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Mikio Nakazono - One of the best experts on this subject based on the ideXlab platform.
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root cortex provides a venue for gas space formation and is essential for Plant Adaptation to waterlogging
Frontiers in Plant Science, 2019Co-Authors: Takaki Yamauchi, Mikio Nakazono, Nobuhiro TsutsumiAbstract:Lysigenous aerenchyma, which develops by death and subsequent lysis of the cortical cells in roots, is essential for internal long-distance oxygen transport from shoot base to root tips of Plants in waterlogged soil. Although many studies focus on the amounts of aerenchyma in roots, significance of the size of the root cortex in which aerenchyma forms has received less research attention. In the present study, we evaluated the cross-sectional area of each root tissue in adventitious roots of upland crops, wheat (Triticum aestivum) and maize (Zea mays ssp. mays), and the wetland crop, rice (Oryza sativa) under aerated or stagnant deoxygenated conditions; the latter can mimic the changes in gas composition in waterlogged soils. Our analyses revealed that the areas of whole root and cortex of the three species increased under stagnant conditions. In rice roots, cortex to stele ratio and aerenchyma to cortex ratio, which is associated with the areas of gas spaces, were much higher than those in wheat and maize roots, suggesting that these anatomical features are essential for a high capacity for oxygen transport along roots. To test this hypothesis, rates of radial oxygen loss, which is the diffusive flux of oxygen from within a root to the external medium, from thick and thin adventitious roots of rice were measured using a cylindrical (root-sleeving) oxygen electrode, for Plants with shoots in air and roots in an oxygen-free medium. As expected, the rate of radial oxygen loss from thick roots, which have larger cortex and aerenchyma areas, was higher than that of thin roots. The rate of radial oxygen loss was highest at the apical part of rice roots, where aerenchyma was hardly detected, but at which cuboidal cell arrangement in the cortex provides tissue porosity. We conclude that high cortex to stele ratio in combination with large root diameter is a feature which promotes oxygen transport from shoot base to root tips of Plants. Moreover, we propose that cortex to stele ratio should be a useful quantitative index for the evaluation and improvement of root traits contributing to tolerance of crops to soil waterlogging.
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Root Cortex Provides a Venue for Gas-Space Formation and Is Essential for Plant Adaptation to Waterlogging
Frontiers Media S.A., 2019Co-Authors: Takaki Yamauchi, Mikio Nakazono, Nobuhiro Tsutsumi, Fumitaka AbeAbstract:Lysigenous aerenchyma, which develops by death and subsequent lysis of the cortical cells in roots, is essential for internal long-distance oxygen transport from shoot base to root tips of Plants in waterlogged soil. Although many studies focus on the amounts of aerenchyma in roots, significance of the size of the root cortex in which aerenchyma forms has received less research attention. In the present study, we evaluated the cross-sectional area of each root tissue in adventitious roots of upland crops, wheat (Triticum aestivum) and maize (Zea mays ssp. mays), and the wetland crop, rice (Oryza sativa) under aerated or stagnant deoxygenated conditions; the latter can mimic the changes in gas composition in waterlogged soils. Our analyses revealed that the areas of whole root and cortex of the three species increased under stagnant conditions. In rice roots, cortex to stele ratio (CSR) and aerenchyma to cortex ratio (ACR), which is associated with the areas of gas spaces, were much higher than those in wheat and maize roots, suggesting that these anatomical features are essential for a high capacity for oxygen transport along roots. To test this hypothesis, rates of radial oxygen loss (ROL), which is the diffusive flux of oxygen from within a root to the external medium, from thick and thin adventitious roots of rice were measured using a cylindrical (root-sleeving) oxygen electrode, for Plants with shoots in air and roots in an oxygen-free medium. As expected, the rate of ROL from thick roots, which have larger cortex and aerenchyma areas, was higher than that of thin roots. The rate of ROL was highest at the apical part of rice roots, where aerenchyma was hardly detected, but at which cuboidal cell arrangement in the cortex provides tissue porosity. We conclude that high CSR in combination with large root diameter is a feature which promotes oxygen transport from shoot base to root tips of Plants. Moreover, we propose that CSR should be a useful quantitative index for the evaluation and improvement of root traits contributing to tolerance of crops to soil waterlogging
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Data_Sheet_1_Root Cortex Provides a Venue for Gas-Space Formation and Is Essential for Plant Adaptation to Waterlogging.PDF
2019Co-Authors: Takaki Yamauchi, Nobuhiro Tsutsumi, Fumitaka Abe, Mikio NakazonoAbstract:Lysigenous aerenchyma, which develops by death and subsequent lysis of the cortical cells in roots, is essential for internal long-distance oxygen transport from shoot base to root tips of Plants in waterlogged soil. Although many studies focus on the amounts of aerenchyma in roots, significance of the size of the root cortex in which aerenchyma forms has received less research attention. In the present study, we evaluated the cross-sectional area of each root tissue in adventitious roots of upland crops, wheat (Triticum aestivum) and maize (Zea mays ssp. mays), and the wetland crop, rice (Oryza sativa) under aerated or stagnant deoxygenated conditions; the latter can mimic the changes in gas composition in waterlogged soils. Our analyses revealed that the areas of whole root and cortex of the three species increased under stagnant conditions. In rice roots, cortex to stele ratio (CSR) and aerenchyma to cortex ratio (ACR), which is associated with the areas of gas spaces, were much higher than those in wheat and maize roots, suggesting that these anatomical features are essential for a high capacity for oxygen transport along roots. To test this hypothesis, rates of radial oxygen loss (ROL), which is the diffusive flux of oxygen from within a root to the external medium, from thick and thin adventitious roots of rice were measured using a cylindrical (root-sleeving) oxygen electrode, for Plants with shoots in air and roots in an oxygen-free medium. As expected, the rate of ROL from thick roots, which have larger cortex and aerenchyma areas, was higher than that of thin roots. The rate of ROL was highest at the apical part of rice roots, where aerenchyma was hardly detected, but at which cuboidal cell arrangement in the cortex provides tissue porosity. We conclude that high CSR in combination with large root diameter is a feature which promotes oxygen transport from shoot base to root tips of Plants. Moreover, we propose that CSR should be a useful quantitative index for the evaluation and improvement of root traits contributing to tolerance of crops to soil waterlogging.
Thomas Van Leeuwen - One of the best experts on this subject based on the ideXlab platform.
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long term population studies uncover the genome structure and genetic basis of xenobiotic and host Plant Adaptation in the herbivore tetranychus urticae
Genetics, 2019Co-Authors: Nicky Wybouw, Wannes Dermauw, Olivia Kosterlitz, Andre H Kurlovs, Sabina Bajda, Astrid Bryon, Robert Greenhalgh, Simon Snoeck, Huyen Bui, Thomas Van LeeuwenAbstract:Pesticide resistance arises rapidly in arthropod herbivores, as can host Plant Adaptation, and both are significant problems in agriculture. These traits have been challenging to study as both are often polygenic and many arthropods are genetically intractable. Here, we examined the genetic architecture of pesticide resistance and host Plant Adaptation in the two-spotted spider mite, Tetranychus urticae, a global agricultural pest. We show that the short generation time and high fecundity of T. urticae can be readily exploited in experimental evolution designs for high-resolution mapping of quantitative traits. As revealed by selection with spirodiclofen, an acetyl-CoA carboxylase inhibitor, in populations from a cross between a spirodiclofen-resistant and a spirodiclofen-susceptible strain, and which also differed in performance on tomato, we found that a limited number of loci could explain quantitative resistance to this compound. These were resolved to narrow genomic intervals, suggesting specific candidate genes, including acetyl-CoA carboxylase itself, clustered and copy variable cytochrome P450 genes, and NADPH cytochrome P450 reductase, which encodes a redox partner for cytochrome P450s. For performance on tomato, candidate genomic regions for response to selection were distinct from those responding to the synthetic compound and were consistent with a more polygenic architecture. In accomplishing this work, we exploited the continuous nature of allele frequency changes across experimental populations to resolve the existing fragmented T. urticae draft genome to pseudochromosomes. This improved assembly was indispensable for our analyses, as it will be for future research with this model herbivore that is exceptionally amenable to genetic studies.
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long term population studies uncover the genome structure and genetic basis of xenobiotic and host Plant Adaptation in the herbivore tetranychus urticae
bioRxiv, 2018Co-Authors: Richard M Clark, Nicky Wybouw, Thomas Van Leeuwen, Olivia Kosterlitz, Andre H Kurlovs, Sabina Bajda, Astrid Bryon, Robert Greenhalgh, Simon Snoeck, Huyen BuiAbstract:Pesticide resistance arises rapidly in arthropod herbivores, as can host Plant Adaptation, and both are significant problems in agriculture. These traits have been challenging to study as both are often polygenic and many arthropods are genetically intractable. Here, we examined the genetic architecture of pesticide resistance and host Plant Adaptation in the two-spotted spider mite, Tetranychus urticae, a global agricultural pest. We show that the short generation time and high fecundity of T. urticae can be readily exploited in experimental evolution designs for high-resolution mapping of quantitative traits. As revealed by selection with spirodiclofen, an acetyl-CoA decarboxylase inhibitor, in populations from a cross between a spirodiclofen resistant and a susceptible strain, and which also differed in performance on tomato, we found that a limited number of loci could explain quantitative resistance to this compound. These were resolved to narrow genomic intervals, suggesting specific candidate genes, including acetyl-CoA decarboxylase itself, clustered and copy variable cytochrome P450 genes, and NADPH cytochrome P450 reductase, which encodes a redox partner for cytochrome P450s. For performance on tomato, candidate genomic regions for response to selection were distinct from those responding to the synthetic compound and were consistent with a more polygenic architecture. In accomplishing this work, we exploited the continuous nature of allele frequency changes across experimental populations to resolve the existing fragmented T. urticae draft genome to pseudochromosomes. This improved assembly was indispensable for our analyses, as it will be for future research with this model herbivore that is exceptionally amenable to genetic studies.
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Does host Plant Adaptation lead to pesticide resistance in generalist herbivores
Current opinion in insect science, 2018Co-Authors: Wannes Dermauw, Chris Bass, Thomas Van Leeuwen, Adam Pym, Rene FeyereisenAbstract:Most herbivorous arthropods feed on one or a few closely related Plant species; however, certain insect and mite species have a greatly expanded host range. Several of these generalists also show a remarkable propensity to evolve resistance to chemical pesticides. In this review, we ask if the evolution of mechanisms to tolerate the diversity of Plant secondary metabolites that generalist herbivores encounter, has pre-adapted them to resist synthetic pesticides. Critical examination of the evidence suggests that a generalist life-style per se is not a predictor of rapid resistance evolution to pesticides. Rather the prevalence of pesticide resistance in generalist herbivores probably reflects their economic importance as pests and thus the strong selection imposed by intensive pesticide use.
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a link between host Plant Adaptation and pesticide resistance in the polyphagous spider mite tetranychus urticae
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Wannes Dermauw, Nicky Wybouw, Stephane Rombauts, Bjorn Menten, John Vontas, Miodrag Grbic, Richard M Clark, Rene Feyereisen, Thomas Van LeeuwenAbstract:Plants produce a wide range of allelochemicals to defend against herbivore attack, and generalist herbivores have evolved mechanisms to avoid, sequester, or detoxify a broad spectrum of natural defense compounds. Successful arthropod pests have also developed resistance to diverse classes of pesticides and this Adaptation is of critical importance to agriculture. To test whether mechanisms to overcome Plant defenses predispose the development of pesticide resistance, we examined Adaptation of the generalist two-spotted spider mite, Tetranychus urticae, to host Plant transfer and pesticides. T. urticae is an extreme polyphagous pest with more than 1,100 documented hosts and has an extraordinary ability to develop pesticide resistance. When mites from a pesticide-susceptible strain propagated on bean were adapted to a challenging host (tomato), transcriptional responses increased over time with ∼7.5% of genes differentially expressed after five generations. Whereas many genes with altered expression belonged to known detoxification families (like P450 monooxygenases), new gene families not previously associated with detoxification in other herbivores showed a striking response, including ring-splitting dioxygenase genes acquired by horizontal gene transfer. Strikingly, transcriptional profiles of tomato-adapted mites resembled those of multipesticide-resistant strains, and Adaptation to tomato decreased the susceptibility to unrelated pesticide classes. Our findings suggest key roles for both an expanded environmental response gene repertoire and transcriptional regulation in the life history of generalist herbivores. They also support a model whereby selection for the ability to mount a broad response to the diverse defense chemistry of Plants predisposes the evolution of pesticide resistance in generalists.
Andres A Borges - One of the best experts on this subject based on the ideXlab platform.
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treating seeds in menadione sodium bisulphite primes salt tolerance in arabidopsis by inducing an earlier Plant Adaptation
Environmental and Experimental Botany, 2015Co-Authors: David Jimenezarias, Jose A Perez, Juan C Luis, Vanesa Martinrodriguez, Francisco Valdesgonzalez, Andres A BorgesAbstract:Abstract For the majority of crops, salinity is one of the most important abiotic stresses, since about 20% of irrigated agricultural land is adversely affected by it. Menadione sodium bisulphite (MSB), a water-soluble vitamin K3 o menadione derivative, has been previously reported as a Plant defence activator against several pathogens in a number of species. We have further explored the MSB effects on salt tolerance. In this study, Arabidopsis thaliana wild ecotype Col-0 Plants were exposed to prolonged salt (50 mM) stress. Salt treatment resulted in severe growth inhibition. This detrimental effect was lower in terms of relative growth rate (RGR) in Plants from seeds soaked in 20 mM of MSB. In these Plants, the drop in RGR was nearly 30% lower than untreated Plants after 7 days in salt. Furthermore, we found that the salt stress imposed was not enough to disturb photosystem II or induce the expression of several detoxification genes. These functional impairments are characteristic of ionic injuries due to high levels of reactive oxygen species (ROS). At the end of the second week of the experiment, salt-treated Plants recover RGR levels close to those of the control. Under our experimental conditions Plants seem to be challenged by an osmotic stress with a minimum ionic imbalance. Those from MSB-treated seeds were primed to induce an earlier proline accumulation. Although no significant expression of ROS detoxification genes was found, several transcription factors involved in ROS signalling were detected after salt addition. In this context, MSB treatment was able to prime these transcription factors, resulting in an early Adaptation of Plants in response to salt stress.
Xin Wang - One of the best experts on this subject based on the ideXlab platform.
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genome wide investigation on transcriptional responses to drought stress in wild and cultivated rice
Environmental and Experimental Botany, 2021Co-Authors: Mufan Geng, Xin Wang, Xiuhua Wang, Meixia Wang, Zhe Cai, Qinglin Meng, Lian Zhou, Jingdan Han, Fumin Zhang, Yalong GuoAbstract:Abstract Whole transcriptomic sequencing of the drought-tolerant (DT) and drought-sensitive (DS) accessions of cultivated and wild rice under drought treatments was performed to uncover the mechanism of Plant Adaptation to drought and to facilitate the development of drought-tolerant cultivars in crops. By analyzing the differentially expressed genes (DEGs) between the drought-treated and untreated samples and their co-expressed pattern, we revealed distinct susceptibilities of different samples to the stress treatments and identified some specific transcription factors (TFs) and genes that play critical roles in rice Adaptation to drought. Some drought-responsive genes or pathways unique to the wild rice were also detected, highlighting the importance of wild rice resources in developing elite cultivars. Furthermore, we showed that the DEGs in the DT accessions were enriched in the genome as clusters or hotspots in which previously identified drought-associated quantitative trait loci (QTLs) were overrepresented. The finding that a single hotspot contained up to 52 QTLs and involved as many as 20 traits implicates the complicated genetic architecture underlying the DT traits. These results provide new insights into the understanding of Plant Adaptation to drought and help effective manipulation of specific genes or gene cluster in crop breeding.
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the gastrodia elata genome provides insights into Plant Adaptation to heterotrophy
Nature Communications, 2018Co-Authors: Yuan Yuan, Xin Wang, Xiaohua Jin, Juan Liu, Xing Zhao, Junhui Zhou, Deyi Wang, Changjiangsheng Lai, Jingwen Huang, Liangping ZhaAbstract:We present the 1.06 Gb sequenced genome of Gastrodia elata, an obligate mycoheterotrophic Plant, which contains 18,969 protein-coding genes. Many genes conserved in other Plant species have been deleted from the G. elata genome, including most of those for photosynthesis. Additional evidence of the influence of genome plasticity in the Adaptation of this mycoheterotrophic lifestyle is evident in the large number of gene families that are expanded in G. elata, including glycoside hydrolases and urease that likely facilitate the digestion of hyphae are expanded, as are genes associated with strigolactone signaling, and ATPases that may contribute to the atypical energy metabolism. We also find that the plastid genome of G. elata is markedly smaller than that of green Plant species while its mitochondrial genome is one of the largest observed to date. Our report establishes a foundation for studying Adaptation to a mycoheterotrophic lifestyle.
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The Gastrodia elata genome provides insights into Plant Adaptation to heterotrophy
Nature Publishing Group, 2018Co-Authors: Yuan Yuan, Xin Wang, Xiaohua Jin, Juan Liu, Xing Zhao, Junhui Zhou, Deyi Wang, Changjiangsheng Lai, Jingwen HuangAbstract:Gastrodia elata is an obligate mycoheterotrophic Plant with highly reduced leaves and bracts in scape. Here, Yuan et al sequence and analyze its 1.06 Gb genome which provides insights in Adaptation to a lifestyle of heterotrophy
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overexpression of shdhn a dehydrin gene from solanum habrochaites enhances tolerance to multiple abiotic stresses in tomato
Plant Science, 2015Co-Authors: Hui Liu, Taotao Wang, Junhong Zhang, Bo Ouyang, Xin WangAbstract:Dehydrins (DHNs) play important roles in Plant Adaptation to abiotic stress. In this study, a cold-induced SK3-type DHN gene (ShDHN) isolated from wild tomato species Solanum habrochaites was characterized for its function in abiotic stress tolerance. ShDHN was constitutively expressed in root, leaf, stem, flower and fruit. ShDHN was continuously up-regulated during cold stress and showed higher expression level in the cold-tolerant S. habrochaites than in the susceptible S. lycopersicum. Moreover, ShDHN expression was also regulated by drought, salt, osmotic stress, and exogenous signaling molecules. Overexpression of ShDHN in cultivated tomato increased tolerance to cold and drought stresses and improved seedling growth under salt and osmotic stresses. Compared with the wild-type, the transgenic Plants accumulated more proline, maintained higher enzymatic activities of superoxide dismutase and catalase, and suffered less membrane damage under cold and drought stresses. Moreover, the transgenic Plants accumulated lower levels of H2O2 and O2(-) under cold stress, and had higher relative water contents and lower water loss rates under dehydration conditions. Furthermore, overexpression of ShDHN in tomato led to the up- or down-regulated expression of several genes involved in ROS scavenging and JA signaling pathway, including SOD1, GST, POD, LOX, PR1 and PR2. Taken together, these results indicate that ShDHN has pleiotropic effects on improving Plant Adaptation to abiotic stresses and that it possesses potential usefulness in genetic improvement of stress tolerance in tomato.
Takaki Yamauchi - One of the best experts on this subject based on the ideXlab platform.
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root cortex provides a venue for gas space formation and is essential for Plant Adaptation to waterlogging
Frontiers in Plant Science, 2019Co-Authors: Takaki Yamauchi, Mikio Nakazono, Nobuhiro TsutsumiAbstract:Lysigenous aerenchyma, which develops by death and subsequent lysis of the cortical cells in roots, is essential for internal long-distance oxygen transport from shoot base to root tips of Plants in waterlogged soil. Although many studies focus on the amounts of aerenchyma in roots, significance of the size of the root cortex in which aerenchyma forms has received less research attention. In the present study, we evaluated the cross-sectional area of each root tissue in adventitious roots of upland crops, wheat (Triticum aestivum) and maize (Zea mays ssp. mays), and the wetland crop, rice (Oryza sativa) under aerated or stagnant deoxygenated conditions; the latter can mimic the changes in gas composition in waterlogged soils. Our analyses revealed that the areas of whole root and cortex of the three species increased under stagnant conditions. In rice roots, cortex to stele ratio and aerenchyma to cortex ratio, which is associated with the areas of gas spaces, were much higher than those in wheat and maize roots, suggesting that these anatomical features are essential for a high capacity for oxygen transport along roots. To test this hypothesis, rates of radial oxygen loss, which is the diffusive flux of oxygen from within a root to the external medium, from thick and thin adventitious roots of rice were measured using a cylindrical (root-sleeving) oxygen electrode, for Plants with shoots in air and roots in an oxygen-free medium. As expected, the rate of radial oxygen loss from thick roots, which have larger cortex and aerenchyma areas, was higher than that of thin roots. The rate of radial oxygen loss was highest at the apical part of rice roots, where aerenchyma was hardly detected, but at which cuboidal cell arrangement in the cortex provides tissue porosity. We conclude that high cortex to stele ratio in combination with large root diameter is a feature which promotes oxygen transport from shoot base to root tips of Plants. Moreover, we propose that cortex to stele ratio should be a useful quantitative index for the evaluation and improvement of root traits contributing to tolerance of crops to soil waterlogging.
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Root Cortex Provides a Venue for Gas-Space Formation and Is Essential for Plant Adaptation to Waterlogging
Frontiers Media S.A., 2019Co-Authors: Takaki Yamauchi, Mikio Nakazono, Nobuhiro Tsutsumi, Fumitaka AbeAbstract:Lysigenous aerenchyma, which develops by death and subsequent lysis of the cortical cells in roots, is essential for internal long-distance oxygen transport from shoot base to root tips of Plants in waterlogged soil. Although many studies focus on the amounts of aerenchyma in roots, significance of the size of the root cortex in which aerenchyma forms has received less research attention. In the present study, we evaluated the cross-sectional area of each root tissue in adventitious roots of upland crops, wheat (Triticum aestivum) and maize (Zea mays ssp. mays), and the wetland crop, rice (Oryza sativa) under aerated or stagnant deoxygenated conditions; the latter can mimic the changes in gas composition in waterlogged soils. Our analyses revealed that the areas of whole root and cortex of the three species increased under stagnant conditions. In rice roots, cortex to stele ratio (CSR) and aerenchyma to cortex ratio (ACR), which is associated with the areas of gas spaces, were much higher than those in wheat and maize roots, suggesting that these anatomical features are essential for a high capacity for oxygen transport along roots. To test this hypothesis, rates of radial oxygen loss (ROL), which is the diffusive flux of oxygen from within a root to the external medium, from thick and thin adventitious roots of rice were measured using a cylindrical (root-sleeving) oxygen electrode, for Plants with shoots in air and roots in an oxygen-free medium. As expected, the rate of ROL from thick roots, which have larger cortex and aerenchyma areas, was higher than that of thin roots. The rate of ROL was highest at the apical part of rice roots, where aerenchyma was hardly detected, but at which cuboidal cell arrangement in the cortex provides tissue porosity. We conclude that high CSR in combination with large root diameter is a feature which promotes oxygen transport from shoot base to root tips of Plants. Moreover, we propose that CSR should be a useful quantitative index for the evaluation and improvement of root traits contributing to tolerance of crops to soil waterlogging
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Data_Sheet_1_Root Cortex Provides a Venue for Gas-Space Formation and Is Essential for Plant Adaptation to Waterlogging.PDF
2019Co-Authors: Takaki Yamauchi, Nobuhiro Tsutsumi, Fumitaka Abe, Mikio NakazonoAbstract:Lysigenous aerenchyma, which develops by death and subsequent lysis of the cortical cells in roots, is essential for internal long-distance oxygen transport from shoot base to root tips of Plants in waterlogged soil. Although many studies focus on the amounts of aerenchyma in roots, significance of the size of the root cortex in which aerenchyma forms has received less research attention. In the present study, we evaluated the cross-sectional area of each root tissue in adventitious roots of upland crops, wheat (Triticum aestivum) and maize (Zea mays ssp. mays), and the wetland crop, rice (Oryza sativa) under aerated or stagnant deoxygenated conditions; the latter can mimic the changes in gas composition in waterlogged soils. Our analyses revealed that the areas of whole root and cortex of the three species increased under stagnant conditions. In rice roots, cortex to stele ratio (CSR) and aerenchyma to cortex ratio (ACR), which is associated with the areas of gas spaces, were much higher than those in wheat and maize roots, suggesting that these anatomical features are essential for a high capacity for oxygen transport along roots. To test this hypothesis, rates of radial oxygen loss (ROL), which is the diffusive flux of oxygen from within a root to the external medium, from thick and thin adventitious roots of rice were measured using a cylindrical (root-sleeving) oxygen electrode, for Plants with shoots in air and roots in an oxygen-free medium. As expected, the rate of ROL from thick roots, which have larger cortex and aerenchyma areas, was higher than that of thin roots. The rate of ROL was highest at the apical part of rice roots, where aerenchyma was hardly detected, but at which cuboidal cell arrangement in the cortex provides tissue porosity. We conclude that high CSR in combination with large root diameter is a feature which promotes oxygen transport from shoot base to root tips of Plants. Moreover, we propose that CSR should be a useful quantitative index for the evaluation and improvement of root traits contributing to tolerance of crops to soil waterlogging.