Seedlings ofMichelia macclurei,Cinnamomum camphora,RhodoleiachampioniiandMytilaria laosensiswere placed in open-top chambers (OTC) with three ozonic treatments including E20 (20 ppb), E40 (nature air, 40 ppb) and E160 (160 ppb) and two water treatments. Root biomass, stem biomass and leaf biomass total biomass and root/shoot ratio of four seedling types were evaluated. The results showed that there were no significant differences in impacts of ozone stress and drought stress on root, stem, leaf, and total biomass ofM. macclureiamong different treatments. The biomass ofM. laosensisdecreased with increasing ozone concentration, whereas biomass ofC. camphoraandR. championiichanged irregularly. Most of the biomass of four kind seedlings under ozone and drought intercross stresses was lower than those under ozone stress. The root/shoot ratios of four seedling species were all low. The ratios under high concentration ozone (160 ppb) were lower than the control treatment. And the ratios of different treatments under drought were lower than those were not under drought when they were under the same concentration of ozone.

In this study, soil pH, organic matter, total N, total P, total K, alkali-hydrolyzable N, available P, available K, number of microorganism and enzyme activity were studied in a burned E. urophylla forest (the burned forest) and an unburned adjacent E. urophylla forest (the control) in Dongyuan County, Guangdong Province, China. This study aims at investigating the effects of a single wildfire on soil properties of an E. urophylla forest to provide basis for the recovery of soil fertility and management of burned E. urophylla forests. Significant differences were observed between the burned forest and the control in most of chemical properties. The wildfire significantly decreased the soil organic matter, total N, total P, total K, alkali-hydrolyzable N and available K by 32.8%, 33.6%, 36.8%, 35.2%, 25.0% and 28.5%, respectively. However, no significant difference was observed in soil pH and available P. The numbers of bacteria and fungi in burned forest were significant lower than those of the control, while there was no difference in actinomycetes between the two forests. The urease, phosphatase and catalase activities were statistically significant lower than those of the control. The results suggested that there were significant effects on the E. urophylla forest 1 year after the wildfire and the recovery from the wildfire may take a long time.

By using a new kind of single-beam normalized photo-acoustic tomography spectroscopy (PAS-CT) technology with non-damage detection, the photo-acoustic tomography spectroscopy and optical absorption properties of green and yellow leaves ofBauhinia blakeanawere studied. The results show that: the photo-acoustic tomography spectroscopy ofBauhinia blakeanaleaves could be obtained from different chopping frequency and different sample positions, and photosynthetic pigment content of their leaves is closely related to their photosynthetic intensity. The more photosynthetic pigment content the leaves ofBauhinia blakeanacontain, the bigger optical absorption coefficient and the higher photosynthetic efficiency they have. The photosynthetic pigment content of the green leaves ofBauhinia blakeanais higher than that of the yellow ones. As a result, the photosynthesis of green leaves is better than that of the yellow ones. According to the results of our research, the photosynthetic efficiency ofBauhinia blakeanacould be improved and its growth time could be effectively controlled to enhance the growth ofBauhinia blakeana. Furthermore, it could play an important role on the development of forestry, and meet the need of forest for 6 billion people. The research showed high science value to the study and applications of the photosynthesis of plants.

Seedlings of Michelia macclurei, Cinnamomum camphora and Rhodoleiachampionii were placed in open-top chambers (OTC) with two ozonic treatments including E40 (nature air, 40 ppb) and E150 (150 ppb) and two water treatments. Physiological indexes such as chlorophyll, soluble sugar, soluble protein, proline, MDA and SOD of three seedling types were evaluated. With increasing experimental time, chlorophyll content generally decreased or remained steady, soluble sugar content increased followed by a decrease and SOD activity increased for the three seedling types in ozone treatment, drought treatment or ozone-drought intercross treatment. Contents of soluble protein and proline increased for the three seedling types in ozone treatment and drought treatment. The MDA content increased for M. macclurei and C. camphora in ozone treatment and drought treatment and for R. championii in the three stress treatments. Principal component analysis indicated that the resistance abilities of ozone, drought or intercross stress for the three seedling types was C. camphora seedlings > M. macclurei seedlings > R. championii seedlings.