Lodging is the most important constraint for soybean growth at seedling stage in maize-soybean relay strip intercropping system.In the field experiments,three soybean cultivars Nandou 032-4(shade susceptible cultivar;...Lodging is the most important constraint for soybean growth at seedling stage in maize-soybean relay strip intercropping system.In the field experiments,three soybean cultivars Nandou 032-4(shade susceptible cultivar; B1),Jiuyuehuang(moderately shade tolerant cultivar; B2),and Nandou 12(shade tolerant cultivar; B3) were used to evaluate the relationship between stem stress and lignin metabolism in the stem of soybean.Results showed that the intercropped soybean was in variable light condition throughout the day time and co-growth stage with maize.The xylem area and cross section ratio played a main role to form the stem stress.The B3 both in intercropping and monocropping expressed a high stem stress with higher xylem area,lignin content,and activity of enzymes(phenylalanine ammonia-lyase(PAL),4-coumarate: CoA ligase(4CL),cinnamyl alcohol dehydrogenase(CAD),and peroxidase(POD)) than those of B1 and B2.Among the soybean cultivars and planting pattern,lignin content was positively correlated with stem stress.However,a negative correlation was found between lignin content and actual rate of lodging.In conclusion,the shade tolerant soybean cultivar had larger xylem area,higher lignin content and activities of CAD,4CL,PAL,and POD than other soybean cultivars in intercropping.The lodging in maize-soybean intercropping can be minimized by planting shade tolerant and lodging resistant cultivar of soybean.The lignin content in stem could be a useful indicator for the evaluation of lodging resistance of soybean in intercropping and activities of enzymes were the key factors that influence the lignin biosynthesis.展开更多
To clarify how shade stress affects lignin biosynthesis in soybean stem, two varieties, Nandou 12（shade tolerant） and Nan 032-4（shade susceptible） grew under normal light and shade conditions（the photosynthetical...To clarify how shade stress affects lignin biosynthesis in soybean stem, two varieties, Nandou 12（shade tolerant） and Nan 032-4（shade susceptible） grew under normal light and shade conditions（the photosynthetically active radiation and the ratio of red：far-red were lower than normal light condition）. Lignin accumulation, transcripts of genes involved in lignin biosynthesis, and intermediates content of lignin biosynthesis were analyzed. Both soybean varieties suffered shade stress had increased plant heights and internode lengths, and reduced stem diameters and lignin accumulation in stems. The expression levels of lignin-related genes were significantly influenced by shade stress, with interactions between the light environment and variety. The gene of 3-hydroxylase（C3H）, cinnamoyl-Co A reductase（CCR）, caffeoylCoAO-methyltransferase（CCoAOMT）, and peroxidase（POD） attributed to lignin biosynthesis under shade stress, and the down-regulation of these genes resulted in lower caffeic, sinapic, and ferulic acid levels, which caused a further decrease in lignin biosynthesis. Under shade stress, the shade tolerant soybean variety（Nandou 12） showed stiffer stems, higher lignin content, and greater gene expression level and higher metabolite contents than shade susceptible one. So these characteristics could be used for screening the shade-tolerant soybean for intercropping.展开更多
Intensively farmed crops used to experience numerous environmental stresses.Among these,shade and drought significantly influence the morpho-physiological and biochemical attributes of plants.However,the interactive e...Intensively farmed crops used to experience numerous environmental stresses.Among these,shade and drought significantly influence the morpho-physiological and biochemical attributes of plants.However,the interactive effect of shade and drought on the growth and development of soybean under dense cropping systems has not been reported yet.This study investigated the interactive effect of PEG-induced osmotic stress and shade on soybean seedlings.The soybean cultivar viz.,C-103 was subjected to PEG-induced osmotic stress from polyethylene glycol 6000(PEG-6000)under shading and non-shading conditions.PEG-induced osmotic stress significantly reduced the relative water contents,morphological parameters,carbohydrates and chlorophyll contents under both light environments.A significant increase was observed in osmoprotectants,reactive oxygen species and antioxidant enzymes in soybean seedlings.Henceforth,the findings revealed that,seedlings grown under non-shading conditions produced more malondialdehyde and hydrogen peroxide contents as compared to the shade-treated plants when subjected to PEG-induced osmotic stress.Likewise,the shaded plants accumulated more sugars and proline than non-shaded ones under drought stress.Moreover,it was found that nonshaded grown plants were more sensitive to PEG-induced osmotic stress than those exposed to shading conditions,which suggested that shade could boost the protective mechanisms against osmotic stress or at least would not exaggerate the adverse effects of PEG-induced osmotic stress in soybean seedlings.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
Soybean is often intercropped with maize,sugarcane,and sorghum.Because of the shade coming from the latter,the soybean stem lodging is often a very serious problem in intercropping systems.The aim of this study is to ...Soybean is often intercropped with maize,sugarcane,and sorghum.Because of the shade coming from the latter,the soybean stem lodging is often a very serious problem in intercropping systems.The aim of this study is to characterize the possible mechanisms in the stem of shade-induced promotion of seedling soybean lodging in intercropping systems at the proteome level.We found that the soybean stem became slender and prone to lodging when it was planted with maize in an intercropping system.The inhibition of lignin biosynthesis and lack of photosynthate(soluble sugar)for the biosynthesis of the cell wall led to the lower internode breaking strength.A total of 317 proteins were found to be affected in the soybean stem in response to shade.Under the shade stress,the down-expression of key enzymes involving the phenylpropanoid metabolic pathway inhibited lignin biosynthesis.The up-regulation of expansin and XTHs protein expression relaxed the cell wall and promoted the elongation of internodes.Although the expression of the enzymes involving sucrose synthesis increased in the soybean stem,the lack of a carbon source prevented rapid stem growth.This metabolic deficit is the principal cause of the lower cellulose content in the stem of intercropped soybean,which leads to weakened stems and a propensity for lodging.展开更多
基金the support of the National Key R&D Program of China (2018YFD1000905,2016YFD0300209)the National Natural Science Foundation of China (31671626)
文摘Lodging is the most important constraint for soybean growth at seedling stage in maize-soybean relay strip intercropping system.In the field experiments,three soybean cultivars Nandou 032-4(shade susceptible cultivar; B1),Jiuyuehuang(moderately shade tolerant cultivar; B2),and Nandou 12(shade tolerant cultivar; B3) were used to evaluate the relationship between stem stress and lignin metabolism in the stem of soybean.Results showed that the intercropped soybean was in variable light condition throughout the day time and co-growth stage with maize.The xylem area and cross section ratio played a main role to form the stem stress.The B3 both in intercropping and monocropping expressed a high stem stress with higher xylem area,lignin content,and activity of enzymes(phenylalanine ammonia-lyase(PAL),4-coumarate: CoA ligase(4CL),cinnamyl alcohol dehydrogenase(CAD),and peroxidase(POD)) than those of B1 and B2.Among the soybean cultivars and planting pattern,lignin content was positively correlated with stem stress.However,a negative correlation was found between lignin content and actual rate of lodging.In conclusion,the shade tolerant soybean cultivar had larger xylem area,higher lignin content and activities of CAD,4CL,PAL,and POD than other soybean cultivars in intercropping.The lodging in maize-soybean intercropping can be minimized by planting shade tolerant and lodging resistant cultivar of soybean.The lignin content in stem could be a useful indicator for the evaluation of lodging resistance of soybean in intercropping and activities of enzymes were the key factors that influence the lignin biosynthesis.
基金supported by the National Natural Science Foundation of China (31671626)
文摘To clarify how shade stress affects lignin biosynthesis in soybean stem, two varieties, Nandou 12（shade tolerant） and Nan 032-4（shade susceptible） grew under normal light and shade conditions（the photosynthetically active radiation and the ratio of red：far-red were lower than normal light condition）. Lignin accumulation, transcripts of genes involved in lignin biosynthesis, and intermediates content of lignin biosynthesis were analyzed. Both soybean varieties suffered shade stress had increased plant heights and internode lengths, and reduced stem diameters and lignin accumulation in stems. The expression levels of lignin-related genes were significantly influenced by shade stress, with interactions between the light environment and variety. The gene of 3-hydroxylase（C3H）, cinnamoyl-Co A reductase（CCR）, caffeoylCoAO-methyltransferase（CCoAOMT）, and peroxidase（POD） attributed to lignin biosynthesis under shade stress, and the down-regulation of these genes resulted in lower caffeic, sinapic, and ferulic acid levels, which caused a further decrease in lignin biosynthesis. Under shade stress, the shade tolerant soybean variety（Nandou 12） showed stiffer stems, higher lignin content, and greater gene expression level and higher metabolite contents than shade susceptible one. So these characteristics could be used for screening the shade-tolerant soybean for intercropping.
基金supported by the National Natural Science Foundation of China(31871552 and 31671445)the Sichuan Science and Technology Program,China(2018HH0108)the Sichuan Innovation Team Project of National Modern Agricultural Industry Technology System,China(sccxtd-2020-20)。
文摘Intensively farmed crops used to experience numerous environmental stresses.Among these,shade and drought significantly influence the morpho-physiological and biochemical attributes of plants.However,the interactive effect of shade and drought on the growth and development of soybean under dense cropping systems has not been reported yet.This study investigated the interactive effect of PEG-induced osmotic stress and shade on soybean seedlings.The soybean cultivar viz.,C-103 was subjected to PEG-induced osmotic stress from polyethylene glycol 6000(PEG-6000)under shading and non-shading conditions.PEG-induced osmotic stress significantly reduced the relative water contents,morphological parameters,carbohydrates and chlorophyll contents under both light environments.A significant increase was observed in osmoprotectants,reactive oxygen species and antioxidant enzymes in soybean seedlings.Henceforth,the findings revealed that,seedlings grown under non-shading conditions produced more malondialdehyde and hydrogen peroxide contents as compared to the shade-treated plants when subjected to PEG-induced osmotic stress.Likewise,the shaded plants accumulated more sugars and proline than non-shaded ones under drought stress.Moreover,it was found that nonshaded grown plants were more sensitive to PEG-induced osmotic stress than those exposed to shading conditions,which suggested that shade could boost the protective mechanisms against osmotic stress or at least would not exaggerate the adverse effects of PEG-induced osmotic stress in soybean seedlings.
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 the National Natural Science Foundation of China (31671626 and 31201170)
文摘Soybean is often intercropped with maize,sugarcane,and sorghum.Because of the shade coming from the latter,the soybean stem lodging is often a very serious problem in intercropping systems.The aim of this study is to characterize the possible mechanisms in the stem of shade-induced promotion of seedling soybean lodging in intercropping systems at the proteome level.We found that the soybean stem became slender and prone to lodging when it was planted with maize in an intercropping system.The inhibition of lignin biosynthesis and lack of photosynthate(soluble sugar)for the biosynthesis of the cell wall led to the lower internode breaking strength.A total of 317 proteins were found to be affected in the soybean stem in response to shade.Under the shade stress,the down-expression of key enzymes involving the phenylpropanoid metabolic pathway inhibited lignin biosynthesis.The up-regulation of expansin and XTHs protein expression relaxed the cell wall and promoted the elongation of internodes.Although the expression of the enzymes involving sucrose synthesis increased in the soybean stem,the lack of a carbon source prevented rapid stem growth.This metabolic deficit is the principal cause of the lower cellulose content in the stem of intercropped soybean,which leads to weakened stems and a propensity for lodging.
