Microencapsulated Rhizosphere Bacteria for Promoting Growth of Corn Plants
-
摘要:
目的 为了提高植物根际促生菌(Plant growth-promoting rhizobacteria, PGPR)对作物促生作用的稳定性,研制出以PGPR复合菌液为原料的微胶囊菌剂,探究其对玉米的促生效果。 方法 从玉米根际土壤中分离得到2株PGPR菌株并制备成复合液体菌液。分别用海藻酸钠(SA)和CaCl2作为包埋剂和交联剂,对复合菌液进行包埋以制备微胶囊菌剂。以复合微胶囊菌剂制备的难易程度和菌株包埋率、增殖前活菌数及增殖后活菌数为评价指标,确定微胶囊菌剂制备的最优条件。通过分析微胶囊菌剂在不同聚乙二醇含量、温度、pH、存储时间以及盐含量下的菌株生长及其对玉米生长和根系形态的影响确定PGPR微胶囊菌剂的特性。 结果 分离得到了2株PGPR菌株,具有多种植物促生功能。使用质量分数为1%SA-3%CaCl2制备的微胶囊菌剂稳定性较好,包埋率达91.27%,增殖后的微胶囊活菌数达到8.73×109 cfu·g−1,增殖7.79倍。微胶囊菌剂在不同干旱、温度、pH、存储时间和盐浓度条件下对PGPR菌株具有较好的保护作用。PGPR微胶囊菌剂对玉米有显著的促生作用,施用微胶囊菌剂使玉米株高、苗干重和根干重分别增加91.83%、81.82%和29.57%。同时微胶囊菌剂也显著提高了玉米总根长、根表面积、根平均直径、根体积和根尖数。 结论 探明了一种PGPR微胶囊菌剂的制备方法,施用该PGPR微胶囊剂能够显著促进玉米生长、改善玉米根系形态,对玉米的促生效果优于液体菌剂。 Abstract:Objective Microencapsulation was applied to improve the stability of PGPRs for promoting corn growth. Method Rhizosphere bacteria that promote corn growth were isolated. The bacteria in broth were encapsulated using sodium alginate (SA) and CaCl2. Based on operation efficiency and PGPR survival rate, optimal conditions for the encapsulation were determined. Properties of the microencapsulated agent were analyzed for field applications with respect to the bacterial proliferation under varied artificial dehydration created by using polyethylene glycol (PEG) and salt, temperatures, pHs, and storage times as well as the growth and root morphology of the treated corn plants. Result Two PGPR strains with multiple plant growth promoting functions were isolated. The microcapsule microbial agent prepared with a mass fraction of 1% SA-3% CaCl2 had good stability. The embedding rate of the microcapsule microbial agent reached 91.27%, the number of live bacteria reached 8.73 × 109 cfu·g−1, and the proliferation was 7.79 times. Significant protection against the imposed adverse conditions was observed. In comparison with the virgin PGPRs broth, the encapsulation also significantly enhanced the growth of the treated corn plants with a 91.83% increase on plant height, 81.82% on seedling dry weight, and 29.57% on root dry weight over control. In addition, the total length, surface area, diameter, volume, and tip number of the roots of the corn plants grown with the encapsulated PGPRs were significantly increased as well. Conclusion Microencapsulation significantly improved the stability as well as the root morphology and growth promoting effect of PGPRs on the corn plants. -
Key words:
- Corn /
- rhizosphere bacteria /
- growth-promoting effect /
- microencapsulated
-
图 9 不同剂型PGPR对玉米根系形态的影响
a:根长;b:根总表面积;c:根平均直径;d:根尖数;e:根体积;不同字母表示不同组别间差异显著(P<0.05)
Figure 9. Effect of PGPR dosage on root morphology of corn plants
a: root length; b: total root surface area; c: average root diameter; d: number of root tips; e: root volume; data with different letters indicate significant differences (P<0.05).
表 1 玉米根际土壤中筛选的具有促生特性的菌株及促生特性分析
Table 1. Strains and properties of corn growth-promoting bacteria from rhizosphere soil
菌株
Strains解磷量
Phosphate solubilizing/
(μg·mL−1)解钾量
Potassium releasing/
(μg·mL−1)固氮量
Nitrogen fixation/
(μg·mL−1)吲哚乙酸
Indoleacetic acid/
(μg·mL−1)铁载体活性
Siderophore activity/%ACC含量
ACC content/
(μg·mL−1)P1 33.50±0.37a — 1.44±0.16b 78.06±0.51a 55.72±0.67a 0.19±0.07e P2 31.49±0.51b — — 65.74±1.61b 44.19±0.94d 0.30±0.07b P3 31.34±0.58b — — — 49.12±0.35b 0.27±0.05c P4 30.85±0.59b — — — 46.47±0.27c 0.22±0.14d P5 30.12±0.03c — — 46.23±3.25d 40.48±0.44e 0.14±0.07f P6 31.13±0.04b — — — 39.65±0.38e 0.20±0.06e N1 — — 1.96±0.35a — 33.5±0.527f 0.27±0.11c N2 — — 1.27±0.21b — — 0.14±0.02f N3 — — 1.23±0.10b — — 0.22±0.03d K1 — 1.22±0.09b — 55.63±0.54c 31.52±0.39g 0.14±0.02f K2 — 1.17±0.07b — — — 0.30±0.06b K3 — 1.26±0.07b — — 29.34±0.35g 0.25±0.13cd K4 — 1.35±0.28b — — — 0.18±0.07e K5 — 2.26±0.07a — 63.43±2.9b 50.46±0.71b 0.34±0.05a 同列数据后不同字母表示差异显著(P<0.05);—表示无此项促生功能。
Data with different letters on same column indicate significant differences (P<0.05); —indicate no growth-promoting function.表 2 菌株P1和K5的生理生化特性
Table 2. Physiological and biochemical characteristics of P1 and K5
菌株
Strains淀粉水解
实验
Starch
hydrolysis蔗糖发酵
实验
Sucrose
fermentation乳糖发酵
实验
Lactose
fermentation葡萄糖发酵
实验
Glucose
fermentation甲基红实验
Methyl red
experiment柠檬酸盐
实验
Citrate
experiment吲哚实验
Indole
experiment革兰氏染色
实验
Gram staining
experiment触酶实验
Catalase
experiment伏-普实验
Volt-P
experiment菌株
StrainsP1 − + − + − − + + + + K5 − − + − − − + + + − +:阳性;−:阴性;
+: positive; −: negative.表 3 不同质量分数SA-CaCl2配比下微胶囊的操作性和成球性
Table 3. Microencapsulation of PGPRs with varied SA-CaCl2 combinations
配比组合
Varied combination操作性
Operation成球性
Sphericity1%SA 2%CaCl2 易
Easy较好,拖尾,无粘连
Better, trailing, no sticking3%CaCl2 易
Easy较好,拖尾,少量粘连
Better, trailing, few sticks4%CaCl2 易
Easy较好,拖尾,少量粘连
Better, trailing, few sticks2%SA 2%CaCl2 易
Easy较好,拖尾,无粘连
Better, trailing, no sticking3%CaCl2 易
Easy较好,拖尾,少量粘连
Better, trailing, few sticks4%CaCl2 易
Easy较好,拖尾,少量粘连
Better, trailing, few sticks3%SA 2%CaCl2 难
Difficult较差,无拖尾,少量破碎
Bad, no tailing, few fragile3%CaCl2 难
Difficult较差,拖尾,少量粘连
Bad, trailing, few sticks4%CaCl2 难
Difficult差,拖尾,少量破碎,易粘连
Poor, trailing, few fragile, sticks表 4 微胶囊菌剂颗粒的理化性质
Table 4. Physicochemical properties of microcapsules
配比组合
Varied combination直径
Diameter/mm机械强度
Mechanical Strength/g增殖前胶囊活菌数
Number of viable cells
before proliferation/
(×109 cfu·g−1)包埋率
Embedding rate/%增殖后胶囊活菌数
Number of viable cells
in after proliferation/
(×109 cfu·g−1)增殖倍数
Multiplication ratioSA1%-CaCl22% 3.14±0.13b 3.29±0.16b 1.01±0.11b 85.60±2.25b 5.68±0.37b 5.62 SA1%-CaCl23% 3.11±0.07c 3.21±0.13c 1.12±0.03c 91.27±1.05c 8.73±0.50c 7.79 SA2%-CaCl22% 3.22±0.04a 3.35±0.03a 1.20±0.03a 81.17±1.91a 6.91±0.49a 5.76 同列数据后不同字母表示差异显著(P<0.05)
Data with different letters on same column indicate significant differences (P<0.05). -
[1] MAHAPATRA S, YADAV R, RAMAKRISHNA W. Bacillus subtilis impact on plant growth, soil health and environment: Dr. Jekyll and Mr. Hyde [J]. Journal of Applied Microbiology, 2022, 132(5): 3543−3562. doi: 10.1111/jam.15480 [2] KESAVAN P C, SWAMINATHAN M S. Modern technologies for sustainable food and nutrition security [J]. Current Science, 2018, 115(10): 1876. doi: 10.18520/cs/v115/i10/1876-1883 [3] RAKLAMI A, BECHTAOUI N, TAHIRI A I, et al. Use of rhizobacteria and mycorrhizae consortium in the open field as a strategy for improving crop nutrition, productivity and soil fertility [J]. Frontiers in Microbiology, 2019, 10: 1106. doi: 10.3389/fmicb.2019.01106 [4] WU Z S, GUO L N, QIN S H, et al. Encapsulation of R. planticola Rs-2 from alginate-starch-bentonite and its controlled release and swelling behavior under simulated soil conditions [J]. Journal of Industrial Microbiology & Biotechnology, 2012, 39(2): 317−327. [5] 项郑昊, 周化岚, 张建国. 海藻酸钠微胶囊制备及其在微生物包埋中的应用 [J]. 工业微生物, 2021, 51(1):43−49. doi: 10.3969/j.issn.1001-6678.2021.01.007XIANG Z H, ZHOU H L, ZHANG J G. Preparation of alginate microcapsules and its application in industrial microbiology [J]. Industrial Microbiology, 2021, 51(1): 43−49. (in Chinese) doi: 10.3969/j.issn.1001-6678.2021.01.007 [6] 董羽嘉, 何艳慧, 武占省. 微胶囊化植物根际促生菌剂的研究进展 [J]. 生物加工过程, 2021, 19(4):404−412.DONG Y J, HE Y H, WU Z S. Research progress of microencapsulated plant growth promoting rhizobacteria [J]. Chinese Journal of Bioprocess Engineering, 2021, 19(4): 404−412. (in Chinese) [7] 徐致远, 郭本恒, 陈卫. 乳酸菌微胶囊技术的研究进展 [J]. 乳业科学与技术, 2005, 28(5):198−201. doi: 10.3969/j.issn.1671-5187.2005.05.002XU Z Y, GUO B H, CHEN W. The development of micro-encapsulation technology applied in LAB production [J]. Journal of Dairy Science and Technology, 2005, 28(5): 198−201. (in Chinese) doi: 10.3969/j.issn.1671-5187.2005.05.002 [8] 陈妮娜, 朱亚燕, 阳丽媛, 等. 海藻酸钠-果胶改性复合膜的制备及表征 [J]. 中国食品添加剂, 2018, (4):154−163. doi: 10.3969/j.issn.1006-2513.2018.04.025CHEN N N, ZHU Y Y, YANG L Y, et al. Preparation and characterization of cross-linking composite films based on sodium alginate and pomelo pectin [J]. China Food Additives, 2018(4): 154−163. (in Chinese) doi: 10.3969/j.issn.1006-2513.2018.04.025 [9] 张琳, 尚校兰, 李秋玲, 等. 海藻酸钠-多聚赖氨酸复合益生菌微胶囊的构建及性能评价 [J]. 饲料博览, 2023, (2):30−35.ZHANG L, SHANG X L, LI Q L, et al. Construction and performance evaluation of sodium alginate poly-L-lysine compound probiotics microcapsule [J]. Feed Review, 2023(2): 30−35. (in Chinese) [10] 靳海洋, 王慧, 张燕辉, 等. 基于基因组的一株土壤固氮菌分离菌株鉴定及其促生作用 [J]. 微生物学报, 2021, 61(10):3249−3263.JIN H Y, WANG H, ZHANG Y H, et al. Genome-based identification and plant growth promotion of a nitrogen-fixing strain isolated from soil [J]. Acta Microbiologica Sinica, 2021, 61(10): 3249−3263. (in Chinese) [11] 黄臣, 杨凯元, 高鹏, 等. 达乌里胡枝子根际解磷细菌的筛选、鉴定及特性研究 [J]. 草地学报, 2022, 30(9):2345−2355.HUANG C, YANG K Y, GAO P, et al. Screening, identification and characteristics of phosphate-solubilizing microorganisms in Lespedeza daurica [J]. Acta Agrestia Sinica, 2022, 30(9): 2345−2355. (in Chinese) [12] 孟丽媛, 邱涵, 谢瑾, 等. 解磷菌、解钾菌和固氮菌的分离筛选与鉴定 [J]. 生物灾害科学, 2022, 45(2):241−246.MENG L Y, QIU H, XIE J, et al. Isolation, screening and identification of phosphorus-solubilizing bacteria, potassium-solubilizing bacteria and nitrogen-fixing bacteria [J]. Biological Disaster Science, 2022, 45(2): 241−246. (in Chinese) [13] 陈越, 李虎林, 朱诗苗, 等. 产吲哚乙酸(IAA)促生菌的分离鉴定及对烟草种子萌发和幼苗生长发育的影响 [J]. 作物杂志, 2020, (2):176−181.CHEN Y, LI H L, ZHU S M, et al. Isolation and identification of IAA-producing rhizobacteria and its effects on seed germination and seedling growth of tobacco [J]. Crops, 2020(2): 176−181. (in Chinese) [14] 葛淼淼, 薄永琳, 刘宸, 等. 土壤产铁载体细菌的筛选及其对铁氧化物的活化与利用 [J]. 微生物学通报, 2023, 50(3):1062−1072.GE M M, BO Y L, LIU C, et al. Screening of soil siderophore-producing bacteria and their activation and utilization of iron oxide [J]. Microbiology China, 2023, 50(3): 1062−1072. (in Chinese) [15] 韩坤, 田曾元, 刘珂, 等. 具有ACC脱氨酶活性的海滨锦葵(Kosteletzkya pentacarpos)内生细菌对小麦耐盐性的影响 [J]. 植物生理学报, 2015, 51(2):212−220.HAN K, TIAN Z Y, LIU K, et al. Effect of endophytic bacteria with ACC deaminase activity in kostel etzkya pentacarpos on wheat salt tolera nce [J]. Plant Physiology Journal, 2015, 51(2): 212−220. (in Chinese) [16] 东秀珠, 蔡妙英. 常见细菌系统鉴定手册[M]. 北京: 科学出版社, 2001: 364-379. [17] 韩梅, 李天华, 彭帅, 等. 微生物肥料的包埋固定化研究 [J]. 植物营养与肥料学报, 2012, 18(4):999−1005.HAN M, LI T H, PENG S, et al. Immobilization of microbial fertilizer in small spherical particles by embedding [J]. Plant Nutrition and Fertilizer Science, 2012, 18(4): 999−1005. (in Chinese) [18] 薛伟明, 于炜婷, 刘袖洞, 等. 载细胞海藻酸钠/壳聚糖微胶囊的化学破囊方法研究 [J]. 高等学校化学学报, 2004, 25(7):1342−1346.XUE W M, YU W T, LIU X D, et al. Chemical method of breaking the cell-loaded sodium alginate/chitosan microcapsules [J]. Chemical Research In Chinese Universities, 2004, 25(7): 1342−1346. (in Chinese) [19] 李琦, 姚拓, 阿不满, 等. 根际促生菌微胶囊剂研发及对苜蓿、燕麦促生效果评价 [J]. 草地学报, 2019, 27(5):1392−1399.LI Q, YAO T, A B M, et al. Development of plant growth promoting rhizobacteria microcapsules and evaluation of its growth promotion effects on alfalfa and oats [J]. Acta Agrestia Sinica, 2019, 27(5): 1392−1399. (in Chinese) [20] 韩梅. 大豆复合微生物肥料功能菌系的构建及包埋固定化研究[D]. 沈阳: 沈阳农业大学, 2013HAN M. Studies on Construction and Immobilization of Functional Flora for Compound Microbial Fertilizer in Soybean[D]. Shenyang: Shenyang Agricultural University, 2013. (in Chinese) [21] 朱峰, 许春丽, 曹立冬, 等. 农药微囊剂及其制备技术研究进展 [J]. 现代农药, 2018, 17(2):12−16,33. doi: 10.3969/j.issn.1671-5284.2018.02.003ZHU F, XU C L, CAO L D, et al. Research advances of pesticide microcapsule and its preparative technique [J]. Modern Agrochemicals, 2018, 17(2): 12−16,33. (in Chinese) doi: 10.3969/j.issn.1671-5284.2018.02.003 [22] BASU A, PRASAD P, DAS S N, et al. Plant growth promoting rhizobacteria (PGPR) as green bioinoculants: Recent developments, constraints, and prospects [J]. Sustainability, 2021, 13(3): 1140. doi: 10.3390/su13031140 [23] AINI N, YAMIKA W, ULUM B. Effect of nutrient concentration, PGPR and AMF on plant growth, yield, and nutrient uptake of hydroponic lettuce [J]. International Journal of Agriculture and Biology, 2019, 21(1): 175−183 [24] GAMEZ R, CARDINALE M, MONTES M, et al. Screening, plant growth promotion and root colonization pattern of two rhizobacteria (Pseudomonas fluorescens Ps006 and Bacillus amyloliquefaciens Bs006) on banana cv. Williams (Musa acuminata Colla) [J]. Microbiological Research, 2019, 220: 12−20. doi: 10.1016/j.micres.2018.11.006 [25] KUMARI G, KUMAR D, SINGH D, et al. Characterization of microbial inoculants and its different formulation for mass production [J]. International Journal of Current Microbiology and Applied Sciences, 2020, 9(7): 621−627. doi: 10.20546/ijcmas.2020.907.070 [26] 车永梅, 刘广超, 郭艳苹, 等. 一种耐盐复合菌剂的制备和促生作用研究 [J]. 生物技术通报, 2023, 39(11):217−225.CHE Y M, LIU G C, GUO Y P, et al. Preparation of compound halotolerant bioinoculant and study on its growth-promoting effect [J]. Biotechnology Bulletin, 2023, 39(11): 217−225. (in Chinese) [27] ANZUAY M S, CIANCIO M G R, LUDUEÑA L M, et al. Growth promotion of peanut (Arachis hypogaea L. ) and maize (Zea mays L. ) plants by single and mixed cultures of efficient phosphate solubilizing bacteria that are tolerant to abiotic stress and pesticides [J]. Microbiological Research, 2017, 199: 98−109. doi: 10.1016/j.micres.2017.03.006 [28] 沙月霞, 邢敏, 李明洋, 等. 微生物菌剂拌土对玉米茎基腐病的预防和促生效果 [J]. 安徽农业科学, 2021, 49(4):141−144,154.SHA Y X, XING M, LI M Y, et al. Preventive and promoting efficacy of microbial agents mixed with soil against the maize stem basal rot in Ningxia [J]. Journal of Anhui Agricultural Sciences, 2021, 49(4): 141−144,154. (in Chinese) [29] 王礼, 杨光, 杨波, 等. 海藻酸钠微球的制备优化及其吸附模型 [J]. 食品与生物技术学报, 2023, 42(8):103−111.WANG L, YANG G, YANG B, et al. Optimization of preparation of sodium alginate microspheres and its adsorption behavior modeling [J]. Journal of Food Science and Biotechnology, 2023, 42(8): 103−111. (in Chinese)