A novel split-pot bioassay to screen indole acetic acid producing rhizobacteria for the improvement of plant growth in tomato [ Solanum lycopersicum L.]

2017 ◽  
Vol 224 ◽  
pp. 351-357 ◽  
Author(s):  
H.G. Gowtham ◽  
P. Duraivadivel ◽  
P. Hariprasad ◽  
S.R. Niranjana
2021 ◽  
Vol 48 (2) ◽  
Author(s):  
Narjes H. Dashti ◽  
◽  
Nedaa Y. Ali Al-Sarraf ◽  
Vineetha M. Cherian ◽  
Magdy S. Montasser ◽  
...  

Indole acetic acid (IAA) production is one of the distinctive traits of plant growth-promoting rhizobacteria (PGPR). Ten different rhizobacterial strains were isolated from the roots of tomato crops (Solanum lycopersicum L.), grown in Kuwait, and then screened for their plant growth-promoting abilities, with emphasis on IAA production. The isolated strains were identified by 16S partial r-RNA sequencing and further characterized by conventional biochemical tests. Based on the nucleotide sequence analysis and homology of the isolates, a phylogenetic tree was constructed. The plant growth-promoting abilities of the strains were determined by testing for ammonium production, hydrogen cyanide and acid production, growth in nitrogen-free media, phosphate solubilization, and IAA production. The potential IAA PGPRs were re-applied onto the rhizosphere of green-house grown tomato plants to determine their effects on tomato growth. The results have indicated that all isolated strains were able to produce indole acetic acid even without the presence of a tryptophan precursor.


Soil Systems ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Rihab Djebaili ◽  
Marika Pellegrini ◽  
Massimiliano Rossi ◽  
Cinzia Forni ◽  
Maria Smati ◽  
...  

This study aimed to characterize the halotolerant capability, in vitro, of selected actinomycetes strains and to evaluate their competence in promoting halo stress tolerance in durum wheat in a greenhouse experiment. Fourteen isolates were tested for phosphate solubilization, indole acetic acid, hydrocyanic acid, and ammonia production under different salt concentrations (i.e., 0, 0.25, 0.5, 0.75, 1, 1.25, and 1.5 M NaCl). The presence of 1-aminocyclopropane-1-carboxylate deaminase activity was also investigated. Salinity tolerance was evaluated in durum wheat through plant growth and development parameters: shoot and root length, dry and ash-free dry weight, and the total chlorophyll content, as well as proline accumulation. In vitro assays have shown that the strains can solubilize inorganic phosphate and produce indole acetic acid, hydrocyanic acid, and ammonia under different salt concentrations. Most of the strains (86%) had 1-aminocyclopropane-1-carboxylate deaminase activity, with significant amounts of α-ketobutyric acid. In the greenhouse experiment, inoculation with actinomycetes strains improved the morpho-biochemical parameters of durum wheat plants, which also recorded significantly higher content of chlorophylls and proline than those uninoculated, both under normal and stressed conditions. Our results suggest that inoculation of halotolerant actinomycetes can mitigate the negative effects of salt stress and allow normal growth and development of durum wheat plants.


1974 ◽  
Vol 29 (1-2) ◽  
pp. 39-41 ◽  
Author(s):  
H. Veen

Abstract Studies in vitro on the binding of phospholipids with IAA, α-NAA and some of their biologically inactive analogues demonstrate that the observed interaction between IA A and lecithin is not related to the primary action of the hormone in plant growth.


2013 ◽  
Vol 22 (3) ◽  
pp. 258
Author(s):  
S Widawati ◽  
Agus Muharam

ABSTRAK. Beberapa mikrob yang bersifat nonpatogenik dan nonsimbiotik yang efektif menambat nitrogen dari udara serta mampu melarutkan P terikat pada Ca, Al, dan Fe dalam tanah, dapat hidup dalam berbagai ekosistem di alam. Sebagian bakteri tersebut dapat diisolasi dari daerah perakaran tanaman hortikultura. Penelitian bertujuan mengetahui peran Azospirillum sp. yang potensial sebagai pendorong pertumbuhan tanaman pada ekosistem pantai dan kondisi lingkungan yang ekstrim. Pengujian terhadap isolat bakteri yang dikumpulkan dari berbagai kondisi ekosistem dilaksanakan di Laboratorium Ekofisiologi, Pusat Penelitian Biologi, LIPI, Bogor dari Bulan Januari sampai dengan Desember 2011. Sebanyak 34 isolat Azospirillum sp. diuji dengan berbagai metode, yaitu (1) uji kualitatif kemampuan isolat Azospirillum sp.  dalam menambat (fiksasi) nitrogen dan kemampuan hidup pada media Okon padat yang mengandung NaCl, (2) uji kualitatif kemampuan isolat Azospirillum sp. dalam melarutkan P terikat pada  Ca3(PO4)2 dalam media  Pikovskaya padat dan indeks efisiensi pelarutan fosfat,  (3) uji kualitatif kemampuan isolat Azospirillum sp. dalam melarutkan P terikat pada media  Pikovskaya cair  dan aktivitas enzim PME-ase asam dan basa, serta kondisi pH selama inkubasi 7 hari pada kultur murni (pH asal= 7), dan (4) analisis kemampuan Azospirillum sp. dalam memproduksi indole acetic acid (IAA).  Hasil penelitian menunjukkan bahwa: (1) semua isolat bakteri yang diuji mampu menambat nitrogen dalam media Okon padat,  (2) isolat B2, B4, B6, B12,  B14, PS2, dan FR13 mampu melarutkan P dari Ca3(PO4)2 dalam medium Pikovskaya padat dengan masing-masing indeks efisiensi pelarutan sebesar  120, 160, 140, 100, 110, 120, dan 100,  (3) isolat B1, B2, B3, B4, B6, B14, B17, PS1, PS2, PS3, FR1, FR5, FR7, FR8, FR10, FR12, dan FR13 mampu tumbuh dalam medium Okon dengan kandungan NaCl sebesar 0, 2, 4, atau 6%, (4)  konsentrasi tertinggi P terlarut dihasilkan oleh isolat B4 (5,80 mg/l), B6 (5,84 mg/l), dan PS2 (5,45 mg/l) dengan PME-ase sebesar 0,58 u m/l, 0,58 u m/l, 0,57 u m/l (asam), 0,52 mg/l, 0,50 mg/l, 0,48 mg/l (basa), dan dengan  pH : 4,20, 4,30, dan 4,22,  dan (5) isolat B4 dan B6 yang diisolasi dari pertanaman padi di pantai Rambut Siwi, Bali, mampu memproduksi IAA tertinggi, yaitu masing-masing sebesar 0,6749 dan 0,4694 ppm pada hari pertama setelah perlakuan. Berdasarkan hasil penelitian ini terbukti bahwa isolat Azospirillum sp. berpotensi sebagai plant growth promoter  untuk ekosistem di daerah pesisir atau pantai. Bakteri tersebut sangat penting untuk pengkayaan nutrisi pada lahan di daerah dataran rendah atau pantai dalam rangka pengembangan tanaman termasuk komoditas hortikultura.<br /><br />ABSTRACT. Widawati, S and Muharam, A 2012. The Laboratory  Test of  Azospirillum sp. Isolated  from Several  Ecosystems. Microbes that are nonpathogenic  and nonsymbiotic bacteria which are effectively fixed up nitrogen from air, and are able to dissolve phosphated bounded on Ca, Al, and Fe in soil, are able to growth in different ecosystems in nature. Some of the bacterial species can be isolated from rizosphere of horticultural crops. The research was aimed to determine the potential role of Azospirillum sp.  as a plant growth promoter in coastal ecosystem and extremely environmental conditions. The laboratory test of Azospirillum sp. isolated from several ecosystems was carried out in the Ecophysiology Laboratory, Research Center for Biology, Indonesian Institute of Sciences, Bogor from January until December 2011. Thirty-four isolates of Azospirillum sp. (B1 to B17;PS1 to PS3; FR1 to FR 14) were investigated with some methods i.e. (1) the qualitative test of the capability of Azospirillum sp. to fix up nitrogen in solid Okon medium containing NaCl, (2) the qualitative test of the capability of Azospirillum sp. in dissolving bounded P in solid Pikovskaya medium and phosphate dissolution efficiency index,  (3) the qualitative test of the capability of Azospirillum sp. in dissolving bounded P in liquid Pikovskaya medium and the activity of acid and base PME-ase, and pH condition after 7 days incubation in pure media, and (4) analysis of the capability of Azospirillum sp. in producing indole acetic acid (IAA).  The results pointed out that : (1) all tested isolates of Azospirillum sp. were  capable to fix up nitrogen in solid Okon medium, (2) isolates of B2, B4, B6, B12,  B14, PS2, and FR13 were capable to solubilize P on Ca3(PO4)2 in solid Pikovskaya medium with its efficiency of  120, 160, 140, 100, 110, 120, and 100, respectively, (3) isolates of B1, B2, B3, B4, B6, B14, B17, PS1, PS2, PS3, FR1, FR5, FR7, FR8, FR10, FR12, and FR13 were able to grow in Okon medium with 0, 2, 4, or 6% of NaCl doses, (4) the highest concentrations of solubilized P was resulted by isolates B4 (5.80 mg/l), B6 (5.84 mg/l), and PS2 (5.45 mg/l) with PME-ase i.e. 0.58 u m/l, 0.58 u m/l, 0.57 u m/l (acid), 0.52 mg/l, 0.50 mg/l, 0.48 mg/l (base), and with pH : 4.20, 4.30, and 4.22, and (5) isolates of B4 and B6 isolated from rice field at Rambut Siwi beach, Bali, were capable to produce highest IAA hormone i.e. 0.6749 and 0.4694 ppm respectively  on the first day after the treatment. Based on the result of this experiment it can be concluded that Azospirillum sp. is a potential plant growth promoting Rhizobacteria for coastal ecosystem. The bacterial species is very important to enrich coastal areas for crop cultivation, including horticulture.<br /><br />


2012 ◽  
pp. 355-359
Author(s):  
M.A. Estrada-Botello ◽  
E. Gómez-Méndez ◽  
E. de la Cruz-Lázaro ◽  
E. Martínez-Moreno ◽  
V. Robledo-Torres

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Ragab A. El-Mergawi ◽  
Mohamed S. A. Abd El-Wahed

Abstract Background Exogenous hormone applications modify the plant growth and development by inducing changes in their endogenous contents. However, it is not clear whether the effects of exogenous hormones on growth are direct or related with changes induced in endogenous hormones. Laboratory and greenhouse experiments were conducted to study the effect of exogenous salicylic acid (SA) or indole acetic acid (IAA) on endogenous levels in soaked seeds, 5-day-old seedlings, and in vegetative growth of foliar-sprayed plants. The effects of different concentrations of two hormones on germination and growth of maize were also studied. Results The effect of presoaking maize seeds in solutions of SA or IAA (0, 0.25, 0.5, 1, and 2 mM) on their endogenous contents in soaked seeds or in 5-day-old seedlings. Soaked seeds absorbed more SA than IAA. In young seedlings, the majority of two hormones which absorbed during seed soaking remained in the residual seeds. Presoaking seeds in SA or IAA solutions suppressed the growth of 5-day-old seedlings. In the greenhouse experiment, endogenous SA and IAA increased after spraying two compounds at 0.25–2 mM, peaking 2 days after treatment then decreased on. However, plants treated with SA at 1 mM or 2 mM continued to pose higher levels of endogenous SA, 8 days later. At 20 days after treatments, all tested concentrations of two hormones significantly increased the fresh and dry weights of the whole plant. These inducing effects disappeared 40 days after spraying. Conclusion The obtained results demonstrated the changes in endogenous SA and IAA in soaked seeds, seedling, and foliar-sprayed plants due to their exogenous application. However, concentrations of two hormones did not produce any permanent enhancement effects on germination and plant growth.


Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 350 ◽  
Author(s):  
Parvin ◽  
Hasanuzzaman ◽  
Bhuyan ◽  
Nahar ◽  
Mohsin ◽  
...  

Salinity toxicity and the post-stress restorative process were examined to identify the salt tolerance mechanism in tomato, with a focus on the antioxidant defense and glyoxalase systems. Hydroponically grown 15 day-old tomato plants (Solanum lycopersicum L. cv. Pusa Ruby) were treated with 150 and 250 mM NaCl for 4 days and subsequently grown in nutrient solution for a further 2 days to observe the post-stress responses. Under saline conditions, plants showed osmotic stress responses that included low leaf relative water content and high proline content. Salinity induced oxidative stress by the over-accumulation of reactive oxygen species (H2O2 and O2•−) and methylglyoxal. Salinity also impaired the non-enzymatic and enzymatic components of the antioxidant defense system. On the other hand, excessive Na+ uptake induced ionic stress which resulted in a lower content of other minerals (K+, Ca2+, and Mg2+), and a reduction in photosynthetic pigment synthesis and plant growth. After 2 days in the normal nutrient solution, the plants showed improvements in antioxidant and glyoxalase system activities, followed by improvements in plant growth, water balance, and chlorophyll synthesis. The antioxidant and glyoxalase systems worked in concert to scavenge toxic reactive oxygen species (ROS), thereby reducing lipid peroxidation and membrane damage. Taken together, these findings indicate that tomato plants can tolerate salinity and show rapid post-stress recovery by enhancement of their antioxidant defense and glyoxalase systems.


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