Inhibition of nitric oxide synthase (NOS) underlies aluminum-induced inhibition of root elongation in Hibiscus moscheutos.
Aluminum (Al) is toxic to plants when solubilized into Al(3+) in acidic soils, and becomes a major factor limiting plant growth. However, the primary cause for Al toxicity remains unknown. Nitric oxide (NO) is an important signaling molecule modulating numerous physiological processes in plants. Here, we investigated the role of NO in Al toxicity to Hibiscus moscheutos. Exposure of H. moscheutos to Al(3+) led to a rapid inhibition of root elongation, and the inhibitory effect was alleviated by NO donor sodium nitroprusside (SNP). NO scavenger and inhibitors of NO synthase (NOS) and nitrate reductase had a similar inhibitory effect on root elongation. The inhibition of root elongation by these treatments was ameliorated by SNP. Aluminum inhibited activity of NOS and reduced endogenous NO concentrations. The alleviation of inhibition of root elongation induced by Al, NO scavenger and NOS inhibitor was correlated with endogenous NO concentrations in root apical cells, suggesting that reduction of endogenous NO concentrations resulting from inhibition of NOS activity could underpin Al-induced arrest of root elongation in H. moscheutos.
Tian
Qiu-Ying
QY
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Sun
Dong-Hua
DH
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Zhao
Min-Gui
MG
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Zhang
Wen-Hao
WH
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
D000535:Aluminum / Q000633:toxicity*; D003497:Cyclic N-Oxides / Q000633:toxicity; D031584:Hibiscus / Q000187:drug effects*; D007093:Imidazoles / Q000633:toxicity; D050901:Nitrate Reductase / Q000037:antagonists & inhibitors; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D009599:Nitroprusside / Q000633:toxicity; D018517:Plant Roots / Q000187:drug effects*
D003497:Cyclic N-Oxides; D007093:Imidazoles; D009599:Nitroprusside; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D009569:Nitric Oxide; D000535:Aluminum; D019001:Nitric Oxide Synthase; D050901:Nitrate Reductase