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Intensive nitrogen (N) application during stem elongation is effective in increasing potential yield but it also increases the risk of lodging. Unfortunately, the increased lodging more than offsets any associated gains from the increase in potential yield. We test the hypothesis that lodging is not induced directly by N application during stem elongation but by increased light competition in the resulting excessively dense canopy. Our results show that lodging was more severe in plants given N early (before stem elongation) compared with in plants where N fertilisation was given later (during stem elongation). When N was given early, the lengths of the lower internodes of the tillers were significantly greater than when N was given later. For the early N application, dry weight of the above-ground plant was 75% greater, leaf area index 66% greater and green area index 81% greater than for the later N application. This likely indicates much greater competition for light in the denser canopy with the early N application. Shading treatments applied during stem elongation resulted in the lower internodes being longer and lighter, than for unshaded plants. The results suggest that by shifting intensive N application before stem elongation to during stem elongation, canopy development and thus light competition are reduced, the basal internodes of the tillers are shorter and lodging is minimised.

Sulfur-based denitrification may be a key biogeochemical nitrate (NO3−) removal process in sulfide-rich regions, but it is still poorly understood in natural terrestrial ecosystems. We examined sulfur-driven NO3− reduction using streambank soils in a headwater catchment underlain by marine sedimentary rock in Akita, Japan. In a catchment exhibiting higher sulfide content in streambed sediment, we sampled two adjacent streambank soils of streambank I (two layers) and of streambank II (eight layers). Anaerobic long-term incubation experiments (40 days, using soils of streambank I) and short-term incubation experiments (5 days, using soils of streambank II) were conducted to evaluate variations of N solutes (NO3−, NO2−, and NH4+), N gases (NO, N2O), and the bacterial flora. In both experiments, two treatment solutions containing NO3− (N treatment), and NO3− and S2O32− (N + S treatment) were prepared. In the N + S treatment of the long-term experiment, NO3− concentrations gradually decreased by 98%, with increases in the SO42−, NO2−, NO, and N2O concentrations and with not increase in the NH4+, indicating denitrification had occurred with a high probability. Temporal accumulation of NO2− was observed in the N + S treatment. The stoichiometric ratio of SO42− production and NO3− depletion rates indicated that denitrification using reduced sulfur occurred even without additional S, indicating inherent S also served as an electron donor for denitrification. In the short-term incubation experiment, S addition was significantly decreased NO3− concentrations and increased NO2−, NO, and N2O concentrations, especially in some subsoils with higher sulfide contents. Many denitrifying sulfur-oxidizing bacteria (Thiobacillus denitrificans and Sulfuricella denitrificans) were detected in both streambank I and II, which dominated up to 5% of the entire microbial population, suggesting that these bacteria are widespread in sulfide-rich soil layers in the catchment. We concluded that the catchment with abundant sulfides in the subsoil possessed the potential for sulfur-driven NO3− reduction, which could widely influence N cycling in and NO3− export from the headwater catchment.

Soil salinity is a major constraint to sustainable crop production. Genetic improvements are needed for growing soybean in salinity-prone environments. Salt-tolerant soybean genotypes alleviate a reduction in photosynthesis and growth under saline conditions; however, the detailed mechanisms involved remain unclear. Here, we aimed to clarify how Na and Cl root-to-leaf transport is quantitatively regulated, and to identify whether photosynthetic tolerance depends on traits associated with either stomata or with mesophyll tissues. Two pairs of pot-grown soybean near-isogenic lines (NILs) consisting of tolerant and susceptible counterparts, derived from a cross between salt-tolerant FT-Abyara and salt-sensitive C01, were subjected to salinity treatment in a rainout greenhouse. Comparison of photosynthetic responses between genotypes indicated that genotypic differences in salinity tolerance depended on the ability for sustained CO2 assimilation in mesophyll tissues, rather than stomatal conductance. The ratio of photosynthetic rate to intercellular CO2 concentration (A/Ci) declined exponentially with increasing Na and Cl concentration regardless of genotype, but tolerant genotypes effectively kept both elements at significantly low levels. Under saline conditions, tolerant genotypes reduced Na and Cl content at the two transport pathways: from root to stem, and from stem to leaf, but the reduction of Cl at each pathway was only minor. These results suggest that integrating genetic capacity for Cl transport regulation and osmotic adjustment should be an important target in salinity-tolerance soybean breeding.

Abstract Background Translocated chromosomal duplications occur spontaneously in many organisms; segmental duplications of large chromosomal regions are expected to result in phenotypic changes because of gene dosage effects. Therefore, experimentally generated segmental duplications in targeted chromosomal regions can be used to study phenotypic changes and determine the functions of unknown genes in these regions. Previously, we performed tandem duplication of a targeted chromosomal segment in Aspergillus oryzae. However, in tandem chromosomal duplication, duplication of chromosomal ends and multiple chromosomal duplication are difficult. In this study, we aimed to generate fungal strains with a translocated duplication or triplication of a targeted chromosomal region via break-induced replication. Results Double-strand breaks were introduced into chromosomes of parental strains by treating protoplast cells with I-SceI meganuclease. Subsequently, strains were generated by nonreciprocal translocation of a 1.4-Mb duplicated region of chromosome 2 to the end of chromosome 4. Another strain, containing a triplicated region of chromosome 2, was generated by translocating a 1.4-Mb region of chromosome 2 onto the ends of chromosomes 4 and 7. Phenotypic analyses of the strains containing segmental duplication or triplication of chromosome 2 showed remarkable increases in protease and amylase activities in solid-state cultures. Protease activity was further increased in strains containing the duplication and triplication after overexpression of the transcriptional activator of proteases prtT. This indicates that the gene-dosage effect and resulting phenotypes of the duplicated chromosomal region were enhanced by multiple duplications, and by the combination of the structural gene and its regulatory genes. Gene expression analysis, conducted using oligonucleotide microarrays, showed increased transcription of a large population of genes located in duplicated or triplicated chromosomal regions. Conclusion In this study, we performed translocated chromosomal duplications and triplications of a 1.4-Mb targeted region of chromosome 2. Strains containing a duplication of chromosome 2 showed significant increases in protease and amylase activities; these enzymatic activities were further increased in the strain containing a triplication of chromosome 2. This indicates that segmental duplications of chromosomes enhance gene-dosage effects, and that the resulting phenotypes play important phenotypic roles in A. oryzae.

Previously, we reported that apple polyphenols and their major active compounds, the flavan-3-ols and the procyanidins, can result in various health benefits in animals and humans, according to clinical studies. Here, we developed a rapid method for quantifying flavan-3-ols and procyanidins using high-performance liquid chromatography with fluorescence detection, where we investigated the amounts of flavan-3-ols and procyanidins in the Japanese major apple production centre, the Aomori Prefecture, from 2016 to 2018. The non-bagged ‘Fuji (n = 609)’, the bagged ‘Fuji (n = 1101)’, and the ‘Orin (n = 504)’ apples were evaluated in terms of their differences in flavan-3-ols and procyanidins based on apple variety and the controlled atmosphere storage. The bagging treatments of the ‘Fuji’ apples resulted in significantly higher concentrations of procyanidins, while changes in flavan-3-ols concentrations were not clearly observed by treatment. In addition, ‘Orin’ had a significantly higher concentration of procyanidins than that of ‘Fuji’. In contrast, the controlled atmosphere storage hardly caused any changes in the flavan-3-ol and procyanidin contents. Hence, we present the concentrations of flavan-3-ols and procyanidins in major Japanese apples using the rapid high-performance liquid chromatography method with fluorescence detection.

Wheat cultivar Haruyutaka, bred in Hokkaido, as a cultivar with improved genetic traits for production in western Japan, had a lower grain yield when grown in Yamaguchi in western Japan than Daichinominori, native to Yamaguchi. We examined the yield and grain growth of these two cultivars in the two areas in 2005/2006, 2006/2007 and 2007/2008 to elucidate theirgrain filling mechanisms under the two environments. When grown in Yamaguchi, Haruyutaka had a lower grain yield due to smaller grains than Daichinominori and when grown in Hokkaido, Daichinominori had a lower grain yield due to smaller grainsthan Haruyutaka. The slower grain growth, especially, at the later period of grain filling was considered to be the major cause of smaller grain in both cultivars, but it was more pronounced in Haruyutaka grown in Yamaguchi. Haruyutaka and Daichinominori ceased total dry mass production earlier when grown in the non-native area, Yamaguchi and Hokkaido, respectively, resulting in less supply of current assimilation products to grain growth. When grown in Yamaguchi, the amount of post-anthesis culm reserves, water soluble carbohydrate (WSC), was smaller in Haruyutaka than in Daichinominori, while they accumulated a similar amount of WSC in Hokkaido. The pattern of remobilization of WSC to grains was similar in both areas. However, the grain filling period was significantly shorter in the non-native area. These results suggested that in the non-native environment, the grain size is decreased due to slower grain growth, mainly due to less current assimilation, and shorter grain filling period.

We found a symptom of abnormally early ripening in a farmer’s field in Natajima, Yamaguchi Prefecture, Japan, in 2004/2005, and examined its physiological mechanisms for two weeks until maturity. In the following two seasons, 2005/2006 and 2006/2007, we examined the mechanisms throughout the grain filling period at another farmer’s field where the symptoms appeared in the preceding four seasons. The grain yield was lower in abnormally early ripening (AER) than in the normal because of lighter grain weight in 2004/2005. The grain weight and water soluble carbohydrate, WSC, in culm were similar at the beginning of symptom, two weeks before maturity, then the grain weight increased and WSC in culm decreased more sharply in the normal than in the AER. So the grain weight was poorer and more WSC in culm remained unutilized at maturity in the AER. Another field showed the symptom of AER in both seasons. The spike dry weight and WSC in culm were the similar between the treatments from anthesis to milk ripe stage in 2005/2006, then they showed almost similar pattern in their change as in 2004/2005 until maturity. It was thought that the slower grain growth in later phase might be due to limited current assimilation and poor remobilization of culm reserves to the grains in AER.

Grain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike.

The spring-type cultivar (Triticum aestivum L.) is usually sown in November. However, the sowing time is sometimes delayed considerably because of much rain in October, and the seed bed does not become suitably dry for sowing due to cold temperature. To find a solution to this problem, we compared the yielding ability of wheat sown early (early-sown group) with wheat sown at the standard date (standard group) in Yamaguchi. The grain yield for nine cultivars averaged for three growing seasons, 1999/2000, 2001/2002 and 2002/2003 was 230 gm-2 in the early-sown group, and significantly lower than that in the standard group (334 gm-2). The spike number and grain number per spike were lower in the early-sown group than in the standard group. Akitakko, Iwainodaichi, Airakomugi had a higher grain yield, and Akitakko had a higher spikelet number per spike and higher grain number per spike than the other cultivars when sown earlier. Iwainodaichi showed higher spike number when sown earlier. Airakomugi showed higher grain number per spike and grain weight when sown earlier. Akitakko was the only cultivar that showed a higher grain yield by early sowing.

Several types of water soluble carbohydrates (WSG) were traced into plant parts of a winter wheat (Triticum aestivum L.) cultivar from heading to physiological maturity. Field grown plants were harvested at intervals of a few days and divided into grain, chaff, leaf blades, leaf sheaths, rachis + peduncle and culm internodes. Leaf blades and sheath showed the peak of WSC contents at about anthesis. Culm internodes accumulated fructan and sucrose during the early grain-filling phase, from a week after anthesis until the milk-ripe stage, then remobilized them during late and final grain filling phases, from the milk-ripe stage until maturity. The amount of sucrose known as short-term storage WSC was higher than fructan known as long-term storage WSC in each internode throughout the grain-filling phase. Chaff showed a large amount of fructan and fructose before anthesis, although it did very little sucrose. A pattern of sucrose accumulation in chaff was very different from that of fructan, unlike the other parts. These patterns of changes in WSC contents in plant organs roughly corresponded with four grain-filling phases, the initial, early, late and final phases.

This study was conducted to reveal the ideotype of wheat (Triticum aestivum L.) canopy structure for high yield and biornass productivity. The assimilation rate and nitrogen contents of the flag, second, third and lower leaves and the ear of the main stem were measured in three spring cultivars with different plant forms (figures), Haruyutaka, Norin 61 and Selpek, under field conditions. The assimilation rate was evaluated based on the amount of water-soluble carbohydrate accumulated during the day (WSC/day). Surface area indexes of the ear and flag leaf in Haruyutaka and Selpek were larger than those in Norin 61. In Haruyutaka and Selpek, the amount of WSC/day was larger in the flag leaf than in the second or third leaf, which had a sufficiently high nitrogen content. On the contrary, in Norin 61, the amount of WSC/day in the flag leaf was similar to that in the second and third leaves during the grain-filling period. The amount of WSC/day in the flag leaf during the last half of the grain-filling period was much higher in Selpek than in Haruyutaka and Norin 61. This may be one of the reasons why Selpek had a heavier total dry weight than Haruyutaka and Norin 61 in 1993 and 1995.

In order to establish the local sustainable hydroponics system by unused bioresources, the objective of this study was to evaluate 1) the feasibility of alternative hydroponics substrates that utilized rice husk and willow as biochar by 1-1) cultivation trial and 1-2) estimation of carbon sequestration and 2) the effectiveness of biochar substrates in low irrigation by the cultivation trial. Rice husk char (RHC) and willow char (WC) were tried as substrates in addition to rock wool (RW) as commercial products to grow cherry tomatoes under different water conditions (low irrigation and conventional irrigation). As a result, the water content of RHC and WC was higher than RW under both irrigations. Nevertheless, under both irrigations, RHC and WC showed similar results of RW in the fruit yield and quality (brix value, acidity, and lycopene). While low irrigation treatment decreased the commercial yield, the quality was improved except for lycopene. Besides, these substrates can contribute to carbon sequestration if they were used for soil amendment after using substrates in hydroponics. The refractory carbon contents of RHC and WC were calculated as 35.5, and 67.5 t CO2eq ha, respectively, in this experiment system. Thus, the utilization of unused bioresources as biochar showed the possibility of providing alternative substrates to RW, and the potential of carbon sequestration locally. [ABSTRACT FROM AUTHOR]

This study aims to compare the 1,4-dioxane removal functions of four willow (Salix spp.) strains during the two seasons (summer and autumn) and to elucidate the function of phytoremediation (volatilization, metabolism, and accumulation) of 1,4-dioxane-containing water by willow during the two seasons. This investigation tests the removal performance of 1,4-dioxane from solution by the strains; KKD strain which shows extremely fast-growing, HB471 which shows similar characteristics as KKD, FXM strain which shows relatively strong drought tolerance, and SEN which shows relatively strong insect resistance. Pot tests of 1,4-dioxane removal by willow revealed significant differences in removal rates between the summer and autumn seasons. In all four willow strains, the autumn removal rates decreased to 15.7 to 25.4% of the summer removal rates. The strain with the highest removal rate was KKD (37.5% of the exposure) during the summer season, making it the most promising strain. When comparing the percentage contribution of 1,4-dioxane removal by plant function in KKD, removal by transpiration was the largest contributor in both summer and autumn. However, in the autumn season, the contribution of transpiration to 1,4-dioxane removal was smaller, while the contribution of accumulation increased. This occurred because transpiration decreased during the autumn, causing 1,4-dioxane absorbed from the roots to remain in the plant body instead of being transpired. Considering the application of willow in arid lands, the importance of water management was suggested, as a decrease in transpiration was found to affect removal performance. [ABSTRACT FROM AUTHOR]