA2,HvFEA3,and HvFEA4,regulate IM size and spike morphogenesis and ultimately affect yield traits.Three HvFEAs genes are highly expressed in developing spikes,and all three loss-of-function mutants exhibit enlarged IM size,shortened spikes,and reduced spikelet number,which may lead to reduced grain yield.Natural variations identified in HvFEAs indicate selection events during barley domestication.We further reveal that HvFEA4,as a transcription factor,potentially targets multiple pathways during reproductive development,including transcriptional control,phytohormone signaling,and redox status.The roles of barley FEA genes in limiting IM size and promoting spikelet formation suggest the potential of increasing yield by manipulating IM activity.

B Class Floral Homeotic Genes are Involved in the Petal Identity and Flower Meristem Determinations in Chrysanthemum morifolium

Chrysanthemum morifolium,an ornamental crop with diverse forms of inflorescence,is a good model for studying flower development in Asteraceae.However,the genetic background is complex and the mechanisms of regulating flower development are still unclear.Here,we identified two natural mutant lines of chrysanthemum and named them M1 and M2 according to the severity of the phenotype.Both lines showed defects in petal identity,and the petals of the M1 line had a mild phenotype:partially loss of petal identity and conversion of petals into green,leaf-like organs.The M2 line had severe phenotypes:in addition to severe petal defects,secondary inflorescences were produced in the capitulum to replace the normal ray and disc florets,which indicated a transformation of a flower meristem into an inflorescence meristem.Transcriptome sequencing of WT and M2 inflorescences was performed and found altered expression of floral organ development A,B and E class genes,where B and E class genes were significantly down-regulated.qRT-PCR analysis in both M1 and M2 lines revealed that the expression of three chrysanthemum class B genes CmAP3.1,CmAP3.2 and CmPI,was negatively correlated with phenotypic severity.This suggests that class B genes in chrysanthemum not only have conserved functions in determining petal identity but also were involved in the determinacy of the flower meristem.This study provides insights into the functions of class B genes in flower development,and is informative for dissecting the molecular mechanisms of flower development in chrysanthemum.

激素调控植物分枝/分蘖的研究进展

分枝/分蘖是植物株型的一个重要特征,也是腋芽起始和芽生长的结果,对经济作物的种子产量以及牧草产量均具有决定性作用。多种激素及其互作效应在植物分枝/分蘖的发生和生长发育过程中起着关键的调控作用,且环境因素也是通过改变植物体内激素含量及其平衡调控分枝的。本研究综述了多种激素对植物分枝/分蘖调控机制的多个方面,包括生长素、细胞分裂素、独脚金内酯、油菜素内酯、脱落酸和赤霉素、乙烯、茉莉酸及不同激素信号相互作用形成的复杂调控网络,旨在为利用激素调控机制培育具有理想株型的高产新作物品种奠定基础。同时分析了激素机制调控植物分枝/分蘖的现存问题,并展望了激素调控植物分枝/分蘖的研究方向,以期为通过激素调控改良作物株型提供理论依据。

小肽调控植物分生组织发育的机制及其在作物改良中的研究进展

在高等植物的生长发育过程中,根尖分生组织和茎尖分生组织不断分裂分化产生根系、茎、叶和花等器官,分别形成植物的地上和地下部分。小肽是胞间通讯的关键信号分子之一,参与了植物生长发育、抗病抗逆等诸多生命活动,其中包括植物根尖和茎尖分生组织的干细胞活性调控,进而影响了植物器官的生成和发育。近年来,越来越多的研究揭示了小肽分子在分生组织维持和发育中的重要性,及其在多种作物农艺性状调控中的关键作用。本文综述了小肽及其受体在拟南芥和作物中维持分生组织稳态的分子机制,探讨了小肽对作物产量性状的影响及在作物改良中的应用策略,并对小肽领域的研究方向进行了分析和展望。

The AGL6-like gene OsMADS6 regulates floral organ and meristem identities in rice

Although AGAMOUS-LIKE6 (AGL6) MADS-box genes are ancient with wide distributions in gymnosperms and angiosperms, their functions remain poorly understood. Here, we show the biological role of the AGL6-1ike gene, OsMADS6, in specifying floral organ and meristem identities in rice (Oryza sativa L.). OsMADS6 was strongly ex- pressed in the floral meristem at early stages. Subsequently, OsMADS6 transcripts were mainly detectable in paleas, lodicules, carpels and the integument of ovule, as well as in the receptacle. Compared to wild type plants, osmads6 mutants displayed altered palea identity, extra glume-like or mosaic organs, abnormal carpel development and loss of floral meristem determinacy. Strikingly, mutation of a SEPALLATA (SEP)-like gene, OsMADS1 (LHS1), enhanced the defect of osmads6 flowers, and no inner floral organs or glume-like structures were observed in whorls 2 and 3 of osmadsl-z osmads6-1 flowers. Furthermore, the osmadsl-z osmads6-1 double mutants developed severely indetermi- nate floral meristems. Our finding, therefore, suggests that the ancient OsMADS6 gene is able to specify "floral state" by determining floral organ and meristem identities in monocot crop rice together with OsMADS1.

Determination of the Photoperiod-Sensitive Inductive Phase in Maize with Leaf Numbers and Morphologies of Stem Apical Meristem

It is vital to determine the effective photoperiods of maize for making full use of tropical germplasm, which is the foundation for determining the effect of latitude and planting date on the development of photoperiod-sensitive maize cultivars. The objective of this study is to determine the photoperiod-sensitive inductive phase using reciprocal transfer between long- day （LD） （15 h d^-1） and short-day conditions （SD） （9 h d^-1）. For Huangzao 4 and CML288, days to tassel and pollen shedding were recorded, and stem apical meristems （SAM） were observed by a laser scanning confocal microscope. The results show that the seedlings are insensitive to photoperiod when they are very young （juvenile）. However, after this period, LD delays flowering and increases the leaf numbers below the inflorescence, and the length of the interval of the photoperiod-sensitive inductive phase is longer under LD conditions than under SD conditions. Transferred from SD to LD, plants show a sudden decrease in leaf numbers once sufficient SD has been received for flower commitment. While transferred from LD to SD, plants have a continuous increase in leaf numbers during the photoperiod sensitive inductive phase under LD conditions. At the same time, when plants are competent to flowers, the obvious morphology is the elongation of maize SAM. There is an obvious variance of the photoperiod sensitive phase under LD and SD conditions in different maize.

AtCDC5 regulates the G2 to M transition of the cell cycle and is critical for the function of Arabidopsis shoot apical meristem

作为一个房间周期管理者， Myb 相关的 CDC5 蛋白质被报导为在酵母和动物的房间周期的 G2 阶段必要，但是很少在植物对它的功能被知道。这里，我们在 Arabidopsisthaliana 报导 CDC5 基因的功能的描述。Arabidopsis CDC5 (AtCDC5 ) 主要与高细胞分裂活动在纸巾被表示，并且在整个胚胎形成的全部过程被表示。AtCDC5 loss-of-functionmutant 是胚胎的致命。以便调查 AtCDC5 体内的函数，我们 AtCDC5 的表达式被 RNA 干扰在减少的 generatedAtCDC5-RNAi 植物。我们发现到 M (G2/M ) 阶段转变的 G2 在 AtCDC5-RNAi 植物被影响，并且 thatendoreduplication 被增加。另外，射击顶端分生组织(SAM ) 的维护功能在 AtCDC5-RNAi 植物被扰乱，在哪个 WUSCHEL (WUS )-CLAVATA (CLV ) 和射击无分裂组织(STM ) 小径被损害。原位杂交分析证明 STM 的表示极大地在 AtCDC5-RNAi 植物的射击顶端细胞被减少。而且， cyclinB1 或 Histone4 被发现当时，在一些这些房间被表示 STMwas 的抄本无法发现。这些结果建议 AtCDC5 为 G2/M 阶段转变是必要的并且可以由控制 STM 和 WUS 的表示调整 SAM 的功能。

The GhREV transcription factor regulate the development of shoot apical meristem in cotton(Gossypium hirsutum)

Background:Manual topping is a routine agronomic practice for balancing the vegetative and reproductive growth of cotton(Gossypium hirsutum)in China,but its cost-effectiveness has decreased over time.Therefore,there is an urgent need to replace manual topping with new approaches,such as biological topping.In this study,we examined the function of Gh REV transcription factors(a classⅢhomeodomain-leucine zipper family,HD-ZIPⅢ)in regulating the development of shoot apical meristem(SAM)in cotton with the purpose of providing candidate genes for biological topping of cotton in the future.Results:We cloned four orthologous genes of At REV in cotton,namely Gh REV1,Gh REV2,Gh REV3,and Gh REV4.All the Gh REVs expressed in roots,stem,leaves,and SAM.Compared with Gh REV1 and Gh REV3,the expression level of Gh REV2 and Gh REV4 was higher in the SAM.However,only Gh REV2 had transcriptional activity.Gh REV2 is localized in the nucleus;and silencing it via virus-induced gene silencing(VIGS)produced an abnormal SAM.Two key genes,Gh WUSA10 and Gh STM,which involved in regulating the development of plant SAM,showed about 50%reduction in their transcripts in VIGS-Gh REV2 plants.Conclusion:Gh REV2 positively regulates the development of cotton SAM by regulating Gh WUSA10 and Gh STM potentially.

The Wheat Plastochron Mutant, fushi-darake, Shows Transformation of Reproductive Spikelet Meristem into Vegetative Shoot Meristem

In wheat plants at the vegetative growth stage, the shoot apical meristem (SAM) produces leaf primordia. When reproductive growth is initiated, the SAM forms an inflorescence meristem (IM) that differentiates a series of spikelet meristem (SM) as the branch. The SM then produces a series of floret meristem (FM) as the branch. To identify the mechanisms that regulate formation of the reproductive meristems in wheat, we have investigated a leaf initiation mutant, fushi-darake (fdk) which was developed by ion beam mutagenesis. The morphological traits were compared in wild type (WT) and fdk mutant plants grown in the experimental field. WT plants initiated leaves from SAM at regular intervals in spiral phyllotaxy, while fdk plants had 1/2 alternate phyllotaxy with rapid leaf emergence. The fdk plants have increased numbers of nodes and leaves compared with WT plants. The time interval between successive leaf initiation events (plastochron) was measured in plants grown in a growth chamber. The fdk plants clearly show the rapid leaf emergence, indicating a shortened plastochron. Each tiller in fdk plants branches at the upper part of the culm. The fine structure of organ formation in meristems of fdk plants was examined by scanning electron microscopy (SEM). The SEM analysis indicated that fdk plants show transformation of spikelet meristems into vegetative shoot meristems. In conclusion, the fdk mutant has a heterochronic nature, i.e., both reproductive and vegetative programs were simultaneously in operation during the reproductive phase, resulting in a shortened plastochron and transformation of reproductive spikelets into vegetative shoots.

Efficient Regeneration System for Genetic Transformation of Mulberry (<i>Morus indica</i>L. Cultivar S-36) Using <i>in Vitro</i>Derived Shoot Meristems

Shoot meristems used for the study were exercised from the in vitro regenerated shoots cultured on MS medium supplemented with 0.5 mg/L of BAP for multiplication. The sensitivity of the in vitro regenerated was studied using shoot meristems of 0.5 cm. Shoot meristems were cultured on medium containing 10-100 mg/l kanamycin to determine the concentration that was lethal for multiple shoot induction and root induction. The response of shoot multiplication decreased (66.2%-6.2%) as the concentration of kanamycin increased (10.0-70.0 mg/L) with complete inhibition of shoot proliferation at 100 mg/L kanamycin. The rooting phase was very sensitive to kanamycin compared to shoot multiplication. The percentage of shoots that rooted decreased (53.8%-4.8%) with increase in the concentration of kanamycin (10.0-70.0 mg/l) on IBA and 2,4-D supplemented medium. For transformation studies, the shoot tips that were infected with Agrobacterium strain were placed on selection medium containing MS medium with 0.5 mg/L BAP and 100 mg/L kanamycin and scored for the putative transformed shoots. An average of 62.2% of shoot tips developed shoot buds from the base and the shoots reached a length of 0.5-1.0 cm at the end of 30 days of culture on the selective medium in comparison to control which showed no response. An average of 66.7% of the regenerated plants showed GUS expression on selection medium where 43.2% and 65% of GUS expression was recorded in the leaves and callus. Leaves and callus induced from the controls did not show GUS activity. Stable integration of nptII gene with the genomic DNA from these transformed plants was confirmed through PCR analysis. Our result presents an efficient regeneration system using in vitro derived shoot meristems for Agrobacterium mediated gene transfer.

Floral Organogenesis and Ring Meristem in <i>Phytolacca</i>

To further study the floral organogenesis and discussing the floral origin of Phytolacca, the procedures of floral organogenesis were observed in Phytolacca esculenta and Phytolacca zhejiangensis. The results showed that the floral organogenesis was consistent in Phytolacca. Their sepals were 2/5 helix, and with counter-clockwise and clockwise, usually the first sepal located at non-median of abaxial side. The first sepal of Phytolacca esculenta was initiated at non-median of adaxial side. There was no evident relationship between sepal and stamen initiating position, and the stamens initiated on ring meristem, they initiated approximately at the same time, and when the androecium member was numerous, they initiated centrifugally, the outer stamen initiated irregularly. Carpel initiated alternately with inner stamens. And the carpels connected by septum, if the septum grew more, the carpel was syncarpous at morphology, otherwise the carpel was apocarpous at morphology. So the syncarpous and the apocarpous have no successively relationship on evolution. Ovule initiated inside the carpel and opposite to carpel. Androecium, carpel and ovule initiated at ring meristem.

Generation of Virus Free Potato Plantlets through Meristem Culture and Their Field Evaluation

Different aspects of micropropagation through meristem culture for the production of virus indexed source plants, in vitro tuberization and field evaluation of the in vitro regenerated plants were studied on four commercial cultivars of potato (Solanum tuberosum L.) viz., Diamant, Cardinal, Shilbilati and Lalpakri. The investigation was conducted at Rajshahi, Bangladesh from December 2010 to March 2012 to produce virus-free potato plantlets through meristem culture, shoot multiplications with root induction as well as their acclimatization and evaluation of morphological characters and tuber yield under field condition. Shoot tips of 25 - 30 day old field-grown plants of above mentioned four cultivars were used for meristem isolation. After isolation, meristems of these varieties of potato were cultured on “M” shaped filter paper bridge in Murashige and Skoog (MS) liquid medium. Four different treatments of media formulations viz. 0.1 mg/L KIN + 0.1 mg/L GA3, 0.1 mg/L KIN + 0.5 mg/L GA3, 0.5 mg/L KIN + 0.1 mg/L GA3 and 0.5 mg/L KIN + 0.5 mg/L GA3 were used as plant growth regulators. From these formulations MS + 0.1 mg/L KIN + 0.5 mg/L GA3 was found to be the best for the primary establishment of meristem culture. The primarily established meristems were subcultured on to MS semisolid basal medium supplemented with four different treatment combinations of hormones viz. 0.5 mg/L BA + 1.0 mg/L IBA;0.1 mg/L KIN + 0.1 mg/L GA3;0.5 mg/L BA + 0.5 mg/L GA3 and 0.5 mg/L KIN + 0.5 mg/L GA3 were used to identify the suitable media compositions for shoot proliferation. Results showed that out of these four media treatments the formulation 0.5 mg/L BA + 0.5 mg/L GA3 was found to be the best suitable for shoot generation. Among the four cultivars of potato higher frequency of shoot proliferation (number of shoots/explant and longest shoot length) was observed in Diamant, though the highest shoot formation (76%) was recorded in Cardinal. Virus free in vitro grown potato plantlets were obtained through DAS-ELISA test and used substantially for micro-propagation. After gradual acclimatization of rooted plantlets of four potato cultivars, they were transferred into the field for cultivation and established successfully. It was observed from the field study of in vitro meristem-derived plantlets that there were no virus-affected plants. The virus-free exotic varieties were much superior in all vegetative attributes and yield compared to those of indigenous varieties with producing potato plants of normal height. In contrast, the indigenous varieties took a longer time to tuber initiation and maturity, lower plant height and number of leaves per plant, a higher number of tubers but a lower amount of tuber weight per plant, and poorer tuber grade than the exotic varieties. However, the variety Cardinal exposed the best performances in the context of survival percentage of plantlets (90%), days to tuber initiation (DTI), a number of leaves per plant (NL), tuber weight per plant (343.40%) and the percentage of rich tuber grade.

The Effects of Lead on the Meristem of Wheat Seedlings

The ultrastructure of apical meristem cells was studied in Triticum aestivum L. cv. “Trizo” seedlings grown on soil without or enriched with selenium and survived 14 days’ stress caused by lead pollution in the soil. The soil treatments: control—the original soil;(Pb1)—50 mg&middot;kg&minus;1;(Pb2)—100 mg&middot;kg&minus;1;(Pb1 + Se1) —0.4 mg&middot;kg&minus;1 Se added to Pb1 treated soil;(Pb1 + Se2)—0.8 mg&middot;kg&minus;1 Se added to Pb1 treated soil;(Pb2 + Se1)—0.4 mg&middot;kg&minus;1 Se added to Pb2 treated soil;(Pb2 + Se2)—0.8 mg&middot;kg&minus;1 Se added to Pb2 treated soil were used. Light and other conditions were optimal for plant growth. A distinctive feature of the cells of the apical meristem of control plants was the absence of nuclear membranes. Proplastids were membrane vesicles 1 - 2 microns in diameter, filled with contents of varying degrees of density, from membrane vesicles containing only plastid DNA up to a fully formed structure of proplastids. In (Pb1)-plants, the amount of cytoplasmic ribosomes and proplastids in the meristematic cells was less than in the control. The structure of the forming proplastids was almost the same as that of the control plants. Signs of degradation of meristematic proplastids, such as a decrease of their diameter, observed in (Pb2)-plants. The introduction of selenium into lead contaminated soil increased the accumulation of Pb in plants, especially in the roots and apical meristem. In (Pb1 + Se1)-, (Pb1 + Se2)-, (Pb2 + Se1)-, and (Pb2 + Se2)-plants, the number of cytoplasmic ribosomes in meristematic cells increased, which indirectly indicates an increase in protein synthesis. Based on our concept about the formation (assembly) of proplastids in the cells of the apical meristem, we believe that toxic agents, such as lead, which inhibit the development of proplastids into chloroplasts in mesophyll cells, act on apical meristem cells at the stage when plastid DNA is replicated in the cytoplasm and is not yet surrounded by a plastid membrane.

Genetic and environmental control of rice tillering

Increasing tiller number is a target of high-yield rice breeding. Identification of tiller-defect mutants and their corresponding genes is helpful for clarifying the molecular mechanism of rice tillering. Summarizing research progress on the two processes of rice tiller formation, namely the formation and growth of axillary meristem, this paper reviews the effects of genetic factors, endogenous hormones, and exogenous environment on rice tillering, finding that multiple molecular mechanisms and signal pathways regulating rice tillering cooperate rice tillering, and discusses future research objectives and application of its regulatory mechanism. Elucidation of theis mechanism will be helpful for breeding high-yielding rice cultivars with ideal plant type via molecular design breeding.

利用CRISPR/Cas9系统研究REVOLUTA参与烟草叶芽发育的调控

作物叶芽受到分生组织调控,调控叶芽是作物增产的有效措施之一。目前关于烟草分生组织调控的分子机理研究偏少,可用于株型改良的种质资源缺乏。本研究通过CRISPR/Cas9编辑系统靶向突变烟草REVOLUTA(REV)基因,分别构建两个不同REV单靶点序列C15NtREV和C16NtREV,通过农杆菌介导的叶盘转化方法获得再生苗,利用PCR测序鉴定转基因阳性单株,测序结果表明Ko-C15Ntrev突变体在NtREV氨基酸第26位置之后发生移码突变,而Ko-C16Ntrev突变体在NtREV氨基酸第60位置之后发生移码突变。此外,借助扫描电镜分别观测两个单靶点纯合突变体顶芽表型,结果表明烟草Ko-C15Ntrev双拷贝同源突变体出现顶芽缺失和叶片畸形的表型,而Ko-C16Ntrev单拷贝同源突变体未表现出顶芽缺失,但顶芽发育迟缓。相较于野生型烟草,Ko-C16Ntrev突变体自然株高较野生型增加3.76%,Ko-C16Ntrev突变体叶片数和腋芽鲜重分别较野生型减少21.47%和23.41%,且均达到极显著差异,说明NtREV参与烟草顶端分生组织发育,进而调节叶和腋芽发育。这些突变体为后续研究烟草的叶芽发育分子机理提供了重要研究材料。

龙葵UNUSUAL FLORAL ORGANS类SnUFO2基因C端序列的保守性对花发育的影响

【目的】UNUSUAL FLORAL ORGANS(UFO)基因属于F-box基因家族,是重要的花器官特征基因。UFO基因N端能与Skp1类基因结合形成Skp1-Cullin1-F-box(SCF)复合体,参与泛素化过程并降解C端结合的靶蛋白。为了探究C端序列对龙葵Solanum nigrum花发育的影响,本研究克隆了一个C末端缺失的SnUFO2*基因并构建其表达载体转入龙葵植株中,观察转基因龙葵植株花器官变化,从而深入探讨UFO基因完整的C末端序列在龙葵花发育中的重要作用。【方法】利用生物信息学分析软件对SnUFO2*和全长的SnUFO2比较分析,采用实时荧光定量PCR(RT-qPCR)对SnUFO2*基因在野生型龙葵植株根、茎、叶、花苞中进行表达分析;通过超表达载体的构建、转基因植株表型的观察及石蜡切片技术验证SnUFO2基因的功能。【结果】SnUFO2*基因ORF长度为1302 bp,编码433个氨基酸,与龙葵中完整的SnUFO2基因相比,其C末端缺失了23个氨基酸。RT-qPCR结果显示:SnUFO2*基因在野生型植株的花苞中特异性表达。对转基因植株的表型观察发现:35S::SnUFO2*转基因龙葵植株的花瓣向萼片转化。石蜡切片分析发现:转基因龙葵植株雄蕊缺失,雌蕊处有不确定的分生组织产生。【结论】35S::SnUFO2*转基因龙葵植株花瓣、雄蕊和心皮发育异常。C端结构缺失可能降低了SnUFO2蛋白特异性识别靶蛋白的能力,说明该基因完整的C末端对龙葵花器官发育至关重要。

胚珠原基起始的信号与分子机制研究进展

种子是高等植物的生殖器官,种子的形成对植物繁衍后代和农作物产量都至关重要。胚珠是种子的前体,胚珠原基起始是种子器官发生的过程,也是植物产生种子的起始步骤。不同植物中胚珠原基起始的方式不同,胚珠原基起始的调控机制研究主要在模式植物拟南芥中进行。拟南芥是多胚珠子房植物,一个果实中含有多个种子,胚珠原基起始对单果实种子数量和种子产量有较大的影响。胚珠原基起始于心皮边缘分生组织(CMM)分化形成的胎座上。已报道一些转录因子、调控蛋白以及重要的植物激素通过影响胎座形成参与调控胚珠原基起始及胚珠数目,最近的研究阐明了拟南芥的多个胚珠在同一胎座上分批发生的现象,并解析了生长素极性运输和信号响应的动态变化决定了胚珠原基异步起始的机制。本文首先介绍了不同植物中CMM和胎座形成过程及其调控因子;接着总结了胚珠原基起始研究的新进展,包括激素调控胚珠原基起始的信号网络,以及多胚珠原基群体起始的规律及其调控机制;最后提出了胚珠原基起始中的未决问题、未来研究方向以及在农业生产上的应用前景。

外源独脚金内酯对烟草腋芽伸长及独脚金内酯代谢途径相关基因表达的影响

通过研究外源独脚金内酯(SL)对烟草Nicotiana tabacum腋芽伸长及其SL代谢途径相关基因表达的影响,探究SL与烟草腋芽生长的关系及烟草腋芽伸长过程中SL相关基因的表达变化,为SL调控烟草腋芽生长的分子机理研究提供理论依据。采用石蜡切片和转录组技术研究烟株打顶后烟草腋芽分生组织发育及在SL生物合成类似物GR24处理下腋芽SL代谢途径相关基因表达的变化。结果表明,烟草腋分生组织由中央母细胞区(CM)、周缘分生组织(PM)和肋状分生组织(RM)三个细胞区域组成,其中CM位于腋分生组织顶端,其可通过基部及侧面细胞的分裂形成PM及RM,PM位于腋分生组织两侧,RM处于CM下方及PM内侧的位置。三个细胞区域的细胞体积、排列方式不同,说明分生组织中各部分细胞分裂存在差异性;腋分生组织发育形成腋芽后,通过外源施加不同植物生长调节剂发现,GR24能抑制1~3节位腋芽的伸长,而BR能促进腋芽伸长;转录组分析发现,SL能影响其自身代谢途径相关基因的表达,与CK和独脚金内酯合成抑制剂(TIS-108)处理相比,SL诱导D27、D14、DAD2和SMAX1-LIKE4的表达,而在TIS-108处理中D27、D14及DAD2下调表达,SMAX1的表达受到SL的抑制,而TIS-108处理诱导SMAX1的表达。烟草腋芽由腋分生组织三个细胞区域发育而来,同时,不同植物生长调节剂对烟草腋芽的影响不同,BR促进烟草腋芽的伸长,而SL抑制腋芽伸长,且在烟草腋芽伸长过程中其代谢途径相关基因可能发挥着重要的调控作用。

马铃薯新品种达芋6号茎尖培养技术研究

本试验以马铃薯新品种达芋6号为试验材料,采用正交试验方法,研究培养基中不同种类、不同浓度激素对达芋6号马铃薯茎尖培养的影响。结果表明:NAA 0.05 mg/L+6-BA 0.5 mg/L+GA_(3)0.1 mg/L的处理成苗率、苗高优于其余处理;影响达芋6号成苗率及苗高的因素重要性排序为NAA浓度>GA3浓度>6-BA浓度;最有利于达芋6号成苗的激素水平为NAA 0.05 mg/L、GA_(3)0.1 mg/L、6-BA 1.0 mg/L;最有利于达芋6号苗高生长的激素水平为NAA 0.05 mg/L、GA_(3)0.1 mg/L、6-BA 0.1 mg/L。

甘蔗茎尖脱毒组织培养技术研究进展

文章从危害甘蔗的主要病害、甘蔗茎尖脱毒技术的发展及原理、甘蔗茎尖脱毒技术在生产上的应用、影响甘蔗茎尖脱毒效率的因素等方面介绍了甘蔗茎尖脱毒组培技术,提出培养基中植物生长调节剂的绝对浓度和配比、培养基的状态及如何解决培养中的酚污染等问题仍是甘蔗茎尖脱毒培养研究的热点。由于碱性孔雀绿、2,4-D、硫尿嘧啶、TS制剂(一种病毒钝化剂)等在其他作物组织培养脱毒培养中可以提高脱毒效率,因此,今后需研究这些化学制剂在甘蔗组培脱毒中的应用效果,并继续深入研究间歇浸没式反应器和植物无糖组培快繁技术等先进技术体系在甘蔗中的应用,运用新技术新设备提高甘蔗组培生产效率并降低生产成本。