Measurement of intracellular pH of maize seeds (Zea mays) during germination by 31P nuclear magnetic resonance spectroscopy.
The 31P NMR spectra of germinating maize seeds showed a single broad resonance that shifted its position as germination proceeded (studied between 0 and 10 days). The resonance was shown to originate from the phosphate groups of phytine (Mg2+, Ca2+ and K+ salt of myoinositol hexakisphosphate) in a subcellular compartment of the embryo scutellar cells. A series of calibration curves for the chemical shift dependence of the phytate resonance in the presence of Mg2+ and Ca2+ were constructed. These calibration curves allowed us to determine that an acidification of the phytate containing compartment in the seed embryo takes place, reaching a minimum at about pH 4 after three days of germination. This acidification could be important in allowing phytate solubilization for export to growing parts of the maize seedling.
Barba
I
I
Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.
Gasparovic
C
C
Cabañas
M E
ME
Alonso
J
J
Murillo
I
I
San Segundo
B
B
Arús
C
C
D002451:Cell Compartmentation; D018525:Germination; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010759:Phosphorus Isotopes; D010833:Phytic Acid / Q000737:chemistry; D012639:Seeds / Q000737:chemistry* / Q000166:cytology / Q000502:physiology*; D003313:Zea mays / Q000737:chemistry*
D010759:Phosphorus Isotopes; D010833:Phytic Acid