Anti-melanogenic properties of FBCC-EP850 derived from Carex pumila Thunb

Objective:To elucidate the anti-melanogenic potential of Carex pumila Thunb.extract(FBCC-EP850).Methods:A collection of 180 plant extracts was tested for inhibition of mushroom tyrosinase activity using an in vitro assay.Among them,FBCC-EP850 exhibited the most promising inhibitory activity.Further analysis was conducted to investigate its mechanisms and therapeutic potential in reducing melanogenesis in B16F10 melanoma cells and zebrafish larvae.Results:FBCC-EP850 inhibited mushroom tyrosinase activity in a dose-dependent manner,with a half-maximal inhibitory concentration of 45.83μg/mL.FBCC-EP850 at concentrations up to 50μg/mL demonstrated minimal cytotoxicity against B16F10 melanoma cells and no adverse effects on zebrafish larvae.Treatment with 50μg/mL of FBCC-EP850 significantly reducedα-melanocyte stimulating hormone-induced melanin production and suppressed cellular tyrosinase activity in B16F10 melanoma cells.Additionally,FBCC-EP850 at 25 and 50μg/mL effectively diminished hyperpigmentation inα-melanocyte stimulating hormone-stimulated zebrafish larvae.Its anti-melanogenic action could be attributed to modulation of the cAMP-CREB-MITF signaling pathway.Conclusions:Carex pumila extract can inhibit melanogenesis by modulating the cAMP-CREB-MITF signaling pathway,which can be used as a promising candidate for treating hyperpigmentation disorders.

Dissecting Multiple Arabidopsis CC-NBS-LRR Proteins Structure and Localization

NBS-LRR (nucleotide binding sites and leucine rich repeat) protein plays a crucial role as sentries and as defense activators in plants. The structure and function of NBS-LRR proteins are closely related. Previous articles have announced that the activated ZAR1 (HopZ-Activated Resistance 1) forms a pentamer in the plasma membrane, which is a calcium permeable channel that can trigger plant immune signaling and cell death. However, the structure of galore NBS-LRRs in Arabidopsis is not yet clear. The functional sites of distinct NBS-LRR in cells may vary. In addition, identifying pathogens and activating defense regions may occur in different subcellular compartments. Therefore, dissecting the specific structure and positioning of NBS-LRRs is an indispensable step in understanding their functions. In this article, we exploit AlphaFold to predict the structure of some designed NBS-LRRs, and utilize Agroinfiltration transient expression system, combined with biochemical fractionation, to dissect the localization of these NBS-LRR receptors from Arabidopsis. Structural data indicates that the identified NBS-LRRs share analogous conformation. Membrane fractionation assay demonstrates these NBS-LRRs are mainly associated with the membrane. These data show that the Ca2+-permeable channel activity may be evolutionarily conserved in NBS-LRR of Arabidopsis, and this study provides some reference clues for analyzing the structure and localization patterns of other plant immune receptors.

Expression Pattern, Interaction Network, and Functional Analysis of the Arabidopsis Botrytis Susceptible1 Interactor

E3 ubiquitin ligases are participated in numerous processes, regulating the response to biotic and abiotic stresses. Botrytis susceptible1 interactor (BOI) is a RING (Really Interesting New Gene)-type E3 ligase that mediates the ubiquitination of BOS1 (Botrytis susceptible1), a transcription factor involved in stress and pathogen responses. Although BOI is an E3 ligase, there are reports to show that BOI interacts with target proteins such as DELLAs or CONSTANS to repress gibberellin responses and flowering without the degradation of the target proteins. In this article, we utilize diversified methods to comprehensively analyze the expression pattern, interaction network and function of BOI gene. Firstly, 1800 bp upstream region of BOI gene from Arabidopsis thaliana (Arabidopsis) genome was isolated, and fused GUS reporter gene. The resulting expression cassette was introduced into wild-type Arabidopsis through Agrobacterium-mediated transformation. The result demonstrated that BOI gene was expressed predominantly in leaves, siliques, young roots, and flowering tissues, indicating that BOI gene may be involved in multiple processes in plant growth and development in Arabidopsis. Besides, eight candidate interacting proteins were obtained from the Arabidopsis cDNA library via yeast two-hybrid technology, including EXO70E2 (AT5G61010), WRKY7 (AT4G24240), WRKY11 (AT4G31550), WRKY17 (AT2G24570), UBP20 (AT4G17895), L5 (AT1G12290), SAUR9 (AT4G36110) and TCP21 (AT5G08330). Functional analysis of these candidate interacting proteins manifested that they related to multiple pathways, including biological and abiotic stress, programmed cell death, protein degradation, material metabolism and transcriptional regulation. In addition, the results of the transient assay proclaimed that BOI protein affects the protein stability of EXO70E2 and L5 through its E3 ubiquitin ligase activity. Our results provide novel clues for a better understanding of molecular mechanisms underlying BOI-mediated regulations.

The NAC Transcription Factor ANAC089 Modulates Seed Vigor through the ABI5-VTC2 Module in Arabidopsis thaliana

Seed viability is an essential feature for genetic resource conservation as well as sustainable crop production.Long-term storage induces seed viability deterioration or seed aging,accompanied by the accumulation of toxic reactive oxygen species(ROS)to suppress seed germination.Controlled deterioration treatment(CDT)is a gen-eral approach for mimicking seed aging.The transcription factor ANAC089 was previously reported to modulate seed primary germination.In this study,we evaluated the ability of ANAC089 to control seed viability during aging.Compared with that in the wild-type line,the mutation of ANAC089 significantly increased H_(2)O_(2),thereby reducing seed viability after CDT,while the overexpression of ANAC089 reduced H_(2)O_(2) and improved seed long-evity,indicating a critical role for ANAC089 in maintaining seed viability through H_(2)O_(2) signaling.A series of stu-dies have shown that ANAC089 targets and negatively regulates the level of ABI5,an important transmitter of abscisic acid(ABA)signals,to affect seed viability after CDT.Furthermore,ABI5 negatively regulated the expres-sion of VTC2,which is involved in the biosynthesis of the antioxidant ascorbic acid and H_(2)O_(2) scavenging.As a result,ANAC089 attenuates the generation of H_(2)O_(2),thereby enhancing seed viability through the ABI5-VTC2 module during the seed aging process.Taken together,our results reveal a novel mechanism by which ANAC089 enhances seed viability by coordinating ABI5 and VTC2 expression,ultimately preventing the overac-cumulation of H_(2)O_(2),which would have led to reduced seed viability.

新疆短命植物小拟南芥(Arabidopsis pumila)种子萌发特性及其生态适应性

通过显微结构及不同处理条件下种子萌发率的观察,对早春短命植物小拟南芥(Arabidopsis pumila)种子萌发特性及影响因素进行了研究,并对其生态适应性进行了讨论。结果表明:(1)温度和光照变化对自然生境和温室收获种子的萌发率影响均不显著,说明此种群在前期萌发阶段对光、温不敏感;(2)自然生境中采收的小拟南芥种子萌发率显著低于温室收获种子,说明环境条件的变化对短命植物种子的发育具有重要作用,可显著改变种子的萌发行为;(3)赤霉素使自然生境收获种子胚活性增强从而对萌发有较大促进作用,可使萌发率增加50%以上;(4)对种皮进行各种机械损伤处理使得种皮松弛或透气,可以显著提高自然生境种子的萌发率(超过70%);(5)盐和干旱胁迫对种子萌发均具有明显的抑制作用,但复水后部分被抑制种子可重新萌发,显示盐和干旱胁迫可导致种子产生浅度休眠。结合小拟南芥自然生存环境及本研究的结果,显示其种子萌发特性与生境具有高度适应性。

不同光照条件下新疆小拟南芥(Arabidopsis Pumila)的表型可塑性研究

田间观测同一区域不同光照条件下小拟南芥可塑性变化,研究表明:1)阴阳两地小拟南芥在株高和茎生叶数、叶重、花序重、茎重、莲座叶重等特征均达到显著差异,但是两地适合度差异不显著,显示出很强的可塑性;2)阴阳两地小拟南芥在叶重与茎生叶数、花序重与花序长、茎重与株高、地下重与主根长、角果重与角果数均表现为极显著相关,表现出很强的特征整合能力。根据现代植物可塑性研究成果,对新疆境内小拟南芥光适应性特点及进化趋势进行了分析。

Molecular and genetic regulations of fleshy fruit shape and lessons from Arabidopsis and rice

Fleshy fruit shape is an important external quality trait influencing the usage of fruits and consumer preference.Thus,modification of fruit shape has become one of the major objectives for crop improvement.However,the underlying mechanisms of fruit shape regulation are poorly understood.In this review we summarize recent progress in the genetic basis of fleshy fruit shape regulation using tomato,cucumber,and peach as examples.Comparative analyses suggest that the OFP-TRM(OVATE Family Protein-TONNEAU1 Recruiting Motif)and IQD(IQ67 domain)pathways are probably conserved in regulating fruit shape by primarily modulating cell division patterns across fleshy fruit species.Interestingly,cucumber homologs of FRUITFULL(FUL1),CRABS CLAW(CRC)and 1-aminocyclopropane-1-carboxylate synthase 2(ACS2)were found to regulate fruit elongation.We also outline the recent progress in fruit shape regulation mediated by OFP-TRM and IQD pathways in Arabidopsis and rice,and propose that the OFP-TRM pathway and IQD pathway coordinate regulate fruit shape through integration of phytohormones,including brassinosteroids,gibberellic acids,and auxin,and microtubule organization.In addition,functional redundancy and divergence of the members of each of the OFP,TRM,and IQD families are also shown.This review provides a general overview of current knowledge in fruit shape regulation and discusses the possible mechanisms that need to be addressed in future studies.

Glucosinolates and Their Hydrolysis Products in Arabidopsis thaliana Influence Performance and Feeding Choice of Pieris rapae and Spodoptera exigua

Glucosinolates and their hydrolysis products, found in plants of the order Brassicales, are well-known for their defensive properties against insect herbivores. Arabidopsis thaliana (Col-0) genetic lines with mutations that modify the type of glucosinolates (i.e. myb28myb29 and cyp79B2cyp79B3 are deficient in the production of aliphatic and indolyl glucosinolates, respectively) make it possible to test for the specific effects of these secondary chemicals on insect herbivores. The Pad3 mutant (deficient in camalexin), which has a role in resistance to pathogens, was also tested. Likewise, the effects of different glucosinolate hydrolysis products can be evaluated using genetically modified (GM) lines of the wild type Col-0 ecotype, which naturally produces isothiocyanates. These GM lines include the nitrile-producing 35S: ESP and the double knockout tgg1tgg2, which virtually lacks hydrolysis products. In both no-choice and choice experiments, the crucifer specialist Pieris rapae was virtually unaffected by differences in the type of glucosinolates or hydrolysis products. In contrast, the generalist insect Spodoptera exigua had statistically significant increases in pupae/adult weight and faster developmental times when reared on mutants deficient in the production of aliphatic and indolyl glucosinolates and their hydrolysis products. There were no differences in the performance of either insect species when reared on wild type Col-0 or Pad3. Results from feeding choice trials showed that Pieris rapae had no statistically significant preference for any of the genetic lines. In contrast, Spodoptera exigua had a significant feeding preference for the double mutant tgg1tgg2. This study provides evidence that variation in the type of glucosinolates and their hydrolysis products can influence insect performance and feeding choices, and that responses are species-specific.

Overexpression of Wheat TaELF3-1BL Delays Flowering in Arabidopsis

EARLY FLOWERING 3(ELF3),a light zeitnehmer(time-taker)gene,regulates circadian rhythm and photoperiodic flowering in Arabidopsis,rice,and barley.The three orthologs of ELF3(TaELF3-1AL,TaELF3-1BL,and TaELF3-1DL)have been identified in wheat too,and one gene,TaELF3-1DL,has been associated with heading date.However,the basic characteristics of these three genes and the roles of the other two genes,TaELF3-1BL and,TaELF3-1AL,remain unknown.Therefore,the present study obtained the coding sequences of the three orthologs(TaELF3-1AL,TaELF3-1BL,and TaELF3-1DL)of ELF3 from bread wheat and characterized them and investigated the role of TaELF3-1BL in Arabidopsis.Protein sequence comparison revealed similarities among the three TaELF3 genes of wheat;however,they were different from the Arabidopsis ELF3.Real-time quantitative PCR revealed TaELF3 expression in all wheat tissues tested,with the highest expression in young spikes;the three genes showed rhythmic expression patterns also.Furthermore,the overexpression of the TaELF3-1BL gene in Arabidopsis delayed flowering,indicating their importance in flowering.Subsequent overexpression of TaELF3-1BL in the Arabidopsis ELF3 nonfunctional mutant(elf3 mutant)eliminated its early flowering phenotype,and slightly delayed flowering.The wild-type Arabidopsis overexpressing TaELF3-1BL demonstrated reduced expression levels of flowering-related genes,such as CONSTANS(AtCO),FLOWERING LOCUS T(AtFT),and GIGANTEA(AtGI).Thus,the study characterized the three TaELF3 genes and associated TaELF3-1BL with flowering in Arabidopsis,suggesting a role in regulating flowering in wheat too.These findings provide a basis for further research on TaELF3 functions in wheat.

Biochemical and Physiological Responses of Arabidopsis thaliana Leaves to Moderate Mechanical Stimulation

Mechanical stimulation of plants can be caused by various abiotic and biotic environmental factors.Apart from the negative consequences,it can also cause positive changes,such as acclimatization of plants to stress conditions.Therefore,it is necessary to study the physiological and biochemical mechanisms underlying the response of plants to mechanical stimulation.Our aim was to evaluate the response of model plant Arabidopsis thaliana to a moderate force of 5 N(newton)for 20 s,which could be compared with the pressure caused by animal movement and weather conditions such as heavy rain.Mechanically stimulated leaves were sampled 1 h after exposure and after a recovery period of 20 h.To study a possible systemic response,unstimulated leaves of treated plants were collected 20 h after exposure alongside the stimulated leaves from the same plants.The effect of stimulation was assessed by measuring oxidative stress parameters,antioxidant enzymes activity,total phenolics,and photosynthetic performance.Stimulated leaves showed increased lipid peroxidation 1 h after treatment and increased superoxide dismutase activity and phenolic oxidation rate after a 20-h recovery period.Considering photosynthetic performance after the 20-h recovery period,the effective quantum yield of the photosystem II was lower in the stimulated leaves,whereas photochemical quenching was lower in the unstimulated leaves of the treated plants.Nonphotochemical quenching was lower in the stimulated leaves 1 h after treatment.Our study suggested that plants sensed moderate force,but it did not induce pronounced change in metabolism or photosynthetic performance.Principal component analysis distinguished three groups–leaves of untreated plants,leaves analysed 1 h after stimulation,while stimulated and unstimulated leaves of treated plants analysed 20 h after treatment formed together the third group.Observed grouping of stimulated and unstimulated leaves of treated plants could indicate signal transduction from the stimulated to distant leaves,that is,a systemic response to a local application of mechanical stimuli.

XRN4/EIN5调控拟南芥对盐胁迫和ABA的耐受性

XRN4/EIN5是植物的5′-3′核酸外切酶,主要参与细胞质中RNA的降解,同时也是乙烯信号通路的核心基因,在植物的生长发育和乙烯信号转导中起着重要作用。为探究该基因在植物抗逆性方面的作用,以XRN4/EIN5 T-DNA插入突变体ein5-6为材料,设计不同浓度NaCl(0、50、100、150、200 mmol/L)和ABA(0、0.10、0.25、0.50、1.00、1.50μmol/L)处理,基于拟南芥种子发芽率、子叶绿化率、叶片数、叶片面积进行统计分析,结果发现,当盐浓度低于50 mmol/L时,ein5-6的种子发芽率、子叶绿化率、叶片数和叶片面积比野生型Col-0高;当盐浓度达到100 mmol/L时,ein5-6的种子发芽率和子叶绿化率在发育前期比Col-0高,60 h和96 h之后比Col-0低,而二者的叶片数和叶片面积没有差异;当盐浓度达到150 mmol/L及以上时,ein5-6的种子发芽率、子叶绿化率、叶片数和叶片面积比Col-0低。另外,ein5-6对ABA与盐胁迫响应的趋势一致,ABA浓度较低时ein5-6的子叶绿化率高于Col-0,但随着处理时间的延长和ABA浓度的增加,其子叶绿化率越来越低,最终明显低于Col-0。表明与野生型相比,ein5-6对盐胁迫和ABA处理更敏感,推测XRN4/EIN5参与了盐胁迫和ABA响应的调节。

一株拟南芥宽叶形突变体atscamp的分离鉴定

叶片是主要的光合作用器官,选育利于光合作用的叶片形态已成为重要的育种目标。atscamp是从拟南芥(Arabidopsis thaliana)突变体库(约6000株系)中筛选获得的1株叶片宽大突变体。Tail-PCR分析该突变体为AT1G11180位点的插入,该基因位点编码1个分泌载体膜蛋白(SCAMP)。RT-PCR检测显示,该基因转录表达水平基本为零。进一步研究发现,该突变体叶片的宽度和叶面积极显著大于野生型植株(P<0.01),但是冠幅基本保持不变;同时atscamp突变体叶绿素含量增加,叶绿素最大荧光、PSⅡ潜在光化学效率显著增加(P<0.05);相应地,突变体植株蒸腾系数(Tr)、净光合速率(Pn)和叶片水分利用效率(WUE)显著增加(P<0.05)。拟南芥AT1G11180基因的时空特异性表达分析显示,该基因仅在叶片中高表达,在其他器官中表达量很低;且随着植物发育成熟,该基因表达量逐渐增加。研究结果表明AtSCAMP基因在叶形发育中发挥着重要作用。

毛果杨×美洲黑杨Ptd-ERF71基因异源表达及功能

杨树叶锈病是杨树上的一种严重病害,对“三北”防护林体系造成极大威胁。ERF亚家族是植物所特有的AP2/ERF转录因子家族的一个主要亚家族,在植物抗病等生物胁迫响应中发挥重要作用。对E4锈菌具有耐病性的杂交杨‘2114’在接种E4锈菌12 h后,Ptd-ERF71持续上调表达。为探究Ptd-ERF71表达在‘2114’与E4锈菌互作过程中的调控作用,对Ptd-ERF71进行基因克隆及生物信息学分析,并采用Gateway转基因技术构建过表达载体,在拟南芥中进行异源表达并验证其功能。结果表明:Ptd-ERF71基因具有AP2保守结构域,属于ERF亚家族。将Ptd-ERF71在拟南芥中进行遗传转化,筛选并获得Ptd-ERF71基因过表达植株Ptd-ERF71-OE#1和Ptd-ERF71-OE#2。拟南芥Ptd-ERF71-OE#1、Ptd-ERF71-OE#2和At-RAP2.6L-OE(拟南芥Ptd-ERF71同源基因过表达株系)对透明壳孢菌感病性均显著高于拟南芥Col-0(WT),但At-RAP2.6L的拟南芥突变体株系At-rap2.6l与WT的感病性无显著差异。进一步分析表明,Ptd-ERF71基因过表达可能影响XGA-β1,3、ATL79、ZFCCCH67等植物防御相关基因表达,抑制‘2114’对E4侵染的过度防御,从而降低免疫反应对生长的影响。这种抑制作用在拟南芥与病原物的亲和型互作关系中促进拟南芥的感病性。

不同栽培密度下拟南芥(Arabidopsis thaliana)的形态分析

为初步阐明双子叶植物响应栽培密度变化的规律,本研究以模式植物拟南芥(Arabidopsis thaliana)为材料,设置不同栽培密度(1×1、2×2、3×3、4×4、5×5、6×6、7×7)进行盆栽试验,分析不同栽培密度下拟南芥不同生长时期的形态指标变化规律。结果表明:(1)在同一栽培密度处理下,随着拟南芥的生长发育,其株高、茎长和根长逐渐增加,莲座叶直径逐渐增加直至稳定,叶面积先增大后减小,顶部分枝数和基部分枝数逐渐增加或逐渐增加直至稳定。在同一生长时期,拟南芥个体大小随着栽培密度增加而减小,且高栽培密度下抽薹和开花时间提前。(2)不同栽培密度对拟南芥株高、茎长、根长、莲座叶直径、顶部分枝、基部分枝和叶面积均存在显著影响。随着栽培密度的增加,拟南芥株高、茎长总体呈降低趋势,根长呈逐渐增加趋势,莲座叶直径、顶部分枝数和基部分枝数呈逐渐减小趋势,叶面积表现为先增大后减小或逐渐减小趋势。本试验从形态上初步阐明了拟南芥响应栽培密度变化的规律,栽培密度对不同生长时期拟南芥各形态指标均产生了显著影响,该结果可为通过合理密植调控双子叶植物形态提供理论依据。

抗氧化途径下大豆GmbHLH130转录因子增强植物耐旱性研究

为了探究大豆GmbHLH130基因参与植物耐旱性调控的分子机制,分析了转基因拟南芥在干旱处理下的表型并测定活性氧含量和抗氧化酶活性,同时检测了拟南芥叶中干旱应答相关基因的表达模式以及转录因子GmbHLH130对下游基因启动子的结合作用。结果显示,GmbHLH130基因过表达拟南芥的耐旱性明显增强。干旱处理下,过表达株系鲜质量和叶片相对含水量均高于WT,而MDA含量和失水率则较低。此外,干旱处理导致拟南芥过表达株系积累更多的可溶性糖和脯氨酸、更少的活性氧以及更高的抗氧化酶活性;同时,干旱胁迫应答基因AtCAT、AtPOD、AtSOD、AtNCED3、AtP5CS1和AtRD29A的表达水平在过表达株系中显著上调。GmbHLH130蛋白则可结合到靶基因的启动子区激活GUS报告基因的表达。本研究初步证明GmbHLH130转录因子通过结合干旱胁迫应答基因启动子激活基因表达,增加转基因植株体内渗透调节物质含量、激活抗氧化途径和提高ROS清除能力,最终缓解干旱胁迫对植株的损伤。

污染物胁迫及环境条件改变对拟南芥根系生长影响的研究进展

拟南芥生长周期短,基因组简单,对其根系的相关研究可为研究污染物和外界条件胁迫对其他植物的毒害作用及影响机制提供依据,污染物胁迫和环境条件的改变,都将会影响拟南芥根系的正常生长。因此,拟南芥根系在胁迫环境中所作出的应激反应和响应机制是至关重要的,相关研究已经取得一系列进展。本文分别从无机污染物、有机污染物、环境条件改变三个方面,综述了拟南芥根系发生的不同应激反应及其机制,发现拟南芥根系在面对不同胁迫环境时的响应不尽相同:1)较低浓度的金属离子会促进拟南芥根系的生长发育,反之,则会抑制根系的生长发育。2)有机污染物对拟南芥根系的影响普遍是抑制的,致使其主根长度降低,侧根数量减少。3)外界条件胁迫发生时则相对复杂,不同外界条件干扰拟南芥会发生不同的应激反应。

铁皮石斛CLE基因家族鉴定与功能分析

CLE多肽是一类小分子分泌蛋白,参与植物的生长发育和细胞间通讯,在维持干细胞的增殖与分化中发挥关键调控作用。为研究兰科药用植物铁皮石斛(Dendrobium officinale Kimura et Migo)中CLE基因家族成员的功能,从铁皮石斛叶、根、茎、花苞、果实的组织中提取RNA,反转录成cDNA,通过半定量PCR检测CLE家族基因成员在各组织中的表达情况。结果表明:在铁皮石斛基因组中鉴定出17个CLE成员,它们均拥有保守的12氨基酸CLE基序。半定量RT-PCR结果表明,CLE基因家族成员在根、茎、叶、花、果实中展示不同的组织表达谱,尤其是CLE 19635在花苞和果实中特异性表达,CLE 22175在果实中特异性表达。用体外合成的CLE多肽处理拟南芥,结果显示,CLE合成肽参与拟南芥根的发育,其中,CLE05351对根生长有促进作用,CLE18468对根影响不明显,其他CLE多肽均对根的生长有抑制作用。mPS-PI染色并未发现根尖分生组织结构模式受到CLE合成肽的影响。此外,CLE 02038过表达的拟南芥T 2代纯合系具有短根表型,与CLE合成肽处理结果一致。研究结果为进一步挖掘CLE家族在铁皮石斛附生根中的作用及其信号调控网络奠定了基础,并为铁皮石斛理想根系的育种提供了潜在靶基因。

拟南芥At ACO3基因的表达对抵御非生物胁迫影响的研究进展

乌头酸酶(Aconitase,ACO)是参与三羧酸循环中柠檬酸可逆异构化过程的关键酶,这种酶有3种亚型(ACO1,ACO2,ACO3),其中ACO3发挥主要的作用。有研究发现,乌头酸酶基因At ACO3还对提高模式植物拟南芥(Arabidopsis thaliana)应对非生物胁迫具有重要的生物学功能。本文着重论述了At ACO3在提高植物的抗寒性、抗旱性、抗金属胁迫、抗氧化胁迫等方面的作用,为深入研究植物ACO3基因和进一步开发植物抗逆功能基因提供参考价值。

天山北麓中段拟南芥(Arabidopsis thaliana)与相邻物种的分布格局及相互关系

天山山脉是世界拟南芥(Arabidopsis thaliana)及其近缘种的分布中心之一,资源优势明显。在北天山中段浅山地带选择拟南芥分布的典型样地50m×50m,分析了样地物种的结构、组成和土壤理化性质,用Ripley’sK(d)函数分析了拟南芥与相邻物种的空间特征和相互关系。发现样地由7科23个物种组成,以新疆绢蒿(Seriphidium kaschgaricum)为建群种,短命植物物种占近70%。拟南芥仅分布于北坡,在3m内聚集强度高于所有分析物种,在5m范围内与新疆绢蒿中株呈显著正关联,与十字花科的涩芥(Malcolmia africana)、藜科的散枝猪毛菜(Salsola brachiata)、木碱蓬(Suaeda dendroides)、角果藜(Ceratocarpus arenarius)呈一定尺度显著负关联。分析认为拟南芥空间分布依赖于新疆绢蒿大株、中株生长塑造的遮阴、保湿和丰富土壤有机质,生态位与藜科物种差异极大,生境特异性高于同属近缘种小鼠耳芥(Arabidopsis pumila),以及涩芥(M.africana)、庭芥(Alyssumdesertorum)、四齿芥(Tetracme quadricornis)、丝叶芥(Leptaleum filifolium)、狭果鹤虱(Lappula semiglabra)等短命植物。在干旱胁迫下,拟南芥环境选择强度大于种内作用,密度依赖的种子扩散表现不明显。扩散对策是通过大量生产种子,依靠果实不易开裂控制种子短距离扩散,充分利用原适宜生境来维持种群繁衍。

生态因子及其交互作用对拟南芥(Arabidopsis thaliana)表型可塑性的影响

以拟南芥(Arabidopsis thaliana)两种基因型(ws-0和col-0)材料,采用复因子混合水平正交试验设计开展盆栽实验,研究了土壤盐分、土壤水分、光照强度、去叶处理等生态因子及其交互作用对受试植株18个表型特征的影响。结果表明生态因子对植物表型可塑性的影响是有针对性的:土壤水分主要影响植物体构件数目;土壤盐分主要影响生物量、角果数及种籽总数等直接反映植株适合度的表型特征;光照条件则主要影响植物的物候表型特征。植物体表型可塑性的方向随水分梯度的变化而发生改变。生态因子交互作用对植物表型可塑性的影响效果不是各因子独立作用的简单加和:对某个表型特征都有显著影响的两个生态因子其交互作用对该特征可能没有影响;反之,受两个生态因子交互作用影响显著的表型特征也可能不受它们的独立影响。在对生态因子交互作用作出响应时,col-0的9个特征表现出可塑性,而ws-0仅有4个表型是可塑的;同一基因型内彼此相关的表型特征在可塑性上也具一致性。抽苔时莲座叶数与角果平均籽粒数不受任何生态因子及其交互作用的影响,这两个表型作为数量特征而未表现出可塑性。