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Respiration and Mitochondrial Characteristics of Imbibing Maize Embryos Damaged by High Temperatures during Desiccation
Author(s) -
Madden R. F.,
Burris J. S.
Publication year - 1995
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1995.0011183x003500060025x
Subject(s) - imbibition , biology , radicle , desiccation , germination , embryo , respiration , seedling , mitochondrion , oxidative phosphorylation , botany , meristem , recalcitrant seed , horticulture , zoology , biochemistry , microbiology and biotechnology , shoot
Hybrid maize ( Zea mays L.) seed artificially dried to 120 g H 2 O kg −1 moisture in air temperatures of either 35 (LT) or 45°C (HT) was used to study the effect of desiccation temperature on mitochondrial function during early imbibition. In embryo culture experiments, embryo growth was delayed for embryos excised from HT treated seed compared with LT samples. After 1 h of imbibition, the rate of O 2 uptake by LT axis tissue was greater than for HT dried samples. Uptake rates continued to increase for LT samples through the first 6 h of imbibition while rates for HT axes remained constant. Mitochondria isolated from LT axis tissue that had undergone imbibition for 4 h exhibited respiratory control with oxidative phosphorylation efficiency values of 0.79 and 0.77 for NADH and succinate assays, respectively. Mitochondria from imbibing HT axis tissue exhibited no respiratory control. Electron micrographs of cells from the radicle meristem region of both treatments showed that mitochondrial development during the initial 24 h of imbibition was impaired in HT samples. These results suggest that mitochondrial function and development, during the initial stages of embryonic tissue hydration, is impaired when maize seed are artificially dried with high air temperatures. We conclude that the development of mitochondrial function during this period is a key element in determining the rate of germination and subsequent seedling growth.