biologia plantarum

Biologia plantarum 60:376-384, 2016 | DOI: 10.1007/s10535-016-0597-3

Crosstalk of nitric oxide with calcium induced tolerance of tall fescue leaves to high irradiance

Y. F. Xu^1,*, X. T. Chu¹, J. J. Fu¹, L. Y. Yang², T. M. Hu^1,*

¹ Department of Grassland Science, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi Province, P.R. China

² Department of Plant Biology, Cornell University, Ithaca, USA

Calcium ion (Ca²⁺) is essential secondary messenger in plant signaling networks. In this study, the effect of Ca²⁺ on oxidative damage caused by a high irradiance (HI) was investigated in the leaves of two cultivars of tall fescue (Arid3 and Houndog5). Pretreatment of the tall fescue leaves with a CaCl₂ solution significantly increased Ca²⁺ content and intrinsic HI tolerance due to a decreased ion leakage and content of malondialdehyde, hydrogen peroxide, and superoxide radicals. Moreover, the activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase increased in both the cultivars in the presence of Ca²⁺ under the HI stress. In contrast, treatments with a Ca²⁺ chelator ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) or a plasma membrane Ca²⁺ channel blocker LaCl₃ reversed these effects. On the other hand, a pronounced increase in nitric oxide synthase-like activity and NO release by exogenous Ca²⁺ treatment was observed in the tolerant Arid3 plants after exposure to the HI, whereas only a small increase was observed in more sensitive Houndog5. Moreover, the inhibition of NO production by 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide or N ^ω-nitro-L-arginine blocked the protective effect of exogenous Ca²⁺, whereas the inhibition of Ca²⁺ by EGTA or LaCl₃ had no influence on the protective effect of NO. The results indicate that NO might be involved in the Ca²⁺-induced activities of antioxidant enzymes further protecting against HI-induced oxidative damage. This protective mechanism was found to be more efficient in Arid3 than in Houndog5.

Keywords: antioxidant enzymes; Festuca arundinacea; hydrogen peroxide; malondialdehyde

Subjects: nitric oxide; calcium; high irradiance; antioxidants; hydrogen peroxide; malondialdehyde; ion leakage; tall fescue

Received: March 19, 2015; Revised: August 8, 2015; Accepted: August 10, 2015; Published: June 1, 2016Show citation