scholarly journals Low-temperature Storage of Micropropagated Plantlets under Selected Light Environments

HortScience ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 449-452 ◽  
Author(s):  
Chieri Kubota ◽  
Nihal C. Rajapakse ◽  
Roy E. Young

Broccoli (Brassica oleracea L. Botrytis Group `Green Duke') and Hosta tokudama F. Maekawa `Newberry Gold' plantlets, which were ready for transplanting after photoautotrophic (sugar-free) culture, were stored 4 to 6 weeks at 5C under various light qualities and photosynthetic photon fluxes (PPF). Illumination during storage maintained quality, photosynthetic ability, and regrowth potential of plantlets stored at low temperature. PPF affected quality of broccoli and Hosta plantlets. Broccoli plantlets responded to storage light quality, while Hosta did not. White light maintained the quality of broccoli plantlets better during 6 weeks of storage than did red or blue light. Red and blue light caused an increase in internode length and reduction in chlorophyll concentrations compared to white light. Photosynthetic and regrowth potentials of plantlets were not affected by spectral quality during storage. Considering changes in dry weight, stem length, and leaf yellowing, the quality of broccoli plantlets was best maintained under white light at 2 μmol·m–2·s–1 PPF. PPF and light quality were shown to be important factors in the preservation of transplant quality and suppression of growth of the plantlets during low-temperature storage.

HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 440c-440
Author(s):  
Chieri Kubota ◽  
Nihal C. Rajapakse ◽  
Roy E. Young

`Green Duke' broccoli plantlets, which were ready for transplanting after 2 weeks of photoautotrophic (sugar free) culture under the conditions of 1100 μmol·mol–l CO2 (outside the vessel), 22 + 4C air temperature, and 140 μmol·m–2·s–1 photosynthetic photon flux (PPF), were stored for 6 weeks at 5C in darkness or in white, red, or blue light at 2 μmol·m–2·s–l PPF (light compensation point at 5C). Photoperiod was set at 24 hour/day during storage. Spectral quality significantly affected plantlet quality: stem length was longer and chlorophyll concentration of leaves was lower in red or in blue light than in white light or in darkness after 6 weeks in storage. Regardless of the spectral quality, light in storage maintained plantlet dry weight at a level comparable to that before storage; dry weight was reduced significantly in dark-stored plantlets. Spectral quality did not significantly affect the photosynthetic and regrowth potential of plantlets. All plantlets stored in light, regardless of light spectra, grew preferably and had similar dry weight and stem length after 9 weeks of transplanting to the greenhouse under natural light.


2017 ◽  
Vol 69 (1) ◽  
pp. 93-101
Author(s):  
Zexiong Chen ◽  
Juan Lou

Light is the source of energy for plants. Light wavelengths, densities and irradiation periods act as signals directing morphological and physiological characteristics during plant growth and development. To evaluate the effects of light wavelengths on tomato growth and development, Solanum lycopersicum (cv. micro-Tom) seedlings were exposed to different light-quality environments, including white light and red light supplemented with blue light (at ratios of 3:1 and 8;1, respectively). Tomatoes grown under red light supplemented with blue light displayed significantly shorter stem length, a higher number of flower buds and rate of fruit set, but an extremely late flowering compared to white-light-grown plants. To illustrate the mechanism underlying the inhibition of stem growth and floral transition mediated by red/blue light, 10 trehalose-6-phosphate synthase (TPS) genes were identified in tomato, and bioinformatics analysis was performed. qRT-PCR analysis showed that SlTPSs were expressed widely throughout plant development and SlTPS1 was expressed at extremely high levels in stems and buds. Further analysis of several flowering-associated genes and microRNAs showed that the expressions of SlTPS1, SlFT and miR172 were significantly downregulated in tomato grown under red and blue light compared with those grown under white light, whereas miR156 transcript levels were increased. A regulatory model underlying vegetative growth and floral transition regulated by light qualities is presented. Our data provide evidence that light quality strongly affects plant growth and phase transition, most likely via the TPS1-T6P signaling pathway.


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