Premium
Evidence of a key role for photosynthetic oxygen release in oil storage in developing soybean seeds
Author(s) -
Rolletschek Hardy,
Radchuk Ruslana,
Klukas Christian,
Schreiber Falk,
Wobus Ulrich,
Borisjuk Ljudmilla
Publication year - 2005
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 - 10.1111/j.1469-8137.2005.01473.x
Subject(s) - photosynthesis , oxygen , biochemistry , biology , sucrose , metabolite , metabolism , biophysics , botany , chemistry , organic chemistry
Summary• Based on the topographical analysis of photosynthesis and oil storage, we propose in a companion paper that photosynthetic oxygen release plays a key role in the local energy state, storage metabolism and flux toward lipid biosynthesis in developing soybean seeds. To test this hypothesis, we combined topographical analysis of ATP gradients across tissues, microsensor quantifications of internal O 2 levels, assays of energy balance, metabolite profiles and isotope‐labelling studies. • Seeds show a marked degree of oxygen starvation in vivo (minimum O 2 levels 0.1 kPa, ≈ 1.3 µ m ), affecting ATP gradients, overall energy state, metabolite pools and storage activity. • Despite the low light availability, photosynthesis supplies significant amounts of oxygen to the hypoxic seed tissue. This is followed by an increase in local ATP levels, most prominently within the lipid‐synthesizing (inner) regions of the embryo. Concomitantly, partitioning of 14 C‐sucrose to lipids is increased, suggesting higher rates of lipid biosynthesis. • It is concluded that both respiratory and biosynthetic fluxes are dynamically adjusted to photosynthetic oxygen supply.