The aim of this study was to evaluate the growth of rape （Brassica napus L.） seedlings under different light intensities to select appropriate conditions for cultivation in an indoor system. Seedlings were grown und...The aim of this study was to evaluate the growth of rape （Brassica napus L.） seedlings under different light intensities to select appropriate conditions for cultivation in an indoor system. Seedlings were grown under different light intensities of red and blue light provided by light-emitting diodes （LEDs） and their self-adjustment ability and changes in leaf microstructure were evaluated. Light was supplied by red LEDs with peak wavelengths of 630 （R1） and 660 nm （R2） and by blue LEDs （B） with a peak wavelength of 445 nm （the light intensity ratio of R1：R2：B was 3：3：2）, at intensities of 400 （R1R2B400）, 300 （R1R2B300）, and 200 μmol m-2 s-1 （R1R2B200）. Natural solar light served as the control （C）. Plant height, stem diameter, root length, leaf area, and dry weight of rape seedlings gradually increased with increasing light intensity. The seedlings in the R1R2B400 treatment grew more vigorously, while those in the R1R2B200 treatment were weaker. The photosynthetic pigment contents did not differ significantly between the R1R2B400 treatment and C, but were significantly lower in the R1R2B300 and R1R2B200 treatments. The highest intercellular CO2concentration, stomatal conductance, and transpiration rate were in the R1R2B300 treatment. The highest photosynthetic rate was in the R1R2B400 treatment, and was related to more compact leaves, thicker and tidier palisade and spongy tissues, and well-developed chloroplasts. In contrast, the seedlings in the R1R2B200 treatment had disordered mesophyll cells, round chloroplasts, and fractured and fuzzy grana lamellae, all of which inhibited plant growth. In conclusion, the seedlings in the R1R2B400 treatment had well-developed leaves, which favored photosynthesis. Compared with the light intensities below 300 μmol m-2 s-1, the light intensity of 400 μmol m-2 s-1 provided by a cembination of red and blue LEDs was beneficial for cultivating strong and healthy rape seedlings in an artificial system.展开更多
[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
基金funded by the National High-Tech R&D Program of China (2013AA103003)the Agricultural Research Special Funds for Public Welfare Projects,China (201303108)
文摘The aim of this study was to evaluate the growth of rape （Brassica napus L.） seedlings under different light intensities to select appropriate conditions for cultivation in an indoor system. Seedlings were grown under different light intensities of red and blue light provided by light-emitting diodes （LEDs） and their self-adjustment ability and changes in leaf microstructure were evaluated. Light was supplied by red LEDs with peak wavelengths of 630 （R1） and 660 nm （R2） and by blue LEDs （B） with a peak wavelength of 445 nm （the light intensity ratio of R1：R2：B was 3：3：2）, at intensities of 400 （R1R2B400）, 300 （R1R2B300）, and 200 μmol m-2 s-1 （R1R2B200）. Natural solar light served as the control （C）. Plant height, stem diameter, root length, leaf area, and dry weight of rape seedlings gradually increased with increasing light intensity. The seedlings in the R1R2B400 treatment grew more vigorously, while those in the R1R2B200 treatment were weaker. The photosynthetic pigment contents did not differ significantly between the R1R2B400 treatment and C, but were significantly lower in the R1R2B300 and R1R2B200 treatments. The highest intercellular CO2concentration, stomatal conductance, and transpiration rate were in the R1R2B300 treatment. The highest photosynthetic rate was in the R1R2B400 treatment, and was related to more compact leaves, thicker and tidier palisade and spongy tissues, and well-developed chloroplasts. In contrast, the seedlings in the R1R2B200 treatment had disordered mesophyll cells, round chloroplasts, and fractured and fuzzy grana lamellae, all of which inhibited plant growth. In conclusion, the seedlings in the R1R2B400 treatment had well-developed leaves, which favored photosynthesis. Compared with the light intensities below 300 μmol m-2 s-1, the light intensity of 400 μmol m-2 s-1 provided by a cembination of red and blue LEDs was beneficial for cultivating strong and healthy rape seedlings in an artificial system.
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.
