Pub Date : 2022-06-21DOI: 10.1080/00380768.2022.2088030
K. Sasaki, M. Obara
ABSTRACT Roots are important plant organs that absorb water and nutrients. Root length responses are influenced by the plants’ sources of nitrogen (N), such as ammonium (NH4 +) and nitrate (NO3 −) ions and their concentrations. Here, to determine the genetic resources with the potential to improve the root system of rice (Oryza sativa L.), the root development traits of a core set of 334 introgression lines (ILs) were assessed in plants grown in hydroponic culture medium containing low (5 μM) or high (500 μM) concentrations of N in the form of NH4 + or NO3 −. ILs were classified into three clusters. The mean value of maximum root length (MRL) in cluster I was significantly higher than that in the other two clusters under all conditions. Root number (RN) differed significantly between clusters IIa and IIb, with the mean RN being higher in cluster IIa. In addition, the order of the mean total root length of the clusters was cluster I > IIa > IIb. Therefore, ILs in cluster I are considered genetic resources for improving root development traits under all tested N conditions. Among the ILs, YTH187 – which is derived from YP5 as a donor – had a longer MRL under all conditions. Quantitative trait loci (QTL) analyses, performed using recombinant inbred lines derived from a cross between IR 64 and YTH187, revealed that qRL5.3-YP5 and qRL6.5-YP5 were detected under all N conditions. In contrast, qRL4.1-YP5 was detected only under low KNO3 concentrations, whereas qRL8.1-YP5 was detected under high concentrations of NH4Cl and KNO3. YP5 alleles at these QTLs increased MRL. QTLs for root length in rice grown in hydroponic culture have not previously been detected in the vicinity of qRL8.1-YP5; thus, this may be a novel QTL that controls root length in rice. Moreover, qRL8.1-YP5 and qRL4.1-YP5 could be useful QTLs to determine the mechanism of root elongation under KNO3 conditions because such QTLs have not yet been detected under these conditions in rice. In future studies, further fine-mapping and characterization of qRL8.1-YP5 could reveal the mechanism of root elongation under high KNO3 concentration conditions.
{"title":"Mapping of quantitative trait loci for root elongation in rice (Oryza sativa L.) treated with various nitrogen sources and concentrations","authors":"K. Sasaki, M. Obara","doi":"10.1080/00380768.2022.2088030","DOIUrl":"https://doi.org/10.1080/00380768.2022.2088030","url":null,"abstract":"ABSTRACT Roots are important plant organs that absorb water and nutrients. Root length responses are influenced by the plants’ sources of nitrogen (N), such as ammonium (NH4 +) and nitrate (NO3 −) ions and their concentrations. Here, to determine the genetic resources with the potential to improve the root system of rice (Oryza sativa L.), the root development traits of a core set of 334 introgression lines (ILs) were assessed in plants grown in hydroponic culture medium containing low (5 μM) or high (500 μM) concentrations of N in the form of NH4 + or NO3 −. ILs were classified into three clusters. The mean value of maximum root length (MRL) in cluster I was significantly higher than that in the other two clusters under all conditions. Root number (RN) differed significantly between clusters IIa and IIb, with the mean RN being higher in cluster IIa. In addition, the order of the mean total root length of the clusters was cluster I > IIa > IIb. Therefore, ILs in cluster I are considered genetic resources for improving root development traits under all tested N conditions. Among the ILs, YTH187 – which is derived from YP5 as a donor – had a longer MRL under all conditions. Quantitative trait loci (QTL) analyses, performed using recombinant inbred lines derived from a cross between IR 64 and YTH187, revealed that qRL5.3-YP5 and qRL6.5-YP5 were detected under all N conditions. In contrast, qRL4.1-YP5 was detected only under low KNO3 concentrations, whereas qRL8.1-YP5 was detected under high concentrations of NH4Cl and KNO3. YP5 alleles at these QTLs increased MRL. QTLs for root length in rice grown in hydroponic culture have not previously been detected in the vicinity of qRL8.1-YP5; thus, this may be a novel QTL that controls root length in rice. Moreover, qRL8.1-YP5 and qRL4.1-YP5 could be useful QTLs to determine the mechanism of root elongation under KNO3 conditions because such QTLs have not yet been detected under these conditions in rice. In future studies, further fine-mapping and characterization of qRL8.1-YP5 could reveal the mechanism of root elongation under high KNO3 concentration conditions.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"117 3 1","pages":"454 - 462"},"PeriodicalIF":2.0,"publicationDate":"2022-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91028632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-21DOI: 10.1080/00380768.2022.2090829
N. Gao, Huanhuan Zhang, Ruonan Xiong, L. Fang, Weishou Shen, K. Senoo
ABSTRACT It is critical to monitor plant growth-promoting rhizobacteria (PGPR) in soils after inoculation. Among common PGPR, the Azospirillum sp. strains TSA2s and TSH100 have the ability to mitigate nitrous oxide (N2O) emissions from agricultural soils; however, their mechanism by which they successfully colonize and achieve beneficial effects in plants remains poorly understood. Here, a simple and robust procedure was developed to design strain-specific primers based on the whole-genome sequences of these two strains. After evaluating their specificity and amplification efficiency, three primer pairs were screened for each Azospirillum sp. strain. Quantification of these two strains in the rhizosphere soils of red clover revealed distinct inoculant dynamics for each strain under greenhouse conditions. Specifically, 22, 34, and 41 days after inoculation with TSA2s, the population size of the inoculant was notably greater than that in the non-inoculated control, and reached a maximum at day 34. In contrast, the population size of the TSH100 inoculant was largest at day 22, then decreased dramatically from 34 days after inoculation. These results suggest that different PGPR may have different strategies for colonization and prevalence after inoculation. Of the 31 rhizosphere carbon sources added to the Biolog Eco Micro plate to simulate plant root exudates, TSA2s utilized 14 whereas TSH100 utilized only one. TSA2s utilized more diverse root exudates of red clover, indicating better colonization and prevalence than TSH100 after inoculation. Therefore, this study presents a method of monitoring PGPR after inoculation. Furthermore, this method can screen PGPR with a better ability to survive and colonize, enabling the development of efficient, stable, and standardized biofertilizers.
{"title":"Different strategies for colonization and prevalence after inoculation with plant growth-promoting rhizobacteria revealed by a monitoring method","authors":"N. Gao, Huanhuan Zhang, Ruonan Xiong, L. Fang, Weishou Shen, K. Senoo","doi":"10.1080/00380768.2022.2090829","DOIUrl":"https://doi.org/10.1080/00380768.2022.2090829","url":null,"abstract":"ABSTRACT It is critical to monitor plant growth-promoting rhizobacteria (PGPR) in soils after inoculation. Among common PGPR, the Azospirillum sp. strains TSA2s and TSH100 have the ability to mitigate nitrous oxide (N2O) emissions from agricultural soils; however, their mechanism by which they successfully colonize and achieve beneficial effects in plants remains poorly understood. Here, a simple and robust procedure was developed to design strain-specific primers based on the whole-genome sequences of these two strains. After evaluating their specificity and amplification efficiency, three primer pairs were screened for each Azospirillum sp. strain. Quantification of these two strains in the rhizosphere soils of red clover revealed distinct inoculant dynamics for each strain under greenhouse conditions. Specifically, 22, 34, and 41 days after inoculation with TSA2s, the population size of the inoculant was notably greater than that in the non-inoculated control, and reached a maximum at day 34. In contrast, the population size of the TSH100 inoculant was largest at day 22, then decreased dramatically from 34 days after inoculation. These results suggest that different PGPR may have different strategies for colonization and prevalence after inoculation. Of the 31 rhizosphere carbon sources added to the Biolog Eco Micro plate to simulate plant root exudates, TSA2s utilized 14 whereas TSH100 utilized only one. TSA2s utilized more diverse root exudates of red clover, indicating better colonization and prevalence than TSH100 after inoculation. Therefore, this study presents a method of monitoring PGPR after inoculation. Furthermore, this method can screen PGPR with a better ability to survive and colonize, enabling the development of efficient, stable, and standardized biofertilizers.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"1 1","pages":"442 - 453"},"PeriodicalIF":2.0,"publicationDate":"2022-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79777770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.1080/00380768.2022.2087198
Thanuja Deepani Panangala Liyanage, M. Maeda, H. Somura, M. Mori, T. Fujiwara
ABSTRACT Ammonium nitrogen (NH4 +-N) content in soil is a key factor affecting nitrous oxide (N2O) emissions due to its role as a primary substrate of nitrification. This study aimed at investigating the effects of different application rates of NH4 +-N on N2O and CO2 emissions from two different types of manure compost-amended soil, along with analysis of relative abundances of narG and nosZ genes under aerobic conditions. Laboratory experiments were conducted using Kochi and Ushimado soils amended with mixed compost (MC: mixture of cattle, poultry, and swine manure) or cattle manure compost (CC) at 3% (dry weight basis). In no compost- and compost-amended soils, (NH4)2SO4 was added as a solution equivalent to 160, 200, and 400 mg-N kg−1 of soil. Soil samples were aerobically incubated at 70% water-holding capacity (WHC) and 25°C. Emissions of N2O and CO2 were measured on days 0, 3, 7, 15, 21, 28, and 42. The abundances of narG and nosZ genes in Kochi (day 7) and Ushimado (day 21) soils were estimated using qPCR tests. Emissions of N2O and CO2 were higher in MC-amended soil because of higher mineral N content and lower C/N ratio of MC than those of CC, regardless of NH4 +-N rates. Emissions of N2O and CO2 were higher in compost-amended Kochi soil due to higher mineral N, total N and C, and clay contents, and possibly because of higher water-filled pore spaces than those in Ushimado soil at the same WHC. In both soils with CC and no compost, raising NH4 +-N rate from 160 to 200 increased N2O emissions due to stimulation of nitrification. In contrast, increasing NH4 +-N rate from 200 to 400 decreased N2O and CO2 emissions except for N2O emissions in MC- and CO2 emissions in CC- and no compost-amended Ushimado soil possibly due to osmotic stress on microorganisms and limited C availability. Emissions of N2O were positively related to narG gene copy numbers in Kochi soil (R 2 = 0.78) due to high N and C contents. Our study revealed that NH4 +-N rate 400 suppresses N2O and CO2 emissions from manure compost-amended soil under aerobic conditions.
{"title":"Nitrous oxide and carbon dioxide emissions from two types of soil amended with manure compost at different ammonium nitrogen rates","authors":"Thanuja Deepani Panangala Liyanage, M. Maeda, H. Somura, M. Mori, T. Fujiwara","doi":"10.1080/00380768.2022.2087198","DOIUrl":"https://doi.org/10.1080/00380768.2022.2087198","url":null,"abstract":"ABSTRACT Ammonium nitrogen (NH4 +-N) content in soil is a key factor affecting nitrous oxide (N2O) emissions due to its role as a primary substrate of nitrification. This study aimed at investigating the effects of different application rates of NH4 +-N on N2O and CO2 emissions from two different types of manure compost-amended soil, along with analysis of relative abundances of narG and nosZ genes under aerobic conditions. Laboratory experiments were conducted using Kochi and Ushimado soils amended with mixed compost (MC: mixture of cattle, poultry, and swine manure) or cattle manure compost (CC) at 3% (dry weight basis). In no compost- and compost-amended soils, (NH4)2SO4 was added as a solution equivalent to 160, 200, and 400 mg-N kg−1 of soil. Soil samples were aerobically incubated at 70% water-holding capacity (WHC) and 25°C. Emissions of N2O and CO2 were measured on days 0, 3, 7, 15, 21, 28, and 42. The abundances of narG and nosZ genes in Kochi (day 7) and Ushimado (day 21) soils were estimated using qPCR tests. Emissions of N2O and CO2 were higher in MC-amended soil because of higher mineral N content and lower C/N ratio of MC than those of CC, regardless of NH4 +-N rates. Emissions of N2O and CO2 were higher in compost-amended Kochi soil due to higher mineral N, total N and C, and clay contents, and possibly because of higher water-filled pore spaces than those in Ushimado soil at the same WHC. In both soils with CC and no compost, raising NH4 +-N rate from 160 to 200 increased N2O emissions due to stimulation of nitrification. In contrast, increasing NH4 +-N rate from 200 to 400 decreased N2O and CO2 emissions except for N2O emissions in MC- and CO2 emissions in CC- and no compost-amended Ushimado soil possibly due to osmotic stress on microorganisms and limited C availability. Emissions of N2O were positively related to narG gene copy numbers in Kochi soil (R 2 = 0.78) due to high N and C contents. Our study revealed that NH4 +-N rate 400 suppresses N2O and CO2 emissions from manure compost-amended soil under aerobic conditions.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"12 1","pages":"473 - 490"},"PeriodicalIF":2.0,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76531789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-04DOI: 10.1080/00380768.2022.2083904
Masatoshi Ooshima, N. Yamaguchi, Y. Nakanishi, Yoshimi Hitomi, S. Hiradate
ABSTRACT Rice bran contains appreciable amount of phosphorus (P), which can be used as P fertilizers. The efficiency of the P in the rice bran to plants, however, is low, and the fermentation of the rice bran is proposed to improve the P availability for plants. In the present study, 20 kg of rice bran was aerobically fermented by adding 5 kg of rice husk, 0.025 kg of mulch, and 7 L of water and incubating for 35 days with 6 times of stirring, and the changes in the chemical form of P during the fermentation process were investigated by 31P nuclear magnetic resonance spectroscopy and chemical extraction. Most part (84%) of P in the raw rice bran was myo-inositol-1,2,3,4,5,6-hexaphosphate (I6P), which is not available for plants. During the fermentation process, I6P was degraded and transformed into plant-available phosphate anions (orthophosphate). The proportions of the orthophosphate increased to 68% after incubating for 19 days with two times of stirring and 92% after incubating for 35 days with six times of stirring. After the fermentation, the orthophosphate was present as plant available precipitates associated with magnesium and the other monovalent cations. In conclusion, rice bran contains low-available I6P as a major P form, and the fermentation of rice bran accelerates the cleavage of the ester bond of I6P and results in the increased proportion of orthophosphate with high availability to plants.
{"title":"Changes in chemical form of phosphorus in rice bran during fermentation process as determined by 31P nuclear magnetic resonance spectroscopy","authors":"Masatoshi Ooshima, N. Yamaguchi, Y. Nakanishi, Yoshimi Hitomi, S. Hiradate","doi":"10.1080/00380768.2022.2083904","DOIUrl":"https://doi.org/10.1080/00380768.2022.2083904","url":null,"abstract":"ABSTRACT Rice bran contains appreciable amount of phosphorus (P), which can be used as P fertilizers. The efficiency of the P in the rice bran to plants, however, is low, and the fermentation of the rice bran is proposed to improve the P availability for plants. In the present study, 20 kg of rice bran was aerobically fermented by adding 5 kg of rice husk, 0.025 kg of mulch, and 7 L of water and incubating for 35 days with 6 times of stirring, and the changes in the chemical form of P during the fermentation process were investigated by 31P nuclear magnetic resonance spectroscopy and chemical extraction. Most part (84%) of P in the raw rice bran was myo-inositol-1,2,3,4,5,6-hexaphosphate (I6P), which is not available for plants. During the fermentation process, I6P was degraded and transformed into plant-available phosphate anions (orthophosphate). The proportions of the orthophosphate increased to 68% after incubating for 19 days with two times of stirring and 92% after incubating for 35 days with six times of stirring. After the fermentation, the orthophosphate was present as plant available precipitates associated with magnesium and the other monovalent cations. In conclusion, rice bran contains low-available I6P as a major P form, and the fermentation of rice bran accelerates the cleavage of the ester bond of I6P and results in the increased proportion of orthophosphate with high availability to plants.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"40 1","pages":"421 - 428"},"PeriodicalIF":2.0,"publicationDate":"2022-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85673490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-20DOI: 10.1080/00380768.2022.2078645
Wataru Masuda, Yusuke Hatanaka, A. Mochizuki, Shin Okazaki, B. Nanzai, A. Saito
ABSTRACT Bacterial strains were isolated from root nodules of red sword bean (Canavalia gladiata var. gladiata) cultivated in Shizuoka, Japan, in order to elucidate the taxonomy of the symbionts. Of the 52 bacterial isolates, 28 strains were identified as the genus Bradyrhizobium and 10 as Rhizobium, based on the nucleotide sequences of 16S rRNA genes. Nine Bradyrhizobium isolates, which were phylogenetically selected from the 28 strains, exhibited nucleotide sequences of ITS regions that were 99.9% or 100% identical with known B. elkanii strains. These nine strains shared more than 70% similarity with B. elkanii USDA 76 T or USDA 94 in DNA-DNA hybridization analysis, indicating that the strains are B. elkanii. In a nodule formation experiment using red sword bean seeds treated with mercury chloride solution, all of the plants which were inoculated with each of the B. elkanii strains (the isolate TI06 or MI08, or the type strain USDA 76 T) formed round-type root nodules (234–664 nodules per plant), while no nodules were observed in control plants that were cultivated without inoculating bacterial strains. The bacterial strains, which were isolated from the obtained nodules, exhibited nucleotide sequences of the ITS regions that were identical to those of the corresponding inoculated strains. The root nodules formed in the experiment exhibited acetylene-reducing activity, suggesting the nitrogen-fixation activity of the nodules. We thus conclude that B. elkanii is a root nodule symbiont of red sword bean.
{"title":"Isolation and characterization of Bradyrhizobium elkanii as a root nodule symbiont of red sword bean Canavalia gladiata var. gladiata","authors":"Wataru Masuda, Yusuke Hatanaka, A. Mochizuki, Shin Okazaki, B. Nanzai, A. Saito","doi":"10.1080/00380768.2022.2078645","DOIUrl":"https://doi.org/10.1080/00380768.2022.2078645","url":null,"abstract":"ABSTRACT Bacterial strains were isolated from root nodules of red sword bean (Canavalia gladiata var. gladiata) cultivated in Shizuoka, Japan, in order to elucidate the taxonomy of the symbionts. Of the 52 bacterial isolates, 28 strains were identified as the genus Bradyrhizobium and 10 as Rhizobium, based on the nucleotide sequences of 16S rRNA genes. Nine Bradyrhizobium isolates, which were phylogenetically selected from the 28 strains, exhibited nucleotide sequences of ITS regions that were 99.9% or 100% identical with known B. elkanii strains. These nine strains shared more than 70% similarity with B. elkanii USDA 76 T or USDA 94 in DNA-DNA hybridization analysis, indicating that the strains are B. elkanii. In a nodule formation experiment using red sword bean seeds treated with mercury chloride solution, all of the plants which were inoculated with each of the B. elkanii strains (the isolate TI06 or MI08, or the type strain USDA 76 T) formed round-type root nodules (234–664 nodules per plant), while no nodules were observed in control plants that were cultivated without inoculating bacterial strains. The bacterial strains, which were isolated from the obtained nodules, exhibited nucleotide sequences of the ITS regions that were identical to those of the corresponding inoculated strains. The root nodules formed in the experiment exhibited acetylene-reducing activity, suggesting the nitrogen-fixation activity of the nodules. We thus conclude that B. elkanii is a root nodule symbiont of red sword bean.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"14 1","pages":"434 - 441"},"PeriodicalIF":2.0,"publicationDate":"2022-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84829846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-04DOI: 10.1080/00380768.2022.2088449
J. Wasaki
The rhizosphere, as defined by Dr. Lorenz Hiltner in 1904, is recognized as the region of soil influenced by plant roots. As the interface of a plant and soil, the rhizosphere is tightly involved in nutrient dynamics. Plant roots have functions not only to uptake water and mineral nutrients but also to release a wide diversity of substances that have strong effects on nutrient availability in soils. Root-secreted compounds have important roles affecting plant–microbial interactions and symbioses, such as nodules and mycorrhiza. Although the term ‘rhizosphere’ was established as important many years ago, many difficulties particularly related to spatial and temporal constraints have hindered approaches to clarify phenomena found in the rhizosphere. Nevertheless, recent progress of analytical methods including omics analyses such as metagenomics, transcriptomics, and metabolomics have supported breakthroughs in rhizosphere research. In fact, publications including ‘rhizosphere’ as a keyword were 6.2 times more numerous in 2020 than in 2000. Recent developments of methodologies such as multiomics analyses using two or more methods of omics approaches, surface analysis, and single-cell analysis have supported great strides in elucidating rhizosphere phenomena. The first international conference on the topic of rhizospheres was held in 2004 in Munich, Germany. The rhizosphere conference has been held every 3–4 years since that first conference, with increasing attendance. Many researchers in broad fields involved in the study of rhizospheres have made important presentations at the recent conference in 2019 at Saskatoon, Canada. Interconnections among related fields including both soil and plant sides have re-emphasized the fields’ importance for further understanding. Recognition of the rhizosphere as an important topic has also been extended by the Japanese Society of Soil Science and Plant Nutrition. Soil Science and Plant Nutrition (SSPN) edited a special section ‘Frontline in the Rhizosphere Research Involved in Phosphorus: for Efficient Use of Unavailable P in Soils (Rhizo-P)’ in 2018. This Special Section, ‘Recent developments on dynamics of substances in the rhizosphere’, has been proposed to introduce current research progress in the fields. White lupin, which is well known as a cluster root forming plant species showing exudative bursts, is addressed in articles on the mineral mobilization topics. Involvement of phytohormones in the unique morphology of roots has been newly suggested in an article. Novel findings related to plant responses to nutrient deficiency and stress environments are also presented in this issue. Topics involved in the symbioses and competition between plants and microbes, and the related substances are also important. The spatial dynamics of mineral nutrients are also addressed. Research papers presented in the section were collected through announcements by the Guest Editorial Board (Dr. Jun Wasaki [chief], Dr. Takur
{"title":"Preface to the special section 'Recent developments on dynamics of substances in the rhizosphere'","authors":"J. Wasaki","doi":"10.1080/00380768.2022.2088449","DOIUrl":"https://doi.org/10.1080/00380768.2022.2088449","url":null,"abstract":"The rhizosphere, as defined by Dr. Lorenz Hiltner in 1904, is recognized as the region of soil influenced by plant roots. As the interface of a plant and soil, the rhizosphere is tightly involved in nutrient dynamics. Plant roots have functions not only to uptake water and mineral nutrients but also to release a wide diversity of substances that have strong effects on nutrient availability in soils. Root-secreted compounds have important roles affecting plant–microbial interactions and symbioses, such as nodules and mycorrhiza. Although the term ‘rhizosphere’ was established as important many years ago, many difficulties particularly related to spatial and temporal constraints have hindered approaches to clarify phenomena found in the rhizosphere. Nevertheless, recent progress of analytical methods including omics analyses such as metagenomics, transcriptomics, and metabolomics have supported breakthroughs in rhizosphere research. In fact, publications including ‘rhizosphere’ as a keyword were 6.2 times more numerous in 2020 than in 2000. Recent developments of methodologies such as multiomics analyses using two or more methods of omics approaches, surface analysis, and single-cell analysis have supported great strides in elucidating rhizosphere phenomena. The first international conference on the topic of rhizospheres was held in 2004 in Munich, Germany. The rhizosphere conference has been held every 3–4 years since that first conference, with increasing attendance. Many researchers in broad fields involved in the study of rhizospheres have made important presentations at the recent conference in 2019 at Saskatoon, Canada. Interconnections among related fields including both soil and plant sides have re-emphasized the fields’ importance for further understanding. Recognition of the rhizosphere as an important topic has also been extended by the Japanese Society of Soil Science and Plant Nutrition. Soil Science and Plant Nutrition (SSPN) edited a special section ‘Frontline in the Rhizosphere Research Involved in Phosphorus: for Efficient Use of Unavailable P in Soils (Rhizo-P)’ in 2018. This Special Section, ‘Recent developments on dynamics of substances in the rhizosphere’, has been proposed to introduce current research progress in the fields. White lupin, which is well known as a cluster root forming plant species showing exudative bursts, is addressed in articles on the mineral mobilization topics. Involvement of phytohormones in the unique morphology of roots has been newly suggested in an article. Novel findings related to plant responses to nutrient deficiency and stress environments are also presented in this issue. Topics involved in the symbioses and competition between plants and microbes, and the related substances are also important. The spatial dynamics of mineral nutrients are also addressed. Research papers presented in the section were collected through announcements by the Guest Editorial Board (Dr. Jun Wasaki [chief], Dr. Takur","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"77 1","pages":"341 - 341"},"PeriodicalIF":2.0,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83891989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-09DOI: 10.1080/00380768.2022.2057786
Kohei Yamashita, M. Nishida, K. Akita, Toyoaki Ito, M. Saito, Hiroki Honjo, M. Shinohara, S. Asakawa
ABSTRACT Potassium (K) is the major intracellular cation in all kinds of organisms including soil microorganisms. This study for the first time presented the potassium pool size in microbial cells in various farmland soils and the effect of land use and organic matter application on the contents. Microbial biomass potassium was determined for several paddy field soils under various managements in different areas, together with some upland, orchard, and pasture field soils, to estimate the potassium pool size in microbial cells in the farmland soils. The contents of microbial biomass potassium ranged from 9 to 65 mg K kg−1 soil in the paddy field soils and showed no difference among soil groups of the paddy fields. The biomass potassium content was higher in the pasture field (183–187 mg K kg−1 soil) than that in the paddy, upland (8–51 mg K kg−1 soil) and orchard (25–50 mg K kg−1 soil) field soils. The average ratio of microbial biomass potassium to exchangeable potassium was 0.25 for all the soils and the average values for paddy field (0.31) and pasture field (0.53) soils were higher than those for upland field (0.06) and orchard field (0.08) soils. Positive correlations were found between the contents of microbial biomass potassium and microbial biomass carbon and nitrogen. Application of organic matter significantly increased microbial biomass potassium in the farmland soils. These findings indicate that microbial biomass potassium plays an important role in potassium supply to crops as a reservoir of potassium and also suggest that the contribution of microbial biomass potassium to the potassium source for crops could be relatively higher in paddy field and pasture field soils than upland field and orchard field soils.
钾(K)是包括土壤微生物在内的各种生物细胞内的主要阳离子。本研究首次揭示了不同农田土壤微生物细胞钾库大小及不同土地利用方式和有机质施用对其含量的影响。测定了不同地区不同管理方式的稻田土壤以及旱地、果园和牧场土壤的微生物量钾，估算了农田土壤微生物细胞中钾库的大小。稻田土壤微生物量钾含量在9 ~ 65 mg K kg−1之间，稻田土壤类群间无差异。草地土壤的生物量钾含量(183 ~ 187 mg K kg−1)高于稻田、旱地(8 ~ 51 mg K kg−1)和果园(25 ~ 50 mg K kg−1)。所有土壤微生物量钾与交换态钾的平均比值为0.25，水田(0.31)和牧场(0.53)高于旱地(0.06)和果园(0.08)。微生物量钾与微生物量碳、氮含量呈显著正相关。施用有机质显著增加了农田土壤微生物钾量。这些结果表明，微生物量钾作为钾库在作物钾供应中起着重要作用，水田和牧场土壤中微生物量钾对作物钾源的贡献可能相对高于旱地和果园土壤。
{"title":"Pool size of microbial biomass potassium in various farmland soils","authors":"Kohei Yamashita, M. Nishida, K. Akita, Toyoaki Ito, M. Saito, Hiroki Honjo, M. Shinohara, S. Asakawa","doi":"10.1080/00380768.2022.2057786","DOIUrl":"https://doi.org/10.1080/00380768.2022.2057786","url":null,"abstract":"ABSTRACT Potassium (K) is the major intracellular cation in all kinds of organisms including soil microorganisms. This study for the first time presented the potassium pool size in microbial cells in various farmland soils and the effect of land use and organic matter application on the contents. Microbial biomass potassium was determined for several paddy field soils under various managements in different areas, together with some upland, orchard, and pasture field soils, to estimate the potassium pool size in microbial cells in the farmland soils. The contents of microbial biomass potassium ranged from 9 to 65 mg K kg−1 soil in the paddy field soils and showed no difference among soil groups of the paddy fields. The biomass potassium content was higher in the pasture field (183–187 mg K kg−1 soil) than that in the paddy, upland (8–51 mg K kg−1 soil) and orchard (25–50 mg K kg−1 soil) field soils. The average ratio of microbial biomass potassium to exchangeable potassium was 0.25 for all the soils and the average values for paddy field (0.31) and pasture field (0.53) soils were higher than those for upland field (0.06) and orchard field (0.08) soils. Positive correlations were found between the contents of microbial biomass potassium and microbial biomass carbon and nitrogen. Application of organic matter significantly increased microbial biomass potassium in the farmland soils. These findings indicate that microbial biomass potassium plays an important role in potassium supply to crops as a reservoir of potassium and also suggest that the contribution of microbial biomass potassium to the potassium source for crops could be relatively higher in paddy field and pasture field soils than upland field and orchard field soils.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"34 1","pages":"400 - 408"},"PeriodicalIF":2.0,"publicationDate":"2022-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86683900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-25DOI: 10.1080/00380768.2022.2056713
Shuo Kong, Zhong Ma, Yonglin Qin, M. Fan
ABSTRACT The split application of P can increase the yield and P use efficiency of potato，however, there is currently a lack of a reliable method for determining the timing and rates for the split application of P fertilizers to optimize potato production. In this three-year field experiment, we tested the possibility of establishing a potato plant P diagnosis method with a reflectometer RQflex. Potato petiole Pi content was linearly correlated to plant P contents and was significantly sensitive to soil phosphorus supply, suggesting that petiole P content determined by a RQflex meter is a good indicator of potato plant P status. Moreover, the relationship between relative potato yield and petiole Pi content fits a linear platform equation, suggesting that RQflex meter may be useful for rapidly determining the threshold petiole P level. Our results will help in developing a viable method for recommending P-fertilizer application rates during potato growth to optimize potato tuber yields.
{"title":"Evaluating phosphorus nutritional status of potato by instant testing of petiole phosphate concentration","authors":"Shuo Kong, Zhong Ma, Yonglin Qin, M. Fan","doi":"10.1080/00380768.2022.2056713","DOIUrl":"https://doi.org/10.1080/00380768.2022.2056713","url":null,"abstract":"ABSTRACT The split application of P can increase the yield and P use efficiency of potato，however, there is currently a lack of a reliable method for determining the timing and rates for the split application of P fertilizers to optimize potato production. In this three-year field experiment, we tested the possibility of establishing a potato plant P diagnosis method with a reflectometer RQflex. Potato petiole Pi content was linearly correlated to plant P contents and was significantly sensitive to soil phosphorus supply, suggesting that petiole P content determined by a RQflex meter is a good indicator of potato plant P status. Moreover, the relationship between relative potato yield and petiole Pi content fits a linear platform equation, suggesting that RQflex meter may be useful for rapidly determining the threshold petiole P level. Our results will help in developing a viable method for recommending P-fertilizer application rates during potato growth to optimize potato tuber yields.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"5 1","pages":"393 - 399"},"PeriodicalIF":2.0,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75787958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-18DOI: 10.1080/00380768.2022.2050662
Hirotsuna Yamada, S. Nishida, J. Wasaki
ABSTRACT White lupin (Lupinus albus L.) plants are tolerant plants under phosphorus (P)deficiency. They form unique morphological roots, so-called cluster roots (CRs) under P deficiency. CRs contribute to P absorption by the expansion of the root surface area and P mobilization activities. Previous research has implied the involvement of several hormonal functions in CR formation. Ethylene is a key regulator responsible for the modification of root architecture and P acquisition in response to low P in plants. However, understanding the effect of ethylene on CR morphogenesis is not enough. Here, the focus was on the effects of ethylene on CR morphology and gene expression for P acquisition. First, a reanalysis of public RNA-Seq data indicated that the gene expression for ethylene synthesis was induced during CR maturation. In turn, the 10-days application of an ethylene synthesis inhibitor, CoCl2, and an ethylene precursor, ACC, to CR formed in hydroponic culture without P was performed. CR morphology, transcript levels of the genes related to P acquisition, and citrate concentration in roots were determined. The results indicated that the elongation of rootlets in CR was promoted in a Co2+ concentration-dependent manner, suggesting that ethylene is responsible for the arrest of rootlet elongation. mRNA accumulation for acid phosphatases, phosphate transporters, citrate synthases, and a putative citrate transporter increased in ACC-treated immature CR, suggesting that ethylene induces the transcription of genes for P acquisition. Additionally, the trend of citrate concentration in roots among treatments was similar to that in the expression of citrate synthases, supporting that ethylene accumulation promotes citrate synthesis. The roles of the arrest of rootlet elongation and regulation of gene expressions for P acquisition are considered independent functions of ethylene. It was concluded that ethylene works as a possible regulator for the rootlet elongation and transcription of genes for P acquisition in CRs, although further studies are required to elucidate the molecular mechanisms of the arrest of rootlet elongation and transcriptional regulation.
{"title":"Ethylene works as a possible regulator for the rootlet elongation and transcription of genes for phosphorus acquisition in cluster roots of Lupinus albus L.","authors":"Hirotsuna Yamada, S. Nishida, J. Wasaki","doi":"10.1080/00380768.2022.2050662","DOIUrl":"https://doi.org/10.1080/00380768.2022.2050662","url":null,"abstract":"ABSTRACT White lupin (Lupinus albus L.) plants are tolerant plants under phosphorus (P)deficiency. They form unique morphological roots, so-called cluster roots (CRs) under P deficiency. CRs contribute to P absorption by the expansion of the root surface area and P mobilization activities. Previous research has implied the involvement of several hormonal functions in CR formation. Ethylene is a key regulator responsible for the modification of root architecture and P acquisition in response to low P in plants. However, understanding the effect of ethylene on CR morphogenesis is not enough. Here, the focus was on the effects of ethylene on CR morphology and gene expression for P acquisition. First, a reanalysis of public RNA-Seq data indicated that the gene expression for ethylene synthesis was induced during CR maturation. In turn, the 10-days application of an ethylene synthesis inhibitor, CoCl2, and an ethylene precursor, ACC, to CR formed in hydroponic culture without P was performed. CR morphology, transcript levels of the genes related to P acquisition, and citrate concentration in roots were determined. The results indicated that the elongation of rootlets in CR was promoted in a Co2+ concentration-dependent manner, suggesting that ethylene is responsible for the arrest of rootlet elongation. mRNA accumulation for acid phosphatases, phosphate transporters, citrate synthases, and a putative citrate transporter increased in ACC-treated immature CR, suggesting that ethylene induces the transcription of genes for P acquisition. Additionally, the trend of citrate concentration in roots among treatments was similar to that in the expression of citrate synthases, supporting that ethylene accumulation promotes citrate synthesis. The roles of the arrest of rootlet elongation and regulation of gene expressions for P acquisition are considered independent functions of ethylene. It was concluded that ethylene works as a possible regulator for the rootlet elongation and transcription of genes for P acquisition in CRs, although further studies are required to elucidate the molecular mechanisms of the arrest of rootlet elongation and transcriptional regulation.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"60 1","pages":"383 - 392"},"PeriodicalIF":2.0,"publicationDate":"2022-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83141172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-04DOI: 10.1080/00380768.2022.2047580
S. Kimani, P. Bimantara, V. Kautsar, Ren Torita, S. Hattori, K. Tawaraya, S. Sudo, W. Cheng
ABSTRACT Our previous pot experiments showed that using Azolla either or both as dual and green manure with rice increases its yield or significantly reduces either or both methane (CH4) and nitrous oxide (N2O) emissions. To confirm these findings in an actual field, Azolla was either grown as a dual crop (herein Cover) or incorporated as green manure plus dual cropping (herein AGM + Cover) at the beginning of the experiment along with rice. Compared with the control (chemical fertilizer; herein NPK), NPK + Cover and AGM + Cover treatments did not influence cumulative CH4 emissions throughout the rice growth period. However, AGM + Cover treatment affected significant CH4 emissions at early, middle, and later rice growth stages by 140.6%, 24.6%, and 33.1%, respectively, compared with NPK + Cover treatment. These emissions were attributed to the readily available carbon substrate for methanogens following the incorporation of Azolla as green manure. Compared with NPK, NPK + Cover and AGM + Cover significantly increased N2O emissions by 645.9% and 816.2%, respectively, during the middle rice growth stage. No significant N2O emission differences were observed in the three treatments in the early or later rice growth stages. The higher N2O emissions from the middle rice growth stage were ascribed to high substrate availability from the dead Azolla by higher summer air temperature in the 2019 season. AGM + Cover significantly decreased rice yield by 37.5% (NPK) and 35.3% (NPK + Cover), with no significant differences between NPK and NPK + Cover. This reduction was attributed to nitrogen immobilization from the incorporated Azolla during the early stage. Therefore, to ascertain the potential of Azolla in paddy fields to address environmental safety while sustaining yield, emphasis on the interaction of different application methods with various management practices is necessary.
{"title":"Influence of Azolla incorporation and/or dual cropping on CH4 and N2O emission from a paddy field","authors":"S. Kimani, P. Bimantara, V. Kautsar, Ren Torita, S. Hattori, K. Tawaraya, S. Sudo, W. Cheng","doi":"10.1080/00380768.2022.2047580","DOIUrl":"https://doi.org/10.1080/00380768.2022.2047580","url":null,"abstract":"ABSTRACT Our previous pot experiments showed that using Azolla either or both as dual and green manure with rice increases its yield or significantly reduces either or both methane (CH4) and nitrous oxide (N2O) emissions. To confirm these findings in an actual field, Azolla was either grown as a dual crop (herein Cover) or incorporated as green manure plus dual cropping (herein AGM + Cover) at the beginning of the experiment along with rice. Compared with the control (chemical fertilizer; herein NPK), NPK + Cover and AGM + Cover treatments did not influence cumulative CH4 emissions throughout the rice growth period. However, AGM + Cover treatment affected significant CH4 emissions at early, middle, and later rice growth stages by 140.6%, 24.6%, and 33.1%, respectively, compared with NPK + Cover treatment. These emissions were attributed to the readily available carbon substrate for methanogens following the incorporation of Azolla as green manure. Compared with NPK, NPK + Cover and AGM + Cover significantly increased N2O emissions by 645.9% and 816.2%, respectively, during the middle rice growth stage. No significant N2O emission differences were observed in the three treatments in the early or later rice growth stages. The higher N2O emissions from the middle rice growth stage were ascribed to high substrate availability from the dead Azolla by higher summer air temperature in the 2019 season. AGM + Cover significantly decreased rice yield by 37.5% (NPK) and 35.3% (NPK + Cover), with no significant differences between NPK and NPK + Cover. This reduction was attributed to nitrogen immobilization from the incorporated Azolla during the early stage. Therefore, to ascertain the potential of Azolla in paddy fields to address environmental safety while sustaining yield, emphasis on the interaction of different application methods with various management practices is necessary.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":"139 1","pages":"246 - 255"},"PeriodicalIF":2.0,"publicationDate":"2022-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90633282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：