Plant growth promoting rhizobacteria from Juan Fernández archipelago improve germination rate of endangered plant Solanum fernandezianum Phil.

Abstract

Robinson Crusoe Island, Chile, has one of the highest densities of endemic plants in the world, however many of its native and endemic species, such as Solanum fernandezianum Phil., are currently declared endangered. Coating the seeds of native plants with locally sourced plant-growth-promoting bacteria can be used as a tool for conservation programs of endangered plant species. Isolation and screening of rhizosphere bacteria from Robinson Crusoe Island resulted in the selection of three bacteria: Serratia sp. RGM 2525, Raoultella sp. RGM 2526, and Pseudomonas sp. RGM 2607, due to their capacity of producing indole compounds (30-45 μL mL -1 ) and indoleacetic acid (IAA) (5-10 μg mL -1 ). The effect of these strains on the seed germination rate of S. fernandezianum was evaluated under five treatments: individual inoculation of each bacteria, inoculation of a mixture of the three bacteria and a treatment without bacteria (control). Inoculation of bacteria improved the seed germination rate of S. fernandezianum compared to the control treatment, with the bacterial mix as the best treatment with 26.9% germination (p < 0.05), 10.2% higher than control. Bioinoculants formulated with bacteria isolated from rhizosphere soils could improve the seed germination rate of the endangered plant S. fernandezianum.

Bacillus megaterium RTS1 enhances resistance of Lycopersicon esculentum to salinity stress through the improvement of antioxidant defenses

“…Where Y is the predicted response, Xi and Xj are independent factors, k is the integer of factors, β 0 is the model intercept, βi is the linear constant, and βii is the quadratic constant ( 27 ).…”

“…The spry dried powder of bacterium was added to the final concentration of 1×10 7 CFUs of spore/g of soil. The pots were incubated in a phytotron under 16 h at 27°C and 22°C during day and night, respectively ( 27 ). All the pots were irrigated with sterile distilled water with an electrical conductivity of 0.043 dS/m, until reaching the 4-leaf stage.…”

Selective screening and characterization of plant growth promoting bacteria for growth enhancement of tomato, Lycopersicon esculentum

“…Sterile soil without any inoculation was used as a negative control. The pots were incubated in a phytotron under 16 h at 27°C and 22°C during day and night, respectively according to the procedure described by Carrasco-Fernández J ( 23 ). The pots were irrigated with sterile distilled water, and shoot length was measured after 42 days.…”

Interactive Effects of Inoculation with Two Isolates Providencia vermicola and Raoultella planticola and Two Levels of Mineral Fertilizers on Wheat Yield Increase

“…The results shown in Table (3) show that if the bio fertilizer treatment outperforms the non-pollinated treatment, if the two overlapping treatments (P3) had the highest grain yield of 7.21 µg H -1 compared to the two single pollination treatments P2 and P1 without Significant difference since they recorded rates of 6.52 µg H -1 and 6.39 µg H -1 respectively, This may be due to the role of the bacterial species used in bio fertilizer preparation (R. planticola and P. vermicola) in regulating the production of growth hormones [9,10]. Which is due to its important role in increasing the various growth indicators and yield components of plants by increasing cell division and elongation, and then expanding the root hairs, which in turn will increase the surface area of the roots Hence, the absorption of nutrients is greater, which reflects positively on increasing the various indicators of vegetative growth and the formation of dry matter, and then increasing the grain fullness and weight gain [11].…”