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Increased Drying Rate Lowers the Critical Water Content for Survival in Embryonic Axes of English Oak ( Quercus robur L.) Seeds F
Author(s) -
Ntuli Tobias M.,
FinchSavage William E.,
Berjak Patricia,
Pammenter Norman W.
Publication year - 2011
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/j.1744-7909.2010.01016.x
Subject(s) - dehydration , desiccation , superoxide dismutase , quercus robur , catalase , recalcitrant seed , water content , biology , glutathione , chemistry , botany , biochemistry , antioxidant , enzyme , geotechnical engineering , engineering
The potential to cryopreserve embryonic axes of desiccation‐sensitive (recalcitrant) seeds is limited by damage during the desiccation necessary for low temperature survival, but the basis of this injury and how to reduce it is not well understood. The effects of drying rate on the viability, respiratory metabolism and free radical‐mediated processes were therefore investigated during dehydration of Quercus robur L. embryonic axes. Viability, assessed by evidence of germination and tetrazolium staining, showed a sharp decline at 0.27 and 0.8 g/g during rapid (<12 h) or slow (3 d) dehydration, respectively. Rapid dehydration therefore lowered the critical water content for survival. At any given water content rapid dehydration was associated with higher activities of the free radical processing enzymes, superoxide dismutase, catalase and glutathione reductase and lower levels of hydroperoxide and membrane damage. Rapid dehydration was also associated with lower malate dehydrogenase activity, and a reduced decline in phosphofructokinase activity and in levels of the oxidized form of nicotinamide dinucleotide. Ageing may have contributed to increased damage during slow dehydration, since viability declined even in hydrated storage after 3 d. The results presented are consistent with rapid dehydration reducing the accumulation of damage resulting from desiccation induced aqueous‐based deleterious reactions.