Open Access is an initiative that aims to make scientific research freely available to all. To date our community has made over 100 million downloads. It’s based on principles of collaboration, unobstructed discovery, and, most importantly, scientific progression. As PhD students, we found it difficult to access the research we needed, so we decided to create a new Open Access publisher that levels the playing field for scientists across the world. How? By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers.
We are a community of more than 103,000 authors and editors from 3,291 institutions spanning 160 countries, including Nobel Prize winners and some of the world’s most-cited researchers. Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too.
To purchase hard copies of this book, please contact the representative in India:
CBS Publishers & Distributors Pvt. Ltd.
www.cbspd.com
|
customercare@cbspd.com
There are microbes that are beneficial to plants. Among these, rhizobacteria, which functions as plant growth promoting rhizobacteria (PGPR) such as Pseudomonas spp. and Bacillus sp., can serve as fertilizer. These organisms have proven to accelerate germination and improve the yield of tomato plants. Colonization of rhizosphere by PGPR results in acceleration of plant growth and protection against plant pathogens. Soaking tomato seeds with Pseudomonas spp. and Bacillus sp. suspension accelerated germination by 2–3 days than the control without immersion with both bacteria. Soaking tomato seeds for 10–30 min in the suspension of Pseudomonas spp. yielded the same effect in tomato germination. Soaking in Bacillus sp. tends to cause faster growth as compared to immersion in Pseudomonas spp. suspension. Mixing these two bacterial suspensions had no significant effect in accelerating the germination of tomato seeds. Soaking tomato seeds for 20 min with a suspension of Pseudomonas spp. and Bacillus sp. at densities of 4 × 105 CFU and 8 × 105 CFU showed significant differences (p < 0.05) in plant height, leaf number, root length, number, and weight of tomato fruits. The highest fruit weight using Pseudomonas spp. and Bacillus sp. at 8 × 105 CFU was 491.7 g tomato plant−1 while the control average fruits weight was 100.0 g tomato plant−1.
Faculty of Agriculture, Laboratory of Agrotechnology, Mahasaraswati University of Denpasar, Denpasar, Bali, Indonesia
*Address all correspondence to: widnyanaketut@gmail.com
1. Tomato and plant growth promoting rhizobacteria
Tomato is a potential horticultural crop for cultivation due to its high economic value. The production of the crop in Indonesia was 864,798 t/ha in 2008–2011, with an average productivity of 21.5 t/ha, which is below production levels of 100 t/ha in the United States and Europe.
Rhizobacteria of Pseudomonas spp. group are beneficial for plants, improving soil fertility, and function as biological control agents for plant pathogens and have the potential of increasing plant resistance (induced systemic resistance; ISR) [1]. Rhizobacteria plays an indirect role as a biological fertilizer and biological stimulant through the production of plant growth hormones, such as indole acetic acid (IAA), gibberellins, cytokinins, ethylene, and solubilizing minerals. These organisms also indirectly function to inhibit pathogenic microorganisms, through the formation of siderophores and antibiotics [1, 2].
Rhizobacteria, such as P. fluorescens, P. putida, and P. aeruginosa, are beneficial to plants as plant growth promoting rhizobacteria (PGPR), with the ability to control plant diseases [3, 4]. Research on the benefits of Pseudomonas spp. still continues to better understand its mechanism in spurring plant growth.
Bacillus sp. is a Gram-positive bacteria used in controlling root disease. These bacteria produce spores that can be stored for long periods and are easily inoculated into the soil. Previous research has shown that the bacteria Bacillus strains PRBS-1 and AP-3 proved to inhibit the growth of pathogenic fungi (Rhizoctonia solani, Colletotrichum truncatum, Sclerotinia sclerotiorum, Macrophomina phaseolina, and Phomopsis sp.) in soybean seeds and enhanced the growth of plants [5].
Rhizobacteria can be used as a bioprotectant that can suppress the development of plant pests/diseases, as a biostimulant that for production of indole acetic acid (IAA), cytokines, and gibberellin, and as a biofertilizer for increasing nutrient availability to plants [6].
2. Concentration levels of Pseudomonas spp. and Bacillus sp. in germination of tomato seeds
Soaking of tomato seeds in Pseudomonas spp. at a concentration of 8 × 108 CFU produced the highest germination percentage that of 91.7%, while germination in distilled water was at 41.6%. Concentrations of Pseudomonas spp. and Bacillus sp. significantly influenced tomato seed germination (Figure 1).
Figure 1.
Percentage of tomato seed germination at different concentrations of Pseudomonas spp. and Bacillus sp.
Soaking tomato seeds with bacterial suspension Pseudomonas spp. and Bacillus sp. gives a significant effect when soaked for 10–20 min at a concentration from 4 × 105 CFU, 8 × 105, and 12 × 105 CFU (Figure 2). Tomato seeds soaked in a mixture of bacterial suspension of Pseudomonas spp. and Bacillus sp. showed significant effect when compared to distilled water. A previous study conducted by Widnyana et al. [7] involving the soaking of swamp cabbage (Ipomoea reptans Poir) seeds for 20 min with suspension of P. alcaligenes TrN2 resulted in 25% faster germination and increased fresh weight of stems up to 67.07%, compared to soaking of seeds in distilled water.
Figure 2.
The percentage of tomato seeds germinated after soaking in bacterial suspensions of Pseudomonas spp. and Bacillus sp.
3. Effect of immersion of tomato seeds in Pseudomonas spp. and Bacillus sp. on plant height and number of leaves
Soaking tomato seeds with Pseudomonas spp. suspension and Bacillus sp. can increase the growth of tomato plants. This is evidenced in Table 1, with the increase in plant height followed by the increase in number of tomato plant leaves. The positive effect of soaking the tomato seeds is obtained on population density of Bacillus sp. and Pseudomonas spp. which is a minimum of 4 × 105 to 12 × 105 CFU. The application of Pseudomonas spp. suspension with concentration of 5 × 105 CFU through seed immersion showed significant difference in tomato plant height, with average tomato height in the first and fourth week at 2.7 cm and 8.5 cm, respectively [8] (Table 2).
Seedling height
Control average
Treatment average
95.00% confidence
t
df
p-value
Significance
1st week
0.5
2.7
1.8
8.589
49.714
0.000
Significant
2nd week
3.0
5.0
1.6
8.596
41.209
0.000
Significant
3rd week
4.3
6.1
1.2
5.612
27.993
0.000
Significant
4th week
7.8
8.4
0.2
2.363
30.688
0.012
Significant
Table 1.
T-test results of the higher tomato seedlings on control and soaking treatment with suspensions of Pseudomonas spp. and Bacillus sp.
Leaves of seedlings
Control average
Treatment average
95.00% confidence bound
t
df
p-value
Significance
1st week
0.5
1.5
0.6
4.923
32.166
0.000
Significant
1st week
2.5
2.7
−0.2
0.740
25.716
0.233
Nonsignificant
1st week
3.9
3.9
−0.2
−0.204
32.195
0.580
Nonsignificant
1st week
5.2
5.1
−0.2
−0.437
30.990
0.667
Nonsignificant
Table 2.
T-test results of the number of leaves of tomato seedlings on control and soaking treatment with suspensions of Pseudomonas spp. and Bacillus sp.
Tomato plants treated with rhizobacteria have higher productivity caused by the ability of PGPR in spurring plant growth and inhibiting the growth of pathogens. This is in accordance with Hatayama et al.’s [9] study that plants treated with PGPR bacteria have higher yields than controls. One of the PGPR product compounds that inhibit the growth of pathogens is siderophore. Siderophore serves as a systemic booster of plant resistance by inducing plants to form salicylic acid at higher level. Mukaromah [10] stated that salicylic acid acts as a signal transduction gene that activates the systemic inducing receptor in plant tissue. Bacillus sp. and Pseudomonas sp. are antagonistic microorganisms that are able to suppress soil pathogens by forming antibiotic compounds such as chitinase enzymes that can hydrolyze fungal cell walls and form siderophores and other antibiotics [11, 12].
The growth of tomato seedlings after the soaking treatment with suspensions of Pseudomonas spp. bacteria, Bacillus sp., and suspense mixture of both types of bacteria with different soaking time for 10, 20, and 30 min are presented in Figures 3–5. It appears that immersion with sterile water provides the smallest seed growth as compared to other treatments. Soaking tomato seeds for 20–30 min in the suspensions gives better growth for tomato germination. This indicates that the soaking of tomato seeds with suspensions of bacterium Pseudomonas spp. and Bacillus sp., or suspense mixture of both types of bacteria is very useful in spurring the growth of tomato seeds when the soaking treatment lasts 20–30 min.
Figure 3.
Growth of tomato seeds with Bacillus sp. suspense at different seed soaking time periods. Note: 1: seeds soaked in distilled water for 20 min; 2–4: seed soaked in Bacillus sp. suspension for 10 min; 5–7: seed soaked in Bacillus sp. suspension for 20 min; 8–10: seed soaked in Bacillus sp. suspension for 30 min.
Figure 4.
Growth of tomato seeds with Pseudomonas spp. suspension at different seed-soaking time periods. Note: 1: seed soaked with distilled water for 20 min; 2–4: seed soaked Pseudomonas spp. suspension for 10 min; 5–7: seed soaked Pseudomonas spp. suspension for 20 min; 8–10: seed soaked Pseudomonas spp. suspension for 30 min.
Figure 5.
Growth of tomato seeds with a suspense mixture of Bacillus sp. and Pseudomonas spp. in different seed soaking times. Note: 1: seed soaked with distilled water for 20 min; 2–4: seed soaked in Bacillus sp. + Pseudomonas spp. suspension for 10 min; 5–7: seed soaked in Bacillus sp. + Pseudomonas spp. suspension for 20 min; 8–10: seed soaked in Bacillus sp. + Pseudomonas spp. suspension for 30 min.
4. Tomato seed immersion treatment on growth and yield of tomato plants
Treatment of tomato seeds with Pseudomonas spp. bacterial suspension in addition to spurring the germination of tomato seeds also has an impact on the growth and yield of tomato fruit [13]. Significant differences were observed (P ≤ 0.01) among plant height and leaf numbers for P. alcaligenes bacteria isolate and the application method used (Table 3). Also significant differences were observed (P ≤ 0.01) among fruit number, total fruit weight per plant, and weight per tomato fruit for P. alcaligenes bacteria isolate and the application method used (Table 4).
Treatment
Application method
Plant height (cm)
Leaf number (leaf)
Distilled water (control)
Root dipping
36.1d
78.6f
Seed soaking
36.1d
78.6f
Seedling watering
36.1d
78.6f
P. alcaligenes KtS1
Root dipping
87.7c
109.2e
Seed soaking
114.1ab
167.6b
Seedling watering
98.5c
150.1bc
P. alcaligenes TrN2
Root dipping
97.6c
118.4de
Seed soaking
116.3a
182.4a
Seedling watering
104.5bc
149.8bc
P. alcaligenes TmA1
Root dipping
98.3c
129.4cd
Seed soaking
120.4a
192.1a
Seedling watering
105.5bc
157.7b
Table 3.
Pseudomonas alcaligenes isolate treatment and the application method on plant height and leaf number of tomato plants.
Notes: Values followed by the same letter in the same column are not significantly different at 5% DMRT.
Treatment
Application methods
Fruit number
Fruit weight/plant (g)
Average weight per fruit (g)
Fruit weight/ha (tons)
Distilled water (control)
Root dipping
30.6c
84.0e
2.8d
3.8e
Seed soaking
30.6c
84.0e
2.8d
3.8e
Seedling watering
30.6c
84.0e
2.8d
3.8e
P. alcaligenes KtS1
Root dipping
41.9b
231.6e
5.1bc
10.4e
Seed soaking
55.0a
278.3d
5.1bc
12.5d
Seedling watering
48.8b
241.0d
5.0bc
10.8d
P. alcaligenes TrN2
Root dipping
58.8a
237.2d
4.1cd
10.7d
Seed soaking
70.7a
393.1b
5.9ab
17.7b
Seedling watering
62.9a
330.4c
5.3bc
14.9c
P. alcaligenes TmA1
Root dipping
54.9b
259.4d
4.8bc
11.7d
Seed soaking
64.3a
451.9a
7.2a
20.3a
Seedling watering
58.9a
376.3b
6.7ab
16.9b
Table 4.
Pseudomonas alcaligenes isolates and the application method on yield of tomato plants.
Notes: Values followed by the same letter in the same column are not significantly different at 5% DMRT.
Soaking tomato seeds with P. alcaligenes suspension yielded a significant effect on the number of tomato leaves, where the number of leaves reached 192.11 strands on immersion with P. alcaligenes TmA1, followed by P. alcaligenes TrN2 where the number of leaves reached 182.4 strands. There were 161.6 strands on soaking the seeds with P. alcaligenes KtS1, whereas in soaking the seeds with distilled water, the number of leaves was only 78.6 strands. Soaking tomato seeds with P. alcaligenes suspension also yields a significant effect on tomato plant height. The highest tomato plant reached 120.4 cm in tomato seed immersion with suspension P. alcaligenes TmA1, followed by 116.3 cm with P. alcaligenes TrN2, and 114.1 cm with P. alcaligenes KtS1, while in soaking the seeds with distilled water, tomato plant height was only 36.1 cm. The abovementioned data indicate that the seed-soaking treatment is the best application method when compared to soaking the roots of the seedlings or watering the tomato seeds (Table 3)
Soaking tomato seeds with P. alcaligenes suspension has a significant effect on the number of fruits per plant, fruit weight per plant, average weight per fruit unit, and fruit weight in hectare. On the weight parameters of tomato per plant, the average weight per fruit unit, and the weight of tomato per hectare, it was found that soaking the tomato seeds with a suspension of P. alcaligenes TmA1 had a significant effect and was significantly different with all other treatments. The highest weight of tomatoes per plant, weight per fruit unit, and fruit weight per hectare was found in tomato seed immersion treatment with P. alcaligenes TmA1 suspension that are 451.9, 7.2, and 20.3 tons, respectively. This value differs significantly with all other treatments (Table 4).
Soaking tomato seeds in a suspension of Pseudomonas spp. and Bacillus sp. can accelerate germination by 2–3 days than when not being immersed in both bacterial suspensions.
Soaking the tomato seed for 10–30 min in Pseudomonas spp. suspension yields the same effect on the speed of germination of tomato seeds.
Soaking of tomato seeds in Bacillus sp. tends to cause tomato growth faster than soaking in Pseudomonas spp. suspension.
Soaking the tomato seed for 20 min with Pseudomonas spp. suspension and Bacillus sp. at a population density of 8 × 105 CFU can increase the weight of tomatoes to 490% compared to controls.
References
1.McMilan S. Promoting Growth with PGPR. The Canadian Organic Grower. Soil Food Web Canada Ltd. Soil Biology Lab. & Learning Centre; 2007
2.Sarma MV, Saharan RK, Prakash K, Bisaria A, Sahai V. Application of fluorescent pseudomonads inoculant formulations on Vignamungo through field trial. International Jour-nal of Biological and Life Sciences. 2009;7:514-525
3.Van Peer R, Schippers B. Plant growth responses to bacterization with selected Pseudomonas Spp. strains and rhizosphere microbial development in hydroponic cultures. Canadian Journal of Microbiology. 1988;35:456-463
4.Weller DM, Cook RJ. Increased growth of wheat by seed treatments with fluorescens pseudomonads, and implications of phytium control. Canadian Journal of Plant Pathology. 1986;8:328-334
5.Araújo FF, Henning AA, Hungria M. Phytohormones and antibiotics produced by Bacillus subtilis and their effects on seed pathogenic fungi and on soybean root development. World Journal of Microbiology and Biotechnology. 2005;21(8):1639-1645
6.Tenuta M. Plant PGPR. Prospects for Increasing Nutrient Acquisition and Disease Control. Department of Soil Science. University of Manitoba; 2004
7.Widnyana IK, Ngga M, Sapanca PLY. The effect of seed soaking with rhizobacteria Pseudomonas alcaligenes on the growth of swamp cabbage (Ipomoea reptans Poir). IOP Con-ference Series: Journal of Physics: Conference Series. 2017;953(2017):012007. DOI: 10.1088/1742-6596/953/1/012007
8.Widnyana IK, Javandira C. Activities Pseudomonas spp. and Bacillus sp. to stimulate germination and seedling growth of tomato plants. Agriculture and Agricultural Science Procedia. 2016, 2016;9:419-423
9.Hatayama K, Kawai S, Shoun H, Ueda Y, Nakamura A. Pseudomonas azotifigens sp. nov., a novel nitrogen-fixing bacterium isolated from a compost pile. International Journal of Systematic and Evolutionary Microbiology. 2005;55:1539-1544
10.Mukaromah F. Relationship between population aphids with CMV disease incidence in the H382 tobacco introduced bacterium Pseudomonas aeruginosa, red worms (Lumbricus rubellus) and virus CMV-48. Essay. Faculty of Agriculture Universitas Jember; 2005 (in bahasa)
11.Habazar T, Yaherwandi. Biological Control of Plant Pests and Diseases. Padang: Andalas Press; 2006 (in Bahasa)
12.Wang SL, Chang WT. Purification and characterization of two bifungsional chitinases/lysozymes extracellularly produced by Pseudomonas aeruginosa K-187 in a shrimp and crab Shell powder medium. Applied and Environmental Microbiology. 1997;63(2):380-386
13.Widnyana IK, Suprapta DN, Sudana IM, Temaja IGRM. Pseudomonas alcaligenes, potential antagonist against Fusarium oxysporum f. sp. lycopersicum the cause of fusarium wilt disease on tomato. Journal of Biology, Agriculture and Healthcare. 2013;3(7):163-169
Written By
I Ketut Widnyana
Submitted: 23 July 2017Reviewed: 17 May 2018Published: 05 November 2018
Open access peer-reviewed chapter
