Foliarly Applied 24-Epibrassinolide Modulates the Electrical Conductivity of the Saturated Rhizospheric Soil Extracts of Soybean under Salinity Stress

Victoria Otie; Ali Ibrahim; Itohowo Udo; Junichi Kashiwagi; Asana Matsuura; Yang Shao; Michael Itam; Ping An; Anthony Egrinya Eneji

doi:10.3390/plants11182330

Foliarly Applied 24-Epibrassinolide Modulates the Electrical Conductivity of the Saturated Rhizospheric Soil Extracts of Soybean under Salinity Stress

Plants (Basel). 2022 Sep 6;11(18):2330. doi: 10.3390/plants11182330.

Authors

Victoria Otie^{1

2}, Ali Ibrahim¹, Itohowo Udo¹, Junichi Kashiwagi³, Asana Matsuura⁴, Yang Shao⁵, Michael Itam⁶, Ping An², Anthony Egrinya Eneji¹

Affiliations

¹ Department of Soil Science, Faculty of Agriculture, Forestry and Wildlife Resources Management, University of Calabar, P.M.B. 1115, Calabar 540271, Nigeria.
² Arid Land Research Centre, Tottori University, Hamasaka, Tottori 6800001, Japan.
³ Research Faculty of Agriculture, Hokkaido University, Kitaku, Kita9 Nishi9, Sapporo 0608589, Japan.
⁴ Faculty of Agriculture, Shinshu University, 8304, Minamiminowa-Village, Kamiina-County, Nagano 3994598, Japan.
⁵ College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
⁶ Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA.

Abstract

The accumulation of salts within the rhizosphere is a common phenomenon in arid and semi-arid regions where irrigation water is high in salts. A previous study established the ameliorative effect of foliarly applied 24-epibrassinolide (BR) on soybean under salinity stress. As a follow-up to that study, this work evaluated the effects of BR on the electrical conductivity of saturated soil extracts (EC_ses) under soybean exposed to salt stress. Three salinity levels (3.24, 6.06 and 8.63 dS/m) in a factorial combination with six frequencies of BR application-control, seedling, flowering, podding, seedling + flowering and seedling + flowering + podding-were the treatments, and the rhizospheric EC_se was monitored from 3 to 10 weeks after the commencement of irrigation with saline water (WAST). The principal component analysis revealed that samples in saline BR treatments clustered together based on the BR application frequencies. There was a significant increase in EC_se with increases in salinity and WAST. The frequent application of BR significantly reduced EC_se to 5.07 and 4.83 dS/m relative to the control with 6.91 dS/m, respectively, at week 10. At 8.63 dS/m, the application of BR (seedling + flowering + podding) reduced EC_se by 31.96% compared with the control. The underlining mechanism is a subject for further investigation.

Keywords: 24-epibrassinolide; arid region; rhizosphere; root exudates; salinity stress; soybean.

Grants and funding

The research was partly supported by the Joint Research Associate Program of the Arid Land Research Center (ALRC), Tottori University, Tottori, Japan.