Characteristics water balance in paddy fields with pipelines or open channels in Hokkaido

Paddy and Water Environment - Hokkaido is an important agricultural area of Japan. The amount of arable land managed per farming household has been increasing because of the aging of farmers and...     

Seasonal fluctuations and temperature dependence of leaf gas exchange parameters of co-occurring evergreen and deciduous trees in a temperate broad-leaved forest

Seasonal fluctuations in leaf gas exchange parameters were investigated in three evergreen (Quercus glauca Thunb., Cinnamomum camphora Sieb. and Castanopsis cuspidata Schottky) and one deciduous (Quercus serrata Thunb.) co-occurring, dominant tree species in a temperate broad-leaved forest. Dark respiration rate (Rn), maximum carboxylation rate (Vcmax) and stomatal coefficient (m), the ratio of stomatal conductance to net assimilation rate after adjustment to the vapor pressure deficit and internal carbon dioxide (CO2) concentration, were derived inversely from instantaneous field gas exchange data (one-point method). The normalized values of Rn and Vcmax at the reference temperature of 25 degrees C (Rn25, Vcmax25) and their temperature dependencies (Delta Ha(Rn), Delta Ha(Vcmax)) were analyzed. Parameter Vcmax25 ranged from 24.0-40.3 micromol m(-2) s(-1) and Delta Ha(Vcmax) ranged from 29.1- 67.0 kJ mol(-1). Parameter Rn25 ranged from 0.6-1.4 micromol m(-2) s(-1) and Delta Ha(Rn) ranged from 47.4-95.4 kJ mol(-1). The stomatal coefficient ranged from 7.2-8.2. For the three evergreen trees, a single set of Vcmax25 and Rn25 parameters and temperature dependence curves produced satisfactory estimates of carbon uptake throughout the year, except during the period of simultaneous leaf fall and leaf expansion, which occurs in April and May. In the deciduous oak, declines in Vcmax25 were observed after summer, along with changes in Vcmax25 and Rn25 during the leaf expansion period. In all species, variation in m during periods of leaf expansion and drought should be considered in modeling studies. We conclude that the changes in normalized gas exchange parameters during periods of leaf expansion and drought need to be considered when modeling carbon uptake of evergreen broad-leaved species.     

Variation in herbivory-induced responses within successively flushing Quercus serrata seedlings under different nutrient conditions

Herbivore damage can induce the host plant to alter the chemical and physical qualities of its leaves, which is thought to be a plant strategy—termed “induced response”—for avoiding further herbivory. In woody plants, many studies have considered variation in induced response with resource availability, but few studies have examined this variation in relation to growth patterns of woody plants. We studied the phenotypic variability of induced response within successively flushing Quercus serrata seedlings. Q. serrata seedlings were grown under controlled conditions. The controlled factors were herbivore damage (herbivore-damaged and -undamaged) and soil fertility (low and high). At each flush stage, the concentrations of condensed tannin (CT), total phenolics (TP), and nitrogen (N) in leaves were analyzed, and the leaf mass per area (LMA) was measured. CT and TP concentrations in leaves and LMA were higher in herbivore-damaged seedlings. Leaves of the first flushes showed greater sensitivity to herbivore damage and had a higher CT concentration than leaves of the later flushes. Furthermore, seedlings growing in low-fertility soil showed a greater induced response. The results suggest that the induced response of Q. serrata seedlings was related to the contributions of the tissue to current productivity. Leaves of the first flush showed a greater induced response, possibly because they play an important role in subsequent growth. The potential of Q. serrata seedlings to adjust the properties of leaves depending on herbivory and soil fertility in relation to growth patterns may be advantageous on the forest floor, where seedlings grow in soil of heterogeneous fertility and are constantly exposed to herbivory.     

Effect of inter-annual climate variability on evapotranspiration and canopy CO2 exchange of a tropical rainforest in Peninsular Malaysia

We investigated inter-annual variation of canopy CO₂ exchange (NEE) and evapotranspiration during a 7-year period over a lowland Dipterocarp forest in Pasoh, Peninsular Malaysia, using the eddy covariance method. Annual rainfall fluctuated between 1,451 and 2,235?mm during this period. Annual evapotranspiration estimated by energy budget correction and gap filling using the relationship between latent heat and available energy was 1,287?±?52?mm. Despite inter-annual variation in rainfall, annual evapotranspiration was stable, except for a slight decrease in the driest year (2009). Evapotranspiration was roughly related to the amount of available energy, but was regulated by stomatal closure to prevent excessive water loss at high vapour pressure deficit. Even during dry periods, no significant decrease in evapotranspiration occurred, as water was supplied from soil layers deeper than 0.5?m. Ecosystem respiration (RE) increased with soil water content. Daytime NEE was also stable during the 7?years, despite climate variability. Afternoon inhibition of canopy photosynthesis was seen every month. Daytime NEE did not become more negative with increasing solar radiation, or with increasing soil water content. During dry periods, gross primary production (GPP) and thus canopy gross photosynthesis decreased slightly, coupled with decreased daytime RE. In this forest, variability in rainfall pattern resulted in seasonal and inter-annual variability in micrometeorology; evapotranspiration, photosynthesis, and RE responded to these changes, and compensated for each other and/or other components of micrometeorology, resulting in rather stable annual evapotranspiration and NEE, even during a very dry year associated with an El Nino Southern Oscillation (ENSO) event.     

Effect of modified ultrafiltration on cytokines and hemoconcentration in dogs undergoing cardiopulmonary bypass

Cardiac surgery using cardiopulmonary bypass (CPB) generates severe inflammatory reactions secondary to hemodilution and surgical stress. This study was conducted to evaluate whether modified ultrafiltration (MUF) could be performed safely and to clarify its effects during mitral valve repair in dogs in terms of hemodilution and the status of inflammatory cytokines. We retrospectively studied 38 dogs with mitral valve disease who underwent MUF immediately after mitral valve repair under CPB. To determine the effect of MUF, we measured the pre- and post-MUF blood dilution and blood cytokine levels. The levels of red blood cells, hematocrit (HCT), and albumin were significantly increased after MUF, whereas interleukin (IL)-6 levels were significantly increased from 24.3 (range 9.6–54.6) to 32.3 (15.9–65.1) pg/ml. The levels of IL-8 and IL-10 declined significantly after MUF, from 368.2 (246.1–669.4) and 45.4 (28.6–76.1) to 272.2 (174.1–414.4) and 28.8 (18.8–44.5) pg/ml, respectively. Our results demonstrated that MUF can be applied in dogs undergoing CPB and is effective in achieving hemoconcentration. Moreover, MUF may be useful for the removal of cytokines. Further studies are needed to validate these findings and clarify the effects of inflammatory cytokines after CPB.     

Quantitative evaluation of antioxidant components in prunes (Prunus domestica L.)

Prunes are known to show high antioxidant activity on the basis of the oxygen radical absorbance capacity (ORAC), and their major antioxidant components are caffeoylquinic acid isomers. The aim of this study is to prove the contribution of caffeoylquinic acid isomers to the ORAC of prunes, and to investigate the existence of other antioxidant components. Caffeoylquinic acid isomers in ethanol (EtOH) extracts of prunes were quantified by HPLC analysis, and the degree of contribution of these isomers to the ORAC was found to be 28.4%; hence, it was speculated that the remaining ORAC is dependent on other antioxidant compounds. EtOH extract was partitioned between hexane and H(2)O. The H(2)O layer was further separated into H(2)O and 2-100% methanol (MeOH) eluates by Diaion HP-20 column chromatography. Both the H(2)O and 50% MeOH eluates showed high values of total phenolics and ORAC, although the contribution of caffeoylquinic acid isomers to the ORAC was low. Therefore, it was predicted that unknown antioxidants exist in these fractions, and several compounds were identified by HPLC analysis. Furthermore, hydrolysis of EtOH extract residue led to higher levels of total phenolics and ORAC, and these results suggested the existence of conjugated antioxidant components in prunes.     

alpha-Klotho as a regulator of calcium homeostasis

alpha-klotho was identified as a gene associated with premature aging-like phenotypes characterized by short lifespan. In mice, we found the molecular association of alpha-Klotho (alpha-Kl) and Na+,K+-adenosine triphosphatase (Na+,K+-ATPase) and provide evidence for an increase of abundance of Na+,K+-ATPase at the plasma membrane. Low concentrations of extracellular free calcium ([Ca2+]e) rapidly induce regulated parathyroid hormone (PTH) secretion in an alpha-Kl- and Na+,K+-ATPase-dependent manner. The increased Na+ gradient created by Na+,K+-ATPase activity might drive the transepithelial transport of Ca2+ in cooperation with ion channels and transporters in the choroid plexus and the kidney. Our findings reveal fundamental roles of alpha-Kl in the regulation of calcium metabolism.     

Digital Microscopy: A Useful Technique for Measuring Root Elongation in Solution

Decreased root elongation and rupture of outer cells, major effects of soluble aluminum (Al), may be studied using digital microscopy with little interference by the experimental technique. Single roots of 3-d-old mungbean ( Vigna radiata L.) or soybean ( Glycine max (L.) Merr.) seedlings were marked with activated charcoal particles and grown for ca. 2 h in 500 mL 1 mM CaCl₂ solution at pH 6, followed by the imposition of an Al treatment. A digital image at 25-time magnification was recorded every 5 min for up to 7 h. Examination of the digital images showed that Al exerted its rhizotoxic effects rapidly (ca. 20–50 min) by reducing cell expansion in the elongation zone. Rupture of epidermal and outer cortical cells occurred later (after≥4 h) and closer to the root tip. Digital microscopy has a number of inherent benefits and problems, but is overall a valuable technique that may find wide use in studies on root growth.     

Germination and growth inhibitors from wheat (Triticum aestivum L.) husks

On the basis of our findings that the germination of intact wheat seeds (with husks) belonging to dormancy varieties was restrained as compared with that of the dehusked seeds (grains), the germination inhibitors in the husks were explored. The water-soluble extracts from the husks were separated by the aid of inhibition assay experiments, resulting in the characterization of 2-phenylethyl alcohol 1, 4-vinylphenol 2 and its 2-methoxy derivative 3, and dihydroactinidiolide 4, all of which showed clear inhibition of germination at 500 ppm in aqueous solution. The related compounds 1-phenylethyl alcohol 5 and tetrahydroactinidiolide 6 were as active as 1 and 4, while no noticeable difference in activity was detected among both enantiomers and the DL-form of compounds 4-6. Clear synergistic relations were observed between 4 and 1 and also 4 and 3. Since the present inhibitors have been isolated from various kinds of seed plants, they may be responsible for the general germination inhibition in the seed plants.     

Satellite Analysis of Volcanic Clouds and Transport of Acidic Substances from Mt. Aso and Mt. Sakurajima

The satellite images of volcanic clouds in Kyushu, Japan during September–November 1989 were studied in connection with the mountain site measurement of atmospheric qualities at Unzen-Nodake and the SO₂ concentration data at Aso Volcano Museum. The images strongly indicate that many high concentration events of SO₂ were the results of the long-range transport of volcanic gas from Mt. Aso and Mt. Sakurajima to these stations. Brief comments on the 2000 eruption of Miyake-jima volcano are added.