Effect of water management on the vivianite content of paddy-rice roots

Abstract

Vivianite is a hydrated ferrous phosphate mineral that can form in reducing environments, and it was recently identified on aged paddy rice (Oryza sativa, L., cultivar Hitomebore) roots. However, the formation and dissolution of vivianite appear highly susceptible to the soil redox potential. We examined the effect of water management on the vivianite content of rice roots in three experimental micro (1 m²) paddy fields. The vivianite content of the roots was estimated using a method based on the alteration of vivianite after heating at 105°C for 48 h. This alteration steeply lowers the dissolution of phosphate from the roots in a mixed acid solution of 0.1 mol L^?1 of hydrochloric acid (HCl) and 1 mol L^?1 of acetic acid (CH₃COOH). Efficiency of the method was confirmed regarding heating temperature and duration of heating. Using this method, we found that water management significantly influenced the vivianite content of the rice roots. The vivianite content of the rice roots was highest, i.e., 2.3 g phosphorus (P) kg^?1 expressed by its estimated P content, when the paddy field was continuously flooded from May to until early September. After flooding stopped, the soil was gradually oxidized, leading to a decrease in vivianite content. In the micro plot exposed to midseason drainage, the vivianite content increased to the level of the continuously flooded plot after reflooding, and finally decreased after flooding was stopped in late August. The plots exposed to midseason drainage followed by intermittent irrigation presented the lowest vivianite contents among the three experimental paddy fields. These results confirm that increases and decreases in the vivianite contents of paddy-rice roots strongly depend on water management.     

Stoichiometry for the decrease in the amount of phosphate-induced negative charges of clay fractions of andisols

Abstract

It is well-known that the amount of negative charges increases with phosphate (P) sorption on soils or soil constituents (Mekaru and Uehara 1972; Schalscha et al. 1972). The increase in the amount of negative charges could be considered as one of the beneficial aspects of P dressing for the retention of cationic nutrients.     

Effect of cashew nut shell liquid on metabolic hydrogen flow on bovine rumen fermentation

Effect of cashew nut shell liquid (CNSL), a methane inhibitor, on bovine rumen fermentation was investigated through analysis of the metabolic hydrogen flow estimated from concentrations of short‐chain fatty acids (SCFA) and methane. Three cows were fed a concentrate and hay diet without or with a CNSL‐containing pellet. Two trials were conducted using CNSL pellets blended with only silica (trial 1) or with several other ingredients (trial 2). Methane production was measured in a respiration chamber system, and energy balance and nutrient digestibility were monitored. The estimated flow of metabolic hydrogen demonstrated that a part of metabolic hydrogen was used for hydrogen gas production, and a large amount of it flowed into production of methane and SCFA in both trial 1 and 2, when CNSL was administered to the bovine rumen. The results obtained by regression analyses showed that the effect of CNSL supply on methane reduction was coupled with a significant (P < 0.01) decrease of acetate and a significant (P < 0.01) increase of propionate and hydrogen gas. These findings reveal that CNSL is able to reduce methane and acetate production, and to increase hydrogen gas and propionate production in vivo.     

Diversity of S-RNase genes and S-haplotypes in Japanese plum (Prunus salicina Lindl.)

Summary

This report demonstrates the diversity of S-haplotypes in Japanese plum by molecular cloning of genomic DNAs and cDNAs that encode S-RNases. Nine different DNA fragments, designated as S^a–Sⁱ, were obtained from 17 Japanese plum cultivars by PCR with an S-RNase gene-specific primer set, Pru-C2 and PCE-R. Eleven different S-haplotypes were found in these cultivars. The banding patterns obtained with another S-RNase gene-specific primer set, Pru-T2 and PCE-R, corresponded to the S-haplotypes predicted from the Pru-C2 and PCE-R primer set. Several cultivars had the same S-haplotypes. Partial genomic DNAs for eight S-RNase genes and cDNAs for two S-RNases were cloned and sequenced. Deduced amino acid sequences contained conserved regions among the rosaceous S-RNases. Comparisons of the sequences from cDNAs and genomic DNAs revealed the presence of two introns in the S-RNase genes of Japanese plum as in other Prunus S-RNase genes. Pollination incompatibility groups and self-compatibility in Japanese plum were discussed with reference to the S-haplotypes.     

Efficient bioethanol production from water hyacinth Eichhornia crassipes by both preparation of the saccharified solution and selection of fermenting yeasts

Although water hyacinth is an adventive aquatic plant that threatens the Japanese ecosystem, its high growth rate may be a benefit in terms of its potential as a raw material for the production of bioethanol. In our study, water hyacinth was saccharified with 3?% (v/v) sulfuric acid and subjected to cellulase treatments to determine optimum bioethanol production conditions. The original saccharified solution yielded both glucose at 5.3?±?0.2?g/l and reducing sugars at 9.7?±?0.1?g/l. Concentration of the saccharified solution under vacuum at 70?°C yielded both glucose at 21.5?±?2.9?g/l and reducing sugars at 33.3?±?2.1?g/l. An aquatic yeast Saccharomyces cerevisiae TY2 produced ethanol at 9.6?±?1.1?g/l from the concentrated saccharified solution. In comparison, Ogawa et al. (Afr J Microbiol Res 2:110?C113, 2008) reported that this yeast produced 0.90?g/l and that the production of bioethanol was about 11.2-fold lower than that obtained in our study. These results suggest that refinement of the saccharification process and application of the selected yeast could improve the efficiency of obtaining bioethanol from the water hyacinth.     

Genetic characterization of the endangered Kiso horse using 31 microsatellite DNAs

In order to contribute to conservation of the endangered Kiso horse, we clarified their genetic information using 31 microsatellite DNAs, and genotyped 125 horses, 83% of the existing breed. First, we clarified the current status of the horses. The horses were confirmed to have experienced rapid loss of population causing a bottleneck, and their effective population size was much smaller than their census size. Moreover, the number of alleles (6.3), observed heterozygosity (0.674), and expected heterozygosity (0.662) were in the same range as other endangered horses all over the world. Therefore, although their inbreeding level was not so severe (F(is): -0.017), the Kiso horse is surely one of the endangered. Second, we obtained genetic information of individuals. This information allowed us to understand the genetic distance of individuals, and might help in development of a reproductive strategy concerning the genetic distance between the mating pairs. Moreover, there appeared to be 4 subpopulations of Kiso horse, and this result was in good agreement with their historical background. Third, we confirmed that the parentage test for identification using the 31 microsatellite DNAs was highly reliable (probability of exclusion: 0.999999993). This identification increases the reliability of stud certification, and is also helpful for effective management. Understanding the genetic diversity within the population and the relationships among individuals is important to ensuring effective management for maintenance of genetic variation, and this study may help in conservation of the endangered Kiso horse.     

基于遗传算法(GA)解甘蔗收割顺序最优化问题的研究

本研究以已建立的栽培方法、收割时期预测甘蔗单产和含糖量的数学模型为基础,提出将寻求最佳收割顺序、收割期归结为最优化组合问题,并探讨了遗传算法(GA)的解题适用性,同时进行了几种基本设定的栽培方法推移、栽培方法构成项量、行列式特性的定性分析,为求最佳的甘蔗收割顺序、收割期、不同栽培方法的面积等提供解析方法.为不使栽培方法的构成比例发生变化,与通常GA算法采用交叉在不同个体问互相交替进行不同,开发了适用本研究的GA的自己交叉具体解析法.将收割第1年期作为过渡状态,第2年期为安定状态,将两期目的函数的合并作为一个适应度进行评价.