Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester...Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester was engaged for testing the stem strength of 661 wheat varieties and of 1183 single plants from a F2 population. The results showed that the suitable time to determine the stem strength should be from milk stage to dough ripe stage. The stem strength at the maturity would decrease and it was not easy to distinguish the difference among the varieties. The single plant with a strong stem could be judged using the prostrate tester from the F2 population. By testing the stem strength and anatomic characters of 30 varieties, a significant negative relationship between the pith diameter of the upper internodes and the stem strength was observed. On the other hand, there was a significant positive relationship between the stem diameter of the lower internodes and stem strength. It was suggested that a wheat breeder should breed the cultivar with a strong stem, because the spike weight and biomass yield were significantly related to the stem strength.展开更多
Lodging is an important factor limiting rice yield and quality by bending or breaking stem in japonica rice（Oryza sativa L.） production. The objectives of this study were to determine the mechanism of lodging resist...Lodging is an important factor limiting rice yield and quality by bending or breaking stem in japonica rice（Oryza sativa L.） production. The objectives of this study were to determine the mechanism of lodging resistance in japonica rice as affected by carbohydrate components, especially its related arrangement in culm tissue and response to top-dressing nitrogen（N） fertilizer. Field experiments were conducted in Danyang County, Jiangsu Province, China, by using two japonica rice varieties Wuyunjing 23（lodging-resistance variety） and W3668（lodging-susceptible variety） with three top-dressing N fertilizer rates（0, 135 and 270 kg N ha^（-1）） in 2013 and 2014. Lodging related physical parameters, morphological characteristics and stem carbohydrate components were investigated at 30 d after full heading stage. Results showed that with increasing N fertilizer rates, the lodging rate and lodging index increased rapidly primarily due to significant reduction of breaking strength in two japonica rice varieties. Correlation analysis revealed that breaking strength was significantly and positively correlated with bending stress, but negatively correlated with section modulus, except for significant correlation at W3668 in 2014. Higher stem plumpness status and structural carbohydrate contents significantly enhanced stem stiffness, despite of lower non-structural carbohydrate. With higher N fertilizer rate, the culm wall thickness was almost identical, and culm diameter increased slightly. The structural carbohydrates, especially for lignin content in culm, reduced significantly under high N rate. Further histochemical staining analysis revealed that high N treatments decreased the lignin deposition rapidly in the sclerenchyma cells of mechanical tissue, large vascular bundle and small vascular bundle region, which were consistent with reduction of bending stress, especially for W3668 and thus, resulted in poor stem strength and higher lodging index. These results suggested that structural carbohydrate plays a vital role for improving stem strength in japonica rice. N rate decreased lodging resistance primarily due to poor stem stiffness, by reducing structural carbohydrate content and lignin deposition in the secondary cell wall of lower internode culm tissue.展开更多
Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wh...Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ)of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons.Plant height,height at center of gravity,length of the basal second internode,and lodging index decreased significantly in this period,and the average annual genetic gains for these traits were–0.50 cm or–0.62%,–0.27 cm or–0.60%,–0.06 cm or–0.63%,and–0.01 or–0.94%,respectively.Different from other traits,stem strength showed a significant increasing trend with the breeding period,and the annual genetic gains were 0.03 N or 0.05%.Correlation analysis showed that lodging index was positively correlated with plant height,height at center of gravity,and length of the basal second internode,but negatively correlated with stem strength.Meanwhile,significantly positive correlations were observed between plant height,height at center of gravity,and length of the basal first and second internodes.By comparison with the wild types,dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength.Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance.Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods.This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range.展开更多
Improving grain yield(GY)and reducing grain moisture(GM)are urgent demands for directly harvesting kernels with combine harvesters in maize production.GY and GM are both related to leaf,stem and root characteristics,b...Improving grain yield(GY)and reducing grain moisture(GM)are urgent demands for directly harvesting kernels with combine harvesters in maize production.GY and GM are both related to leaf,stem and root characteristics,but the relationships are not fully understood.To better understand these relationships,we conducted a field trial involving 12 maize hybrids with two sowing dates in 2017 and 10 maize hybrids with one sowing date in 2019.GY ranged from 6.5–14.6 t ha^(–1) in early-sown varieties and 9.3–12.7 t ha^(–1) in late-sown varieties in 2017,and 5.9–7.4 t ha^(–1) in 2019,respectively,with corresponding GM variations of 29.8–34.9%,29.4–34.5%and 31.9–37.1%at harvest.A large maximum leaf area contributed to a high yield,a fast leaf senescence rate accelerated grain dehydration in the late growth period,and a compact root structure resulted in both of high-yield and fast-grain dehydration.A strong stem improved lodging resistance but maintained a high GM at harvest,and it is challenging to combine high GY and low GM in maize.High GY co-existed with low GM in some varieties that should have a rapid grain filling,a relatively long grain-filling duration,and a rapid grain dehydration in the late growth period.A high daily temperature in the late growth period also improved GY and reduced GM by influencing grain filling and dehydration,suggesting that adjusting the sowing date should be an alternative strategy to combine high GY and low GM in kernel harvesting.展开更多
探究聚-γ-谷氨酸(γ-PGA)对直播稻抗倒伏性、产量和品质的影响,为高产优质的水稻栽培技术提供理论依据和技术参考。于2022和2023年在湖北省武穴市花桥镇开展田间试验,采用双因素裂区设计,以直播方式水直播(W)和旱直播(D)为主区,不施加...探究聚-γ-谷氨酸(γ-PGA)对直播稻抗倒伏性、产量和品质的影响,为高产优质的水稻栽培技术提供理论依据和技术参考。于2022和2023年在湖北省武穴市花桥镇开展田间试验,采用双因素裂区设计,以直播方式水直播(W)和旱直播(D)为主区,不施加γ-PGA发酵液(P0)和施加25 kg hm–2γ-PGA发酵液(P1)为副区,共4个处理,对水稻抗倒伏能力相关指标、产量、稻米品质进行测定。结果表明,施加γ-PGA能分别使水、旱直播下水稻第一基节茎粗增加10.3%~10.6%和7.5%~13.3%,第二基节茎粗增加10.5%~11.8%和8.2%~17.5%,茎秆壁厚增加23.7%~27.9%和12.5%~22.0%,抗折能力提高37.3%~52.7%和50.8%~54.5%,弯曲力矩提高3.8%~7.6%和4.1%~5.9%,折断弯矩提高37.3%~52.7%和50.8%~54.5%,倒伏指数降低21.9%~29.1%和30.2%~32.2%。施加γ-PGA能改变水稻的茎秆强度,提高产量和稻米品质。展开更多
Shades caused by neighboring tall plants in intercropping systems and weak sunlight are constraints in yield optimization. Shade influences many aspects of plant growth and development, leading to weak stems and susce...Shades caused by neighboring tall plants in intercropping systems and weak sunlight are constraints in yield optimization. Shade influences many aspects of plant growth and development, leading to weak stems and susceptibility to lodging. The plant cell wall is composed of certain proteins that allow the walls to stretch out, a process called cell wall loosening. Shade affects anatomical, morphological, and physiological traits of plants, thus reducing the physical strength of the stem in crops by changing the loosening of cell walls. Flexibility of cells facilitates further modifications such as wall loosening. In addition, shade stress causes increased internode length, and reduced xylem synthesis and photosynthesis. In shaded plants, lignin deposition in vascular bundles and sclerenchyma cells of stems is decreased. Lignin is a light sensitive phenolic compound and shading decreases the transcript abundance of several phenolic compound(flavone and lignin) related genes. Shading significantly influences the metabolic activities of phenylalanine ammonia-lyase(PAL), peroxidase(POD), 4-coumarate: CoA ligase(4 CL), and cinnamyl alcohol dehydrogenase(CAD) involved in lignin biosynthesis. Furthermore, suppression of lignin biosynthesis activities by abiotic stresses causes abnormal phenotypes such as collapsed xylem, bent stems, and growth retardation. In this review, the underlying mechanisms illustrate that under shading conditions reduced lignin content results in slender, weak, and unstable stems. The objective of this review is to elaborate lignin biosynthesis and its variability under stressful environmental conditions, especially in shade stress environments. The effects of shade on stem lignin metabolism are discussed on the morphogenetic, physiological, and proteomic levels.展开更多
[ Objective ] The paper was to explore the relationship between character of rice stem and compressive strength. [ Method] The morphological and anatomical characters of stems of 10 rice varieties （including 3 intern...[ Objective ] The paper was to explore the relationship between character of rice stem and compressive strength. [ Method] The morphological and anatomical characters of stems of 10 rice varieties （including 3 internedes） were systematically studied by paraffin sectioning technology; the digital force tester was used to measure the compressive strengths of various varieties; the correlation between various characters and stem compressive strengths was analyzed. [ Result ] Correlation analysis showed that the outer diameter and cress-sectional area of stem had clese relation with longing resistance of stem, which could be adopted as the important factors for stem lodging resistance. The outer diameter and cross-sectional area of 63 Liangyou 636 was significantly higher than other tested varieties, 3 intemedes all had high comoressive strength, and the vleld was also high. [Conclusion] 63 Liangyou 636 could be used as the rice cultivar with super yield.展开更多
In order to explore the differences in the compressive strength parallel to grain （CSPG） between different clones and individual woods of Populus deltoides Marsh., the CSPGs of 5 15-year-old P. deltoides clones were...In order to explore the differences in the compressive strength parallel to grain （CSPG） between different clones and individual woods of Populus deltoides Marsh., the CSPGs of 5 15-year-old P. deltoides clones were determined and analyzed. The results showed that there were significant differences in CSPG of wood between different clones of P. deltoides . The CSPG of the tested clones reached more than 41 MPa, which was higher than the average compressive strength of P. deltoides （32.94 MPa）. Similar to the changes of stem height, the CSPG of the clones gradually increased with the increase of stem height. However, there were significant differences in CSPG of an individual plant at different tree heights. The CSPG of P. deltoides clones was related with their growth traits, but not significantly. Therefore, it is expected to achieve simultaneous and independent improvement on CSPG and the growth of P. deltoides , so as to get excellent individuals with fast growth and high CSPG.展开更多
The effects of different nitrogen application rate on the physical characteristics and anatomic structure of rice stems were investigated with rice cultivars Guangliangyou 1128 （with high resistance） and Zhunliangyo...The effects of different nitrogen application rate on the physical characteristics and anatomic structure of rice stems were investigated with rice cultivars Guangliangyou 1128 （with high resistance） and Zhunliangyou 527 （with low resistance） as materials. The results showed that, firstly, plant height, gravity center height and basal internode length of the 2 rice cultivars increased with the increase of nitrogen application rate, while wall thickness and internode filling degree decreased. The breaking-resistance strength per stem and thrust-resistance strength of plants declined with the increase of nitrogen application rate. Secondly, as nitrogen input increased, the number of vascular bundles and the area of vascular bundles increased between the 2 rice cultivars. Thirdly, with the increase of nitrogen application rate, the stem section area of Guangliangyou 1128, which had strong lodging resistance, gradually increased, while that of Zhunliangyou 527 increased firstly and then decreased. The maximum application amount of nitrogen was 240 kg/hm 2. Nitrogen fertilizer mainly affected the relative gravity center height, stem wall thickness and internode filling degree of the 2 cultivars, thereby reducing the basal stem breaking resistance and plant thrust-resistance strength.展开更多
文摘Stem strength affects directly the resistance of wheat plant to lodging. Unfortunately, the determination of the stem strength is not perfect for wheat breeding and genetics up to now. In this study a prostrate tester was engaged for testing the stem strength of 661 wheat varieties and of 1183 single plants from a F2 population. The results showed that the suitable time to determine the stem strength should be from milk stage to dough ripe stage. The stem strength at the maturity would decrease and it was not easy to distinguish the difference among the varieties. The single plant with a strong stem could be judged using the prostrate tester from the F2 population. By testing the stem strength and anatomic characters of 30 varieties, a significant negative relationship between the pith diameter of the upper internodes and the stem strength was observed. On the other hand, there was a significant positive relationship between the stem diameter of the lower internodes and stem strength. It was suggested that a wheat breeder should breed the cultivar with a strong stem, because the spike weight and biomass yield were significantly related to the stem strength.
基金Funding was provided by the National Key Technologies R&D Program of China during the 12th Five-Year Plan period (2011BAD16B14,2012BAD20B05,2012BAD04B08)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Lodging is an important factor limiting rice yield and quality by bending or breaking stem in japonica rice（Oryza sativa L.） production. The objectives of this study were to determine the mechanism of lodging resistance in japonica rice as affected by carbohydrate components, especially its related arrangement in culm tissue and response to top-dressing nitrogen（N） fertilizer. Field experiments were conducted in Danyang County, Jiangsu Province, China, by using two japonica rice varieties Wuyunjing 23（lodging-resistance variety） and W3668（lodging-susceptible variety） with three top-dressing N fertilizer rates（0, 135 and 270 kg N ha^（-1）） in 2013 and 2014. Lodging related physical parameters, morphological characteristics and stem carbohydrate components were investigated at 30 d after full heading stage. Results showed that with increasing N fertilizer rates, the lodging rate and lodging index increased rapidly primarily due to significant reduction of breaking strength in two japonica rice varieties. Correlation analysis revealed that breaking strength was significantly and positively correlated with bending stress, but negatively correlated with section modulus, except for significant correlation at W3668 in 2014. Higher stem plumpness status and structural carbohydrate contents significantly enhanced stem stiffness, despite of lower non-structural carbohydrate. With higher N fertilizer rate, the culm wall thickness was almost identical, and culm diameter increased slightly. The structural carbohydrates, especially for lignin content in culm, reduced significantly under high N rate. Further histochemical staining analysis revealed that high N treatments decreased the lignin deposition rapidly in the sclerenchyma cells of mechanical tissue, large vascular bundle and small vascular bundle region, which were consistent with reduction of bending stress, especially for W3668 and thus, resulted in poor stem strength and higher lodging index. These results suggested that structural carbohydrate plays a vital role for improving stem strength in japonica rice. N rate decreased lodging resistance primarily due to poor stem stiffness, by reducing structural carbohydrate content and lignin deposition in the secondary cell wall of lower internode culm tissue.
基金supported by the National Key Research and Development Program of China (2016YFD0101600 and 2016YFD0100102)the National Natural Science Foundation of China (31401468 and 31771881)the Innovation Team and the National Engineering Laboratory of Crop Molecular Breeding of Chinese Academy of Agricultural Sciences
文摘Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ)of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons.Plant height,height at center of gravity,length of the basal second internode,and lodging index decreased significantly in this period,and the average annual genetic gains for these traits were–0.50 cm or–0.62%,–0.27 cm or–0.60%,–0.06 cm or–0.63%,and–0.01 or–0.94%,respectively.Different from other traits,stem strength showed a significant increasing trend with the breeding period,and the annual genetic gains were 0.03 N or 0.05%.Correlation analysis showed that lodging index was positively correlated with plant height,height at center of gravity,and length of the basal second internode,but negatively correlated with stem strength.Meanwhile,significantly positive correlations were observed between plant height,height at center of gravity,and length of the basal first and second internodes.By comparison with the wild types,dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength.Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance.Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods.This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range.
基金supported by the National Natural Science Foundation of China(31701361)the National Key Research and Development Program of China(2016YFD300301)。
文摘Improving grain yield(GY)and reducing grain moisture(GM)are urgent demands for directly harvesting kernels with combine harvesters in maize production.GY and GM are both related to leaf,stem and root characteristics,but the relationships are not fully understood.To better understand these relationships,we conducted a field trial involving 12 maize hybrids with two sowing dates in 2017 and 10 maize hybrids with one sowing date in 2019.GY ranged from 6.5–14.6 t ha^(–1) in early-sown varieties and 9.3–12.7 t ha^(–1) in late-sown varieties in 2017,and 5.9–7.4 t ha^(–1) in 2019,respectively,with corresponding GM variations of 29.8–34.9%,29.4–34.5%and 31.9–37.1%at harvest.A large maximum leaf area contributed to a high yield,a fast leaf senescence rate accelerated grain dehydration in the late growth period,and a compact root structure resulted in both of high-yield and fast-grain dehydration.A strong stem improved lodging resistance but maintained a high GM at harvest,and it is challenging to combine high GY and low GM in maize.High GY co-existed with low GM in some varieties that should have a rapid grain filling,a relatively long grain-filling duration,and a rapid grain dehydration in the late growth period.A high daily temperature in the late growth period also improved GY and reduced GM by influencing grain filling and dehydration,suggesting that adjusting the sowing date should be an alternative strategy to combine high GY and low GM in kernel harvesting.
文摘探究聚-γ-谷氨酸(γ-PGA)对直播稻抗倒伏性、产量和品质的影响,为高产优质的水稻栽培技术提供理论依据和技术参考。于2022和2023年在湖北省武穴市花桥镇开展田间试验,采用双因素裂区设计,以直播方式水直播(W)和旱直播(D)为主区,不施加γ-PGA发酵液(P0)和施加25 kg hm–2γ-PGA发酵液(P1)为副区,共4个处理,对水稻抗倒伏能力相关指标、产量、稻米品质进行测定。结果表明,施加γ-PGA能分别使水、旱直播下水稻第一基节茎粗增加10.3%~10.6%和7.5%~13.3%,第二基节茎粗增加10.5%~11.8%和8.2%~17.5%,茎秆壁厚增加23.7%~27.9%和12.5%~22.0%,抗折能力提高37.3%~52.7%和50.8%~54.5%,弯曲力矩提高3.8%~7.6%和4.1%~5.9%,折断弯矩提高37.3%~52.7%和50.8%~54.5%,倒伏指数降低21.9%~29.1%和30.2%~32.2%。施加γ-PGA能改变水稻的茎秆强度,提高产量和稻米品质。
基金supported by the National Natural Science Foundation of China (31671626)
文摘Shades caused by neighboring tall plants in intercropping systems and weak sunlight are constraints in yield optimization. Shade influences many aspects of plant growth and development, leading to weak stems and susceptibility to lodging. The plant cell wall is composed of certain proteins that allow the walls to stretch out, a process called cell wall loosening. Shade affects anatomical, morphological, and physiological traits of plants, thus reducing the physical strength of the stem in crops by changing the loosening of cell walls. Flexibility of cells facilitates further modifications such as wall loosening. In addition, shade stress causes increased internode length, and reduced xylem synthesis and photosynthesis. In shaded plants, lignin deposition in vascular bundles and sclerenchyma cells of stems is decreased. Lignin is a light sensitive phenolic compound and shading decreases the transcript abundance of several phenolic compound(flavone and lignin) related genes. Shading significantly influences the metabolic activities of phenylalanine ammonia-lyase(PAL), peroxidase(POD), 4-coumarate: CoA ligase(4 CL), and cinnamyl alcohol dehydrogenase(CAD) involved in lignin biosynthesis. Furthermore, suppression of lignin biosynthesis activities by abiotic stresses causes abnormal phenotypes such as collapsed xylem, bent stems, and growth retardation. In this review, the underlying mechanisms illustrate that under shading conditions reduced lignin content results in slender, weak, and unstable stems. The objective of this review is to elaborate lignin biosynthesis and its variability under stressful environmental conditions, especially in shade stress environments. The effects of shade on stem lignin metabolism are discussed on the morphogenetic, physiological, and proteomic levels.
基金Supported by National Natural Science Foundation of China (31100240)
文摘[ Objective ] The paper was to explore the relationship between character of rice stem and compressive strength. [ Method] The morphological and anatomical characters of stems of 10 rice varieties （including 3 internedes） were systematically studied by paraffin sectioning technology; the digital force tester was used to measure the compressive strengths of various varieties; the correlation between various characters and stem compressive strengths was analyzed. [ Result ] Correlation analysis showed that the outer diameter and cress-sectional area of stem had clese relation with longing resistance of stem, which could be adopted as the important factors for stem lodging resistance. The outer diameter and cross-sectional area of 63 Liangyou 636 was significantly higher than other tested varieties, 3 intemedes all had high comoressive strength, and the vleld was also high. [Conclusion] 63 Liangyou 636 could be used as the rice cultivar with super yield.
基金Supported by the Major Science and Technology Program of Hunan Province(2017NK1010)the Research on High Efficient Cultivation of Populus deltoids Industrial Resources in Dongting Lake Area,the Special Found for the Development and Efficient Utilization Technology Innovation of Forestry Resources during the"13th Five-Year Plan"(2016YFD0600402-2)the Research and Demonstration of Populus Engineering Structural Materials Directional Cultivation and Value-Added Key Technologies,the Science and Technology Planning Project for Forestry of Hunan Province(XLK201506)
文摘In order to explore the differences in the compressive strength parallel to grain （CSPG） between different clones and individual woods of Populus deltoides Marsh., the CSPGs of 5 15-year-old P. deltoides clones were determined and analyzed. The results showed that there were significant differences in CSPG of wood between different clones of P. deltoides . The CSPG of the tested clones reached more than 41 MPa, which was higher than the average compressive strength of P. deltoides （32.94 MPa）. Similar to the changes of stem height, the CSPG of the clones gradually increased with the increase of stem height. However, there were significant differences in CSPG of an individual plant at different tree heights. The CSPG of P. deltoides clones was related with their growth traits, but not significantly. Therefore, it is expected to achieve simultaneous and independent improvement on CSPG and the growth of P. deltoides , so as to get excellent individuals with fast growth and high CSPG.
基金Supported by the National Key R&D Program of China during the 13th Five-Year(2016YFD030010803)the Project for the Key(Preponderant)Discipline of Crop Science(Yangtze University)of Hubei Provincethe Training Program of Innovation for Undergraduates of Hubei Province(201810489059)
文摘The effects of different nitrogen application rate on the physical characteristics and anatomic structure of rice stems were investigated with rice cultivars Guangliangyou 1128 （with high resistance） and Zhunliangyou 527 （with low resistance） as materials. The results showed that, firstly, plant height, gravity center height and basal internode length of the 2 rice cultivars increased with the increase of nitrogen application rate, while wall thickness and internode filling degree decreased. The breaking-resistance strength per stem and thrust-resistance strength of plants declined with the increase of nitrogen application rate. Secondly, as nitrogen input increased, the number of vascular bundles and the area of vascular bundles increased between the 2 rice cultivars. Thirdly, with the increase of nitrogen application rate, the stem section area of Guangliangyou 1128, which had strong lodging resistance, gradually increased, while that of Zhunliangyou 527 increased firstly and then decreased. The maximum application amount of nitrogen was 240 kg/hm 2. Nitrogen fertilizer mainly affected the relative gravity center height, stem wall thickness and internode filling degree of the 2 cultivars, thereby reducing the basal stem breaking resistance and plant thrust-resistance strength.
