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Investigations into the heat-shock response and HSP22 expression as they relate to mitochondrial integrity, seed vigor and viability maintenance in primed and non-primed seeds of Zea maize
Abstract
In seeds of Zea maize, priming increased seed germination percentage and growth rate of derived seedlings. However, grow-out assays on controlled deteriorated maize seeds indicated that vigor and viability maintenance (VVM) in primed seeds was inferior to that in non-primed seeds. Heat-shock (HS) treatments improved primed maize seed VVM. In seeds of genotypes identified as 166 (Mo17 type) and 171 (B73 type), HS increased germination percentage by 28.9% and 10.0%, normal seedling percentage by 91.7% and 35.4%, and total dry weight by 87.3% and 38.7%, respectively in controlled deteriorated, primed seeds. HS influenced integrity of mitochondria from germinating non-aged and CD-conditioned primed seed embryos and etiolated seedlings. In embryo mitochondria from non-aged, HS-primed 166 and 171 seeds, ADP/Os were improved by 19.8% in 171 at 26°C and 229.8% in 166 at 42°C and respiratory control ratios (RC) were improved by 13.3% in 171 at 26°C and 17.9% in 166 at 42°C. In embryo mitochondria from CDconditioned HS-primed seeds, ADP/Os were improved by 5.3 and 22.6% at 26 and 42°C, respectively, in 166 and 21.3% in 171 at 26°C. In mitochondrial fractions from heat-shocked etiolated 166 and 171 seedlings, ADP/Os at 42°C were improved by 81.2 and 27.3%, respectively. Low base levels of acidic and basic 22-kD proteins (HSP22) were increased in primed seed embryo mitochondria through HS, and in non-primed and primed seeds through CD conditioning. Increased levels of HSP22 persisted through germination in a non-stress growth temperature regime. Elevated levels of HSP22 in embryo mitochondria from primed, heat-shocked seeds prior to CD-conditioning correlated with VVM improvements in primed maize seeds. Overall, HS appeared to promote VVM in primed maize seeds. This effect was associated with mitochondrial integrity and HSP22 expression.
Subject Area
Plant sciences
Recommended Citation
Petersen, Chris L, "Investigations into the heat-shock response and HSP22 expression as they relate to mitochondrial integrity, seed vigor and viability maintenance in primed and non-primed seeds of Zea maize" (2008). ETD collection for University of Nebraska-Lincoln. AAI3341869.
https://digitalcommons.unl.edu/dissertations/AAI3341869