The 2011 ASHS Annual Conference

Effect of temperature on growth and physiological metabolism of one and two year old seedlings of Dendrobium nobile were measured. D. nobile were planted in the environmental controlled growth chambers at 4, 15, 25, 35 and 45C. The content of malondialdehyde, soluble sugar, free proline in leaves and shoots, the activities of POD, SOD and CAT in leaves were measured after growth for 20 and 40d, respectively. The results showed that the content of MDA, soluble sugar and free proline for one year old leaves were 0.13μmol g^-1, 2.25μmol g^-1, 58.4μg g^-1. The plant height was 3.100cm taller at 25C than that of other treatments at 20d. Activities of POD, SOD, CAT in leaves had a little changes with the extension of time. Plants were stressed more or less at 4, 15, 35C. There was a negative correlation between the MDA and plant growth (height, p=0.961). The results of two year old seedings had the similar trend as that of one year old seedlings. The resistant physiological index decreased with prolonging planting time (except soluble sugar). The optimum temperature for growing one or two year old seedlings of D. nobile was 25C.