TITLE	Are polyamines involved in the heat-shock protection of mung bean seedlings?
AUTHOR	Ranjit K. Basra Department of Botany, Punjab Agricultural University, Ludhiana-141004, India Amarjit S. Basra Department of Botany, Punjab Agricultural University, Ludhiana-141004, India C.P. Malik Department of Botany, Punjab Agricultural University, Ludhiana-141004, India I.S. Grover Department of Botany, Guru Nanak Dev University, Amritsar-143005, India
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ABSTRACT	Germinating seeds of Vigna radiata (Linn) Wilczek cv. ML 311, with a radicle length of 5 mm, were subjected to a heat-shock episode of 50°C for 2 h followed by transfer to the normal temperature (28°C) for 3 days in the dark. Exogenous effects of polyamines (putrescine, spermidine, and spermine) on the recovery growth and membrane integrity of seedling tissues were studied. Application of polyamines, either as a pre-treatment at 28°C for 2 h prior to heat-shock or as a co-treatment (50°C, 2 h) during the heat-shock period itself, enhanced the recovery growth of both roots and hypocotyls but especially the former with the order of effectiveness being putrescine, spermidine, and spermine. Treatment with polyamine biosynthetic inhibitors, i.e. D,L a-diflouromethylarginine (DFMA) and D,L a-diflouromethylornithine (DFMO) resulted in thermosensitization, making seedlings vulnerable to heat-shock. This effect could be ameliorated by putrescine application. An important role of polyamines in heat-shock protection is thus indicated.
KEYWORD	Heat-shock; Ion leakage; Lipid peroxidation; Polyamines; Root growth; Seedling growth; Vigna radiata;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 38 Number 3 July 1997, page 165-169, 5 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China