Phyllochron Dynamics Under Controlled Environments in Rice (Oryza Sativa L.)     

Youki Itoh  Yoshio Sano 《Euphytica》2006,150(1-2):87-95

Previously, we reported that phyllochron of rice greatly fluctuated in the course of development under natural conditions. The present study was carried out to examine the phyllochron dynamics using the five near-isogenic lines (NILs) for heading time and the recurrent parent. The change of phyllochron was investigated under four different controlled conditions regarding daylength and temperature. Growth duration (days to heading) showed a large variation among different growth regimes as well as genotypes. Changes of phyllochron were evaluated in the genotypes by using a quartic polynomial regression that was well fitted to the change of phyllochron in the present controlled environments as previously observed under natural conditions. Phyllochron began to drastically increase after around the 5th phytomer order and decreased with the progress of reproductive development in similar manners under different environments. The pattern of phyllochron change varied from a flat to non-flat shape. The shape of the equation was affected by genotypes as well as daylengths and temperatures. In addition, the shape was closely related to the growth duration (days to heading) of the genotype, suggesting that the phyllochron might internally increase depending on the genotype controlling the heading date. Therefore, the present results showed that the sufficient examination of phyllochron dynamics is necessary for understanding a variation in the heading date of rice.  相似文献   

Theoretical studies on the methodological procedures of radiation breeding     

Yoshio Yoshida 《Euphytica》1964,13(1):65-74

If the expectation of the number of desirable mutants for equal size of X ₂-populations decreases with decreasing number of plants per X ₂-line, the one-plant-one-grain method (method C), the one-plant-two-grain method (method D), and the one-plant-three-grain method (method E), especially method C, would be disadvantageous in comparison with the improved ear-to-row method (method B) and the conventional ear-to-row method (method A).From theoretical considerations it can be shown that a probability of occurrence of an X ₂-line containing desirable mutant (p ₁) and a conditional probability of occurrence of such desirable mutant for each one of the plants in such an X ₂-line (p ₂) are not affected by the number of X ₂-lines (m), but by the number of plants per X ₂-line (n). Consequently, the expectation of the number of desirable mutants in an X ₂-population, E(I), can be given by E(I) = mp ₁(1– q ₂ n · n p ₂/(1 –q ₂ n) = mn p ₁ p ₂ where p ₁+q ₁=1 and p ₂+q ₂=1.Therefore, with respect to E(I), method A=B=C=D=E for equal size of X ₂-populations. However, method ABE>D>C for different sizes of X ₂-populations.Most of this work was carried out in the National Institute of Agricultural Sciences, Hiratsuka, Japan.  相似文献   

Developmental changes of phyllochron in near-isogenic lines of rice (Oryza sativa L.) with different growth durations     

Youki Itoh  Shigetoshi Sato  Yoshio Sano 《Euphytica》2001,119(3):271-278

The repeated elements called phytomers, which consist of leaf, node, internode and axillary bud, play an important role in the development of modular organization in plants. Rice has the striking feature that the rate of the phytomer production is closely synchronized with the rate of leaf emergence (phyllochron). We examined developmental changes of phyllochron by using 10 near-isogenic lines (NILs) showing diversified growth durations in rice. The NILs were established by backcrosses with a strain practically insensitive to photoperiod, and they consisted of early- or late-flowering NILs whose differences of growth duration were caused by the combinations of alleles at 6 loci. The developmental patterns of phyllochron were evaluated by means of a quartic polynomial, which fitted well in most cases. The results indicated that phyllochron greatly changed during development, especially in late-flowering NILs as well as the recurrent parents, although the fluctuation of phyllochron was not so marked in the early-flowering NILs. Thus, the developmental change of phyllochron was highly dependent upon the genotypes and/or growth duration; however, it was associated with neither floral initiation nor temperature, indicating that the change of phyllochron might reflect internal or physiological changes which occur during the life cycle of rice. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Influence of Acid Deposition on Inland Water Chemistry - A Case Study from Hyogo Prefecture, Japan -     

Yukio Komai  Satoshi Umemoto  Takanobu Inoue 《Water, air, and soil pollution》2001,130(1-4):1535-1540

The Influence of acid deposition on stream and lake water chemistry was studied in a forested watershed of Hyogo prefecture, Japan. Monthly sampling of four streams, one artificial lake, and precipitation was carried out from 1995 to 2000. The pH of the monthly bulk precipitation and rainwater were ranged from 4.06 to 7.10. No trends were evident during the monitoring periods. The pH and alkalinity in the four streams, which flow into the artificial lake, ranged from 6.37 to 8.72 and 0.077 meqL^?1 to 0.485 meqL^?1, respectively. The differences in the water quality of the four streams were related to the geology of each watershed. Lower pH and alkalinity were observed during high- discharge periods. On the other hand, the pH and alkalinity of the outflow from the lake ranged from 6.47 to 7.36 and 0.195 meqL^?1 to 0.339 meqL^?1, respectively. No acidification of the aquatic environment was observed during the investigated periods. The results suggest that this forested ecosystem has the capacity to neutralize incoming acid deposition.  相似文献   

A comparison of regression methods for estimating soil-atmosphere diffusion gas fluxes by a closed-chamber technique     

Tomoko Nakano  Takuji Sawamoto  Gen Inoue 《Soil biology & biochemistry》2004,36(1):107-113

Continuous changes in methane (CH₄) and carbon dioxide (CO₂) concentrations inside a closed chamber were measured on the forest floor at three sites: a deciduous forest and a coniferous forest in Hokkaido, Japan, and a birch forest in West Siberia, Russian Federation. Flux estimations by three types of regression methods, exponential, nonlinear, and linear, were examined using field-collected concentration data. The pattern of change with time of the gas concentration in the headspace differed, mainly according to site but also, to a lesser extent, according to the gas. This was a function of both the chamber height and surface soil property relating to soil gas diffusion and the gas concentration profile. Flux estimations did not differ statistically between the exponential and nonlinear methods for either gas at any site, because both of those regression methods were based on diffusion theory. However, the flux values estimated by linear regression were significantly different from those estimated by the other two methods for both CH₄ and CO₂ at the deciduous forest site and for CO₂ at the coniferous forest site. Shortening the chamber deployment period improved the linearity of the curve, but did not completely eliminate the error. Our results suggest that linear regression is not a good model of the change in headspace concentration with time.  相似文献   

Study of the Water Solubility and Sorption on Particulate Matters of Phthalate in the Presence of Humic Acid Using 14C Labelled Di-(2-Ethylhexyl)Phthalate     

Satoshi Mitsunobu  Yoshio Takahashi 《Water, air, and soil pollution》2006,175(1-4):99-115

Phthalate esters have become widespread contaminants in the aquatic environment, because of their extensive use as non-reactive plasticizers. There is, however, little accurate data on their solubility, transportation, and distribution in the aquatic environment. In this work, we have investigated the influence of humic acid on the water solubility of di-(2-ethylhexyl)phthalate (DEHP), one of the most frequently used phthalate esters in the laboratory studies for DEHP. We have also studied the solid–water distribution of DEHP in the presence of humic acid and particulate matter (activated carbon, ferrihydrite, and kaolinite) to simulate their distribution in a natural aquifer (ternary system). The results show that the water solubility of DEHP can be significantly increased by humic acid. The shape K _eq value, the binding constant of DEHP between water and humic acid at equilibrium, was obtained by fitting experimental data for each humic acid. The shape K _eq values in the ternary system apparently decreased in the order of ferrihydrite ≤ kaolinite ≈ octanol/water partition activated carbon systems. This result shows that the increase in the hydrophobicity of HA remaining in the solution will lead to the apparent increase of shape K _eq in the system since more hydrophilic solid sorbs relatively more hydrophilic HA molecule. The solid–water partition coefficient (shape K _W-P ) for DEHP in the environment estimated from this study is consistent with those reported based on the experiments for natural samples. Quantitative values obtained in this study, such as K'_ow, shape K _eq, and shape K _W-P , can be useful for estimating the behavior of DEHP.  相似文献   

Antitumor activity of compounds isolated from leaves of Eriobotrya japonica   总被引：3，自引：0，他引：3  

Ito H  Kobayashi E  Li SH  Hatano T  Sugita D  Kubo N  Shimura S  Itoh Y  Tokuda H  Nishino H  Yoshida T 《Journal of agricultural and food chemistry》2002,50(8):2400-2403

In a search for possible antitumor agents from natural sources, megastigmane glycosides and polyphenolic constituents isolated from the leaves of Eriobotrya japonica (Rosaceae) were found to inhibit the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced activation of Epstein-Barr virus early antigen in Raji cells. Roseoside and procyanidin B-2 were among the active compounds found in an in vitro assay; these compounds were further assessed for antitumor activity in vivo in a two-stage carcinogenesis assay on mouse skin. Roseoside significantly delayed carcinogenesis induced by peroxynitrite (initiator) and TPA (promoter), and its potency was comparable to that of a green tea polyphenol, (-)-epigallocatechin 3-O-gallate, in the same assay.  相似文献   

Breakdown and macroinvertebrate colonization of needle and leaf litter in conifer plantation streams in Shikoku,southwestern Japan     

Mayu Hisabae  Shin Sone  Mikio Inoue 《Journal of Forest Research》2011,16(2):108-115

Breakdown and macroinvertebrate colonization of conifer needles (Cryptomeria japonica) and deciduous broadleaves (Euptelea polyandra) were investigated using litter bags in two study sites in streams flowing through a conifer plantation of C. japonica in Shikoku, southwestern Japan (one site with conifer canopy and another with mixed conifer and broadleaved canopy). Breakdown rates and macroinvertebrate densities were compared between litter species (conifer needle vs broadleaf) and between the two sites (conifer vs mixed canopy) to determine (1) whether breakdown rate of broadleaves is higher than conifer needles, (2) whether macroinvertebrates prefer broadleaves to conifer needles, and (3) whether the difference in riparian canopy is reflected in macroinvertebrate abundance. The results indicated that breakdown rates of broadleaves were higher than those of conifer needles, suggesting poorer quality of the latter as food for macroinvertebrates. Differences in macroinvertebrate density between needles and broadleaves were generally consistent with those in breakdown rates: broadleaves tended to have higher densities than needles, suggesting that conifer needles were not preferred by macroinvertebrates. However, total macroinvertebrate density in the conifer site was not significantly different from that in the mixed site, although the dominant shredder taxon differed (conifer site: gammarids; mixed site: lepidostomatids). Although conifer needles are low-quality food for macroinvertebrates, this may offer some advantages. Conifer needles remain on the streambed for longer periods owing to their lower breakdown rates, being a constantly available resource. In addition, accumulations of conifer litter may effectively trap and retain particulate organic matter.  相似文献   

Conjugated linoleic acid-induced fatty liver can be attenuated by combination with docosahexaenoic acid in C57BL/6N mice     

Yanagita T  Wang YM  Nagao K  Ujino Y  Inoue N 《Journal of agricultural and food chemistry》2005,53(24):9629-9633

We investigated the effect of dietary combination of conjugated linoleic acid (CLA) and docosahexaenoic acid (DHA) to attenuate CLA-induced fatty liver in C57BL/6N mice. Mice were fed semisynthetic diets that contained either 6% high linoleic safflower oil (HL-SAF), 4% HL-SAF + 2% CLA, or 3.5% HL-SAF + 2% CLA + 0.5% DHA for 4 weeks. This 4 week feeding of CLA showed hepatic lipid accumulation concomitant with the decrease in adipose tissue weight in mice. However, 0.5% supplementation of DHA to the CLA diet could alleviate fatty liver without decreasing the antiobesity effect of CLA. The CLA diet promoted fatty acid synthesis in the liver, but DHA supplementation significantly attenuated the increase in enzyme activity induced by CLA. On the other hand, serum adipocytokines, leptin and adiponectin, were drastically decreased by CLA feeding, and DHA supplementation did not affect those levels. These results show that DHA supplementation to the CLA diet can attenuate CLA-induced fatty liver through the reduction of hepatic fatty acid synthesis without affecting adipocytokine production in C57BL/6N mice.  相似文献   

暴雨径流期间前次洪水对悬移质传输影响的研究     

OkazawaHiromu  NagasawaTetuaki 《中国水土保持》2002,(7):17-17

对日本北海道西南部的两个不同土地利用方式流域的几场降雨中的悬移质输沙量进行了观测。一个流域完全被森林所覆盖 ,另一个流域农业用地占 35%。这个地区主要种植日耕型的高原作物 ,该作物系喂养菜牛的饲料。从 1 997年 5月到 1 998年 1 0月 (不包括 1 997年 1 1月至1 998年 4  相似文献