PJB-2017-259
Effects of exogenous nitric oxide on the physiological characteristics of Indocalamus barbatus McClure seedlings under acid rain stress
Tao Wang, Wanhong Yang, Yinfeng Xie, Mei He, Xing Bu and Li Dai
Abstract
The effects of four concentrations (100, 400, 700, and 1000 mg/L) of sodium nitroprusside (SNP, adonor of NO) on physiological characteristics were investigated in the leaves of bamboo (Indocalamus barbatus McClure) seedlings exposed to simulated acid rain (SAR; pH3.0) stress.The results showed that a foliar application of 100 - 400 mg/L SNP pretreatment mitigates the SAR-inflicted decrease in net photosynthetic rate (Pn), chlorophyll (SPAD) content, soluble protein (SP) content, and superoxide dismutase (SOD) activity, and the increase in peroxidase (POD) activity as well as in preventing an increase in membrane permeability (MP) and superoxide anion radical generation rate (O2.). This promoting effect was most pronounced at 400 mg/L SNP treatment, which also exhibited a time-dependent effect. However, seedlings subjected to higher concentrations of SNP such as 700 or 1000 mg/L showed little recovery from damage, and even showed signs of toxic damage, demonstrating the concentration-dependent effect of NO against acid rain. Further analysis showed that acid rain exposure caused oxidative stress by elevating MP and O2. in I. barbatus seedlings. Treatment with 400 mg/L SNP partly alleviated the acid rain toxicity by reducing O2. and stimulating SOD and POD activities. The recovery of Pn, SPAD, and SP was also significantly correlated with oxidative status in the seedlings. Moreover, the changes in the physiological indicators mentioned above, were consistent with the morphological observations. Based on these results, it can be concluded that SNP exerted an advantageous effect on alleviating the inhibitory effect of acid rain by regulating the balance of ROS metabolism and reducing the accumulation of ROS.
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