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Desiccation‐induced loss of seed viability is associated with a 10‐fold increase in CO 2 evolution in seeds of the rare tropical rainforest tree Idiospermum australiense
Author(s) -
Franks P. J.,
Drake P. L.
Publication year - 2003
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00776.x
Subject(s) - desiccation , desiccation tolerance , biology , recalcitrant seed , botany , water content , ecology , horticulture , geotechnical engineering , engineering
Summary• Here the relationship was investigated between metabolic activity, state of hydration and seed viability in the desiccation‐intolerant (recalcitrant) seeds of Idiospermum australiense , a rare and primitive angiosperm tree restricted to wet tropical forest. • Seed CO 2 evolution rate, R , was monitored in fully hydrated (control) seeds and seeds that were allowed to desiccate under ambient conditions over a period of c. 90 d. • During desiccation R increased dramatically toward a peak at a seed relative water content of 39 ± 3% (relative to maximum water content, which corresponded to 0.45 ± 0.03 g water g ‐1 d. wt) followed by a decline toward zero with total desiccation. This peak constituted a 10‐fold increase in mean R , relative to the control. Exposing seeds to O 2 ‐free air at this peak induced a further large, but transient, increase in CO 2 evolution, indicating that the peak developed in the presence of oxidative phosphorylation, rather than due to the absence of it. • The magnitude and mode of the observed increase in CO 2 evolution in response to desiccation is unlike any reported so far and thus adds new information about metabolic changes that may occur as the water content of desiccation‐intolerant seeds declines.