[Objective]This study was to reveal the physiological and ecological mechanism of growth and development of test-tube seedlings.[Methods]Leaf stomata of test-tube seedlings of D.loddigesii and D.candidum at different ...[Objective]This study was to reveal the physiological and ecological mechanism of growth and development of test-tube seedlings.[Methods]Leaf stomata of test-tube seedlings of D.loddigesii and D.candidum at different growth and development stages were observed under scanning electron microscope,and their fluorescence induction response curve was assayed by using modulate fluorometer.[Results] At each growth and development stage,D.loddigesii test-tube seedling has a higher leaf stomatal density over D.candidum,while a lower stomata opening rate.Along with the growth,the size of stomata of both D.loddigesii and D.candidum did not change obviously,but their stoma density increased by 83% and 17.6% respectively.Leaf stomata opening rate reached the highest at the age of 240-day-old.Under the conditions of three settled light intensities,stomatal opening degree of D.loddigesii was increased by the intensity of illumination,the maximum aperture occurred at the light intensity of 54 μmol/m2·s.Given the same culture condition,both the maximum electron transport rate（14 μmol/m2·s）and light saturation point（318 μmol/m2·s）of D.loddigesii test-tube seedling are lower than that of D.candidum（20 μmol/m2·s,483 μmol/m2·s）.Moreover,the potential photosynthetic capacity of D.loddigesii is relatively poor.[Conclusion]The photosynthetic rate varies among different species of Dendrobium,which could be attributed to their different stomatal characteristics.Usually,the light intensity of tissue culture chamber is set up as 27 μmol/（m2·s）,where both D.loddigesii and D.candidum do not acquire an optimal state for their leaf stomatal opening.Considering the characteristics to select suitable culture condition,the stomatal aperture and photosynthetic rate could be enhanced,which can promote the growth and development of test-tube seedlings.展开更多
Aqueous ethanol extracts of powdered stems of Dendrobium loddigesii afforded three new phenolics including threo-7-Oethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol(1),(R)-4,5,4ʹ-trihydroxy-3,3ʹ,α-trimethoxybibe...Aqueous ethanol extracts of powdered stems of Dendrobium loddigesii afforded three new phenolics including threo-7-Oethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol(1),(R)-4,5,4ʹ-trihydroxy-3,3ʹ,α-trimethoxybibenzyl(2)and(S)-5,5′,7-trihydroxy-3′,4′-dimethoxyflavanone(3),together with eleven known analogues.Their structures were determined by extensive spectroscopic analysis.To identify natural antioxidants,whitening,and anti-aging agents,the abilities of these phenolics were assessed to scavenge the 1,2-diphenyl-2-picrylhydrazyl(DPPH)radical,their abilities to inhibit tyrosinase production,and their abilities to stimulate collagen production by human dermal fibroblasts-adult(HDFa)assay.It was found that compounds 1,4-8,13 and 14 exhibited significant DPPH radical scavenging activities,compound 10 exhibited tyrosinase inhibitory activity(IC_(50)37.904μg/mL),and compound 9 showed significant collagen production with an EC_(50)value of 3.182μg/mL.These results suggest that phenolic constituents from D.loddigesii may be candidate antioxidants,skin-whitening and/or anti-aging agents.展开更多
环草石斛 Dendrobium loddigesii Rolfe是中药石斛的源植物之一，以茎入药，具有滋阴清热、益胃生津的功效。本文采用红外光谱法对不同产地、不同采收期的环草石斛分别进行分析比较。结果显示，不同产地环草石斛红外光谱中，1035，1051...环草石斛 Dendrobium loddigesii Rolfe是中药石斛的源植物之一，以茎入药，具有滋阴清热、益胃生津的功效。本文采用红外光谱法对不同产地、不同采收期的环草石斛分别进行分析比较。结果显示，不同产地环草石斛红外光谱中，1035，1051，1078，1156，1500，1511，1736 cm -1等附近峰的相对峰强皆有显著差异，表明不同产地环草石斛的多糖、酮、酯类等成分的组成和含量有明显差异。在二维相关红外光谱中，越南、云南、广西、贵州的环草石斛分别有7，8，8，9个自动峰，且广西环草石斛的最强峰在1220 cm -1附近，不同于其他三个产地样品（980 cm -1）。不同采收期环草石斛的红外光谱中，1034～1023 cm -1主强峰的波数，（1617±177;4）cm -1次强峰的波数以及1078（1076，1079）cm-1峰的有无，皆随季节呈现出明显的阶段性变化，显示了环草石斛生长过程中所含多糖、酮类等成分积累的阶段性变化规律。应用红外光谱法能较好把握环草石斛的生长状况，帮助全面了解其成分组成与含量变化，对环草石斛的合理开发与高效利用有重要意义。展开更多
基金Supported by the Key Projects in the National Science & Technology Pillar Program during 11th 5-year Plan Period(2006BAI06A11-11)~~
文摘[Objective]This study was to reveal the physiological and ecological mechanism of growth and development of test-tube seedlings.[Methods]Leaf stomata of test-tube seedlings of D.loddigesii and D.candidum at different growth and development stages were observed under scanning electron microscope,and their fluorescence induction response curve was assayed by using modulate fluorometer.[Results] At each growth and development stage,D.loddigesii test-tube seedling has a higher leaf stomatal density over D.candidum,while a lower stomata opening rate.Along with the growth,the size of stomata of both D.loddigesii and D.candidum did not change obviously,but their stoma density increased by 83% and 17.6% respectively.Leaf stomata opening rate reached the highest at the age of 240-day-old.Under the conditions of three settled light intensities,stomatal opening degree of D.loddigesii was increased by the intensity of illumination,the maximum aperture occurred at the light intensity of 54 μmol/m2·s.Given the same culture condition,both the maximum electron transport rate（14 μmol/m2·s）and light saturation point（318 μmol/m2·s）of D.loddigesii test-tube seedling are lower than that of D.candidum（20 μmol/m2·s,483 μmol/m2·s）.Moreover,the potential photosynthetic capacity of D.loddigesii is relatively poor.[Conclusion]The photosynthetic rate varies among different species of Dendrobium,which could be attributed to their different stomatal characteristics.Usually,the light intensity of tissue culture chamber is set up as 27 μmol/（m2·s）,where both D.loddigesii and D.candidum do not acquire an optimal state for their leaf stomatal opening.Considering the characteristics to select suitable culture condition,the stomatal aperture and photosynthetic rate could be enhanced,which can promote the growth and development of test-tube seedlings.
基金This project was supported financially by the Yunnan Provincial Science and Technology Department(Nos.2017ZF003-04,2015HB093 and 2019HA001).Authors are grateful to the staff of the analytical group of the State Key Laboratory of Phytochemistry and Plant Resources in West China,Kunming Institute of Botany,Chinese Academy of Sciences,for measurements of all spectra.
文摘Aqueous ethanol extracts of powdered stems of Dendrobium loddigesii afforded three new phenolics including threo-7-Oethyl-9-O-(4-hydroxyphenyl)propionyl-guaiacylglycerol(1),(R)-4,5,4ʹ-trihydroxy-3,3ʹ,α-trimethoxybibenzyl(2)and(S)-5,5′,7-trihydroxy-3′,4′-dimethoxyflavanone(3),together with eleven known analogues.Their structures were determined by extensive spectroscopic analysis.To identify natural antioxidants,whitening,and anti-aging agents,the abilities of these phenolics were assessed to scavenge the 1,2-diphenyl-2-picrylhydrazyl(DPPH)radical,their abilities to inhibit tyrosinase production,and their abilities to stimulate collagen production by human dermal fibroblasts-adult(HDFa)assay.It was found that compounds 1,4-8,13 and 14 exhibited significant DPPH radical scavenging activities,compound 10 exhibited tyrosinase inhibitory activity(IC_(50)37.904μg/mL),and compound 9 showed significant collagen production with an EC_(50)value of 3.182μg/mL.These results suggest that phenolic constituents from D.loddigesii may be candidate antioxidants,skin-whitening and/or anti-aging agents.
文摘环草石斛 Dendrobium loddigesii Rolfe是中药石斛的源植物之一，以茎入药，具有滋阴清热、益胃生津的功效。本文采用红外光谱法对不同产地、不同采收期的环草石斛分别进行分析比较。结果显示，不同产地环草石斛红外光谱中，1035，1051，1078，1156，1500，1511，1736 cm -1等附近峰的相对峰强皆有显著差异，表明不同产地环草石斛的多糖、酮、酯类等成分的组成和含量有明显差异。在二维相关红外光谱中，越南、云南、广西、贵州的环草石斛分别有7，8，8，9个自动峰，且广西环草石斛的最强峰在1220 cm -1附近，不同于其他三个产地样品（980 cm -1）。不同采收期环草石斛的红外光谱中，1034～1023 cm -1主强峰的波数，（1617±177;4）cm -1次强峰的波数以及1078（1076，1079）cm-1峰的有无，皆随季节呈现出明显的阶段性变化，显示了环草石斛生长过程中所含多糖、酮类等成分积累的阶段性变化规律。应用红外光谱法能较好把握环草石斛的生长状况，帮助全面了解其成分组成与含量变化，对环草石斛的合理开发与高效利用有重要意义。
