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Plant Cell Environ. 2016 Feb;39(2):245-58. doi: 10.1111/pce.12521. Epub 2015 Apr 17.

Silicon-mediated changes in polyamines participate in silicon-induced salt tolerance in Sorghum bicolor L.

Author information

1
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, 712100, China.
2
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China.
3
Faculty of Agriculture, Tottori University, Koyama Minami 4-101, Tottori, 680-8533, Japan.
4
NARO Agricultural Research Center, Kannondai 3-1-1, Tsukuba, 305-8666, Japan.

Abstract

Silicon (Si) is generally considered a beneficial element for the growth of higher plants, especially under stress conditions, but the mechanisms remain unclear. Here, we tested the hypothesis that Si improves salt tolerance through mediating important metabolism processes rather than acting as a mere mechanical barrier. Seedlings of sorghum (Sorghum bicolor L.) growing in hydroponic culture were treated with NaCl (100 mm) combined with or without Si (0.83 mm). The result showed that supplemental Si enhanced sorghum salt tolerance by decreasing Na(+) accumulation. Simultaneously, polyamine (PA) levels were increased and ethylene precursor (1-aminocyclopropane-1-carboxylic acid: ACC) concentrations were decreased. Several key PA synthesis genes were up-regulated by Si under salt stress. To further confirm the role of PA in Si-mediated salt tolerance, seedlings were exposed to spermidine (Spd) or a PA synthesis inhibitor (dicyclohexylammonium sulphate, DCHA) combined with salt and Si. Exogenous Spd showed similar effects as Si under salt stress whereas exogenous DCHA eliminated Si-enhanced salt tolerance and the beneficial effect of Si in decreasing Na(+) accumulation. These results indicate that PAs and ACC are involved in Si-induced salt tolerance in sorghum and provide evidence that Si plays an active role in mediating salt tolerance.

KEYWORDS:

1-aminocyclopropane-1-carboxylic acid (ACC); arginine; ethylene; ion concentration; salt stress; spermidine

PMID:
25753986
DOI:
10.1111/pce.12521
[Indexed for MEDLINE]
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