Planting maize at high densities leads to early leaf senescence,and the resulting reduction in the number of lower leaves affects the plant’s root function and lowers its grain yield.However,the nature of the process...Planting maize at high densities leads to early leaf senescence,and the resulting reduction in the number of lower leaves affects the plant’s root function and lowers its grain yield.However,the nature of the process by which lower leaf senescence affects biomass accumulation and grain yield formation in maize is not clear.This study aimed to shed light on how these factors are related by investigating the effects of the plant growth regulator 6-benzyladenine(6-BA)on the senescence of lower leaves of maize plants.In two maize cultivars planted at densities of 67,500(low density,LD)and 90,000(high density,HD)plants ha^(-1),plants treated with 6-BA maintained a high green leaf area index(LAI)longer than control(CK)plants,enabling them to maintain a higher photosynthetic rate for a longer period of time and produce more biomass before reaching physiological maturity.Spraying the lower leaves of maize plants with a 6-BA solution increased the distribution of;C-photosynthates to their roots,lower leaves and bracts,a result that can be ascribed to a decreased retention of;C-photosynthates in the stem and grain.In both seasons of the experiment,maize plants treated with 6-BA accumulated more N in grain and maintained a higher N content in roots and leaves,especially in lower leaves,than CK.Increased C assimilation in the lower leaves may explain why N uptake in plants subjected to the 6-BA treatment exceeded that in CK plants and why both photosynthesis rate and dry matter accumulation were maintained throughout grain filling.Our results suggest that a suitable distribution of C and N in leaves post-silking may maintain plant root function,increase N use efficiency,maximize the duration of high LAI,and increase grain yield.展开更多
[Objectives]This study was conducted to clarify the differences and abundance or deficiency of various elements in tobacco leaves from different positions of CB-1 in Zhangping City,so as to guide the production of pre...[Objectives]This study was conducted to clarify the differences and abundance or deficiency of various elements in tobacco leaves from different positions of CB-1 in Zhangping City,so as to guide the production of precision fertilization.[Methods]The element contents of CB-1 were determined by an X-ray fluorescence spectrometer.[Results]In terms of the contents of carbon,the upper leaves(45.73%)were significantly higher than the cutters(41.53%),and the lower leaves(43.15%)had no significant differences from both of them.For the content of oxygen element,there was no significant difference between the cutters(44.77%)and the lower leaves(43.40%),both of which were significantly higher than the upper leaves(40.75%).The contents of nitrogen,phosphorus,sulfur,boron and nickel all increased with the increase of the position,and they were significantly higher in the upper leaves than in the cutters and lower leaves.The contents of potassium,calcium,magnesium,chlorine and silicon all decreased with the increase of the position,and the lower leaves were significantly higher than the cutters and upper leaves.The contents of aluminum,titanium and chromium increased significantly with the increase of the position.The contents of strontium,zirconium and arsenic decreased significantly with the increase of the position.The element contents of tobacco leaves had significant or extremely significant differences between different parts of CB-1 in Zhangping City mostly.The contents of nitrogen,potassium,calcium,sulfur,chlorine,molybdenum and nickel in tobacco leaves were appropriate,and the contents of manganese and iron were too high,while the contents of phosphorus and copper were slightly low.The contents of magnesium,silicon,boron and sodium were too low.[Conclusions]This study can guide targeted fertilization and regulation of element contents in the tobacco leaves from different parts in production,and is of great significance to improving the production,quality and industrial availability of CB-1.展开更多
基金financially the National Key Research and Development Program of China(2016YFD0300106,2018YFD0300603)the Shandong Modern Agricultural Technology&Industry System(SDAIT-02-08)。
文摘Planting maize at high densities leads to early leaf senescence,and the resulting reduction in the number of lower leaves affects the plant’s root function and lowers its grain yield.However,the nature of the process by which lower leaf senescence affects biomass accumulation and grain yield formation in maize is not clear.This study aimed to shed light on how these factors are related by investigating the effects of the plant growth regulator 6-benzyladenine(6-BA)on the senescence of lower leaves of maize plants.In two maize cultivars planted at densities of 67,500(low density,LD)and 90,000(high density,HD)plants ha^(-1),plants treated with 6-BA maintained a high green leaf area index(LAI)longer than control(CK)plants,enabling them to maintain a higher photosynthetic rate for a longer period of time and produce more biomass before reaching physiological maturity.Spraying the lower leaves of maize plants with a 6-BA solution increased the distribution of;C-photosynthates to their roots,lower leaves and bracts,a result that can be ascribed to a decreased retention of;C-photosynthates in the stem and grain.In both seasons of the experiment,maize plants treated with 6-BA accumulated more N in grain and maintained a higher N content in roots and leaves,especially in lower leaves,than CK.Increased C assimilation in the lower leaves may explain why N uptake in plants subjected to the 6-BA treatment exceeded that in CK plants and why both photosynthesis rate and dry matter accumulation were maintained throughout grain filling.Our results suggest that a suitable distribution of C and N in leaves post-silking may maintain plant root function,increase N use efficiency,maximize the duration of high LAI,and increase grain yield.
基金Supported by Science and Technology Project of China Tobacco Hebei Industrial Co.Ltd.(2021130000300029).
文摘[Objectives]This study was conducted to clarify the differences and abundance or deficiency of various elements in tobacco leaves from different positions of CB-1 in Zhangping City,so as to guide the production of precision fertilization.[Methods]The element contents of CB-1 were determined by an X-ray fluorescence spectrometer.[Results]In terms of the contents of carbon,the upper leaves(45.73%)were significantly higher than the cutters(41.53%),and the lower leaves(43.15%)had no significant differences from both of them.For the content of oxygen element,there was no significant difference between the cutters(44.77%)and the lower leaves(43.40%),both of which were significantly higher than the upper leaves(40.75%).The contents of nitrogen,phosphorus,sulfur,boron and nickel all increased with the increase of the position,and they were significantly higher in the upper leaves than in the cutters and lower leaves.The contents of potassium,calcium,magnesium,chlorine and silicon all decreased with the increase of the position,and the lower leaves were significantly higher than the cutters and upper leaves.The contents of aluminum,titanium and chromium increased significantly with the increase of the position.The contents of strontium,zirconium and arsenic decreased significantly with the increase of the position.The element contents of tobacco leaves had significant or extremely significant differences between different parts of CB-1 in Zhangping City mostly.The contents of nitrogen,potassium,calcium,sulfur,chlorine,molybdenum and nickel in tobacco leaves were appropriate,and the contents of manganese and iron were too high,while the contents of phosphorus and copper were slightly low.The contents of magnesium,silicon,boron and sodium were too low.[Conclusions]This study can guide targeted fertilization and regulation of element contents in the tobacco leaves from different parts in production,and is of great significance to improving the production,quality and industrial availability of CB-1.
