Water balance characteristics of Kashima plateau basins assuming variable areas of underground catchments

Agricultural water use on upland fields depends mainly on precipitation and irrigation by small wells in the Kashima plateau basins. To establish a stable supply of water for irrigated upland fields, an evaluation of water-cycle mechanisms on an arable plateau near plain lakes is important. Previous research suggests that groundwater catchments do not necessarily coincide with the corresponding surface catchments in the plateau basins. However, a physical mechanism of groundwater movement has not yet been clearly demonstrated. In this paper, therefore, we aimed to estimate the areas of groundwater catchments that did not coincide with their corresponding surface catchments, by observing groundwater flow in boreholes and by evaluating water balances of four small basins on the Kashima plateau. As a result, hydrological and groundwater observations in the Kashima-Kohoku basin showed: (1) the groundwater catchment was larger than the surface catchment, as inferred from continuous groundwater observations and the observed directions of groundwater flow, (2) groundwater potential may change after intensive rains, especially after precipitation events of more than 50 mm, and (3) estimates of the long-term water balance confirmed that groundwater flowed into the surface catchment from the outside. The area of the Kashima-Kohoku groundwater catchment was 1.3–2.4 times the area of the surface catchment. Furthermore, the same result was obtained for two other basins.     

干旱区人工绿洲间作农田蒸散研究

在黑河流域中游的张掖绿洲区建立了大田环境下的春小麦和夏玉米间作农田能水平衡研究观测点,以气象观测资料为基础,采用波文比能量平衡法(BREB)和参考作物蒸散量—作物系数法(ET₀-K_c)对作物的蒸散进行了计算。结果表明：在一个完整的生长期内,利用波文比能量平衡法得到的间作作物蒸散量为688 mm,日均3.4 mm/d,用参考作物蒸散量—作物系数法得到的作物蒸散量为666 mm,日均3.3 mm/d,两种计算方法得到的蒸散量总值差别小。同期,水文平衡法计算结果为733 mm。利用波文比能量平衡法所得结果的分析表明,试验地在不同生长阶段,ET变化剧烈,生长初期、中期、末期分别为1.19、4.41和2.58 mm/d,其蒸散量分别占全年蒸散总量的7.79%、78.73%和13.48%。ET月变化显示,3月维持在一个较低水平;4月和5月剧烈增加;6月达到最大;此后的7月和8月降低,但仍维持在一个高水平;9月,随着作物进入生长末期,蒸散急剧减小。对ET日内变化分析可知,作物蒸散开始于早晨7∶00～8∶00,在14∶00左右达到最大,19∶00～20∶00趋于0 mm/d。不同生长阶段蒸散强度差异明显。     

Estimated amount of carbon accumulation of hybrid larch in three 31-year-old progeny test plantations

Hybrids generated by crossing Kuril larch (Larix gmelinii var. japonica) and Japanese larch (L. kaempferi) are expected to have high carbon accumulation ability because of fast growth and high wood density in Hokkaido, Japan. We estimated the amount of carbon accumulation of the hybrid larch in three progeny test plantations consisting of 21 full-sib families and compared the results to the carbon accumulation of open-pollinated progenies of Japanese larch plus-trees (improved Japanese larch). Gene-environment interactions were not observed for tree height and diameter at breast height but were seen for wood density (area-weighted density, AWD). The amount of carbon accumulated per unit area (C_stand) positively correlated with the stand volume. The AWD did not correlate with the C _stand; therefore, families with high wood density can be selected independent of the C _stand. The C _stand of the best full-sib family, female parent half-sib family, and male parent half-sib family at three sites were 106.1, 84.6, and 93.2 Cton·ha⁻¹, respectively. All these values exceed the mean for the improved Japanese larch, which has a C _stand value of 82.5 Cton·ha⁻¹.     

Stabilizing effect of Ca<Superscript>2+</Superscript> on myosin and myofibrils of squid mantle muscle as affected by heating conditions

The suppressive effects of Ca²⁺ on the thermal denaturation of myosin and myofibrils of squid mantle muscle were compared. The stabilization effect on myosin was smaller than that on myofibrils and was not affected by KCl concentration. The stabilizing effect of Ca²⁺ on myosin decreased as the heating temperature dropped, showing no stabilization at 20°C, while the effect on myofibrils was the same at all temperatures tested. The stabilizing effect of Ca²⁺ on myosin disappeared even at 30°C in the presence of sorbitol, where a small inactivation rate was found, while the effect of Ca²⁺ on myofibrils was equally detected irrespective of the reduction in inactivation rate in the presence of sorbitol. Stabilization of myosin by Ca²⁺ again appeared even in the presence of sorbitol when the heating temperature was raised to 38°C. It was suggested that Ca²⁺ confers stabilization on myosin only when myosin is under unstable conditions. The stabilization effect of Ca²⁺ on myosin was enhanced upon F-actin binding: Ca²⁺-bound myosin was more significantly stabilized by F-actin binding, and the effect was no longer affected by the conditions for heating.     

High temperatures activate local viral multiplication and cell-to-cell movement of Melon necrotic spot virus but restrict expression of systemic symptoms

The infection of melon plants by Melon necrotic spot virus (MNSV) and the development of necrotic disease symptoms are a seasonal occurrence in Japan, which take place between winter and early summer, but not during mid-summer. In this paper we investigate the effect of three different temperatures (15, 20, and 25 degrees C) on the local and systemic expression of MNSV in melon plants. Previously, the incidence of plants expressing systemic symptoms caused by MNSV and other viruses was found to be greater at temperatures less than 20 degrees C. In this study, our temperature-shift experiments support previous studies that found the expression of systemic symptoms increases as temperature falls from 25 to 20 degrees C and decreases as temperature rises from 20 to 25 degrees C. However, MNSV replication in melon cells and local viral movement within leaves following the inoculation of melon protoplasts or cotyledons were more frequent at 25 degrees C than at 15 or 20 degrees C.     

Fishery characteristics of barfin flounder Verasper moseri in southern Tohoku,the major spawning ground,after the start of large-scale stock enhancement in Hokkaido,Japan

Commercial landings of a rare pleuronectid flatfish, barfin flounder Verasper moseri, recovered drastically after large-scale stock enhancement in Hokkaido conducted since 2006. This study investigated commercial landings, fishing grounds, size distributions, and sex and age compositions of barfin flounder during 2007–2011 in southern Tohoku, their major spawning ground, which is over 700 km south of Hokkaido. Landings, mostly comprising stocked fish, increased drastically in southern Tohoku: from 2.0 tons in 2007 to 20.8 tons in 2010. Over 98 % of them were landed during January–April, with the peak period during February–March. Fishing logbook data of offshore bottom-trawl vessels during 2007–2010 revealed the upper continental slope off southernmost Tohoku as the main fishing ground (35°40′–36°50′N, annual weighted mean depth 267–299 m). Two size modes in the landings consisted of males (ca. 40 cm) and females (ca. 60 cm). The main age at fishery recruitment in southern Tohoku was younger for males (age 2+) than for females (ages 3+ and 4+), the result of which was that the female percentage was lowest at 1.5 % in 2009 and highest at 7.9 % in 2011. Our results showed clearly how the effectiveness of large-scale stock enhancement in Hokkaido extended to southern Tohoku in association with spawning migration of stocked barfin flounder.     

An application of mixed-effects model to evaluate the effects of initial spacing on radial variation in wood density in Japanese larch (Larix kaempferi)

The effects of initial tree spacing on wood density at breast height were examined for 22-year-old Japanese larch (Larix kaempferi). The experiment involved the use of three plots with different initial tree spacing densities (300, 500, and 1000 trees/ha). For five trees selected from each plot, the total tree height, diameter at breast height, height to the base of the live crown, and crown diameter were measured. Ring width and wood density for individual growth rings were determined by X-ray densitometry. A mixed-effects model was applied for fitting the radial variation in wood density in relation to initial spacing. Models having various mean and covariance structures were tested in devising an appropriate wood density model. The model, consisting of the mean structure with quadratic age effects and heterogeneous first-order autoregressive covariance, was able to describe the radial variation in wood density. Closer spacing of trees (1000 trees/ha) resulted in a faster increase in wood density from the pith outward than for more widely spaced trees, indicating that initial tree spacing may influence the age of transition from juvenile to mature wood.     

A clinical case of a subepiglottic cyst in a Japanese Black calf

A 36-day-old Japanese Black calf exhibited wheezing associated with dyspnea from birth. Arterial blood gas analysis revealed a low oxygen partial pressure of 51 mmHg, low oxygen saturation of 83%, and high carbon dioxide partial pressure of 58.8 mmHg. Computed tomography, endoscopy, and ultrasonography showed cyst formation under the epiglottis. When the cyst was aspirated under ultrasonic guidance to secure the airway, 30 ml of viscous white turbid content was aspirated. The cyst shrank immediately after aspiration, but the wheezing and respiratory symptoms resumed 7 days after aspiration. Therefore, the cyst was surgically removed from the ventral side of the neck. No cyst remodeling was observed 30 days after surgical removal.     

Modeling the effects of growth rate on the intra-tree variation in basic density in hinoki cypress (Chamaecyparis obtusa)

The purpose of this study is to evaluate the effect of growth rate on intra-tree variation in basic density of hinoki cypress (Chamaecyparis obtusa) quantitatively using the statistical modeling technique. Nineteen sample trees were harvested from 50-year-old hinoki stand which consists of two different growth rate plots. Disks were cut from sample trees at height positions of 2, 4 m, and then 4 m intervals until 16 m position. Radial strips were cut from the disks, and ring widths and basic density were measured at 5-ring intervals. The basic density decreased with age at any height positions. The linear mixed model was fitted to the age trend data having two nested grouping levels, i.e., tree and position within tree. Models having various mean and covariance structures were tested in devising an appropriate wood density model. The model, consisting of the mean structure with quadratic function of cambial age was able to describe the intra-tree variation in basic density. The model containing the random effects which consist of effect of the tree level and vertical stem position level explained the density variation adequately. The growth rate did not show the significant effect on the basic density variation within the stem.     

Development of real-time PCR assay using TaqMan probe for detection and quantification of <Emphasis Type="Italic">Rosellinia necatrix</Emphasis> in plant and soil

We developed real-time PCR assays using TaqMan probes to detect and quantify Rosellinia necatrix, the causal agent of white root rot in many plant species. Two sets of PCR primers and TaqMan probe indicated that their detection limits could be as low as 1 fg of template DNA. Using the real-time PCR assays with the TaqMan probes, we were able to quantify R. necatrix DNA in naturally diseased roots of Japanese pear and in artificially infested soil samples. Although the new assays were inadequate for use with naturally infested soil samples, nested PCR procedures improved the detectability of the new assays.