The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Erik H. Murchie - One of the best experts on this subject based on the ideXlab platform.
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Increasing Leaf Vein Density via Mutagenesis in Rice Results in an Enhanced Rate of Photosynthesis, Smaller Cell Sizes and Can Reduce Interveinal Mesophyll Cell Number.
Frontiers in plant science, 2017Co-Authors: Aryo B. Feldman, Hei Leung, Marietta Baraoidan, William Paul Quick, Abigail Elmido-mabilangan, Irma Canicosa, J. E. Sheehy, Erik H. MurchieAbstract:Improvements to leaf photosynthetic rates of crops can be achieved by targeted manipulation of individual component processes, such as the activity and properties of RuBisCO or photoprotection. This study shows that simple forward genetic screens of mutant populations can also be used to rapidly generate photosynthesis variants that are useful for breeding. Increasing leaf vein density (concentration of vascular tissue per unit leaf area) has important implications for plant hydraulic properties and assimilate transport. It was an important step to improving photosynthetic rates in the evolution of both C3 and C4 species and is a foundation or prerequisite trait for C4 engineering in crops like rice (Oryza sativa). A previous high throughput screen identified five mutant rice lines (cv. IR64) with increased vein densities and associated narrower leaf widths (Feldman et al., 2014). Here, these high vein density rice variants were analyzed for properties related to photosynthesis. Two lines were identified as having significantly reduced Mesophyll to bundle sheath Cell number ratios. All five lines had 20% higher light saturated photosynthetic capacity per unit leaf area, higher maximum carboxylation rates, dark respiration rates and electron transport capacities. This was associated with no significant differences in leaf thickness, stomatal conductance or CO2 compensation point between mutants and the wild-type. The enhanced photosynthetic rate in these lines may be a result of increased RuBisCO and electron transport component amount and/or activity and/or enhanced transport of photoassimilates. We conclude that high vein density (associated with altered Mesophyll Cell length and number) is a trait that may confer increased photosynthetic efficiency without increased transpiration.
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Variation in vein density and Mesophyll Cell architecture in a rice deletion mutant population
Journal of experimental botany, 2012Co-Authors: Ian R. A. Smillie, Kevin A. Pyke, Erik H. MurchieAbstract:There is a need to develop rice plants with improved photosynthetic capacity and efficiency in order to enhance potential grain yield. Alterations in internal leaf morphology may be needed to underpin some of these improvements. One target is the production of a 'Kranz-like' anatomy, commonly considered to be required to achieve the desired levels of photosynthesis seen in C(4) crops. Kranz anatomy typically has two or three Mesophyll Cells interspersing adjacent veins. As a first step to determining the potential for such anatomical modifications in rice leaves, a population of rice deletion mutants was analysed for alterations in vein patterning and Mesophyll Cells in the interveinal regions. Significant variation is demonstrated in vein arrangement and the sequential distribution of major and minor veins across the leaf width, although there is a significant correlation between the total number of veins present and the width of the leaf. Thus the potential is demonstrated for modifying rice leaf structure. Six distinct rice mutant lines, termed altered leaf morphology (alm) mutants, were analysed for the architecture of their interveinal Mesophyll Cell arrangement. It is shown that in these mutant lines, the distance between adjacent minor veins and adjacent minor and major veins is essentially determined by the size of the interveinal Mesophyll Cells rather than changes in Mesophyll Cell number across this region, and hence interveinal distance changes as a result of Cell expansion rather than Cell division. This observation will be important when developing screens for traits relevant for the introduction of Kranz anatomy into rice.
Jiwang Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of light intensities after anthesis on the photosynthetic characteristics and chloroplast ultrastructure in Mesophyll Cell of summer maize zea mays l
Journal of Applied Ecology, 2018Co-Authors: Jia Gao, Haiyan Cui, Shuting Dong, Peng Liu, Bin Zhao, Jianguo Shi, Jiwang ZhangAbstract:We examined the changes of photosynthetic characteristics and chloroplast ultrastructure in Mesophyll Cell of summer maize in response to different light intensities in the field, with the summer maize hybrid Denghai 605 as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to physiological maturity stage were designed, with the ambient sunlight treatment as control (CK). Under shading treatment, poorly developed thylakoid structure, blurry lamellar structure, loose granum, large gap between slices and warping granum were the major characteristics in chloroplast. Meanwhile, photosynthetic rate (Pn), transpiration rate, stomatal conductance, chlorophyll content, and actual photo-chemical efficiency (ΦPSII) decreased, whereas the maximal photochemical efficiency and non-photochemical quenching increased, which resulted in decreases in grain yield under shading treatment. However, a better development was observed in chloroplasts for L treatment, with the number of grana and lamellae increased and lamellae arranged compactly. In addition, Pn and ΦPSII increased under L treatment, which increased grain yield. The chloroplast arrangement dispersed in Mesophyll Cells and chloroplast ultrastructure was destroyed after shading, and then chlorophyll synthesis per unit leaf area and photosynthetic capacity decreased. In contrast, the number of grana and lamellae increased and lamellae arranged compactly after increasing light, which are beneficial for corn yield.
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effects of waterlogging on leaf Mesophyll Cell ultrastructure and photosynthetic characteristics of summer maize
PLOS ONE, 2016Co-Authors: Baizhao Ren, Shuting Dong, Peng Liu, Jiwang Zhang, Bin ZhaoAbstract:A field experiment was performed to study the effects of waterlogging on the leaf Mesophyll Cell ultrastructure, chlorophyll content, gas exchange parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content of summer maize (Zea mays L.) hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The waterlogging treatments were implemented for different durations (3 and 6 days) at the third leaf stage (V3), the sixth leaf stage (V6), and the 10th day after the tasseling stage (10VT). Leaf area index (LAI), chlorophyll content, photosynthetic rate (Pn), and actual photochemical efficiency (ΦPSII) were reduced after waterlogging, indicating that waterlogging significantly decreased photosynthetic capacity. The chloroplast shapes changed from long and oval to elliptical or circular after waterlogging. In addition, the internal structures of chloroplasts were degenerated after waterlogging. After waterlogging for 6 d at V3, the number of grana and grana lamellae of the third expanded leaf in DH605 were decreased by 26.83% and 55.95%, respectively, compared to the control (CK). Those in ZD958 were reduced by 30.08% and 31.94%, respectively. Waterlogging increased MDA content in both hybrids, suggesting an impact of waterlogging on membrane integrity and thus membrane deterioration. Waterlogging also damaged the biological membrane structure and mitochondria. Our results indicated that the physiological reactions to waterlogging were closely related to lower LAI, chlorophyll content, and Pn and to the destruction of chloroplast ultrastructure. These negative effects resulted in the decrease of grain yield in response to waterlogging. Summer maize was the most susceptible to damage when waterlogging occurred at V3, followed by V6 and 10VT, with damage increasing in the wake of waterlogging duration increasing.
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Effects of shading on the photosynthetic characteristics and Mesophyll Cell ultrastructure of summer maize.
Die Naturwissenschaften, 2016Co-Authors: Baizhao Ren, Haiyan Cui, James J Camberato, Shuting Dong, Peng Liu, Bin Zhao, Jiwang ZhangAbstract:A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and Mesophyll Cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of Mesophyll Cell ultrastructure, chloroplast configuration of Mesophyll Cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in Mesophyll Cells and the endomembrane system was destroyed, which resulted in the dissolution of Cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged Mesophyll Cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK.
Peng Liu - One of the best experts on this subject based on the ideXlab platform.
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effects of light intensities after anthesis on the photosynthetic characteristics and chloroplast ultrastructure in Mesophyll Cell of summer maize zea mays l
Journal of Applied Ecology, 2018Co-Authors: Jia Gao, Haiyan Cui, Shuting Dong, Peng Liu, Bin Zhao, Jianguo Shi, Jiwang ZhangAbstract:We examined the changes of photosynthetic characteristics and chloroplast ultrastructure in Mesophyll Cell of summer maize in response to different light intensities in the field, with the summer maize hybrid Denghai 605 as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to physiological maturity stage were designed, with the ambient sunlight treatment as control (CK). Under shading treatment, poorly developed thylakoid structure, blurry lamellar structure, loose granum, large gap between slices and warping granum were the major characteristics in chloroplast. Meanwhile, photosynthetic rate (Pn), transpiration rate, stomatal conductance, chlorophyll content, and actual photo-chemical efficiency (ΦPSII) decreased, whereas the maximal photochemical efficiency and non-photochemical quenching increased, which resulted in decreases in grain yield under shading treatment. However, a better development was observed in chloroplasts for L treatment, with the number of grana and lamellae increased and lamellae arranged compactly. In addition, Pn and ΦPSII increased under L treatment, which increased grain yield. The chloroplast arrangement dispersed in Mesophyll Cells and chloroplast ultrastructure was destroyed after shading, and then chlorophyll synthesis per unit leaf area and photosynthetic capacity decreased. In contrast, the number of grana and lamellae increased and lamellae arranged compactly after increasing light, which are beneficial for corn yield.
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effects of waterlogging on leaf Mesophyll Cell ultrastructure and photosynthetic characteristics of summer maize
PLOS ONE, 2016Co-Authors: Baizhao Ren, Shuting Dong, Peng Liu, Jiwang Zhang, Bin ZhaoAbstract:A field experiment was performed to study the effects of waterlogging on the leaf Mesophyll Cell ultrastructure, chlorophyll content, gas exchange parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content of summer maize (Zea mays L.) hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The waterlogging treatments were implemented for different durations (3 and 6 days) at the third leaf stage (V3), the sixth leaf stage (V6), and the 10th day after the tasseling stage (10VT). Leaf area index (LAI), chlorophyll content, photosynthetic rate (Pn), and actual photochemical efficiency (ΦPSII) were reduced after waterlogging, indicating that waterlogging significantly decreased photosynthetic capacity. The chloroplast shapes changed from long and oval to elliptical or circular after waterlogging. In addition, the internal structures of chloroplasts were degenerated after waterlogging. After waterlogging for 6 d at V3, the number of grana and grana lamellae of the third expanded leaf in DH605 were decreased by 26.83% and 55.95%, respectively, compared to the control (CK). Those in ZD958 were reduced by 30.08% and 31.94%, respectively. Waterlogging increased MDA content in both hybrids, suggesting an impact of waterlogging on membrane integrity and thus membrane deterioration. Waterlogging also damaged the biological membrane structure and mitochondria. Our results indicated that the physiological reactions to waterlogging were closely related to lower LAI, chlorophyll content, and Pn and to the destruction of chloroplast ultrastructure. These negative effects resulted in the decrease of grain yield in response to waterlogging. Summer maize was the most susceptible to damage when waterlogging occurred at V3, followed by V6 and 10VT, with damage increasing in the wake of waterlogging duration increasing.
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Effects of shading on the photosynthetic characteristics and Mesophyll Cell ultrastructure of summer maize.
Die Naturwissenschaften, 2016Co-Authors: Baizhao Ren, Haiyan Cui, James J Camberato, Shuting Dong, Peng Liu, Bin Zhao, Jiwang ZhangAbstract:A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and Mesophyll Cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of Mesophyll Cell ultrastructure, chloroplast configuration of Mesophyll Cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in Mesophyll Cells and the endomembrane system was destroyed, which resulted in the dissolution of Cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged Mesophyll Cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK.
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deregulation of maize c4 photosynthetic development in a Mesophyll Cell defective mutant
Plant Physiology, 2008Co-Authors: Sarah Covshoff, Peng Liu, Wojciech Majeran, Judith M Kolkman, Klaas J Van Wijk, Thomas P. BrutnellAbstract:During maize (Zea mays) C4 differentiation, Mesophyll (M) and bundle sheath (BS) Cells accumulate distinct sets of photosynthetic enzymes, with very low photosystem II (PSII) content in BS chloroplasts. Consequently, there is little linear electron transport in the BS and ATP is generated by cyclic electron flow. In contrast, M thylakoids are very similar to those of C3 plants and produce the ATP and NADPH that drive metabolic activities. Regulation of this differentiation process is poorly understood, but involves expression and coordination of nuclear and plastid genomes. Here, we identify a recessive allele of the maize high chlorophyll fluorescence (Hcf136) homolog that in Arabidopsis (Arabidopsis thaliana) functions as a PSII stability or assembly factor located in the thylakoid lumen. Proteome analysis of the thylakoids and electron microscopy reveal that Zmhcf136 lacks PSII complexes and grana thylakoids in M chloroplasts, consistent with the previously defined Arabidopsis function. Interestingly, hcf136 is also defective in processing the full-length psbB-psbT-psbH-petB-petD polycistron specifically in M chloroplasts. To determine whether the loss of PSII in M Cells affects C4 differentiation, we performed Cell-type-specific transcript analysis of hcf136 and wild-type seedlings. The results indicate that M and BS Cells respond uniquely to the loss of PSII, with little overlap in gene expression changes between data sets. These results are discussed in the context of signals that may drive differential gene expression in C4 photosynthesis.
Bin Zhao - One of the best experts on this subject based on the ideXlab platform.
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effects of light intensities after anthesis on the photosynthetic characteristics and chloroplast ultrastructure in Mesophyll Cell of summer maize zea mays l
Journal of Applied Ecology, 2018Co-Authors: Jia Gao, Haiyan Cui, Shuting Dong, Peng Liu, Bin Zhao, Jianguo Shi, Jiwang ZhangAbstract:We examined the changes of photosynthetic characteristics and chloroplast ultrastructure in Mesophyll Cell of summer maize in response to different light intensities in the field, with the summer maize hybrid Denghai 605 as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to physiological maturity stage were designed, with the ambient sunlight treatment as control (CK). Under shading treatment, poorly developed thylakoid structure, blurry lamellar structure, loose granum, large gap between slices and warping granum were the major characteristics in chloroplast. Meanwhile, photosynthetic rate (Pn), transpiration rate, stomatal conductance, chlorophyll content, and actual photo-chemical efficiency (ΦPSII) decreased, whereas the maximal photochemical efficiency and non-photochemical quenching increased, which resulted in decreases in grain yield under shading treatment. However, a better development was observed in chloroplasts for L treatment, with the number of grana and lamellae increased and lamellae arranged compactly. In addition, Pn and ΦPSII increased under L treatment, which increased grain yield. The chloroplast arrangement dispersed in Mesophyll Cells and chloroplast ultrastructure was destroyed after shading, and then chlorophyll synthesis per unit leaf area and photosynthetic capacity decreased. In contrast, the number of grana and lamellae increased and lamellae arranged compactly after increasing light, which are beneficial for corn yield.
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effects of waterlogging on leaf Mesophyll Cell ultrastructure and photosynthetic characteristics of summer maize
PLOS ONE, 2016Co-Authors: Baizhao Ren, Shuting Dong, Peng Liu, Jiwang Zhang, Bin ZhaoAbstract:A field experiment was performed to study the effects of waterlogging on the leaf Mesophyll Cell ultrastructure, chlorophyll content, gas exchange parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content of summer maize (Zea mays L.) hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The waterlogging treatments were implemented for different durations (3 and 6 days) at the third leaf stage (V3), the sixth leaf stage (V6), and the 10th day after the tasseling stage (10VT). Leaf area index (LAI), chlorophyll content, photosynthetic rate (Pn), and actual photochemical efficiency (ΦPSII) were reduced after waterlogging, indicating that waterlogging significantly decreased photosynthetic capacity. The chloroplast shapes changed from long and oval to elliptical or circular after waterlogging. In addition, the internal structures of chloroplasts were degenerated after waterlogging. After waterlogging for 6 d at V3, the number of grana and grana lamellae of the third expanded leaf in DH605 were decreased by 26.83% and 55.95%, respectively, compared to the control (CK). Those in ZD958 were reduced by 30.08% and 31.94%, respectively. Waterlogging increased MDA content in both hybrids, suggesting an impact of waterlogging on membrane integrity and thus membrane deterioration. Waterlogging also damaged the biological membrane structure and mitochondria. Our results indicated that the physiological reactions to waterlogging were closely related to lower LAI, chlorophyll content, and Pn and to the destruction of chloroplast ultrastructure. These negative effects resulted in the decrease of grain yield in response to waterlogging. Summer maize was the most susceptible to damage when waterlogging occurred at V3, followed by V6 and 10VT, with damage increasing in the wake of waterlogging duration increasing.
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Effects of shading on the photosynthetic characteristics and Mesophyll Cell ultrastructure of summer maize.
Die Naturwissenschaften, 2016Co-Authors: Baizhao Ren, Haiyan Cui, James J Camberato, Shuting Dong, Peng Liu, Bin Zhao, Jiwang ZhangAbstract:A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and Mesophyll Cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of Mesophyll Cell ultrastructure, chloroplast configuration of Mesophyll Cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in Mesophyll Cells and the endomembrane system was destroyed, which resulted in the dissolution of Cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged Mesophyll Cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK.
Tadashi Hirasawa - One of the best experts on this subject based on the ideXlab platform.
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Leaf photosynthetic rate and Mesophyll Cell anatomy changes during ontogenesis in backcrossed indica × japonica rice inbred lines.
Photosynthesis research, 2017Co-Authors: Shunsuke Adachi, Rowan F. Sage, Taiichiro Ookawa, Tadashi HirasawaAbstract:The high-yielding indica rice variety, 'Takanari', has the high rate of leaf photosynthesis compared with the commercial japonica varieties. Among backcrossed inbred lines from a cross between 'Takanari' and a japonica variety, 'Koshihikari', two lines, BTK-a and BTK-b, showed approximately 20% higher photosynthetic rate than that of 'Takanari' for a flag leaf at full heading. This is a highest recorded rate of rice leaf photosynthesis. Here, the timing and cause of the increased leaf photosynthesis in the BTK lines were investigated by examining the photosynthesis and related parameters, as well as Mesophyll Cell anatomy during ontogenesis. Their photosynthetic rate was greater than that of 'Takanari' in the 13th leaf, as well as the flag leaf, but there were no differences in the 7th and 10th leaves. There were no consistent differences in the stomatal conductance, or the leaf nitrogen and Rubisco contents in the 13th and flag leaves. The total surface area of Mesophyll Cells per leaf area (TAmes) in the 13th and flag leaves increased significantly in the BTK lines due to the increased number and developed lobes of Mesophyll Cells compared with in 'Takanari'. The Mesophyll conductance (g m) became greater in the BTK lines compared with 'Takanari' in the flag leaves but not in the 10th leaves. A close correlation was observed between TAmes and g m. We concluded that the increased Mesophyll conductance through the development of Mesophyll Cells during the reproductive period is a probable cause of the greater photosynthetic rate in the BTK lines.
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leaf photosynthetic rate and Mesophyll Cell anatomy changes during ontogenesis in backcrossed indica japonica rice inbred lines
Photosynthesis Research, 2017Co-Authors: Shunsuke Adachi, Rowan F. Sage, Taiichiro Ookawa, Tadashi HirasawaAbstract:The high-yielding indica rice variety, 'Takanari', has the high rate of leaf photosynthesis compared with the commercial japonica varieties. Among backcrossed inbred lines from a cross between 'Takanari' and a japonica variety, 'Koshihikari', two lines, BTK-a and BTK-b, showed approximately 20% higher photosynthetic rate than that of 'Takanari' for a flag leaf at full heading. This is a highest recorded rate of rice leaf photosynthesis. Here, the timing and cause of the increased leaf photosynthesis in the BTK lines were investigated by examining the photosynthesis and related parameters, as well as Mesophyll Cell anatomy during ontogenesis. Their photosynthetic rate was greater than that of 'Takanari' in the 13th leaf, as well as the flag leaf, but there were no differences in the 7th and 10th leaves. There were no consistent differences in the stomatal conductance, or the leaf nitrogen and Rubisco contents in the 13th and flag leaves. The total surface area of Mesophyll Cells per leaf area (TAmes) in the 13th and flag leaves increased significantly in the BTK lines due to the increased number and developed lobes of Mesophyll Cells compared with in 'Takanari'. The Mesophyll conductance (g m) became greater in the BTK lines compared with 'Takanari' in the flag leaves but not in the 10th leaves. A close correlation was observed between TAmes and g m. We concluded that the increased Mesophyll conductance through the development of Mesophyll Cells during the reproductive period is a probable cause of the greater photosynthetic rate in the BTK lines.