EFFECT OF PLANT GROWTH PROMOTING RHIZOBACTERIA AND SALINITY LEVELS ON TOMATO PLANT GROWTH USING N15 TECHNIQUE

Authors

1 Dept. Plant Res., Cent. Nuclear Res., Authority Atomic Energy, Egypt.

2 Dept. Plant Prod., Fac. Environ. Agric. Sci., Arish Univ., Egypt.

Abstract

Pot experiments were conducted at the Experimental Greenhouse at Nuclear Research Center, Atomic Energy Authority, Egypt, during the two growing seasons of 2017 and 2018 for studying the effect of soil salinity levels and inoculation with Rhizobacteria on improving tomato (hybrid “Anfoway F1) plant growth and its productivity, using salty soil of Ras-Sudr, South Sinai Governorate. Saline treatments were prepared as follows: A) In the first season (2017), three saline treatments were used In the second season 2018, four saline treatments were used Rhizobacteria treatments were as follows: A) In the first season: 1) control (pots without inoculation with Rhizobacteria); 2) inoculation with Azosperillum sp.; 3) inoculation with Azotobacter sp.; 4) inoculation with a mixture from Azosprillum sp.+ Azotobacter sp.; B) In the second season: 1) control, (pots without inoculation with Rhizobacteria); 2) inoculation with a mixture from Azosprillum sp.+ Azotobater sp. Ammonium sulphate as a nitrogen fertilizer have an atom excess of 2% N at a rate of 2.14g/pot were used to measure nitrogen derived from fertilizer and then determine the fertilizer-N yield by tomato plant. Treatments were arranged randomly in a factorial experiment with a randomized complete block design included four replicates for each treatment. Results indicated that plants grown under low salinity (0.3 dSm-1) and applicated by  plant growth promoting bacteria (PGPR) had increased number of leaves/plants, number of branches/plants compared with that grown in high salinity and did not applicated with PGPR. The interaction between high levels of salinity (6.6 and 5.8 dSm-1) and each of Azotobacter and Azosprillium increased total chlorophyll in tomato leaves significantly compared to the leaves untreated with PGPR. Inoculation by plant growth promoting rhizobacteria (PGPR) with the low level of salinity (0.3 dSm-1) increased number of flowers per plant compared to its same interaction with the high level of salinity (3.6 dSm-1). The effect of interaction between Rhizobacteria and soil salinity on nitrogen labeled showed a significant increment at all salinity levels and all Rhizobacteria forms. Nitrogen derived from ammonium sulphate by tomato plants were improved significantly with treating soil by Rhizobacteria. Plant growth promoting rhizobacteria in different forms increased significantly fertilizer nitrogen yield (FNY) and nitrogen use efficiency in tomato plants.

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