Effects of Photosynthetic Photon Flux Density during ex vitro Acclimatization and Duration of Culture in vitro on the Growth of Several Micropropagated Ariod Plantlets

• Main Authors: Yu-Chun Chu, 褚昱均
• Other Authors: Der-Ming Yeh
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/fyd85k

碩士 === 國立臺灣大學 === 園藝學研究所 === 92 === Effects of photosynthetic photon flux (PPF) during ex vitro acclimatization and duration of culture in vitro were studied on the growth of several micropropagated ariod plantlets. The aims were to determine the proper acclimating PPF ranges and duration of culture in vitro for the aroids which could promote the subsequent growth of plantlets after transferring. In the PPFD experiments, the plantlets were transplanted to soilless mix and placed in a growth room at a temperature of 25±1℃ under cool-white fluorescent light providing 16 h daily photosynthetic photon flux density of 80, 130, 200 or 250 μmol m-1s-1. After having acclimatized for 60 to 70 days in the growth room, the plantlets were then transferred to a shaded greenhouse for 90-120 days and their growth was measured. Plantlets of Syngonium ‘Pixie’ under 130 to 200 μmol m-2 s-1 during acclimatization grew better than those under 80 μmol m-2 s-1. For Philodendron selloum ‘Xanadu’, maximum subsequent growth occurred at 200 μmol m-2 s-1, while higher PPFD at 250 μmol m-2 s-1 treatment reduced dry weight and survival percentage. The PPFD at 130 μmol m-2 s-1 resulted in maximum dry weight and survival percentage in Alocasia reginula ‘Black Diamond’. For Aglaonema ‘White Tip’, the optimal PPFD was 130 μmol m-2 s-1 while the plantlets under 200 μmol m-2 s-1 during acclimatization had little subsequent growth after transferring for 70 days. The optimal PPFD during ex vitro acclimatization for Dieffenbachia ‘Tropic Marianne’ and ‘Star Bright’ was 80 μmol m-2 s-1. During ex vitro acclimatization, the photoinhibition of micropropagated plantlets could be measured by chlorophyll fluorescence, a nondestructive measurement technique. All the Fv/Fm values in the in vitro formed leaf of the tested aroids decreased in the early period after transplanting to soilless mix, and then increased thereafter. The lowest Fv/Fm value in Syngonium ‘Pixie’ was 0.6 on day 3 after transplanting and the value increased to 0.75-0.8, considered as unstressed status on day 10. For Philodendron ‘Xanadu’, the Fv/Fm value decreased to 0.64 at transplanting but increased and recovered on day 1. Minimum Fv/Fm value of 0.67 was measured in Alocasia ‘Black Diamond’ at 200 μmol m-2 s-1, and the Fv/Fm increased and recovered on day 14. The lowest Fv/Fm value in Aglaonema ‘White Tip’ was 0.64 on day 1 after transplanting, and recovered on day 2, while this value decreased again in the 200 μmol m-2 s-1 treatment. High PPFD at 200 μmol m-2 s-1 greatly reduced the Fv/Fm values in Dieffenbachia ‘Tropic Marianne’ and ‘Star Bright’ to 0.55 and 0.64, respectively, clearly exhibiting photoinhibition and the Fv/Fm values did not increase to unstressed range afterwards. For all the aroids tested, the stomatal conductance and transpiration rate values in the in vitro formed leaf were high in the early stage after transplanting to soilless mix, and then decreased dramatically. For Aglaonema ‘White Tip’, maximum growth occurred in the 20-week-old plantlets in vitro. The in vitro formed leaf of 20-week-old plantlets had higher photosynthetic rate than the 14 to 18-week-old plantlets. For Alocasia ‘Dwarf Amazonica’, the 12-week-old plantlets in vitro had greater growth than did the 10 or 14-week-old plantlets. The 6 to 8-week-old plantlets accumulated dry weight slowly after transferring.