Effects of Space Mutation on Photosynthetic Characteristics and Growth of Dendrobium nobile

Abstract:

In order to understand the effects of space mutation on development of Dendrobium nobile, the leaf structure, photosynthetic characteristics and growth index between space mutation and wild type were compared. The results showed that there were thick leaf, dense stoma, and big stomatal apparatus in space mutation D. nobile. Diurnal variation of net photosynthetic rate (Pn) of the two kinds of D. nobile showed a similar bimodal curve. However, Pn of space mutation D. nobile was lower than that of wide type. The maximum photosynthetic rates of space mutation and wild D. nobile were 4.6 and 6.8 μmol m^-2s^-1, light compensation rates (LCP) were 18.3 and 12.6 μmol m^-2s^-1, light saturation points (LSP) were 1180 and 720 μmol m^-2s^-1, CO₂ compensation points (CCP) were 100 and 102 μmol mol^-1, CO₂ saturation points (CSP) were 2215 and 2090 μmol mol^-1, respectively. Fresh weight (FW) and dry weight (DW) per shoot of space mutation D. nobile was lower than that of wide type. However, due to the increment of tiller number, total biomass per pot in the space mutation D. nobile was more than that of the wild type. Additionally, the total alkaloid and polysaccharide contents in space mutation D. nobile was significantly higher than those of wide type. So, space mutation would provide a new way for breeding and quality improvement of D. nobile.