Dual Role of Acid Rain and Pyricularia oryzae on Growth, Photosynthesis and Chloroplast Ultrastructure in Rice Seedlings

Hongru Li,Zhong Qin,Qiuyuan Xu,Chao Li,Yiliang Liu,Qi Wang,Hui Wei,Huimin Xiang,Jiaen Zhang

doi:10.3390/agronomy12030567

Abstract

Rice is widely planted and serves as staple food in the world, but it is often exposed to acid rain and rice blast (Pyricularia oryzae). In this work, we analyzed the effects of co-exposure to simulated acid rain (SAR) and P. oryzae on the photosynthetic growth of rice seedlings. We found that the growth, photosynthesis, and chloroplast ultrastructure of rice seedlings were damaged under single treatments of P. oryzae and strong acid rain (pH 2.0) but increased under medium acidity acid rain (pH 4.0). Similarly, when plants were exposed to both P. oryzae and acid rain, pH 4.0 mitigated the changes of growth, photosynthetic characteristics, and chloroplast ultrastructure induced by P. oryzae, but pH 2.0 aggravated these changes. In addition, we found that significant differences in chlorophyll content (chlorophyll a and chlorophyll b) correlated with transpiration rate (Tr) under the combined stress of acid rain and P. oryzae at pH 4.0 and pH 2.0. Medium-acidity acid rain alleviated the harm caused by P. oryzae on rice growth by enhancing synergistic regulatory mechanisms of photosynthetic traits to increase plant resistance tolerance. The effect of P. oryzae on photosynthetic traits of rice was regulated by acidity of acid rain.

Highlights

IntroductionRice blast caused by the filamentous fungus Pyricularia oryzae significantly and negatively impacts global rice yields each year [1,2]
Rice (Oryza sativa) is a critical economic crop worldwide
The plant height, leaf area, and biomass treated with pH 2.0 showed a significant decrease compared with control, but they did not show changes in those treated with pH 4.0 (Table 1)

Summary

Introduction

Rice blast caused by the filamentous fungus Pyricularia oryzae significantly and negatively impacts global rice yields each year [1,2]. Rice blast induces diamond-shaped brown necrosis spots with a grayish white center on the surface of the infected leaves, thereby reducing the green leaf area [3,4]. Rice leaves infected with P. oryzae will cause leaf tissue senescence and death, cell deformations or collapse, destruction of chloroplast ultrastructure, interference with photosynthesis and the protective system, and inhibits rice growth [8]. Acid rain is another severe global environmental problem [9].

Objectives

Methods

Results

Discussion

Conclusion