Biological Response of Lallemantia iberica to Brassinolide Treatment under Different Watering Conditions.

Saeid Naservafaei,Parviz Moradi,Eileen Mac Sweeney,Andrea Mastinu,Yousef Sohrabi

doi:10.3390/plants10030496

Abstract

Lallemantia iberica (L. iberica) is an important dry season medicinal plant. Drought, an important abiotic stress, adversely affects the plant’s metabolism, which can be alleviated by plant growth regulators like brassinolides. A two-year field experiment was conducted in 2017–2018 to determine the effects of three different irrigation regimes and four brassinolide concentrations on the L. iberica biochemical properties. A split-plot based on a completely randomized block design in three replicates was used as an experimental design with the following irrigation regimes: full watering, watering until flowering and watering until branching. These were the main plots, and 0, 0.5, 1 and 1.5 μM brassinolide concentrations were applied as the subplots. The results showed that many antioxidant enzymes and some biochemical parameters were affected by brassinolide treatment. Furthermore, the highest membrane stability and grain yield were produced in full watering treatment in the second year, and these treatments were not affected by brassinolide application. Several concentrations of brassinolide differently affected the studied treatments, and our study suggests that the amelioration of the effects of the drought stress on L. iberica could possibly be achieved through brassinolide-induced elevation of reactive oxygen species (ROS) scavenging defense systems. There is a need for complementary research to prove the effectiveness of foliar application of this growth regulator to improve the growth and yield of L. iberica under water shortage conditions.

Highlights

Lallemantia iberica (L. iberica) (Figure 1), which belongs to the Lamiaceae family [1], is a source of secondary metabolites, and its seeds contain mucilage, polysaccharide, fiber, oil and protein [2]
Antioxidant products like ascorbate, α-tocopherol and carotenoids, as well as antioxidant enzymes like catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione reductase exist in cell organelles and the cytoplasm
It was observed in apples that, without considering the brassinolide concentration, plants that were under more severe drought stress produced higher catalase activity [18]

Summary

Introduction

Lallemantia iberica (L. iberica) (Figure 1), which belongs to the Lamiaceae family [1], is a source of secondary metabolites, and its seeds contain mucilage, polysaccharide, fiber, oil and protein [2]. Antioxidant products like ascorbate, α-tocopherol and carotenoids, as well as antioxidant enzymes like catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione reductase exist in cell organelles and the cytoplasm. They play a critical role in the detoxification of ROS [9]. Brassinolide (BR), a phytohormone belonging to the brassinosteroids family, is involved in different plant physiological processes, including adaptation to various abiotic and biotic stresses [14]. BR leads to stress tolerance by improving the plant’s defense system, which includes enhancing the activities of antioxidant enzymes (APX, SOD, peroxidase (POD), CAT and GR) [15]. Elevated activities of CAT, APX and SOD through the application of BR reduce the H2O2 content [13] and the peroxidation of membrane lipids, which is assessed by the levels of malondialdehyde (MDA) content [16]

Methods

Results

Discussion

Conclusion