Expression of Ferric Chelate Reductase Gene in Citrus junos and Poncirus trifoliataTissues

It has been hypothesized that under iron stress high ferric chelate reductase (FCR) activity in the absorptive root of plants tolerant to iron_deficiency will be induced and result in subsequent Fe 2+ transport across the plasmalemma. The activity of FCR and expression of FCR gene (FRO2) in Citrus junos Sieb. ex Tanaka tolerant to iron_deficiency and Poncirus trifoliata (L.) Raf. susceptible to iron_deficiency were determined to elucidate the physiological difference which causes the different tolerance of the two citrus rootstocks to iron stress. The activity of FCR was detectable in excised roots and was stimulated about 20_times in C. junos and only about 3_times in P. trifoliata under iron deficiency for four weeks. The FRO2 of Arabidopsis was used as a probe, the tissue print technique was used to ascertain the expression of the FCR gene in C. junos and P. trifoliata under iron stress. High_level transcripts were observed in the absorptive root, young green stem as well as new leaf of C. junos under iron stress for two weeks, and the transcripts were accumulated only slightly in P. trifoliata at the same time. The results showed that the obvious increase of FCR activity was an important reason for the tolerance of C. junos to iron_deficiency, and the regulation of FCR activity seemed to be at the transcriptional level, and the expression of FRO2 occurred in the root, stem and leaf.

沙培条件下磷、钾、钙亏缺对枳(Poncirus trifoliata)幼苗根系形态及营养吸收的影响

【目的】根系是吸收水分和养分的主要器官,对于多年生木本果树的生长发育尤为重要。由于果树根系庞大、分布错综复杂,对根系构型和空间分布等的研究相对较少。本文利用计算机扫描系统及其图像分析软件观测根系二维形态参数,并用原子吸收法测定植株养分含量,以探索养分亏缺对枳根系形态的影响,以及根系形态变化与植株养分吸收的关系。【方法】本试验在沙培条件下,以柑橘砧木枳(Poncirus trifoliata)实生苗为试材,研究了缺磷、钾和钙对其根系形态以及植株体内营养元素含量的影响。利用爱普生数码扫描仪(Expression 10000XL 1.0,Epson Inc.Japan)扫描根系,并用WinRhizo Pro(S)v.2004b软件(Regent Instruments Inc.,Canada)分析获取根系总长、总体积和总表面积等二维形态参数。利用原子吸收光谱仪(SPECTR AA220)测定样品K、Ca、Mg、Fe、Cu、Zn等元素含量。【结果】从扫描数据可知,3种缺素处理对枳幼苗根系形态结构有较大的影响,即在缺素时根系总长、表面积和体积均显著降低,缺P处理使枳实生苗粗根的根系长度、表面积、体积显著降低,但是增加了中等粗根的表面积和体积;缺K和缺Ca处理的中等粗根根系长度、表面积和体积均显著低于对照;3种缺素处理均显著降低了细根和粗根的根系长度、表面积和体积。不同缺素处理对植株根系和地上部生长的影响也存在差异,缺P对地上部的抑制作用显著强于根系,缺K处理对根系生长的抑制作用较强,缺Ca对根系和地上部生长的抑制作用均较小。缺Ca处理植株体内Zn和Fe浓度均显著增加但Ca浓度降低,缺P时植株体内Ca和地上部Zn浓度增加,而缺K时植株体内Ca、Zn浓度增加但Fe和K浓度均显著降低。【结论】不同缺素条件下枳实生苗根系形态各异,导致根系对不同养分的吸收能力不同,从而使植株体内K、Ca、Zn、Fe等养分含量发生改变,最终影响整个植株根系和地上部的生长,表现出各缺素环境所特有的树体特征。

抗寒资源枳(Poncirus trifoliata)miR168a克隆、鉴定及遗传转化

基于生物信息学和实验预测,克隆了柑橘抗寒资源枳ptf-miR168a成熟序列和前体序列,并预测了其靶基因。结果表明:ptf-miR168a在植物中高度保守,靶基因是NAC(UCU2)和锌指结构基因(FEZ)家族同源基因;同时,构建了ptf-miR168a前体的超表达载体并在烟草中进行遗传转化,得到了18个转基因系,为进一步鉴定ptf-miR168a在低温胁迫应答中的调控作用奠定基础。

Genome resequencing and transcriptome profiling reveal structural diversity and expression patterns of constitutive disease resistance genes in Huanglongbing-tolerant Poncirus trifoliata and its hybrids

Huanglongbing(HLB)is the most destructive bacterial disease of citrus worldwide.While most citrus varieties are susceptible to HLB,Poncirus trifoliata,a close relative of Citrus,and some of its hybrids with Citrus are tolerant to HLB.No specific HLB tolerance genes have been identified in P.trifoliata but recent studies have shown that constitutive disease resistance(CDR)genes were expressed at much higher levels in HLB-tolerant Poncirus hybrids and the expression of CDR genes was modulated by Candidatus Liberibacter asiaticus(CLas),the pathogen of HLB.The current study was undertaken to mine and characterize the CDR gene family in Citrus and Poncirus and to understand its association with HLB tolerance in Poncirus.We identified 17 CDR genes in two citrus genomes,deduced their structures,and investigated their phylogenetic relationships.We revealed that the expansion of the CDR family in Citrus seems to be due to segmental and tandem duplication events.Through genome resequencing and transcriptome sequencing,we identified eight CDR genes in the Poncirus genome(PtCDR1-PtCDR8).The number of SNPs was the highest in PtCDR2 and the lowest in PtCDR7.Most of the deletion and insertion events were observed in the UTR regions of Citrus and Poncirus CDR genes.PtCDR2 and PtCDR8 were in abundance in the leaf transcriptomes of two HLB-tolerant Poncirus genotypes and were also upregulated in HLB-tolerant,Poncirus hybrids as revealed by real-time PCR analysis.These two CDR genes seem to be good candidate genes for future studies of their role in citrus-CLas interactions.

The extract of the immature fruit of Poncirus trifoliata induces apoptosis in colorectal cancer cells via mitochondrial autophagy

The immature fruits of Poncirus trifoliate are used as a medicine for the treatment of gastrointestinal disorders,inflammation,and allergies in East Asia.However,their effect on colon cancer cells remains unclear.We investigated the effect of the immature fruit of P.trifoliate extract on colorectal adenocarcinoma.The extract of the immature fruit of P.trifoliata inhibited the proliferation of CT-26 cells compared with untreated cells and it induced autophagy and apoptosis through the protein kinase B/mammalian target of rapamycin and 5'-AMP-activated protein kinase pathways.The number of autophagic vacuoles and autophage markers increased in response to the extract.At later time-points,apoptosis increased dose/time-dependently.In CT-26 cells pre-treated a pan-caspase inhibitor prior to P.trifoliata immature fruit extract treatment,we did not find any change in pro-caspase 3 and pro-PARP levels.Additionally,in cells pre-treated autphage inhibitor,SQSTM1/p62 and LC3AB,pro-caspase 3 and pro-PARP levels did not change.Our results indicate the molecular mechanisms that the extract of the immature fruit of P.trifoliata induces apoptosis in colorectal carcinoma cells by inducing mitochondrial autophagy.In this study,we provided a draft for further investigate the use of MEPT for colorectal cancer inhibition.

DR5 is a Suitable System for Studying the Auxin Response in the Poncirus trifoliata-Xanthomonas axonopodis pv.citri Interaction

The local auxin distribution characteristics in the roots,stems,and leaves of stably transformed plantlets of trifoliate orange(Poncirus trifoliata)with auxin reporter system DR5::GUS-YFP were elucidated in this research.The auxin response maxima could be observed in the apex of the root tip,primary phloem of the tender stem,and the margin of the young leaves according to the activity of theβ-glucuronidase(GUS)reporter gene triggered by the auxin responsive DR5 promoter.Auxin responses in the apex of the root tips increased when treated with synthetic auxin 1-naphthylacetic acid(NAA),but decreased when treated with the auxin polar transportation inhibitor 2,3,5-triiodobenzoic acid(TIBA).These results indicated that the DR5 reporter system worked in P.trifoliata for auxin distribution and response observation.Trifoliate orange is highly susceptible to citrus canker disease.Auxin accumulation was observed visually in the invasion sites of the detached leaves inoculated with Xanthomonas axonopodis pv.citri(Xac)by GUS staining;the upregulated expression of the YFP,GH3.1,GH3.9,and SAUR genes assessed by quantitative real-time PCR(qRT-PCR)also identified auxin accumulation in the inoculated tissues following Xac infection.Overall,these findings indicated that the plantlets of P.trifoliata engineered with the auxin reporter gene provided a promising system for studying auxin responses during Xac infection.

Extraction and characterization of gelling pectin from the peel of Poncirus trifoliata fruit

In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relatively simple experimental design for optimization, in which only the variable was the extraction pH (1.0, 1.5, and 2.0) on the basis of our previous studies on diverse pectin sources. The results showed that the yield of pectin (7.4%-19.8%) was strongly influenced by the extraction pH when the other parameters, namely the solid to liquid extractant (S/L) ratio, temperature (T &degC), and time (t) were fixed to 1:25 (w/v), 75&degC, and 90 min, respectively. Likewise, the galacturonic acid content (GalA: 61.4%-79.2%), total neutral sugar content (TNS: 9.1%-22.5%), degree of branching (3.5%-13.9%), homogalacturonan (HG) to rhamnogalacturonan-I (RG-I) ratio (2.2-5.6), degree of methylesterification (DM: 54-77), viscosity average molecular weight (Mν: 57-82), and gelling capacity (GC: 124-158) were all affected by the extraction pH. The optimum pH for producing pectin with good yield, quality characteristics (GalA > 65%, DM > 60, Mν > 80 kDa), and gelling capacity (GC > 150), from the peel of P. trifoliata fruit, was found to be pH 1.5.

Antifungal Activity of Poncirus trifoliata Roots against Colletotrichum Species

Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fungal and bacterial pathogens. These pathogens can cause significant quantitative and qualitative losses from harvest to consumption during the handling and storage processes. Chemical fungicides are commonly used but are likely to leave residues on the produce, rendering short shelf-life produce, such as berries, unsuitable for human consumption. Identifying eco-friendly methods to control post-harvest disease is, therefore, of utmost importance. The presence of antifungal constituents in the roots of Poncirus trifoliata extracts was detected by thin layer chromatography-based bioautography. The active constituents were isolated and identified by bioautography assay-guided fractionation using flash chromatography followed by spectroscopic techniques. In this study, xanthoxyletin, demethylsuberosin, dentatin, nordentatin, ponfolin, and clausarin were isolated from the root extracts. The antifungal activity of these compounds was moderate to weak compared to the commercial fungicide captan. This study reports the isolation and identification of natural compounds from Poncirus trifoliata that exhibited antifungal activity against Colletotrichum fragariae and Botrytis cinerea, two major post-harvest pathogens.

Mapping of QTLs and candidate genes associated with multiple phenotypic traits for Huanglongbing tolerance in citrus

Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the disease.Commercial citrus varieties are highly susceptible to HLB,whereas trifoliate orange(Poncirus trifoliata)is considered highly tolerant to HLB.An F1 segregating population and their parent trifoliate orange and sweet orange,which had been exposed to intense HLB pressure for three years,was evaluated for disease symptoms,ACP colonization,C Las titer and tree vigor repeatedly for two to three years.Trifoliate orange and sweet orange showed significant differences for most of the phenotypic traits,and the F1 population exhibited a large variation.A high-density SNP-based genetic map with 1402 markers was constructed for trifoliate orange,which exhibited high synteny and high coverage of its reference genome.A total of 26 quantitative trait locus(QTLs)were identified in four linkage groups LG-t6,LG-t7,LG-t8 and LG-t9,of which four QTL clusters exhibit a clear co-localization of QTLs associated with different traits.Through genome-wide analysis of gene expression in response to C Las infection in‘Flying Dragon’and‘Larger-Flower DPI-50-7’trifoliate orange,85 differentially expressed genes were found located within the QTL clusters.Among them,seven genes were classified as defense or immunity protein which exhibited the highest transcriptional change after C Las infection.Our results indicate a quantitative genetic nature of HLB tolerance and identified candidate genes that should be valuable for searching for genetic solutions to HLB through breeding or genetic engineering.

Marker Assisted Selection in Citrus Rootstock Breeding Based on a Major Gene Locus ‘Tyr1’Controlling Citrus Nematode Resistance

Based on the former constructed ＇Tyrl＇ locus genetic map in family 9145, from LB6-2 [Clementine mandarin （C. reticulata） × Hamlin orange （C. sinensis）] × Swingle citrumelo （C. paradise × P. trifoliata）, 9 markers were chosen for application in evaluating their effectiveness in marker-assisted selection （MAS） for citrus rootstock breeding program from many F1 progeny of Poncirus trifoliata. As the mapping revealed that these markers were estimated within a range of 12.1 cM in the linkage group, and among them, SCO07 co-segregated with ＂Tyrl＇, and 7A4R as the closest to ＇Tyrl＇ with a distance of 1.5 cM, these markers were basically fitful to go MAS screening. The results of screening P. trifoliata F1 progeny indicated that all the markers were inherited in codominant fashion and most of them were heterozygous on PT （Pomery of P. trifoliata）., marker 4L17R/CfoI and 7A4（1407）/BfaI were proved to be consistently reliable for accurate scoring of genotypes and the revealed polymorphism was basically coincided with the citrus nematode resistant phenotype within tested populations. The polymorphic genotype with marker 4L17R/Cfol was found completely matched up with the phenotype of individuals that conferred high resistance to citrus nematode when the USDA hybrid rootstocks were screened. Utilization of these markers, especially the highly specific 4L17R/Cfol and 7A4（1407）/Bfal, should result in great benefit to world citrus industry for early selection in rootstock-breeding program.

基于UPLC特征图谱和多成分定量评价不同采收时间枸橘药材质量

目的:基于不同采收时间枸橘药材UPLC特征图谱,结合黄酮类和香豆素类成分的含量测定,明确枸橘成分积累规律,为枸橘的采收和质量控制提供依据。方法:采用UPLC法构建30批枸橘特征图谱,采用相似度评价、聚类分析、主成分分析和正交偏最小二乘判别分析对数据进行处理。采用HPLC法测定其中6个成分的含量。结果:30批样品UPLC特征图谱共标定25个共有峰,相似度为0.913~0.993,指认了7个成分,其中6个成分芸香柚皮苷、柚皮苷、枸橘苷、欧前胡素、异欧前胡素、葡萄内酯的含量分别为0.62~2.40 mg/g、5.75~27.52 mg/g、7.00~53.86 mg/g、0.63~2.94 mg/g、0.11~0.45 mg/g、3.69~9.29 mg/g;聚类分析可将样品分为3类,正交偏最小二乘判别分析筛选出5个质量差异标志性成分。不同采收时间枸橘药材可以通过果皮颜色区分,枸橘苷、柚皮苷、欧前胡素等是导致枸橘药材质量产生差异的主要标志物。结论:果皮颜色可作为枸橘药材的采收依据;枸橘苷、柚皮苷和欧前胡素等是枸橘药材质量差异标志物。

不同氮素形态对枳橙幼苗根系生长及氮素吸收动力学特性的影响

【目的】积橙是柑橘的主要砧木,因其具有抗柑橘衰退病等特性而被大力推广应用。本研究探讨积橙对氮素吸收利用机理,为柑橘生产上提高氮素利用效率和科学施肥提供科学依据。【方法】以积橙为材料,采用水培方法在Hoagland配方的基础上进行调节,研究不同形态氮素配比对积橙幼苗根系生长特性的影响及对硝态氮、铵态氮溶液的吸收动力学特性。【结果】不同处理的积橙幼苗根系生长特性表现为随着培养液中铵态氮比例的增加,幼苗根系的主根长度、侧根数及根系活力都呈先增加后降低的趋势,其中混合氮素培养对主根长度的促进作用好于单一氮素;而一定比例的铵态氮可促进根系侧根的发生,全硝、全铵及4号处理(NO3-:NH4+=3:7)萌发的侧根数之间无显著差异;根系活力则表现为2号处理(NO3-:NH4+=7:3)最佳,其次是1号处理(NO3-:NH4+=10:0)和3号处理(NO3-:NH4+=5:5),而全铵处理的根系活力则最小。故利于幼苗根系生长和根系活力增加的是2号处理,其次是3号处理;不同处理的幼苗对硝态氮溶液吸收动力学特征表现为:随着铵态氮比例的增加,动力学最大速率(V_m)米氏常数(K_m)值和α值均为先增加后降低的趋势,其中2号处理对硝态氮溶液的V_m K_m和α值均显著高于其他处理;对铵态氮溶液吸收动力学特征则表现为:随着铵态氮比例的增加,Vm Km均表现为先增加后降低的趋势,α值变化较为复杂,其中2号处理的V_m值显著高于其他处理,Km值则低于3号处理但显著高于4号和全铵处理,而α值虽与全铵处理间无差异但都显著高于其他处理。说明2号处理对外界的硝态氮和铵态氮均有较强的喜好性和竞争能力。【结论】所有处理均表现出V_m NO3^->V_mNH4^+,K_mNO3^->K_m NH4+,这表明积橙喜混合态氮对硝态氮的需求大于对铵态氮的需求。

接种丛枝菌根真菌对枳吸收利用磷酸铝的影响

在温室沙培条件下,以枳实生苗为试材,研究了丛枝菌根真菌摩西球囊霉和地表球囊霉对枳吸收利用难溶性磷酸盐(Al-P)的影响.结果表明:接种菌根真菌显著增加了枳的干物质量、含磷量及磷吸收量,且随Al-P施用量的提高,菌根贡献率、全株磷吸收量、真菌磷吸收量及真菌磷吸收贡献率显著增加;接种处理显著增加了枳根系与菌丝磷酸酶的分泌量,特别是酸性磷酸酶和中性磷酸酶的分泌量,但二者随施磷量的增加而降低.真菌磷吸收贡献率与酸性磷酸酶、中性磷酸酶、碱性磷酸酶和总磷酸酶含量呈极显著正相关.

缺铁和过量重碳酸盐胁迫下丛枝菌根真菌对枳生长的影响

采用盆栽沙培试验,研究了缺铁及重碳酸盐胁迫下丛枝菌根(arbuscular mycorrhiza,AM)真菌地表球囊霉(Glomus versiforme)对枳[Poncirus trifoliata(L.)Raf.]实生苗生长及植株铁营养状况的影响。结果表明,在pH7.0和pH8.0的重碳酸盐胁迫下,与未接种处理相比,接种AM真菌显著增加了枳实生苗的株高、茎粗、地上部和地下部干样质量,并且明显促进了叶片叶绿素和活性铁的积累,显著提高了叶片Fe/P的比值,减轻了枳因缺铁引起的黄化现象。

不同氮素形态对枳橙幼苗生长特性的影响

采用水培方法研究了不同形态氮素配比对枳橙[Citrus.sinensis(L.)Osb×Poncirus trifoliate(L.)Raf]幼苗生长特性的影响。结果表明,不同氮素形态配比营养液对枳橙幼苗的生长均有一定的促进作用,其中混合态氮素对植株地上部形态特征的影响好于单一态氮素,NO3-∶NH4+=5∶5处理更利于株高、茎粗和叶片数的增加;其次是NO_3^-∶NH_4^+=7∶3处理;单一态氮素形态处理中,全硝培养好于全铵培养。NO_3^-∶NH_4^+=5∶5处理促进了地下部主根的伸长和侧根的增加,却对主根粗度无明显影响。全铵培养对幼苗地上部和地下部生长均有抑制作用,甚至是毒害作用。不同氮素形态配比对枳橙幼苗叶绿素a、叶绿素b及叶绿素总量的影响趋势基本一致,混合态氮素对叶绿素a、叶绿素b和叶绿素总量的促进好于单一态氮素,且当处理为NO_3^-∶NH_4^+=5∶5时叶绿素含量持续增加,并且更利于其积累;而全铵处理则不利于叶绿素的增加与积累。

枳SPL9和SPL13全长cDNA克隆、亚细胞定位和表达分析

【目的】从枳[Poncirus trifoliata(L.)Raf.]中克隆SBP类[SQUAMOSA(SQUA)promoter-binding-like]转录因子基因SPL9和SPL13全长,构建SPL9和SPL13亚细胞定位表达载体验证其是否具有核定位功能,利用荧光定量PCR研究其在枳不同组织的表达特性,初步确定SPL9和SPL13在枳生长发育过程中的作用。【方法】利用生物信息学结合RACE技术以枳花器官的cDNA为模板,克隆出SPL9和SPL13基因全长,分别命名Pt-SPL9和Pt-SPL13,大小分别是1519bp和1824bp,在GenBank的登录号分别是FJ502237和FJ502238;构建Pt-SPL9和Pt-SPL13亚细胞定位载体35S-GW-FJ502237/FJ502238-GFP,基因枪转化洋葱表皮细胞,暗培养24h后激光共聚焦显微镜下观察;利用SYBR Green I实时定量RT-PCR方法检测Pt-SPL9和Pt-SPL13在根、茎、叶、花序、花和果等不同组织中的表达。【结果】生物信息学分析表明,Pt-SPL9和Pt-SPL13的cDNA序列中都有microRNA156的识别位点,Pt-SPL9与金鱼草、拟南芥和玉米SPL9的同源性分别为48.9%、42.5%和41.7%;Pt-SPL13与拟南芥SPL13、水稻的SPL16和玉米的TGA1同源性分别为40.8%、38.1%和35.8%。Pt-SPL9和Pt-SPL13与其它植物的SBP一样有着高度保守的序列,即SBP结构域和一个双向核定位信号KRXXXRRRK。亚细胞定位结果表明,Pt-SPL9和Pt-SPL13均定位于细胞核中。SYBR Green I实时定量RT-PCR结果表明,Pt-SPL9和Pt-SPL13在各个器官均有表达,但表达量不同,Pt-SPL9在茎中的表达量最高,在花和叶中的表达量次之,在根、花芽和幼果中的表达量最低;Pt-SPL13在幼果中的表达量最高,在茎和花芽中的表达量相当,其次为叶,在花和根中的表达量很低。【结论】转录因子Pt-SPL9和Pt-SPL13均具有核定位功能,Pt-SPL9和Pt-SPL13对枳的茎和果实的发育可能有着重要作用。

农杆菌介导的枳壳转化系统建立研究初报

以枳壳为对象 ,进行了农杆菌介导的上胚轴转化系统建立研究 ,得到了携带柑桔衰退病病毒外壳蛋白基因的枳壳转化植株。研究表明 :枳壳各类外植体中 ,上胚轴是较好的转化材料 ;上胚轴出芽部位主要在形态学上端。以卡那霉素为选择剂 ,外植体水平面放置时 ,选择剂的剂量是 50～ 70mg/ L。转化研究中发现感染液中乙酰丁香酮 10 0μmol/ L的加入促进转化外植体 Gus表达阳性率的提高。延迟 1a的选择培养 ,有助于 Gus阳性芽的增多。所得 Gus阳性无性系经 Southern blot杂交检测 ,证明外源基因已稳定整合到了植物基因组中 ,所得

柑橘MYB15基因的克隆与表达分析

采用电子克隆和RT-PCR方法从柚(Citrus maxima(Burm.)Merr.)、枳(Poncirus trifoliata(L.)Raf.)和柠檬(Citrus limon(L.)Burm.f.)实生苗中克隆了3个MYB蛋白基因,分别命名为CmMYB15、PtMYB15和ClMYB15;并用实时定量qRT-PCR技术检测了该基因在脱落酸(ABA)、干旱、低温和高盐胁迫处理下的时空表达。结果显示,CmMYB15、PtMYB15和ClMYB15的cDNA序列全长分别为994、992、988 bp,分别编码267、266、265个氨基酸,且编码的氨基酸序列N端均含有2个串联的不完全重复的MYB DNA-binding结构域,由此推测该3个基因均属于R2R3亚类;MYB15基因均能被ABA、干旱、低温和高盐胁迫诱导表达,且在柚、枳和柠檬中存在表达差异。本研究表明柚CmMYB15、枳PtMYB15和柠檬ClMYB15是MYB基因家族成员,可能在柑橘响应非生物胁迫过程中起到一定的作用。

丛枝菌根对枳实生苗抗旱性的影响研究

在自然水分干旱胁迫和胁迫解除复水条件下 ,研究了丛枝菌根对 1年生枳实生苗生长和抗旱性的影响 .结果表明 ,接种丛枝菌根真菌Glomusmosseae 93显著增加枳实生苗的株高、茎粗和鲜重 ,提高了幼苗移栽成活率 .在自然水分干旱胁迫和胁迫解除复水过程中 ,丛枝菌根提高或者极显提高了叶片可溶性糖含量、叶片和根系的可溶性蛋白质含量、超氧化物歧化酶活性、过氧化物酶活性和过氧化氢酶活性 ,从而提高了枳实生苗的渗透调节能力 ,增强了其保护系统能力 ,降低了细胞膜脂过氧化 ,使枳实生苗抗旱能力增强 .表明丛枝菌根真菌增强寄主植物抗旱能力的作用机制与保护系统相关 .

杂草发酵物对枳生长和VA菌根形成的影响

在具有高密度VAM真菌生长的枳 (PoncirustrifoliataRaf.)苗的培养土中分别加入 1%的 4种杂草的发酵物 ,70d后测量结果表明 :枳菌根感染率普遍较高 ,但与对照相比 ,杂草发酵物在显著促进枳苗生长的同时降低了枳菌根感染率 ,其中发酵杂草处理对生长的促进作用更大 ,降低菌根感染率更低 ;高氮也降低菌根感染水平 ;过高的菌根感染率导致寄生 。