Effects of simulated acid rain on the activity of antioxidant enzyme and the emission of induced green leaf volatiles in Phyllostachys pubescens

Abstract

Aims In order to understand the effects of acid rain on Phyllostachys pubescens seedlings, we analyzed the composition and content of green leaf volatiles (GLVs) and the activity of antioxidant enzyme in 3-year-old seedlings of P. pubescens under simulated acid rain stress (i.e. at pH values of 5.6, 4.0 and 2.5). We aim to elucidate the adaptation mechanisms of P. pubescens leaves to acid rain stress from aspects of GLVs emission and their biochemical characteristics. Methods The composition and content of GLVs were analyzed under near-natural conditions using the thermal desorption system/gas chromatography/mass spectrometer technique (TDS-GC-MS), and the content of soluble protein and malondialdehyde (MDA), activity of antioxidant enzymes in the leaves of P. pubescens seedlings were measured under different acid rain treatments. Important findings Results showed that the MDA content did not respond to the pH 5.6 treatment in P. pubescens. The content of MDA was elevated in treatments of pH 4.0 and pH 2.5 after 75 days and 45 days, respectively (p < 0.01). The content of soluble protein in P. pubescens leaves was significantly influenced by acid rain; under the treatments of pH 4.0 and pH 2.5, the content of soluble protein was 32% and 65%, respectively, of the controls (p < 0.01). In the pH 5.6 treatment, the content of soluble protein was only slightly increased. There were differences in the timing of responses to acid rain stress among the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), reflecting possibly a coordinative reaction of those antioxidant enzymes to stress. Compared with the control, GLVs were increased by 26.4% and 132.9% (p < 0.01), respectively, under the treatments of pH 4.0 and pH 2.5. (E)-2-nonenal, 2-ethyl-hexanal, 2-hexenal and (E)-2-nonenal were newly found 郭慧媛等: 模拟酸雨对毛竹叶片抗氧化酶活性及释放绿叶挥发物的影响 897 doi: 10.3724/SP.J.1258.2014.00084 GLVs under the acid rain stress. The results indicated that P. pubescens could enhance its ability to resist acid rain stress by adjusting its activities of antioxidant enzymes, improving contents of soluble protein and releasing GLVs.