不同成熟度茶籽外植体诱导发生体胚的研究

为了探究不同成熟度的茶籽作为外植体诱导体细胞胚胎发生的差异,本文选择成熟度依次递增的茶籽E1、E2、E3和E4作为外植体进行培养研究,结果表明：E4外植体接种成活率最高,但是诱导体细胞胚发生率较低。E1外植体在灭菌时耗损率相对较高,而且体胚诱导发生能力并非最佳。E2和E3外植体诱导分化体细胞胚的频率以及诱导获得的二级体胚的频率都较高,E最佳,E3次之。以上结果说明E2茶籽外植体可以作为诱导体胚发生的优良材料。     

Somatic embryogenesis in Cymbopogon pendulus and evaluation of clonal fidelity of regenerants using ISSR marker

An efficient plant propagation system through somatic embryogenesis was established in Cymbopogon pendulus, an aromatic grass followed by analysis of genetic status of regenerants using ISSR markers. Optimum embryogenic callus induction was observed on MS basal medium supplemented with 13.57 μM 2,4-dicholorophenoxyacetic acid (2,4-D) with 8.88 μM N⁶-benzyladenine (BA). Subsequent culturing of embryogenic calli on MS medium containing 4.52 μM 2,4-D and 8.88–13.32 μM BA gave maximum number of somatic embryos. Addition of coconut water (CW) promoted induction, growth and differentiation of callus and somatic embryogenesis. Further development of embryos into plantlets was achieved on MS medium supplemented with lower concentration of biotin and calcium pantothenate (CaP) along with BA (4.44–13.32 μM) and kinetin (2.32–4.65 μM). The root meristems were established on half strength MS medium containing 2% sucrose and 2.46–9.84 μM Indole3-butyric acid (IBA) and successfully established in soil with 77.8% survival rate in field condition. Thirteen randomly selected regenerated clones were screened using six ISSR primers. Nine clones produced similar monomorphic amplification profiles while remaining clones showed minor variation with absence of certain parental bands and appearance of unique band. Majority of the regenerants maintained genetic fidelity with the generation of few variants as evidenced from similarity matrix estimates using Nei Li's coefficient of similarity data.     

翠菊‘花束绯红’叶片的植株再生体系建立

以翠菊‘花束绯红’无菌苗为材料,研究了植物生长调节剂浓度及组合、光照条件、不同附加物对叶片及其愈伤组织再生植株的影响。结果表明:(1)在光照培养条件下,诱导翠菊叶片不定芽形成的最适培养基为MS+6-BA3.0mg·L-1+IBA1.0mg·L-1,诱导率为56.7%,平均不定芽数为3.3;(2)黑暗培养不利于叶片不定芽的分化,但促进叶片愈伤组织的形成;(3)培养基中分别添加脯氨酸、水解酪蛋白和NH4NO3等均能明显促进愈伤组织不定芽的诱导,最适培养基为MS+6-BA1.0mg·L-1+IBA0.1mg·L-1+脯氨酸300mg·L-1,诱导率为82.8%,平均不定芽数为4.5;(4)不定芽移到幼苗生根培养基(1/2MS+IBA0.1mg·L-1)上,生根率为89.1%,移栽后成活率达89.3%。     

Characterization of a new fungal antagonist of Phytophthora capsici

The capacity of many microorganisms for antagonism towards pathogens is unknown and previously uncharacterized species may be potentially useful in this respect. This work presents the evaluation of the capacity of a previously uncharacterized Ascomycete, denominated here as UA to protect chili pepper (Capsicum annuum) against Phytophthora capsici, and other soil-borne plant pathogens and establishes the role of UA as a biocontrol agent. Inoculation of UA 2 days before the inoculation of P. capsici led to 77.8% survival of pepper plants. Simultaneous confrontation of both microorganisms in vitro led to 53.1% growth inhibition of P. capsici, while the inoculation of P. capsici 3 days after the inoculation with UA improved growth inhibition up to 73%. Simultaneous confrontation in vitro of UA with Fusarium oxysporum and Fusarium solani led to 41.2 and 50% growth inhibition, respectively, but had no effect on Rhizoctonia solani or a binucleate Rhizoctonia isolate. Moreover, formation of zoosporangia and the germination of zoospores were completely inhibited by exposure to undiluted filter sterilized filtrate. UA produces septate mycelia, but could not be classified in detail due to a lack of spores or reproductive structures. However, sequencing of Internal Transcribed Spacer 1, 2 and the 5.8S genes indicated that this fungus is a member of the Ascomycetes.     

不同光照强度对林下栽培三叶青块根产量及总黄酮含量的影响

[目的]提高林下栽培三叶青单株块根产量和总黄酮含量。[方法]选择光照强度差异较大的5个地块,研究不同光照强度对林下栽培三叶青块根产量和总黄酮含量的影响。[结果]林下栽培三叶青随着光照强度的增强,三叶青单株块根产量明显提高,块根中总黄酮含量随着光照强度的增强而增加。[结论]建议种植地光照强度在2 000 lx以上,三叶青块根产量和总黄酮含量较高。     

君迁子休眠芽及叶片离体培养体系优化及植株再生

以君迁子(Diospyros lotus Linn.)休眠芽和叶片为外植体,研究基础培养基种类和外植体基因型对休眠芽初代培养的影响,比较叶片放置方式、TDZ浓度、ZT与TDZ不同浓度组合及暗培养时间对叶片愈伤组织形成和不定芽再生的影响;然后对再生芽进行生根。结果表明:君迁子休眠芽初代培养中,DKW培养基最适合其生长发育,休眠芽生长势最佳;初代培养中,不同基因型的外植体在DKW培养基中生长势基本相同,说明外植体基因型对其初代培养没有影响,但对继代培养影响较大。叶片下表面朝上放置在MS+ZT 0.1 mg/L+TDZ2.0mg/L中暗培养20d,愈伤组织形成率达100%,在(1/2N)MS+2.200 mg/L TDZ上愈伤组织形成率为81.4%;叶片下表面朝上放置在MS+ZT 1.0mg/L+TDZ 2.0mg/L中暗培养0d,不定芽再生率和外植体平均不定芽数最高,分别为34.4%和2.1±0.3。组培苗在1/2MS(1/2N)+IBA 1.0mg/L中培养5d后,转入1/2MS(1/2N)+1g/L活性炭培养20d,生根率为58.14%,平均根数为4条。     

大青山林区米老排人工林伐桩萌芽更新研究

以33年生米老排伐桩为研究对象,分析了不同伐桩基径(≤30 cm、30＜X≤40 cm、40＜X≤50 cm、＞50 cm)及伐桩高度(≤5 cm、5＜Y≤10 cm、10＜Y≤20 cm、＞20 cm)对其萌芽植株数量、胸径及高度等生长状况的影响。结果表明,4个不同的伐桩基径级之间,30＜X≤40 cm其萌芽植株数量、胸径及高生长较大;伐桩基径对其萌芽植株数量影响差异显著,但对胸径及高生长影响差异不显著。伐桩高度在≤5 cm和5＜Y≤10 cm时,其萌芽植株数量、胸径及高生长较大,且随着伐桩高度的增加而降低。     

Comparative proteomic analysis of cucumber roots infected by Fusarium oxysporum f. sp. cucumerium Owen

Cucumber Fusarium wilt (CFW), caused by the soil-borne fungus Fusarium oxysporum f. sp. cucumerium, is a serious disease in cucumber (Cucumis sativus) production worldwide. For the efficient control of the pathogenic fungi, a better understanding of its interaction and associated resistance mechanisms at the molecular level is required. Here, we report a comparative proteomics analysis of total root protein isolated from infected cucumber root of susceptible bulk (SB) and resistant bulk (RB) of cucumber generation F2. Two-dimensional gel electrophoresis (2-DE) coupled with MS/MS approaches identified 15 over-accumulated proteins from the RB plants. Identified proteins are mainly involved in defense and stress responses, oxidation reduction, metabolism and transport and other process. These proteins are likely to be a part of resistance-related protein network, playing different roles in cucumber disease resistance. Three vital clues regarding wilt resistance of C. sativus are gained from this study. First, jasmonic acid and redox signaling components were found in response to F. oxysporum infection in resistant plants. Second, the LRR family protein may play an important role in the defense reaction against CFW. Third, biotic and abiotic stress-related proteins were induced by the CFW fungus F. oxysporum, indicating the activation of common stress pathway.     

老化漂白紫胶的碱法再生工艺优化

研究旨在为老化漂白紫胶的回收与再利用提供技术支撑和科学依据。该文采用碱法再生技术,通过单因素试验及双响应值优化法,建立了老化漂白紫胶可控水解的回归模型,并求得老化漂白紫胶碱法再生的最优工艺条件:在90℃条件下,以浓度为0.3 mol/L的Na OH按照液料比为14:1 m L/g、水解时间1.84 h,再生漂白紫胶得率为76.1%±0.5%,热乙醇不溶物可达0.360%±0.030%。再生漂白紫胶热乙醇不溶物、冷乙醇可溶物、热寿命等均达到国标要求,分别为0.360%、92.6%、9.80 min;其中颜色指数为1.68,达到了普通漂白胶2级标准;但酸值升高到178 mg/g、软化点降低至44.5℃。结果表明,采取碱法再生技术回收老化漂白紫胶是可行的。     

根系分泌物对根际土壤关键氮转化过程的影响

根系分泌物是影响土壤氮素转化、N₂O排放和植株氮肥利用率的重要因素之一,也是土壤学、植物营养学、作物生理生态与耕作栽培学、环境科学等学科的重要关注点。为全面认识根系分泌物在土壤氮循环中的作用,综述了根系分泌物的种类和测定方法,介绍了根系分泌物影响土壤关键氮转化过程及N₂O排放的机理,根系分泌物对土壤硝化和反硝化过程及N₂O排放的抑制作用,并对该领域未来的研究方向进行了展望。为土壤氮素转化的土壤–植物–微生物互作机制研究提供一定参考,以进一步提高氮肥利用率,减少氮肥引起的环境污染。