Functions of Plant Growth Substances in the Growth of Dendrobium officinale Kimura et Migo

[Objectives] To study the effects of plant growth substance on the growth and development of Dendrobium officinale Kimura et Migo. [Methods] Comparative methods were applied to study the effects of plant growth substance on the growth and development of D. officinale Kimura et Migo. [Results] Plant growth regulators play an important role in the process of tissue culture rapid propagation of D. officinale Kimura et Migo,and the main regulatory pathways are as follows.( i) Plant growth regulators promote the growth and development of D. officinale Kimura et Migo through regulating the changes of its endogenous hormones.( ii) Plant growth regulators affect the accumulation of polysaccharide content in D. officinale Kimura et Migo through regulating the changes in chlorophyll content and enzymes involved in sucrose metabolism.( iii) Plant growth regulators can increase the activity of antioxidant enzymes of D. officinale Kimura et Migo,to increase its stress resistance. [Conclusions]Using molecular biology techniques,combined with the changes of plant hormones in D. officinale Kimura et Migo,and analysis on key enzyme in the synthesis of plant hormones and gene expression,it is feasible to study the rules o changes in the content of active content of D. officinale Kimura et Migo.

The Improvement of Phytomediation on the Treatment Effectiveness of Heavy Metals with Energy Sunflower Plants with Calcium Peroxide and Phytohormones

Phytomediation is an environmentally friendly green rehabilitation technology that is often incorporated with an application to improve calcium peroxide and phytohormones required for the growth of agricultural plants with the expectation to improve the effectiveness of plant rehabilitation. This study mainly consists of two parts: 1) water culture experiment and 2) pot culture experiment. In the water culture experiment, we attempt to understand the influence of the addition of calcium peroxide, phytohormones (IAA and GA3) and a chelating agent on the growth of sunflower plants. From the growth, we are then able to know the effectiveness of the addition of phytohormones. However, in the pot culture experiment, when hormones and the chelating agent EDTA are introduced to different plant groups at the same time, if the nutrition in the water required by plants is not available, the addition of the hormone cannot negate the toxicity caused by EDTA. In terms of calcium peroxide, due to quick release of oxygen in water, this study fails to apply calcium peroxide to the water culture experiment. When the pot culture experiment is used to examine the influence of hormones at different concentration levels on the growth of sunflowers, GA3 10-8 M is reported to have the optimal effectiveness, followed by IAA 10-8 M;IAA 10-12 M has the lowest effectiveness. According to an accumulation analysis of heavy metals at different levels, GA3 concentrates in leaves to transport nutrition in soil to leaves. This results in an excellent TF value of 2.329 G of GA3 than 1.845 of the control group indicating that the addition of the hormone and chelating agent to GA3 increases the TF value and the chelating agent is beneficial to the sunflower plant. If we examine phytoattenuation ability, the one-month experiment was divided into three stages for ten days each. The concentration level of heavy metals in the soil at each stage dropped continuously while that of the control group decreased from 31.63 mg/kg to 23.96 mg/kg, GA3 from 32.09 mg/kg to 23.04 mg/kg and EDTA from 30.65 mg/kg to 25.93 mg/kg indicating the quickest growth period of the sunflowers from the formation of the bud to blossom. During the stage, the quick upward transportation of nutrition results in quick accumulation of heavy metals;the accumulated speed of heavy metals is found higher than that of directly planted plants. This study shows an improvement in the effectiveness of the addition of hormones on plant extraction and when rehabilitation is incorporated with sunflowers with the beginning bud formation, better treatment effectiveness can be reached.

Effects of Uniconazole on Stem and Leaf Growth and Endogenous Hormone Contents of Dahlia ( Dahlia pinnata Cav.)

[Objectives]This study was conducted to investigate the physiological mechanism of the response of Dahlia pinnata to exogenous uniconazole during vegetative growth.[Methods]The effects of different concentrations(20,30,60 and 80 mg/L)of foliar fertilization on stem and leaf growth,chlorophyll and endogenous hormone contents were investigated using dahlia seedlings(cultivar‘Shiwucaiqiu’)cultivated in the open field.[Results]Different concentrations of uniconazole could make dahlia plants dwarf,shorten internodes,increase stem diameter,and deepen leaf color,and the higher the application concentration,the more significant the effects.Compared with the control group,the relative contents of chlorophyll(SPAD value)in various treatment groups increased,the contents of endogenous GA_(3) and IAA decreased,and the contents of ABA increased.Among them,the contents of IAA and ABA also showed a trend of increasing first and then decreasing.[Conclusions]The results indicated that uniconazole could affect the growth of stems and leaves and plant type by regulating photosynthetic pigments and the levels of endogenous hormones in dahlia,and good dwarfing effect and ornamental value could be obtained under the condition of foliar application concentration of 30 mg/L.This study provides a new experimental basis for the cultivation and application of dahlia.

盐爪爪根际土壤产IAA菌株分离及促生特性分析

为丰富具有产吲哚-3-乙酸(IAA)功能的植物根际促生菌(PGPR),开发高效微生物菌肥,从南疆克孜勒苏柯尔克孜自治州耐盐植物盐爪爪根际土壤中分离产IAA的菌株。结合16S rDNA的限制性片段长度多态性PCR技术(PCR-RFLP)与16S rDNA序列分析进行菌种鉴定,分析高产IAA菌株对玉米和小麦种子发芽的影响,并通过盆栽试验验证其对盐碱胁迫下植株幼苗生长(株高、茎粗、地上干重等)的影响。结果表明,共筛选到67株PGPR菌株,其分泌IAA能力为16.65~71.63 mg·L^(-1),尤以PM14、PM18分泌量较高。PM14和PM18菌株同时兼具解磷、固氮能力。所有菌株分属6个菌属,以肠杆菌属占绝对优势。接种PM14和PM18均促进了玉米和小麦种子萌发,但菌液浓度高低对种子发芽的影响有显著差异(P<0.05)。接种处理增加了玉米株高、鲜重、地上干重、茎粗和根干重,分别增加了4.7%~37.2%、28.8%~94.5%、15.8%~157.9%、4.4%~35.5%和23.5%~82.4%,但叶绿素含量无显著变化。接种处理增加了小麦株高、茎粗、鲜重和地上干重,分别增加了9.5%~33.1%、13.0%~49.6%、57.4%~112.8%和71.4%~114.3%。除接种灭活的PM14导致小麦根干重与对照相比无显著差异,其他处理均有积极作用,提高了52.8%~69.0%,而所有处理对叶绿素含量均无显著影响。综上,本研究筛选的产IAA菌株提高了植株在盐碱胁迫下的抗性,对开发适用于盐碱地区的微生物菌肥有重要意义。

糯高粱叶中IAA产生菌的分离筛选及其促植物生长作用

糯高粱是白酒酿造的重要原料,其生长过程需要大量的化学肥料,作为环境友好型肥料,微生物菌剂有很广阔的应用前景。为开发对糯高粱生长有促进生长功能的微生物菌剂,该研究以糯高粱叶片为材料,分离筛选具有植物生长激素吲哚乙酸(IAA)产生功能的微生物菌株,基于菌株的16S rDNA保守序列对菌株进行系统发育分析,确定菌株的分类学地位;通过菌悬液浸种处理,分析菌株对糯高粱种子萌发的影响;通过盆栽实验,分析菌株对高粱幼苗生长的影响。结果表明:(1)从糯高粱叶片中分离筛选得到4株具有产IAA功能的微生物菌株,分别编号为HY1-1、HY1-2、HY1-3和HY1-4。其中,IAA单位浓度产生量最高的菌株是HY1-1,为2.56 mol·L^(-1)。(2)运用贝叶斯推断树对菌株16S rDNA进行系统发育分析,结果显示这4株菌都属于枯草芽孢杆菌(Bacillus subtilis)。(3)HY1-1、HY1-2、HY1-3和HY1-4都能促进糯高粱种子萌发,与对照组相比,经菌悬液浸泡的糯高粱种子发芽率显著提高了40.04%~165.52%,其中促进效果最明显的是HY1-1,种子发芽率提高了165.52%。(4)选取HY1-1菌株做盆栽实验,在糯高粱幼苗根部接种HY1-130 d后,糯高粱幼苗的株高显著增加了29.17%、全磷含量显著增加了5.12%;糯高粱根际基质中速效氮显著增加了31.70%,有效磷显著增加了28.88%。综上认为,糯高粱叶内生菌HY1-1能够通过分泌植物生长激素IAA以及为植物提供营养元素等方式促进糯高粱植株的生长。该研究结果为进一步开发促糯高粱生长菌剂提供了种质资源。

阴沟肠杆菌B8发酵液对植物的促生作用和IAA分析

以甜玉米 Sh2和番茄为试验材料 ,研究阴沟肠杆菌 B8发酵液对植物的促生作用 ,并对其所含的主要生理活性物质进行了分析 .结果表明 :以适当浓度的发酵液喷施植株幼苗期的叶面 ,两周后 ,发现其株高与对照相比明显增加 ,根系也较对照发达 . HPL C证实该发酵液中含有植物生长激素吲哚乙酸( IAA) .在最适条件下 ,培养基中添加 0 .2 %色氨酸时 ,发酵液中 IAA含量可达 90 4 .38mg/ L.试验还发现 ,喷施发酵液后的植株内源

2株溶磷、解钾与产IAA的内生真菌菌株的筛选、鉴定及促生作用研究

从钾矿区优势蕨类植物-芒萁内生真菌中筛选出具溶磷、解钾、分泌吲哚乙酸(IAA)的功能菌株,并研究其对农作物的促生作用。采用菌株的形态学特性、培养特征及5.8S rDNA、18S rDNA ITS序列分析方法对菌株进行鉴定,并结合液体培养和固体培养方法初步测定菌株的溶磷、解钾能力,采用回接及盆栽试验研究它们对玉米幼苗的促生作用。从42株芒萁内生真菌中筛选得到2株具有高效溶磷、解钾、分泌IAA功能的内生真菌菌株(编号为MQ013和MQ039),经鉴定MQ013菌株为泡盛曲霉(Aspergillus awamori),MQ039菌株为黑曲霉(Aspergillus niger)。促生作用试验结果显示,MQ013、MQ039菌株能有效提高玉米植株体内叶绿素及磷、钾含量。MQ013、MQ039菌株具有一定的溶磷、解钾和分泌IAA活性,并对玉米幼苗的生长有明显的促进作用,该菌株在研制高效生物肥料接种剂方面可能具有较大潜力。

内源IAA、GA_3调控对百合试管苗生长的影响研究

以东方百合‘Sorbonne’试管苗为对象,对不同浓度IAA及其抑制剂(TIBA)添加后试管苗茎叶和根的生长情况进行了研究,测定了试管苗中内源激素(IAA,GA_3,Zeatin)的变化。数据显示10 mg·L^(^(-1))IAA促进试管苗茎叶、根生长的效果最佳而40 mg·L^(^(-1))IAA抑制试管苗的生长,TIBA抑制试管苗茎叶、根生长的效果显著。内源激素测定结果表明外源IAA及TIBA处理影响了内源激素的变化,IAA对生长的影响可能是通过调节内源激素的变化而实现的。结合生长情况及内源激素变化的分析结果表明:过高浓度的IAA、过低浓度的GA_3都不利于试管苗生长,内源IAA和GA_3在适宜浓度下才能发挥促进生长的作用;内源Zeatin在试管苗的生长调控中可能不发挥作用。本实验为百合种植中外源激素的合理使用提供了依据,有助于提升百合种植者的经济效益。

IAA和GA3对WL215苜蓿细胞培养过程的影响

对WL215苜蓿细胞生长过程中生物量、蛋白含量、pH值以及生长素（IAA）和赤霉素（GA3）含量进行检测,结果表明,WL215苜蓿细胞生长过程中首先启动的是GA3,且GA3对细胞的生物量有显著的促进作用。IAA的形成是在WL215苜蓿GA3形成之后,处于细胞生长的对数生长期。IAA和GA3的产生对WL215苜蓿细胞蛋白的影响没有线性关系,但可以通过对细胞生长的影响来调节苜蓿细胞的蛋白生产。细胞生长过程中的pH值变化对IAA和GA3的产生没有影响。IAA/GA3含量比例在0.2-0.3范围时,可很好地促进细胞的生长,同时也是在愈伤组织筛选中的最佳生长调节剂比例。

潜在促生菌Bacillus tequilensis U36的产IAA特性及其对辣椒的促生效果

对从土壤中分离到的一株潜在根围促生菌U36进行了系统分析,通过形态学、生理生化特性及16S r RNA分析鉴定其为特基拉芽孢杆菌Bacillus tequilensis。盆栽试验发现,U36对植物生长有促进作用,而且在正常土壤中植株的生长优于无菌土。但就促生效率而言,在灭菌土中加入U36后的促生效率高于正常土中的促生效率:正常土中U36对辣椒根长、根重、茎长、茎重和叶面积的促进效率分别达到47.7%、37.5%、21.5%、69.2%和8.1%;而在灭菌土中,辣椒根长、根重、茎长、茎重和叶面积的促进效率分别为49.2%、58.8%、25.7%、58.2%和24.1%。通过研究发现U36不仅具有固氮、解磷的功能,还可产生促生长物质吲哚乙酸(IAA),且IAA的产生具有色氨酸依赖性。该菌株的优良促生特性可以作为潜在促生菌用于生物肥料研发,具有很好的应用价值。

Effect of CO_2 Elevation on Root Growth and Its Relationship with Indole Acetic Acid and Ethylene in Tomato Seedlings

A hydroponic experiment was carried out to study the effect of elevated carbon dioxide(CO2) on root growth of tomato seedlings.Compared with the control(350 μL L-1),CO2 enrichment(800 μL L-1) significantly increased the dry matter of both shoot and root,the ratio of root to shoot,total root length,root surface area,root diameter,root volume,and root tip numbers,which are important for forming a strong root system.The elevated CO2 treatment also significantly improved root hair development and elongation,thus enhancing nutrient uptake.Increased indole acetic acid concentration in plant tissues and ethylene release in the elevated CO2 treatment might have resulted in root growth enhancement and root hair development and elongation.

Origin, evolution, and molecular function of DELLA proteins in plants

Gibberellic acid(GA), a ubiquitous phytohormone, has various effects on regulators of plant growth and development. GAs promote growth by overcoming growth restraint mediated by DELLA proteins(DELLAs). DELLAs, in the GRAS family of plant-specific nuclear proteins, are nuclear transcriptional regulators harboring a unique N-terminal GA perception region for binding the GA receptor GIBBERELLIN INSENSITIVE DWARF1(GID1) and a C-terminal GRAS domain necessary for GA repression activity via interaction with multiple regulatory proteins. The N-terminal conserved region of DELLAs evolved to form a mode of GID1/DELLA-mediated GA signaling originating in bryophytes and ferns. Binding of GA to GID1 increases the affinity between DELLAs and a SCF E3 ubiquitin–ligase complex, thus promoting the eventual destruction of DELLAs by the 26 S proteasome. DELLAs negatively regulate GA response by releasing transcription factors to directly activate downstream genes and indirectly regulate GA biosynthesis genes increasing GA responsiveness and feedback control by promoting GID1 transcription. GA communicates extensively with other plant hormones and uses crosstalk to regulate plant growth and development. In this review, we summarize current understanding of evolutionary DELLA-mediated gibberellin signaling and functional diversification of DELLA, focusing primarily on interactions of DELLAs with diverse phytohormones.

Comparison of Effect of Brassinosteroid and Gibberellin Biosynthesis Inhibitors on Growth of Rice Seedlings

Brassinosteroid（BR） and gibberellin（GA） are two predominant plant hormones that regulate plant cell elongation. Mutants disrupt the biosynthesis of these hormones and display different degrees of dwarf phenotypes in rice. Although the role of each plant hormone in promoting the longitudinal growth of plants has been extensively studied using genetic methods, their relationship is still poorly understood. In this study, we used two specific inhibitors targeting BR and GA biosynthesis to investigate the roles of BR and GA in growth of rice seedlings. Yucaizol, a specific inhibitor of BR biosynthesis, and Trinexapac-ethyl, a commercially available inhibitor of GA biosynthesis, were used. The effect of Yucaizol on rice seedlings indicated that Yucaizol significantly retarded stem elongation. The IC_（50） value was found to be approximately 0.8 μmol/L. Yucaizol also induced small leaf angle phenocopy in rice seedlings, similarly to BR-deficient rice, while Trinexapac-ethyl did not. When Yucaizol combined with Trinexapac-ethyl was applied to the rice plants, the mixture of these two inhibitors retarded stem elongation of rice at lower doses. Our results suggest that the use of a BR biosynthesis inhibitor combined with a GA biosynthesis inhibitor may be useful in the development of new technologies for controlling rice plant height.

产IAA菌的筛选、鉴定及其培养基的优化

从菜园土壤中以稀释平板法分离得到纯化单菌株,经摇床培养筛选出一株高产IAA菌(29.127 mg·L-1)GMZB-12,经细菌检测仪及16S r DNA鉴定为产酸克雷伯菌(Klebsiella oxytoca)。在试验了培养时间、碳源、氮源等单因素培养条件对高产IAA菌GMZB-12生长影响基础上,以响应面法优化了高产IAA菌的培养条件,确定最佳培养条件:蔗糖浓度为10 g·L-1,酵母粉浓度为11.2 g·L-1,Mg SO4浓度为0.22 g·L-1,Ca Cl2浓度为0.22 g·L-1。种子萌发试验表明,GMZB-12菌悬液具有促进水稻侧根生长作用。

Regeneration of <i>in Vitro</i>Shoot and Root Structure through Hormone Manipulation of Coconut (MATAG F2) Zygotic Embryos

Zygotic embryos tissues have found to be more responsive explants for clonal propagation of coconut. In the present study, the feasibility of using zygotic embryos explants for clonal propagation of a local coconut variety MATAG F2 was assessed. Callus was induced by incorporating of cytokinin and auxin into the medium. The sliced embryos explants were immersed in 1 M maltose for 60 mins, then with 0.05 M maltose for 1 min and followed by 0.01 M maltose for 5 mins was the best for prevention of phenolic compounds excretion. The callus formation depended on the concentration of 2,4-D in the media and the best effect was observed with the high level (2,4-D and BAP) tested. Attempts at inducing multiple shoot from the zygotic embryos callus were unsuccessful. No multiple shoots was present;most of the callus became root structure.

植物生长调节剂对甜樱桃果实发育及内源激素动态变化的影响

以7年生萨米脱甜樱桃为试材,研究甜樱桃果实、果柄生长发育及内源激素含量的变化趋势,并探讨GA_(3)+6-BA处理对果实、果柄生长发育及内源激素含量变化的影响。结果表明:甜樱桃果实生长发育期内,果实重量相关性状中单果重、果实纵径和果实横径的动态模型符合Logistic方程,果实重量最大相对生长速率出现的时间在花后28 d左右,果实中ABA、GA_(3)、IAA、ZR含量均呈先下降后上升的变化趋势,果柄与果实内源激素含量变化趋势并不协同;GA_(3)+6-BA配施处理后,促进了甜樱桃果实及果柄的生长,使内源激素IAA、GA_(3)、ZR的含量显著增加,并显著增加了果柄(GA_(3)+ZR+IAA)/ABA值。研究结果为植物生长调节剂在甜樱桃上的应用提供了一定的理论参考依据。

撑绿杂交竹基腐病生防菌的促生机制

【目的】探究已筛选出的贝莱斯芽孢杆菌(Bacillus velezensis BD2231)和奇异链霉菌(Streptomyces mirabilis BD2233)2株拮抗菌的促生特性及其机制,为杂交竹基腐病防治和植物生长提供有效的微生物菌剂。【方法】采用定性和定量方法,测定BD2231和BD2233在分泌吲哚乙酸(IAA)、溶磷、产铁载体、生物固氮、产ACC脱氨酶和纤维素酶等方面的能力;分析2株菌株对番茄和烟草种子萌发以及对番茄、烟草和杂交竹幼苗生长的影响;利用ELISA试剂盒和实时荧光定量PCR方法,探究菌株对番茄、烟草和杂交竹叶片生长素、赤霉素、水杨酸和茉莉酸的质量浓度及其相关基因表达的影响。【结果】BD2231和BD2233均能产生生长素(IAA)、铁载体和纤维素酶,但不具有溶磷、生物固氮和产ACC脱氨酶的能力,其中,BD2233分泌IAA的质量浓度达12.44 mg·L^(-1),BD2231的载体活性单位(SU)和纤维素酶活性(CMC酶活)分别达26.75%和0.43 U·mL^(-1)。2株菌株可显著促进番茄和烟草种子萌发,经BD2231发酵液处理的番茄和烟草种子发芽率更高,分别为61%和87%。2株菌株可显著促进杂交竹幼苗生长,提高植物的株高、茎粗、鲜质量和干质量。BD2231和BD2233能够显著促进植物叶片内源激素生长素、赤霉素、水杨酸和茉莉酸途径相关基因IAA9、GA20ox、PR-1和MYC2的表达,提高内源激素的质量浓度,BD2233对植物的生长素质量浓度提高效果较好,BD2231对植物的赤霉素、水杨酸和茉莉酸质量浓度提高效果较好。【结论】贝莱斯芽孢杆菌BD2231和奇异链霉菌BD2233通过产生IAA、铁载体和纤维素酶促进植物种子萌发和幼苗生长,且可提高植物生长素、赤霉素、水杨酸和茉莉酸的质量浓度及其相关基因的表达,BD2231在促进植物生长方面表现更好。

玉米根际多功能促生菌的筛选及其对冬小麦-夏玉米轮作体系产量提升效果

【目的】黄淮海平原小麦玉米生产区主要实行冬小麦-夏玉米轮作种植模式。砂质潮土是广泛分布于黄淮海地区的土壤,属性和衍生障碍较多,包括结构性较差、蓄水保肥能力较弱等。为了提高肥料利用率、改善土壤肥力,综合实现作物产量提升和品质优化,筛选了一株多功能促生菌,并在该轮作体系验证其广谱促生效应。【方法】从玉米根际砂质潮土中筛选多功能促生菌,测定其产吲哚乙酸(IAA)、溶有机磷、解钾能力。通过形态学、生理生化及16SrDNA序列分析方法对其种属进行鉴定。摇瓶条件下探究其产IAA的最适条件,通过玉米盆栽验证其促生能力,通过冬小麦-夏玉米大田试验验证其在轮作体系中的广谱性增产效果。【结果】(1)试验筛选得到一株命名为YM3的多功能根际促生菌枯草芽孢杆菌(Bacillus subtilis),其产IAA能力达到59.21 mg/L、解有机磷能力达到0.72 mg/L、解钾能力达到18.56 mg/L。当装液量为25 mL/250 mL,pH 6-8范围内,分别以麦芽糖、蛋白胨为碳、氮源时,YM3产IAA能力最佳。(2)玉米盆栽试验结果可见,与接种灭活菌相比,接种YM3菌水剂的土壤IAA、速效磷、速效钾含量分别显著提高75.00%、48.66%、20.00%。玉米幼苗的根长、根表面积、根体积、根尖数、根分枝数分别显著增加67.95%、59.21%、51.13%、71.34%、92.06%。玉米植株的鲜重、株高、相对叶绿素含量、全氮、全磷、全钾分别显著提高了39.86%、23.51%、18.27%、17.68%、52.26%和36.53%。(3)小麦玉米轮作大田试验结果表明,接种YM3菌剂的小麦大田土壤有效氮、速效磷、速效钾分别显著增加了9.08%、13.78%、16.66%,增产率达到42.18%。玉米大田土壤速效磷和速效钾含量分别显著增加了19.18%和15.95%,增产率达到13.22%。【结论】筛选得到的枯草芽孢杆菌YM3菌株兼具产IAA、溶有机磷、解钾功能,在黄淮海平原小麦玉米轮作体系土壤中适应性强,广谱性强,能够提升砂质潮土土壤肥力,提高冬小麦-夏玉米轮作体系的产量。

广西亚热带植物根际促生菌的筛选、鉴定及促生作用研究

[目的]本文旨在从植物根际土壤中分离具有多种促生性能的菌株,并明确其促生特性和抗病效果。[方法]采用选择培养方法从植物根际土壤中筛选具有固氮、产氨、溶磷、解钾、分泌吲哚乙酸(indole acetic acid,IAA)、产铁载体和产蛋白酶等特性的菌株,通过16S rRNA对菌株分类学鉴定。测定其对小麦根腐病菌(Bipolaris sorokiniana)、小麦冠腐病菌(Fusarium gramiuearum)、黄瓜织球壳菌(Plectosphaerella cucumerina)、香蕉炭疽病菌(Colletotrichum musae)、交链格孢菌(Alternaria alternate)和尖孢镰刀菌(Fusarium oxysporum)的抑制作用,并通过盆栽试验探究植物根际促生菌对植物的促生效果。[结果]从植物根际土壤中分离细菌191株,固氮及产氨菌171株,解有机磷菌66株,解无机磷菌62株,解钾菌28株,产铁载体菌98株,产IAA菌41株,产蛋白酶菌45株。抑菌试验表明贝莱斯芽胞杆菌C32对6种致病菌均表现出较强的抑菌活性,抑菌率均在50%以上。盆栽试验结果表明,1株IAA高产菌株川大肠杆菌0208对番茄和玉米植株促生效果最为显著。与对照组相比,玉米盆栽株高、茎粗、根长、地上部鲜重和地下部鲜重分别增加21.49%、19.35%、42.98%、19.58%和56.67%,番茄盆栽分别增加53.51%、14.90%、12.28%、43.12%和48.62%。[结论]从广西亚热带植物根际土壤中筛选到多株具有高效促生和防病功能的菌株,为微生物肥料的开发提供优质菌种资源。

干旱地区植物根际促生菌鉴定及促生和耐旱特性研究

本试验以干旱区3种植物为材料,利用选择性培养基从植物根际分离筛选具有固氮、溶磷、分泌植物激素及耐旱的菌株,进行16S rRNA分子生物学鉴定,并通过纸上发芽试验验证菌株促生效果,以期为干旱地区专用微生物菌肥提供优良菌种资源。结果表明:从3种植物根际共分离出37株菌株,其中兼具溶磷、固氮促生特性的占35.1%,菌株固氮酶活性介于17.92~169.74 nmol C2H4/(h·mL),溶无机磷量为13.39~363.31μg/mL,溶有机磷量为58.69~99.37μg/mL。选择12株固氮、溶磷能力较好的菌株进行分泌植物激素及耐旱特性测定,发现12株菌株均能分泌吲哚乙酸且分泌量为2.86~27.60μg/mL;大部分菌株也均能分泌玉米素和脱落酸,分泌量分别为1.75~7.78μg/mL、1.98~4.61μg/mL。从中筛选出特性优良的菌株5株,经鉴定菌株YB6和HC7分别为枯草芽孢杆菌(Bacillus subtilis)和氧化微杆菌(Microbacterium oxydans),菌株HL7、HC9和HC3分别属于无色杆菌属(Achromobacter sp.)、苍白杆菌属(Ochrobactrum sp.)和叶杆菌属(Phyllobacterium sp.)。纸上发芽试验结果显示,5株植物根际促生菌既能促进种子的萌发,又能缓解干旱胁迫对种子生长的抑制作用,其中,菌株YB6和HC9对种子的萌发和生长效果较为突出,具有作为微生物肥料菌种资源在干旱区应用的潜力。