HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Madden, R. F. Articles by Burris, J. S. Search for Related Content PubMed Articles by Madden, R. F. Articles by Burris, J. S. Agricola Articles by Madden, R. F. Articles by Burris, J. S.

Respiration and Mitochondrial Characteristics of Imbibing Maize Embryos Damaged by High Temperatures during Desiccation

Northrup King Seeds, Hampton, IA 50441
Seed Science Center, Iowa State University, Ames, IA 50011

^* Corresponding author (jsburris{at}iastate.edu).

Hybrid maize (Zea mays L.) seed artificially dried to 120 g H₂O 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 O₂ 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.

Received for publication November 9, 1994.