Impact of chemical stimuli and temperature on water transport and mobility in germinating rape seeds by pulsed 1H NMR spectroscopy

Abstract

Pulsed 1H NMR in vivo di †erence spectroscopy and germination were combined to elucidate the e †ect of exogenously applied estriol or ethanol on water retention in fully hydrated rape seeds. The presence of estriol or ethanol in the imbibition medium resulted in a reduction of the photoreversible phytochrome. An approach to the assessment of cell membrane permeability related to the intracellular water exchange rate, using the bi-exponential feature in the water proton spin-lattice relaxation rate and spin-spin relaxation rate is presented. The R 1 R 2 , intracellular water exchange rate increases approximately two-and three-fold in seeds pre-treated with estriol or ethanol solution in comparison with water imbibed seeds. The activation energy for the germination rate was 61 » 6, 42 » 4 and 37 » 4 kJ mol-1 and the transition temperature was 281 » 2, 286 » 2 and 284 » 2 K for seeds imbibed with water, estriol and ethanol solution, respectively. The temperature dependence of the intracellular water exchange rate showed comparable values of activation energy and transition temperatures. All the results support the hypothesis that the two e †ects, thermal activation and increase in the seed cell membrane permeability, combine during water transport into the cell and result in the germination of rape seeds imbibed with estriol or ethanol solution.

Water uptake and distribution in germinating lupine seeds studied by magnetic resonance imaging and NMR spectroscopy

“…In NMR experiments, only mobile proton‐bearing components like water are visible. Proteins, oils and carbohydrates also contain protons, but their FID signals are not easily detected because they disappear as a result of the short spin–spin relaxation time, before the signals from water are detected (Miedziejko 1997, Ratković 1987). Proteins, stored in protein bodies, are the most abundant storage reserve of lupine seeds and constitute up to 45% of the DW of the seed.…”

Water Mobility and Microstructure Evolution in the Germinating Medicago truncatula Seed Studied by NMR Relaxometry. A Revisited Interpretation of Multicomponent Relaxation

“…MRI is a powerful means for following water trajectories during seed imbibition and to potentially detect developmental defects during the process of germination; however, access to the instrument and data treatment can represent a limit for routine quality control of seeds. Low-field NMR relaxometry remains a nondestructive alternative, which is commonly used to investigate water contents, mobility, and interactions in matrix systems, such as plant organs , and particularly in imbibing and germinating seeds. ,− Deconvolution of the multiexponential curves obtained from longitudinal ( T 1 ) and transverse ( T 2 ) relaxations allows identifying groups and proportions of water protons that share environments, interactions or molecular exchange rates. − At subzero temperature, residual NMR signals of water arising from the hydration shell of molecules and from water in interaction within small pores of matrixes report on the microstructure of the damaged material due to ice formation. − Freeze–thawing behavior is a helpful assignment tool because differences in the concentration of free sugars, local changes in tissue architecture and composition, can result in different compartments’ having different freeze–thawing behaviors. Thus, on thawing, the redistribution of water in the degraded microstructure leads to new groups of water protons according to their relaxation characteristics.…”

Detection of Pre-Harvest Sprouting in Rice Seeds by Using 1H-NMR

“…Nuclear magnetic resonance (NMR) spectroscopy is a successful, nondestructive method of studying the state of water in many biological systems (Iwaya-Inoue et al, 2004;Miedziejko et al, 1997;Lenk et al, 1991). Water plays an important role not only as a solvent for biochemical reactions, but also as a stabilizer of macromolecular structure.…”