Exogenous 24-epibrassinolide alleviates the detrimental effects of suboptimal root zone temperature in cucumber seedlings

ABSTRACT

Suboptimal root zone temperature (RZT) is major hurdle for vegetables production that causes a remarkable reduction in growth and yield during winter and early spring. The aim of this study is to assess the effects of 24-epibrassinolide (EBR) on physiological and biochemical mechanism on cucumber seedling under suboptimal RZT. The treatments were NT (normal RZT [22 ± 2°C]), LT (suboptimal RZT [14 ± 2°C]), EBR (0.1 µM EBR + suboptimal RZT [14 ± 2°C]) and BZR (brassinazole, a specific EBR biosynthesis inhibitor) (4 µM BZR + suboptimal RZT [14 ± 2°C]). The results showed that LT and BZR significantly decline cucumber seedlings growth, chlorophyll (Chl) contents, photosynthetic capacity, antioxidant enzyme activities and nutrients accumulation. Exogenous EBR application significantly enhanced cucumber seedling growth, Chl contents, photosynthetic capacity, nutrient contents, activities of antioxidant enzymes and reduced the contents of H₂O₂ (hydrogen peroxide), ${\mathrm{O}}_2^{\cdot -}$ (superoxide radical) and malondialdehyde. The transcript levels of EBR-biosynthesis genes are reduced by LT, while reported significantly higher in EBR treated seedling. Our results suggest that exogenous EBR could alleviate the harmful effects of suboptimal RZT by modulating EBR-biosynthesis genes expression and antioxidant, nutrient, Chl and photosynthetic machinery, thus leading to improved plant growth.

KEYWORDS:

• 24-epibrassinolide
• antioxidant
• EBR-biosynthesis genes
• hormones
• suboptimal root zone temperature
• cucumber

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China: [Grant Number 2016YFD0201006];the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences: [Grant Number CAAS-ASTIP-IVFCAAS];the Earmarked fund for Modern Agro-industry Technology Research System: [Grant Number CARS-25-C-01] to Xianchang Yu and the Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture, China. The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript.