The effect of calcium chloride on growth, photosynthesis, and antioxidant responses of Zoysia japonica under drought conditions.

Chengbin Xu,Lihong Zhang,Xuemei Li,Mark R Muldoon

doi:10.1371/journal.pone.0068214

Chengbin Xu, Lihong Zhang + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0068214

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Journal: PloS one	Publication Date: Jul 2, 2013
Citations: 110	License type: CC BY 4.0

Affiliation: Liaoning University, Shenyang Normal University

Abstract

Few attempts have been made to study the alleviating effects of signal molecules on zoysiagrass ( Zoysia japonica ) under drought stress. Calcium chloride has been shown to ameliorate the adverse effects of drought stress on many plants. It is necessary to investigate how to enhance drought tolerance of zoysiagrass using calcium chloride. The study elucidated the effects of calcium chloride on zoysiagrass under drought conditions by investigating the following parameters: biomass, chlorophyll (Chl) content, net photosynthetic rate (Pn), chlorophyll fluorescence, antioxidant enzymes, proline content, and malondialdehyde (MDA) content. Experimental conditions consisted of an aqueous CaCl2 solution at 5, 10, and 20 mM sprayed on zoysiagrass leaves for 3 d, following by an inducement of drought conditions by withholding water for 16 d. Under drought conditions, all CaCl2 pretreatments were found to increase the above-ground fresh biomass, as well as below-ground fresh and dry biomass. The resulting Chl (a, b, a+b) contents of the 5 and 10 mM CaCl2 pretreatment groups were higher than those of the control. In the later stages of drought conditions, the chlorophyll fluorescence parameter Fv/Fm was higher in leaves treated with 10 mM CaCl2 than in the leaves of the other two treatment groups. Zoysiagrass pretreated with 10 mM CaCl2 possessed both the maximum observed Pn and antioxidant enzyme activities. Meanwhile, lower MDA and proline contents were recorded in the plants pretreated with 5 and 10 mM CaCl2 under drought conditions. As a whole, the drought tolerance of zoysiagrass was improved to some extent by the application of a moderate calcium concentration.

Highlights

Drought is a major environmental factor that adversely affects the productivity and survival of plants [1]
The soil water content (SWC) values for all CaCl2 pretreatments and the control significantly decreased to approximately 8% at 7 days after drought
Changes in above- and below-ground biomass An increase in the above- and below-ground fresh biomass was observed for all CaCl2 pretreatment groups, and the greatest increase was observed for the 10 mM CaCl2 pretreatment group (Figure 2A)

Summary

Introduction

Drought is a major environmental factor that adversely affects the productivity and survival of plants [1]. Plants utilize various mechanisms to adapt to and withstand drought conditions [4]. In plants subjected to drought, the generation of a variety of active oxygen species (ROS) has been observed. These include: superoxide anion (O-2), hydrogen peroxide (H2O2), and hydroxyl radical (·OH), all of which can cause oxidative damage to plants, including membrane lipid peroxidation [5]. When plant capacity to detoxify ROS increases, an increase in drought tolerance can be observed [6,7]. The rapid accumulation of proline, an osmoregulation substance in cells, constitutes another biochemical mechanism in plants that acts to achieve drought tolerance [8,9]

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