Effect of p-chlorophenyl dimethyl urea on the degradation of chlorophyll in detached rice leaf in the light

It was observed previously that, when a fully developed leaf of the rice plant (Oryza sativa) was detached and kept in the light, more rapid loss of chlorophyll took place than in the dark during their incubation. Since this had been considered to be associated with photosynthesis, the effects of CMU (p-chlorophenyl dimethyl urea) and other compounds on the degradation of chlorophyll were studied. CMU had a significant effect in retarding the degradation of chlorophyll in the light irrespective of the presence of sucrose, whereas monoiodo acetic acid was far less effective. The degradation of chlorophyll was greatly promoted, especially in the light, when a detached leaf was kept in oxygen gas, but was delayed in nitrogen gas.

Electron microscopic observation showed that grana fret-work system and chlorophyll membrane were maintained in a healthy condition for the first few days during treatment with CMU. But they were completely degraded without CMU, and the disorganization of chloroplasts was accompanied by a rapid degradation of chlorophyll. It was assumed that oxygen evolved in photosynthetic reaction causes light-induced degradation of chlorophyll, and CMU represses degradation by inhibiting oxygen evolution in the light reaction of photosynthesis. A suggestion was made as to the scheme of light-induced degradation of chlorophyll relative to photosynthetic reaction and the mode of action of CMU.     

Nitrogen accumulation in soybean [Glycine max (L.) Merr.] is increased by manure compost application in drained paddy fields as a result of increased soil nitrogen mineralization

The application of manure compost is an effective way to increase soybean [Glycine max (L.) Merr.] yield and nitrogen (N) fertility in drained paddy fields. We investigated changes in soil N mineralization during soybean cultivation using reaction kinetics analysis to determine the contribution of increased N mineralization after manure compost application (at a rate of 0 to 6?kg?m^?2) on N accumulation and seed yield of soybean under drained paddy field conditions. The seed yield and N accumulation decreased markedly in the second and third year of the experiment, but soil N mineralization increased in both years. No decrease in soil N mineralization occurred even after two soybean crops. Soil N availability was not the main cause of decreased soybean yield in the second and third years. The differences in plant aboveground N content between plots with and without manure compost was similar to the increase in N mineralization caused by manure compost application in the second and third years. The application of 6?kg?m^?2 of manure compost increased the amount of ureide-N and nitrate-N in soybean in the third year. Our results suggest that manure compost application increases soil N mineralization and soybean N₂ fixation, resulting in increased N accumulation and seed yield. However, the soybean yield remained less than 300?g?m^?2 in the second and third years (i.e., below the yield in the first year) at all levels of manure compost application due to the remarkable decrease of N accumulation in the second and the third crops.     

Manure application has an effect on the carbon budget of a managed grassland in southern Hokkaido,Japan

Abstract

The carbon (C) budget of managed grassland in a cool-temperate region of Japan was estimated using a combination of eddy covariance and the biometric method for five years, to evaluate the effect of manure application. Chemical fertilizer was applied to the fertilizer (F) plot at a rate of 79 ± 20 kg N ha^?1 yr^?1. In the manure (M) plot, dairy cattle manure was applied at a rate of 10 Mg fresh matter ha^?1 yr^?1 (1923 ± 407 kg C ha^?1 yr^?1, 159 ± 68 kg N ha^?1 yr^?1). There was no significant difference in seasonal gross primary production (GPP) and harvest between the treatment plots, indicating that both fertilizer and manure can increase the biomass production. Annual net ecosystem production (NEP) and ecosystem respiration (RE) was significantly different between the treatment plots. The difference in RE, and between M and F plots approximates heterotrophic respiration of manure (RHm), which ranged from 0.9 to 1.3 Mg C ha^?1 yr^?1. Average annual RHm was 1.1 ± 0.4 Mg C ha^?1 yr^?1, and accounted for 56% of the total amount of applied manure C. The annual net biome production (NBP) in the M plot (from 0.0 to 1.5 Mg C ha^?1 yr^?1) was significantly higher than in the F plot (?1.4 to 0.5 Mg C ha^?1 yr^?1). The long-term effect of manure application combined with chemical fertilizer did not reduce grass production compared with chemical fertilizer only; however, manure application decreased the NEP throughout manure decomposition, and long-term manure application enhanced the NBP.     

Enrichment of natural 15N abundance in frankia-infected nodules

Abstract

The enrichment of ¹⁵N in the nodules of some N₂-fixing leguminous plants is an interesting finding (Shearer et al. 1982). The extent of ¹⁵N enrichment differed depending on the plant species (Shearer et al. 1982; Yoneyama 1987) and bacterial strains (Steele et al. 1983), and in soybeans it was apparently related to the nitrogen fixation efficiency (Shearer et al. 1984)     

Ethanol production from sugi pulp under simultaneous saccharification and fermentation using a cocktail enzyme of T. reesei and A. tubingensis produced by solid-state fermentation

The process of solid-state fermentation was used to produce a cocktail enzyme of Trichoderma reesei ATCC 66587 and Aspergillus tubingensis KRCF 700-33. Wheat bran, corncob, and sugi pulp were supplemented with ammonium sulfate as an enzyme-producing medium using T. reesei and A. tubingensis. The corncob blend ratio, duration of incubation, and ammonium sulfate concentration were optimized for enhancing cellulase production from T. reesei using a Box-Behnken design. Filter paper degrading activity more than tripled when T. reesei was grown in the optimized medium, as compared with the initial medium. The highest activity of 4.03 FPU/ml (about 29 FPU/g of dry material) was obtained with a cocktail enzyme having a 25 % content of A. tubingensis and 75 % of T. reesei. The sugi pulp was then fermented to ethanol with the cocktail enzyme and thermotolerant yeast (Saccharomyces cerevisiae BA-11) under simultaneous saccharification and fermentation (SSF) at 40 °C. An ethanol concentration of 4.48 % (w/v) was achieved using the cocktail enzyme (4 FPU/g-pulp) that was produced on-site with a substrate loading level of 12.5 wt %, which achieved an ethanol yield of 76 % after 72 h.     

Strength properties and effect of moisture content on the bending and compressive strength parallel to the grain of sugi (Cryptomeria japonica) round timber

Static bending tests and compressive test parallel to the grain of sugi (Japanese cedar, Cryptomeria japonica) green round timber were conducted to confirm whether its strength would satisfy the referenced strength determined by the Construction Ministry. The strength of green round timber and air-dried round timber were compared for bending and compression parallel to the grain. The strength change ratio in response to a 1 % change in the moisture content of round timber was compared with that of small clear specimens and timber. The results revealed that a 5 % parametric tolerance limit of bending and compressive strength parallel to the grain satisfied the referenced strength, even when using green round timber. The average strength of air-dried round timber was higher than that of green round timber, in both bending and compression parallel to the grain, with significant differences indicated at a 5 % significance level. The relation between the cross-section area that includes round timber, timber and the small clear specimens, and the strength change ratio in response to a 1 % change in moisture content change was fitted to a logarithm curve. Thus, the size of the specimen was considered to affect the strength change ratio.     

Analysis of RAPD and AFLP markers linked to resistance to Fusarium oxysporum f. sp. lactucae race 2 in lettuce (Lactuca sativa L.)

Root rot of lettuce, which is caused by Fusarium oxysporum f. sp. lactucae (FOL), is a critical problem in the production of lettuce. FOL-resistant lettuce genetic resources have been identified and used in breeding programs to produce FOL-resistant cultivars. However, the genetic characteristics of resistance genes have not been studied in depth and, therefore, no DNA markers are presently available for these genes. In this study, we analyzed the RRD2 (resistance for root rot disease race 2) locus, which confers resistance to FOL race 2. Resistance loci were analyzed using two cultivars of crisphead lettuce: VP1013 (resistant) and Patriot (susceptible). The segregation patterns of resistant phenotypes in F₂ indicated a single major locus. To define the positions of resistance loci, a linkage map was constructed using amplified fragment length polymorphism and random amplified polymorphic DNA (RAPD) markers. Quantitative trait loci analysis revealed the position of the major resistance locus. A high LOD score was observed for RAPD-marker WF25-42, and this marker showed good correspondence to the phenotype in different cultivars and lines. We successfully developed a sequence characterized amplified region marker from WF25-42.     

Fixed–fixed flexural vibration testing method of actual-size bars for timber guardrails

Resonance frequencies of bars with various types of end supports were examined in terms of flexural vibration. Sugi (Japanese cedar, Cryptomeria japonica D. Don) was used for the specimens. Small rectangular bars with dimensions of 25?mm (R)?×?5?mm (T)?×?300?mm (L), small round bars of 25?mm in diameter and 250?mm in length, actual-size rectangular bars with the dimensions of 45?mm (R)?×?95?mm (T)?×?1500?mm (L) and actual-size round bars of 180?mm in diameter and 2000?mm in length were made. Varying compression stress was applied to the parts around both ends of test specimen, whereupon flexural vibration tests were performed. The measured resonance frequency rose rapidly early in the increasing compression load process and was nearly stable for the larger compression load. The significant increases in the resonance frequency for round bars are thought to be derived from the wide area between the round bar and jig. It is necessary to compare the resonance frequency of a bar tightly fixed to a post with that of the same bar loosely fixed to the post.     

Ferroelectric columnar liquid crystal featuring confined polar groups within core-shell architecture

Ferroelectric liquid crystals are materials that have a remnant and electrically invertible polar order. Columnar liquid crystals with a ferroelectric nature have potential use in ultrahigh-density memory devices, if electrical polarization occurs along the columnar axis. However, columnar liquid crystals having an axial nonzero polarization at zero electric field and its electrical invertibility have not been demonstrated. Here, we report a ferroelectric response for a columnar liquid crystal adopting a core-shell architecture that accommodates an array of polar cyano groups confined by a hydrogen-bonded amide network with an optimal strength. Under an applied electric field, both columns and core cyano groups align unidirectionally, thereby developing an extremely large macroscopic remnant polarization.