TITLE	Ammonium accumulation in relation to senescence of detached maize leaves
AUTHOR	Shu Jiuan Chen Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China Ching Huei Kao Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China
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ABSTRACT	We investigated the role of ammonium in the regulation of dark-induced senescence of detached maize leaves. Ammonium levels were found to increase prior to senescence. The accumulation of ammonium was associated with a decrease in glutamine synthetase (GS). Exogenous NH4Cl and methionine sulfoximine (MSO), an inhibitor of GS, increased ammonium level and promoted senescence. Benzyladenine, a synthetic cytokinin, retarded senescence and decreased ammonium level. Methyl jasmonate promoted senescence and increased the ammonium level. The addition of L-glutamine had no effect on dark-induced, MSO- and MJ-promoted senescence. Our results suggest that an increase in ammonium level is associated with the senescence of detached maize leaves in the dark.
KEYWORD	Ammonium; Benzyladenine; Leaf senescence; Methyl jasmonate; Methionine sulfoximine; Zea mays;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 37 Number 4 October 1996, page 255-259, 5 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China