Effects of Endophytic Bacteria on Some Physiological Traits and Nutrient Contents in Pepper Seedlings Under Drought Stress

Abstract

The present study was conducted to determine the effects of the endophytic bacteria (EB) on some physiological traits and nutrient contents in pepper (Capsicum annuum L.) seedlings grown under drought stress. The pepper cv. Mostar F1 and two EB isolates [Bacillus thurigiensis (CA41/1) and Ochrobactrum sp. (CB36/1)] were employed under drought stress condition. The first EB application was at a density of 108 CFU mL-1 as 10 mL plant-1 at the first cotyledon leaf stage and the second one was two weeks later. The seedlings were irrigated by gravimetric method on a regular basis every two days. Twenty days after EB application, irrigation was terminated completely in half of the applications in order to form drought stress for 7 days. Among the studied traits, membrane damage index, leaf relative water content, amount of malondialdehyde, catalase enzyme activity, ascorbate peroxidase enzyme activity, and the contents of some mineral elements (K, Ca and Mg) were significantly different in drought stressed seedlings compared the control (regularly irrigated) seedlings. EB (Especially CA41/1) had generally positive effects on most studied traits, whereas drought stress had generally negative effects on the mentioned traits. There might be a high potential of EB fighting against drought stress in pepper; however, one keeps in mind that there is variation in the performance of EB; therefore, the best EB combinations have to be determined even for cultivars in each plant species in future studies. © 2021, Centenary University. All rights reserved.