Affiliations: Key Laboratory of Crop Growth Regulation, Ministry of
Agriculture, College of Life Science, Nanjing Agriculture University, Nanjing
210095, China | Department of Life Science, Zhoukou Normal College,
Zhoukou, 466000, China
Abstract: The effects of osmotic stress on the ATPase activity, the contents
of -SH group and conjugated polyamines in mitochondrial membrane from wheat
seedling [Triticum aestivum L. cv. Yumai No.18 (drought-tolerant) and cv. Yumai
No.9(drought-sensitive)] roots were investigated. The results showed that
ATPase activity and -SH group content decreased with polyethylene glycol (PEG)
6000 (−0.55 MPa) treatment for 7 d, in concert with the decrease of the
ratio of noncovalently conjugated spermidine (NCC-Spd)/noncovalently conjugated
putrescine (NCC-Put) and increase of the covalently conjugated putrescine
(CC-Put). Osmotic stress injury to Yangmai No.9 seedlings was alleviated
greatly with 1 mmol/L exogenous spermidined (Spd), in concert with marked
increases of the ratio of NCC-Spd/NCC-Put, -SH group contents and ATPase
activity in mitochondrial membrane. Under osmotic stress, the concomitant
treatment of Yumai No.18 seedlings with methylglyoxyl bis (guanylhydrazone)
(MGBG), an inhibitor of S-adenosyl methionine decarboxylase (SAMDC), and
phenanthrolin (o-Phen), an inhibitor of transglutaminase (TGase), caused a
significant decrease of the ratio of NCC-Spd/NCC-Put, CC-Put contents,
respectively, in concert with the marked decreases of ATPase activity, -SH
group content and its tolerance to osmotic stress. All the results above
suggested that osmotic stress tolerance of wheat seedlings was associated with
the ATPase activity, the contents of -SH group, NCC-Spd and CC-Put in
mitochondrial membrane.
