title: Effects of osmotic stress on the kinds, forms and levels of polyamines in wheat coleoptiles.
abstract: The changes in levels and forms of polyamine (Pa) in the coleoptiles of two wheat (triticum aestivum L.) cultivars differing in drought tolerance were investigated under osmotic stress. The drought-tolerant 'Yumai 18' showed marked increases in free spermidine (Spd) and spermine (Spm) levels in coleoptiles after being treated with polyethylene glycol (PEG)-6000 for 2 d in the dark, while drought-sensitive 'Yangmai 9' showed a significant increase in free putrescine (Put) content. Treatment of coleoptiles with methylglyoxal-bis (guanylhydrazone) (MGBG), an S-adenosylmethionine decarboxylase (S-AMDC) inhibitor, resulted in reduction of free Spd and free Spm levels in coleoptiles and aggravation of PEG-induced injury to 'Yumai 18' coleoptile, while exogenous Spd treatment resulted in an increase in free Spd + free Spm content of coleoptiles, and an alleviation of PEG-induced injury to 'Yangmai 9' coleoptile. Osmotic stress induced significant increases in perchloric acid-soluble conjugated PA (PS conjugated PA) and perchloric acid-insoluble conjugated PA (PIS conjugated PA) levels in coleoptiles of 'Yumai 18' whereas osmotic stress affected only slightly the PS-conjugated PA and PIS-conjugated PA levels in 'Yangmai 9' coleoptiles. Treatment of coleoptiles with phenanthroline (o-Phen), an inhibitor of transglutaminase (TGase), also aggravated the PEG-induced injury to 'Yumai 18' coleoptiles, accompanied by the decreases in the level of PIS-conjugated PA. These results suggest that free Spd, free Spm and conjugated PA enhance the osmotic stress tolerance of wheat coleoptiles.
authors.affiliation: Henan Key Laboratory of Crop Growth and Development Regulation, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Huai-Pan
authors.initials: HP
authors.lastname: Liu
authors.forename: Zi-Xue
authors.initials: ZX
authors.lastname: Zhu
authors.forename: Tian-Xue
authors.initials: TX
authors.lastname: Liu
authors.forename: Chao-Hai
authors.initials: CH
authors.lastname: Li
mesh_terms: D018548:Cotyledon / Q000378:metabolism*; D009995:Osmosis; D011073:Polyamines / Q000378:metabolism*; D014908:Triticum / Q000378:metabolism*
chemical_list: D011073:Polyamines