No abstract

The movement of cellular water accompanies changes in growth within dormant buds. To further understand this process, accumulation of tonoplast deltaTIP1 and plasma membrane PIP2 aquaporin transcripts was measured by quantitative reverse transcriptase-polymerase chain reaction and the water dynamics in dormant peach (Prunus persica L.) flower buds was studied by magnetic resonance imaging. Proton density (PD), spin-spin relaxation time (T(2)) and apparent diffusion coefficient (ADC) were used to observe water dynamics during dormancy. The expression of deltaTIP1 and PIP2 aquaporins, PD and T(2) in the upper part of the bud including primordia, in the basal part of the bud and the bud trace increased earlier in the low-chill cultivar 'Coral' than in the high-chill cultivar 'Kansuke Hakuto,' reflecting the difference in timing for the end of endodormancy in the two cultivars. deltaTIP1 mRNA accumulated mainly in the basal part of the bud, whereas PIP2 mRNA was detected mainly in the upper part. These findings may reflect the activation of inter- and intracell communication through membrane transport properties of aquaporins resulting in a gradual increase in water content to that required for bud activity at the end of endodormancy. An apparent decrease in the expression of deltaTIP1 and PIP2 mRNAs was, however, observed in late winter in some portions of the buds of both cultivars just before sprouting.

No abstract

Cereal Chem. 83(3):235-242Moisture diffusion in spaghetti during boiling and holding after boiling was analyzed with a cylinder diffusion model based on moisture content mapped by magnetic resonance imaging. The images showed water penetrating concentrically in the cross section of a cooked spaghetti strand. The moisture profiles calculated from the images refracted near the central part in undercooked spaghetti due to the presence of ungelatinized starch. The moisture profiles of the samples with different holding times intersected around one-third of the radius from the surface. The slope of the moisture profile decreased along with the holding time while the moisture content at the intersection remained unchanged. The dif-fusion coefficients were determined statistically for the fully gelatinized region with a cylinder model. The theoretical moisture profiles calculated using such coefficients fitted very well to experimental data. The diffusion coefficients of dried spaghetti were smaller than those of fresh spaghetti at both boiling and holding periods, suggesting that the moisture transport property had been reduced by the drying process during manufacture of spaghetti. The diffusion coefficients decreased with increases in boiling and holding times. The diffusion model with a constant diffusion coefficient is, therefore, valid in a limited boiling or holding time.