This study reports the anatomical structures of a kind of lepidodendralean stem in coal balls from the early Early Permian Taiyuan Formation in Yanzhou Mining District, southwestern Shandong Province, North China. The...This study reports the anatomical structures of a kind of lepidodendralean stem in coal balls from the early Early Permian Taiyuan Formation in Yanzhou Mining District, southwestern Shandong Province, North China. The leaf cushion is slightly rhomboid in outline with a height of 9 - 10 mm and a width of 7.5 9.0 mm and its lower sides are slightly longer than the upper ones. The top and basic angles of the leaf cushion are truncate and the basic angle is slightly elongate. The upper part of the leaf cushion is strongly high-rising. The leaf sear is large and lenticular in shape. The leaf trace is wide and V-shaped in the leaf scar, and horizontally elongate within the leaf cushion. The leaf trace and lateral parichnos strand extend at a nearly horizontal course outward within the leaf cushion. The ligular pit is deep and extends outward at an oblique course and its aperture is located near the top angle of the leaf scar. No infrafoliar parichnos strands are present. The stem is probably siphonostelic and its pith is probably parenchymatous. The primary xylem is exarch with a nearly smooth outer margin. Only the outer cortex is present and it consists of alternately-arranged radial cell bands and gaps within which the are-shaped or V-shaped leaf traces can be seen. The concave side of the leaf trace is toward the center of the stem. No bundle sheath is developed. Periderm is well-developed and consists of phelloderm and phellem in nearly equal thickness. Compared with the lepidodendralean stems of the Cathaysian and Euramerican Floras, the present specimens are most close to an impression-compression species Lepidodendron pulchrum Zhang in morphology of the leaf cushion and they are put into this species temporarily. Whether the present specimens or the type specimens of L. pulchrum are very different from Lepidodendron Sternburg sensu DiMichele, thus the correct nomenclature and classification of L. pulchrum needs to be reconsidered based on the study of better- and anatomically-preserved stems and fertile organs in the future. Because 'L'. pulchrum possesses the mixed features of several genera of Euramerican lepidodendralean stems, it bears significance to study the origin and evolution of the Cathaysian lepidodendralean lycopods.展开更多
DNA methylation is a kind of important epigenetic phenomenon,which could regulate gene expression in cells by affecting the transcription and duplication of DNA without changing cell DNA base sequence. Azalea is one o...DNA methylation is a kind of important epigenetic phenomenon,which could regulate gene expression in cells by affecting the transcription and duplication of DNA without changing cell DNA base sequence. Azalea is one of the ten famous flowers in China,as well a famous flower in the world,and the whole plant has medicinal value. This study investigated the change profile of gene methylation during the four flowering stages of Rhododendron pulchrum by methylation sensitive amplification polymorphism（ MSAP）,and 412 differential bands were obtained after selective amplification with screened 18 pairs of effective primers. Among the differential bands,23 differential bands were selected and subjected to recovery,sequencing and data alignment,and it was found that chalcone synthase,cowpox mitochondria,birch liana mitochondria,HDR reductase in camellia,Vaccinium macrocarpon mitochondria,Cyperus rotundus mitochondria protein,Shigella flexneri plasmid and Scophthalmus maximus cD NA-AFLP fragment have a regulating effect on azalea epigenetic inheritance,and next,genes related to the flowering period of R. pulchrum would be further studied,thereby improving the economic value of R. pulchrum.展开更多
将BP人工神经网络技术与传统的正交试验方法相结合,提出一种新的试验分析和处理方法,利用神经网络特有的自学能力,对主要影响因素进行仿真优化,获得锦锈杜鹃黄酮物质提取的最佳工艺:料液比1∶20(g/mL),超声波提取时间为40 m in,提取温度...将BP人工神经网络技术与传统的正交试验方法相结合,提出一种新的试验分析和处理方法,利用神经网络特有的自学能力,对主要影响因素进行仿真优化,获得锦锈杜鹃黄酮物质提取的最佳工艺:料液比1∶20(g/mL),超声波提取时间为40 m in,提取温度为60℃,乙醇质量分数为40%.应用优化得到的工艺条件进行验证试验。展开更多
文摘This study reports the anatomical structures of a kind of lepidodendralean stem in coal balls from the early Early Permian Taiyuan Formation in Yanzhou Mining District, southwestern Shandong Province, North China. The leaf cushion is slightly rhomboid in outline with a height of 9 - 10 mm and a width of 7.5 9.0 mm and its lower sides are slightly longer than the upper ones. The top and basic angles of the leaf cushion are truncate and the basic angle is slightly elongate. The upper part of the leaf cushion is strongly high-rising. The leaf sear is large and lenticular in shape. The leaf trace is wide and V-shaped in the leaf scar, and horizontally elongate within the leaf cushion. The leaf trace and lateral parichnos strand extend at a nearly horizontal course outward within the leaf cushion. The ligular pit is deep and extends outward at an oblique course and its aperture is located near the top angle of the leaf scar. No infrafoliar parichnos strands are present. The stem is probably siphonostelic and its pith is probably parenchymatous. The primary xylem is exarch with a nearly smooth outer margin. Only the outer cortex is present and it consists of alternately-arranged radial cell bands and gaps within which the are-shaped or V-shaped leaf traces can be seen. The concave side of the leaf trace is toward the center of the stem. No bundle sheath is developed. Periderm is well-developed and consists of phelloderm and phellem in nearly equal thickness. Compared with the lepidodendralean stems of the Cathaysian and Euramerican Floras, the present specimens are most close to an impression-compression species Lepidodendron pulchrum Zhang in morphology of the leaf cushion and they are put into this species temporarily. Whether the present specimens or the type specimens of L. pulchrum are very different from Lepidodendron Sternburg sensu DiMichele, thus the correct nomenclature and classification of L. pulchrum needs to be reconsidered based on the study of better- and anatomically-preserved stems and fertile organs in the future. Because 'L'. pulchrum possesses the mixed features of several genera of Euramerican lepidodendralean stems, it bears significance to study the origin and evolution of the Cathaysian lepidodendralean lycopods.
基金Supported by Open fund of Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization(2017BX06)Fund of College students'Innovative and Entrepreneurial Activities of Huanggang Normal University
文摘DNA methylation is a kind of important epigenetic phenomenon,which could regulate gene expression in cells by affecting the transcription and duplication of DNA without changing cell DNA base sequence. Azalea is one of the ten famous flowers in China,as well a famous flower in the world,and the whole plant has medicinal value. This study investigated the change profile of gene methylation during the four flowering stages of Rhododendron pulchrum by methylation sensitive amplification polymorphism（ MSAP）,and 412 differential bands were obtained after selective amplification with screened 18 pairs of effective primers. Among the differential bands,23 differential bands were selected and subjected to recovery,sequencing and data alignment,and it was found that chalcone synthase,cowpox mitochondria,birch liana mitochondria,HDR reductase in camellia,Vaccinium macrocarpon mitochondria,Cyperus rotundus mitochondria protein,Shigella flexneri plasmid and Scophthalmus maximus cD NA-AFLP fragment have a regulating effect on azalea epigenetic inheritance,and next,genes related to the flowering period of R. pulchrum would be further studied,thereby improving the economic value of R. pulchrum.
文摘将BP人工神经网络技术与传统的正交试验方法相结合,提出一种新的试验分析和处理方法,利用神经网络特有的自学能力,对主要影响因素进行仿真优化,获得锦锈杜鹃黄酮物质提取的最佳工艺:料液比1∶20(g/mL),超声波提取时间为40 m in,提取温度为60℃,乙醇质量分数为40%.应用优化得到的工艺条件进行验证试验。
