Effects of Physiological Characters and Salicylic Acid on the Ozone Tolerance of Bedding Plants
Date Issued
2008
Date
2008
Author(s)
Liao, Hsiu-Ting
Abstract
Tropospheric ozone is considered to be the most widespread atmospheric pollution and has a major impact on plants. The tolerance to ozone is quite different in various plants. In order to compare to the bedding plants’ tolerance to ozone, some frequently used bedding plants of Taiwan were exposed to ozone 800 ppb for 4 hours in the chamber of greenhouse. According to the experimental results, wax begonia ‘Super Olympia White’ (Begonia semperflorens-cultorum ‘Super Olympia White’) and ‘Super Olympia Pink’ are the most sensitive plants to ozone. However, torenia ‘Clown’ (Torenia founieri ‘Clown’), melanpodium ‘Sky Star’ (Melampodium paludosum ‘Sky Star’), and copper leaf (Acalypha pendulala) are the most tolerance. In order to adapted suitable physiological markers for benefit to select, we analyzed the correlation between the plants’ tolerance to ozone and some physiological markers. The results showed disc leachates (%), relative chlorophyll fluorescence Fv/Fm (%), and air pollution tolerance index (APTI) values have the correlation with degree of foliar injury, r = 0.818***, 0.896***, 0.784***, respectively. It represented that those are good selection markers for estimating plants’ tolerance to ozone.olerance to ozone was affected by complex morphological, physiological, and biochemical characters of plants. These characters and responses also affect their tolerance to ozone when they exposed to ozone. The results of this study shows plants which are have high level air pollution tolerance index (APTI) values are often tolerant to ozone. The plants which were with higher level of stomatal resistance and ascorbic acid have better ability to avoid ozone to enter mesophyll and scavenged ozone or its’ generate products, the reactive oxygen species (ROS). In addition, when plants exposed to high concentration ozone, the lower degree of ion leakage and changed of chlorophyll fluorescence Fv/Fm values of plants, showed that cell membranes are more stable and the PSII are destroyed by ozone slightly. Moreover, the increased of stomatal resistance and amounts of ascorbic acid would benefit to plants to reduced the ozone injury. ntioxidant activity of plants would be regulated by salicylic acid. It played an important role in biotic and abiotic stress. Pretreatment with exogenous 25 μM salicylic acid to star-cluster ‘Sky Star’ (Pentas lanceolata ‘Sky Star’) and 100, 400 μM to wax begonia (Begonia semperflorens-cultorum ‘Super Olympia’) would reduced the ozone injury, and their chlorophyll fluorescence Fv/Fm values were higher than control. Furthermore, pretreatment salicylic acid to wax begonia could elevate the ascorbate peroxidase (APX) activity, and the catalase (CAT) activity was increased after wax begonia ‘Super Olympia’ exposed to ozone. It might be the explanation that pretreatment with salicylic acid to wax begonia could reduce leaf injury.
Subjects
ozone
stress physiology
SA
bedding plants
Type
thesis
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