| As an important plant resources, the Orchidaceae not only has in economic and medicinal value, but also play a great role in the ornamental value and scientific research. However, wild orchid resource were decreasing and sufferring serious destruction because of the officinal and ornamental demand. The critical moment, Orchid conservation biology is particularly important. Doritis pulcherrima, an endemic species in Southeast Asia, present two kinds of different ecotypes:green (G) and mauve (M) on the leaf dorsal side and symbiosis with mycorrhizal fungi to complete the life under the natural conditions. This study comparative analysis in leaves'anatomical structure and photosynthetic characteristics of G and M. Discussed the differences with the tissue culture (green on the leaf dorsal side GZ; mauve on the leaf dorsal side MZ) and wild seedlings (green on the leaf dorsal side GY; mauve on the leaf dorsal side MY). Fungi were inoculated on different ecotype, analyse differences with the growth and development between them.It will provide a theoretical basis for the Doritis pulcherrima' re-introduced. Mycorrhizal fungi application is essential for conservation of orchid species.The main results were as followed:(1) Both ecotypes had no palisade tissue. Upper and lower epidermal'cells with rectangular single layer cell. Leaf surface have thick Waxy layer and corneum. Leaf thickness slightly different with the two ecotypes.GZ's leaf is about 1.76 mm thick and MZ' is 1.57 mm thick. Under strong light, two ecotypes'leaf thick was significantly higher than that growth in the understory plants (P<0.01)Stomatic density of GZ and MZ were no differences. The upper and lower epidermis' stomatal density of MY's were significantly greater than GY's. GZ and MZ'total chlorophyll content were 0.307 and 0.286 mg-g-1, chlorophyll a/b value were 1.750,1.621. The ratio of carotenoid content/total chlorophyll content was significantly higher in the mauve plants than that in the green plants (P<0.01).The chlorophyll content in two ecotypes'leaf were not significant.(2) Doritis pulcherrima was CAM plant. Open pores and absorb CO2 at night. Almost no absorption of CO2 during the daytime. There is no light compensation point. Intercellular CO2 concentration is lower at night.In the same weather conditions, GZ and MZ' CO2 exchange rate are lower, the maximum absorption peak at night were 0.594μmol-m-2·s-1,0.470μmol-m-2·s-1; GY and MY' CO2 exchange rate Respectively were 0.975,0.762μmol-m-2·s-1. Wild Doritis pulcherrima of CAM activity was significantly higher than tissue culture at night (P<0.01) (3) Mycorrhization had different effects on biomass growth.The seeding in vitro by mycorrhization and inoculated Guignardia and Pestalotia made distinct significant effect on the growth rate of the fresh weight (P<0.01). The seeding in vitro by Nodulisporium,Chaetomium,Myrothecium also made significant effect on the growth rate of the fresh weight (P<0.05)(4) The chlorophyll a,b content, total chlorophyll content of Guignardia inoculated GZ were significantly higher than that of CK (P< 0.01); The chlorophyll a content, chlorophyll a/b, total chlorophyll content of Guignardia inoculated MZ were higher than that of CK (P< 0.05). The chlorophyll b content, total chlorophyll content of Nodulisporium inoculated GZ were higher than that of CK (P<0.05, P<0.01); as was the chlorophyll a content and chlorophyll a/b value of Nodulisporium inoculated MZ (P<0.05)The same fungi has different effects on accumulated of CO2 at night with two ecotypes' Doritis pulcherrima. The accumulated of CO2 at night of Guignardia and Myrothecium inoculated GZ were significantly higher than that of CK (P<0.01). Five fungis inoculated MZ were no difference.Guignardia inoculated Doritis pulcherrima with two ecotypes have promoter action of CO2 absorption. Chaetomium has the inhibitory action to the GZ's CO2 absorption.
|
PDF Full Text Request