Effect of Streptomyces Inoculation on Ipomoea aquatica and Pachyrhizus erosus Grown Under Salinity and Low Water Irrigation Conditions

Abstract

The distribution of salty areas and drought conditions caused by climate change can limit successful crop production. The co-occurrence of salinity and drought gives a unique challenge for plant growth-promoting bacteria (PGPB) in agricultural purposes. In this study, the effect of irrigation and salinity on the abilities of isolates of plant growth-promoting bacteria (Streptomyces sp. St1 and St8) to promote the growth of Ipomoea aquatica and Pachyrhizus erosus was investigated. Both plants were planted in pots with combinations of salinity (non-saline or saline soil), different irrigation levels, and different bacterial inoculations. The results showed that the salinity decreased the root dry weight of I. aquatica and decreased the shoot and root dry weight of P. erosus. Salinity also decreased the tuber formation and root efficiency of P. erosus. Low irrigation and bacterial species did not affect either plant’s shoot or root growth. However, the chlorophyll content in the leaves of both plants decreased in the inoculated plants compared to the non-inoculated plants. Among the three factors in this study, salinity was the most influential factor, and irrigation was the least effective factor on plant growth for both parts. Soil salinity may concern plant growth-promoting bacteria, and salt-tolerant strains may be an interesting choice for use in combination with saline and low water conditions.