杉木内生细菌的促生效应初步研究毕业论文_林学毕业论文

杉木内生细菌的促生效应初步研究毕业论文

2021-04-21更新

摘 要

杉木(Cunninghamia lanceolata)因具有生长速度快、干形通直圆满、木材纹理通直、抗虫耐腐、经济价值高等优点,在我国长江流域、秦岭以南地区广泛栽培,是我国最重要的速生用材树种之一。目前,我国杉木栽培区普遍存在土壤肥力减退、病虫害严重和生产力下降等问题。植物内生细菌在植物体内普遍存在,是一类与植物长期协同进化、互惠共生的一类微生物,在植物的促生、抗逆与抗病等方面具有显著的促进作用,但目前关于杉木内生细菌的应用研究还十分有限。

本研究从健康杉木枝条中分离获得了22株内生细菌,其中菌株SMEB16、SMEB18、SMEB19、SMEB20、SMEB22在实验中表现出明显的促生效果。研究结果表明,对于杉木而言,只有SMEB16具有促生效果;在萝卜上有4株菌表现出促生效果,其促生效果顺序为SMEB19gt;SMEB22=SMEB18gt;SMEB16;在番茄上有5株菌表现出促生效果,其促生效果顺序为SMEB22gt;SMEB16gt;SMEB18=SMEB20gt;SMEB19;而在辣椒上的3株菌的促生效果按大小排列为SMEB18gt;SMEB16gt;SMEB22。此外,这5株菌中SMEB16、SMEB18和SMEB22能产生大量的生物膜从而有利于其在植物体表面的定殖。SMEB19、SMEB20虽不能产生大量的生物膜,但因其具有发达的鞭毛,所以生长速度很快。

本研究将在筛选杉木内生细菌的基础上,通过形态学、生理生化特性和16SrRNA的分子鉴定,将SMEB16、SMEB18和SMEB22鉴定为贝莱斯芽孢杆菌(B. velezensis),SMEB19鉴定为枯草芽孢杆菌(B. subtilis subsp. Inaquosorum),SMEB20鉴定为蜡状芽孢杆菌(B. cereus),并对其在萝卜、番茄、辣椒及杉木植物体上的促生效应和机制进行分析,以期为杉木优良内生细菌的应用奠定重要基础。

关键词:杉木;内生细菌;促生;生物膜

Preliminary Study on the Promoting Effect of Endophytic Bacteria from Cunninghamia lanceolata

ABSTRACT

Cunninghamia lanceolata is one of the most important species of fast growing timber in China. It has many advantages such as fast growing speed, straight trunk shape, Texture straight wood, pests and rot resistance and the economic values. Therefore it is widely cultivated in Yangtze River Basin, south of the Qinling Mountains in China. At present, there are many problems such as soil fertility decline, serious pests and diseases and productivity decline in Cunninghamia lanceolata cultivated area. Plant endophytic bacteria is prevalent in plants, and it is a kind of microorganism with long-term co-evolution and reciprocal symbiosis. It has a significant effect on plant growth promotion, stress resistance and disease resistance. However, the application of endophytic bacteria from Cunninghamia lanceolata is also very limited.

In this study, 22 strains of endophytic bacteria were isolated from the branches of healthy Cunninghamia lanceolata . The strains SMEB16, SMEB18, SMEB19, SMEB20 and SMEB22 showed remarkable growth promoting effects in the experiment. The results showed that, for Cunninghamia lanceolata, only SMEB16 has a growth promoting effect. There are four strains on the radish to show the effect of growth promoting and the order of the effect is SMEB19gt; SMEB22 = SMEB18gt; SMEB16. 5 strains of bacteria on the tomato showed the effect of growth promoting, the order of the effect is SMEB22gt; SMEB16gt;SMEB18=SMEB20gt; SMEB19. And there are three strains on the pepper showed the effect of growth promoting, the order of the effect is SMEB18gt;SMEB16gt;SMEB22. In addition, SMEB16, SMEB18 and SMEB22 can produce a large number of biofilms in order to facilitate its colonization on the surface of the plant. SMEB19 and SMEB20 can not produce a large number of biofilm, but because they have well-developed flagella, the growth rate is very fast.

In this study, SMEB16、SMEB18 and SMEB22 was identified as B. velezensis, SMEB19 was identified as B. subtilis subsp. Inaquosorum and SMEB20 was identified as B. cereus by morphological, physiological and biochemical characteristics and molecular identification of 16SrRNA based on the screening of endophytic bacteria of Cunninghamia lanceolata. Furthermore this study will analyze the effects and mechanism of growth promotion on radish, tomato, pepper and Cunninghamia lanceolata in order to lay an important foundation for the application of good endophytic bacteria from Cunninghamia lanceolata .

Key words:Cunninghamia lanceolata; endophytic bacteria; growth promotion; biofilm

目 录

1. 前言 1

2. 实验材料和方法 3

2.1实验材料 3

2.1.1植物材料 3

2.1.2供试内生细菌 3

2.1.3试剂材料 3

2.2实验方法 3

2.2.1杉木内生细菌的种类鉴定 3

2.2.1.1杉木内生细菌的形态及生理生化鉴定 3

2.2.1.2杉木内生细菌的分子鉴定 4

2.2.2 杉木内生细菌生物膜的形成及其粘附细胞的含量 4

2.2.2.1 杉木内生细菌生物膜的形态观察 4

2.2.2.2 杉木内生细菌粘附细胞的含量测定 4

2.2.3杉木内生细菌在不同植物上的促生试验 4

3. 结果与分析 5

3.1杉木内生细菌的形态与生理生化特性 5

3.2 杉木内生细菌的生物膜形成能力 7

3.3杉木内生细菌对不同植物的促生效果 9

3.3.1杉木内生细菌对杉木的促生效果 10

3.3.2杉木内生细菌对萝卜的促生效果 11

3.3.3杉木内生细菌对番茄的促生效果 13

3.3.4杉木内生细菌对辣椒的促生效果 15

4. 结论与讨论 18

致 谢 20

参考文献: 21

前言

杉木(Cunninghamia lanceolata)因具有生长速度快、干形通直圆满、木材纹理通直、抗虫耐腐、经济价值高等优点,在我国长江流域、秦岭以南地区广泛栽培,是我国最重要的速生用材树种之一。我国现有杉木林754.1万hm2,蓄积量2.637亿m3,其中人工林面积449.8万hm2,蓄积1.498亿m3,人工林面积占全国人工林总面积的24.0%,人工林蓄积占全国人工林蓄积的28.3%。目前,我国杉木栽培区普遍存在土壤肥力减退、病虫害严重和生产力下降等问题。植物内生细菌在植物体内普遍存在,是一类与植物长期协同进化、互惠共生的一类微生物,在植物的促生、抗逆与抗病等方面具有显著的促进作用。

植物内生菌 (endophyte) 是生活在植物体内部、不引起植物病害的、并对植物生长、抗病、抗逆及植物修复等具有促进作用的一类微生物,多功能性内生菌与植物体的内共生关系成为近年来研究的热点(许明双,2014)。目前国内外关于内生菌的筛选与开发应用主要集中在农作物上,在针叶树上的报道较少。此外,在针叶树上的生防菌的应用也主要来自于植物的根际与土壤等环境条件,且大都集中于其对病虫害的生防价值的研究,而关于杉木及其内生菌的促生研究还未见大量报道。从现有的研究来看 , 植物内生细菌有革兰氏阴性杆菌和革兰氏阳性菌约 50 个属。研究领域主要针对内生菌的分离、鉴定、促生作用和拮抗作用及其他生物学作用。

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