碩士 / 國立臺灣大學 / 園藝暨景觀學系 / 101 / Impatiens (Impatiens walleriana Hook. f.) and wax begonia (Begonia × semperflorens-cultorum Hort.) are the most important bedding plants in cool-season. Their year-production amounts are the top two among all cool-season bedding plants in Taiwan. However, the continuous global warming effect has brought negative impacts to the growth and quality of cool-season bedding plants. Therefore, the aim of this research is to select proper types of both single and combined-chemicals that may improve the heat tolerance of impatiens and wax begonias, and to optimize the concentrations of these chemical treatments.
Chlorophyll fluorescence determination method is a fast, efficient and accurate indicator of heat tolerance. Under specific time, the key temperature can be used as an indicator of heat tolerance of plants. The results indicated that the relative chlorophyll fluorescence under 40oC in 30 min treatment and 45oC in 30 min treatment are good indicators for the evaluation of the heat tolerance of cool-season vegetables and cool-season bedding plants, respectively.
In the first part of this research, the impatiens were treated by foliar sprays of salicylic acid (SA) (50, 100, 150 μM), calcium chloride (Ca) (5, 10, 15 mM), glycine betaine (GB) (5, 10, 15 mM) and trehalose (Tre) (0.5, 1.5, 2.5 mM) individually in 2 h and followed by 45oC heating. The result showed that 100 μM SA, 10 mM Ca, 10 mM GB and 1.5 mM increased the relative Fv/Fm value and net photosynthetic rate, survival rate of impatiens, as well as maintain the quality of leaf, lower the loss of leaf water potential under heat stress.
After selecting the appropriate concentrations of the single chemicals (100 μM SA, 10 mM Ca, 10 mM GB、1.5 mM Tre), the detailed studies of the combined-chemicals are approached. The results indicated that 50 μM SA + 5 mM Ca improved the relative Fv/Fm value, net photosynthetic rate and Pn/Ci of impatiens under heat stress. Next, the experiment of the concentration ratio between SA and Ca are performed. The results showed that 75 μM SA + 2.5 mM Ca is the best composition for impatiens to tolerate heat.
Furthermore, the wax begonias are treated with the sprays of 100 μM SA、10 mM Ca、10 mM GB、1.5 mM Tre、50 μM SA+ 5 mM Ca、50 μM SA+ 5 mM GB and 50 μM SA+ 0.75 mM Tre, followed by cultivation under 35/30oC phytotron for 14 days. The results showed that all single- and combined-chemicals are efficient for wax begonia to tolerate high temperature, and they also are able to maintain compact shape, good quality and net photosynthetic rate. Moreover, the chemicals could protect chlorophyll from degradation due to high temperature. Both single- and combined-chemicals improved heat tolerance for wax begonia. Overall, 50 μM SA+ 5 mM Ca is most cost-effective for growers.
In conclusion, according to the result, the spray with 50 μM SA+ 5 mM Ca combined-treatment has been proven to have premium effect for enhancing heat tolerance of impatiens and wax begonias, which is better than applying SA or CA individually. Nevertheless, 75 μM SA + 2.5 mM Ca is considered to be the most cost-effective combined treatment, which can be further applied to commercial grower. For future development of new combined-chemical treatments, considering other stress factors, such as high light intensity, will be necessary.
| Identifer | oai:union.ndltd.org:TW/101NTU05378040 |
| Date | January 2013 |
| Creators | Kai-Chun Chang, 張凱淳 |
| Contributors | Yu-Sen Chang, 張育森 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 141 |
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