Cinnamaldehyde inhibits enzymatic browning of cut lettuce by repressing the induction of phenylalanine ammonia-lyase without promotion of microbial growth

Cinnamaldehyde treatment inhibited the browning of cut lettuce during cold storage. In this study, to clarify the mechanism of inhibitory action of cinnamaldehyde against the browning and to show its microbiological merit, its effect on the browning of cut lettuce was compared to that of mild heat treatment. Both cinnamaldehyde and mild heat treatments inhibited the induction of phenylalanine ammonia-lyase (PAL) activity because of cutting. As a result, the biosynthesis of polyphenols, which are substrates of polyphenol oxidase, was inhibited. This reduction of polyphenol synthesis caused the inhibition of the browning. Cinnamaldehyde treatment repressed the induction of PAL mRNA, while mild heat treatment did not repress its induction. The increase in microbes in cut lettuce treated with cinnamaldehyde was less than that treated with mild heat after 12 days.     

Patchy stomatal behavior during midday depression of leaf CO₂ exchange in tropical trees

We investigated effects of heterogeneous stomatal behavior on diurnal patterns of leaf gas exchange in 10 tree species. Observations were made in middle and upper canopy layers of potted tropical rainforest trees in a nursery at the Forest Research Institute Malaysia. Measurements were taken from 29 January to 3 February 2010. We measured in situ diurnal changes in net photosynthetic rate and stomatal conductance in three leaves of each species under natural light. In both top-canopy and sub-canopy species, midday depression of net assimilation rate occurred in late morning. Numerical analysis showed that patchy bimodal stomatal behavior occurred only during midday depression, suggesting that the distribution pattern of stomatal apertures (either uniform or non-uniform stomatal behavior) varies flexibly within single days. Direct observation of stomatal aperture using Suzuki's Universal Micro-Printing (SUMP) method demonstrated midday patchy stomatal closure that fits a bimodal pattern in Shorea leprosula Miq., Shorea macrantha Brandis. and Dipterocarpus tempehes V.Sl. Inhibition of net assimilation rate and stomatal conductance appears to be a response to changes in vapor pressure deficit (VPD). Variable stomatal closure with increasing VPD is a mechanism used by a range of species to prevent excess water loss from leaves through evapotranspiration (viz., inhibition of midday leaf gas exchange). Bimodal stomatal closure may occur among adjacent stomata within a single patch, rather than among patches on a single leaf. Our results suggest the?occurrence of patches at several scales within single leaves. Further analysis should consider variable spatial scales in heterogeneous stomatal behavior between and within patches and within single leaves.     

Carbon-nitrogen interaction related to P,K, Ca,and Mg nutrients in field crops

Carbon (dry matter)-nitrogen relationship was expressed as DM_t = DM₀ × exp(CNI × N_t) in Gramineae crops (including root crops), and DM_t = DM₀ + CNF × N_t in Leguminosae crops, where DM_t is the amount of dry matter at various growth stages, N_t is the amount of nitrogen absorbed at various growth stages, DM₀ is the initial value, and CNI and CNI′ are coefficients. Thus, since the carbon-nitrogen relationship was different between Gramineae and Leguminosae crops, it is expected that the accumulation processes of other minerals such as phosphorus (P), potassium (K), calcium (Ca), or magnesium (Mg) during growth would be different between Gramineae and Leguminosae crops if these nutrients are closely related to the carbon and nitrogen metabolism. As nitrogen is the most important nutrient for plant growth, the relationship between N_t and the amount of other minerals such as phosphorus (P_t), potassium (K_t), calcium (Ca_t), or magnesium (Mg_t) absorbed in plants at various growth stages was examined in field crops.

In Gramineae crops, the P_t-N_t, K_t-N_t, and Mg_t-N_t relationships during growth were described as follows:

where P₀ and Mg₀ are initial values, and PNI, KNI, K_max, and MgNI are coefficients. Since the P_t-N_t and K_t-N_t relationships changed according to the growing conditions, the values of PNI and KNI were statistically estimated from the data of various growth stages at each treatment. As PNI showed a linear regression with CNI, P_t and also K_t was expressed by the equation which included CNI. Thus both phosphorus and potassium accumulation were closely related to the carbon-nitrogen interaction. While the Mg_t-N_t relationship was less affected by various growing conditions, MgNI was estimated from the data including all treatments, indicating that Mg accumulation was regulated only by nitrogen nutrient. Ca_t was not related to N_t.

In Leguminosae crops, the P_t-N_t, K_t-N_t, and Mg_t-N_t relationships were described as follows:

where P_0, K₀, and Mg₀ are initial values, and PNI′ and KNI′ are coefficients. Since the P_t-N_t, K_t-N_t, and Mg_t-N_t relationships were less affected by various growing conditions as in the case of DM_t-N_t, the values of PNI′ and KNI′, and MgNI were estimated from the data including all treatments. Thus, P, K, and Mg accumulation was closely regulated by N nutrient. Ca_t was not related to N_t.

Consequently, in Gramineae crops, P and K accumulation was assumed to be related to the carbon-nitrogen interaction, while in Leguminosae crops, P and K accumulation was assumed to be related to only nitrogen nutrient, indicating that the role of P and K nutrients differed according to differences in the balance of the carbon-nitrogen metabolism. Since MgNI was estimated from the same form of Mg_t-N_t regression regardless of Gramineae and Leguminosae crops, Mg accumulation was assumed to be closely regulated by only nitrogen nutrient. Ca accumulation was neither related to N nutrient nor carbon-nitrogen interaction.     

Effects of chloride and sulfate application on root growth of rice

In several studies, the beneficial effects of the application of chloride on root growth have been reported. However, the effect of chloride application on the morphology of roots has not been studied extensively. The effects of the use of chloride salts and sulfate salts on the growth of rice (Oryza sativa L.) until the 7-leaf stage were investigated in soil and water culture experiments. In the soil culture experiments, the root biomass in the chloride treatment showed a 58% increase compared with the sulfate treatment. Total root length, top root ratio (T / R ratio) and root length per primary root revealed the existence of root growth promotion by chloride. In the water culture experiments, root growth was also stimulated by chloride, as in the soil culture experiments. In order to analyze the effect of chloride application, the ion composition and pH of the soil solution or water culture solution were used to determine the amounts of ion species in the solution using the MINTEQA2 computer program, and the results were applied to estimate the osmotic pressure of these solutions. The osmotic pressure of chloride salts was obviously higher than that of sulfate salts based on van't Hoff's law of osmotic pressure and a positive correlation between the osmotic pressure and root length was obtained. The results suggest that the higher osmotic pressure induced by chloride would be involved in the root growth promotion of rice.     

Changes in serum vitellogenin levels and immunohistochemical localization of vitellogenin in hepatic cells during ovarian development in the Japanese eel

ABSTRACT: The present study was designed to quantify changes in serum vitellogenin (VTG) levels and to localize VTG in hepatic cells immunohistochemically during artificial maturation of the Japanese eel Anguilla japonica . Hormone treatment resulted in a gradual rise in serum VTG levels, in which the highest values were attained at the migratory nucleus stage. Hepatocytes responded to hormone treatment by increased immunoreactivity; both staining area and intensity were enhanced with ongoing gonadal development. Moreover, cytoplasmic vacuoles increased in number during artificial maturation, occupying large areas inside hepatocytes. The unusual appearance of hepatocytes may reflect the effect of artificial maturation.     

Dielectric anisotropy of oven- and air-dried wood evaluated using a free space millimeter wave

To evaluate the dielectric anisotropy caused by wood structure at a millimeter wave frequency of 100 GHz, the dielectric parameters for flat-sawn specimens of nine wood species at 0 and 11 % moisture content (MC) were measured using a free space method devised for reducing the multiple reflections under an electric field of millimeter waves parallel to longitudinal and tangential directions of wood, and those in radial direction were estimated using a conventional approximation theory. The dielectric parameters in the tangential and radial directions were almost identical and constantly smaller than those in the longitudinal direction. All the dielectric parameters increased with wood density and were larger at 11 than 0 % MC. The dielectric parameters in the longitudinal and transverse directions and the dielectric anisotropy between them were well fitted to the regression lines based on a dielectric mixture model composed of pores and dielectric isotropic wood substance, and a parallel capacitor and Lichtenecker’s exponential formulas were employed to represent the dielectric parameters of the mixture in the longitudinal and transverse directions, respectively. It was concluded that the dielectric anisotropy at 100 GHz is caused by the pore alignment and that the dielectric parameters are almost unaffected by anatomical structures, such as the rays. It was also confirmed that the free space method was effective for the measurement of the dielectric parameters for the flat-sawn specimens.     

Effect of annual rings on transmission of 100 GHz millimeter waves through wood

For the application of millimeter wave (MMW) technique to nondestructive evaluation of wood, the effect of annual rings on the behavior of a 100 GHz MMW transmitted through wood was examined. The complex amplitude was measured for 2 mm thick flat- (LT) and quarter-sawn (LR) specimens of several species with different annual ring structures at 11 % moisture content, of which the density distribution was measured using X-ray radiography. For the LT specimens of all species and the LR specimens with small density fluctuation or with earlywood width smaller than the wavelength of the MMW (=3 mm), the amplitude and phase of the transmitted wave were similar to those of the wave without a specimen. For the LR specimen with large density fluctuation and with earlywood width close to or larger than the wavelength, the amplitude and phase were different from those of the wave without a specimen. All the measured complex amplitudes were well expressed using a diffraction model. It was concluded that the MMW is deformed by the density distribution, and then its components with periods shorter than the wavelength by diffraction are attenuated.     

Seasonal changes in cellular compartmentation and membrane permeability to sugars in relation to early or high temperature-induced watercore in ‘Orin’ apples

Summary

The intensity of watercore in ‘Orin’ apples (Malus domestica Borkh.) from the outer canopy increased from early-July to mid-August, followed by a decrease through late-October, while no watercore was detected in inner canopy fruit during the same period. Seasonal changes in sorbitol content in each cellular compartment paralleled the development of watercore. Significantly higher sorbitol, fructose and glucose contents in the vacuoles of cells in outer canopy fruit than in inner canopy fruit suggest that active metabolism and uptake of sorbitol might occur in watercored apples in mid-August. The permeability of sorbitol across the tonoplast was significantly higher in outer than in inner canopy fruit after mid-August, whereas no difference was observed between bearing position for the other sugars or for the plasma membrane. These data suggest that elevated sorbitol levels in the intercellular spaces might result from active apoplastic unloading and not from an inhibition of metabolism and/or an increase in leakage from cells.     

Annual reproductive cycle of the greasyback shrimp Metapenaeus ensis in Ise Bay,Japan

The greasyback shrimp Metapenaeus ensis is widely distributed along the coast of India and the West Pacific where it is an important fisheries species. We have examined seasonal changes in ovarian development, spermatogenesis, and mating of Me. ensis in histological studies and by external observations on specimens collected in Ise Bay, its northernmost habitat. Ovaries were found to be previtellogenic from February to May, with the first signs of development being the accumulation of yolk in oocytes in late May. Ovarian shadow ratios were high during the period late July to mid-September. The formation of cortical rods in the peripheries of oocytes and germinal vesicle breakdown were observed in ovaries from late June to September. Male shrimps had sperm in the testes during the period early June to early October, and female shrimps had spermatophores in spermatheca after early July. In late July, some post-spawn female shrimps had exogenous vitellogenic oocytes in their ovaries, indicating that ovarian development had been repeated in preparation for the next spawning. Ovarian shadow ratios, which were positively correlated with gonadosomatic indices and ovarian development, seem to be a useful marker to determine ovarian development. Our results indicate that mating in Me. ensis started in early July and that the spawning season ranged from July to September with more than two cycles of spawning in Ise Bay.