碩士 / 國立臺灣大學 / 園藝學研究所 / 96 / Some native Begonia species may have potential for the breeding of heat-tolerance or ornamental purposes. This thesis aimed to determine the effects of temperature and irradiance of propergation of leaf cuttings, and to study the the effects of temperature, irradiance, photoperiod and nutrient solution concentration on growth of several Begonia species native to Taiwan.
For leaf cutting propagation, highest survival rate of B. chitoensis, B. palmate, B. fenicis and B. formosana occurred at 25/20 ℃. The highest adventitious shoot number, length and new leaf number were measured in cuttings at 25/20 ℃ and 30/25 ℃. Survival rate was higher at 53 and 107 µmol∙m-2∙s-1, while the adventitious root number decreased with increasing photosynthetic photon flux.
To evaluate heat tolerence among species, plants of three Begonia species were grown at 20/15℃, 25/20℃, and 30/25 ℃. Plant height, leaf number, leaf area, shoot and root dry weight decreased with increasing temperature. Reduced dry weight and net photosynthetic rate were not so apparent in B. fenicis at 30/25 ℃, as compared with other species. B. palmate was heat sensitive and could not survive at 30/25 ℃.
Plant of B. fenicis, B. formosana, B. chitoensis and B. palmate were grown at 30.6 ℃ for two months, and their recently development leaves species were evaluated for cell membrane thermostability measured at water bath temperatures of 24, 30, 36, 42, 48, 54, 60 or 66 ℃ for 20 minutes. The relationship between the relative injury value occurring in leaf tissue discs and treatment temperature was sigmoidal. Reduce relative injury value at 48 ℃ was more apparent in B. fenicis and B. chitoensis than the heat-intolerance B. palmate after 30/25 ℃ treatment for 75 days.
Effects of irradiance on growth and net photosynthesis were studied in four Begonia species grown in controlled environments at 97, 211, and 315 µmol∙m-2∙s-1. Leaf area, leaf nimber, shoot and root dry weight, light saturation point and maximum values of net photosynthetic of B. fenicis increased as light intensity increased from 97 µmol∙m-2∙s-1 to 315µmol∙m-2∙s-1. Light saturation point and maximum values of net photosynthetic of B. chitoensis also increased as light intensity increased, while light saturation point and of B. formosana and B. palmata was not affected with increasing light intensity. Light compensation point of four begonia species was affected little with increased light intensity.
For photoperiod treatments, plants of B. fenicis, B. formosana, B. chitoensis, B. palmate and B. aptera were grown under natural daylength (10.3-12.3 h), day length extension (14.7-15.3 h) or night interruption (natural daylength with night interruption at 22:00 - 02:00) treatments for 142 days. Flowers initiated earlier under daylength extension and night interruption in B. formosana. Flower initiation occurred earlier under natural day length and night interruption in B. fenicis, but no visible bud formation was observed under day length extension. B. chitoensis, B. palmate and B. aptera did no show visible bud formation at the termination of the experiment.
B. fenicis, B. formosana, B. lukuana, B. ravenii and B. chitoensis were fertigated with 0%, 25%, 50% and 100% Johnson’s solution for four months. Plant height, leaf number, leaf area, shoot and root dry weight of five begonia species were higher at 25% and 50% Johnson’ solution than 0% or 100% Johnson’s solution.
| Identifer | oai:union.ndltd.org:TW/096NTU05379030 |
| Date | January 2008 |
| Creators | Yi-Ting Chung, 鍾伊婷 |
| Contributors | Der-Ming Yeh, 葉德銘 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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