Effects of photoperiod and temperature on growth and development of Primula maximowiczii.

In order to explore the growth and development of Primula maximowiczii and develop the cultivation techniques, the effects of two temperatures (15, 20 c) combined with three photoperiods (16, 12 , 8 hours) on the growth and development of P. maximowiczii were investigated in this paper. The results were as followings: 1) Photoperiod and temperature had significant effects on both terminal bud germination and growth, and photoperiod was the key factor, of which the contribution to bud germination reached 79.89%,to the growth above 78.66%. Sixteen hours'day length and last for 20 days could thoroughly break the dormancy of P. maximowiczii plants with terminal buds and promote the growth, however, the plants grew slowly or kept dormancy for long time under photoperiod less than 12 hours. 2) The plants grown under day length of 16 hours and temperature of 15 c had the greatest biomass with dry mass reached 2.375 g, strong roots, and stronger flower buds. When day length was 16 hours, plants grew faster under 20 c than 15 c in early stage, and later, the basal leaves of plants grown under 20 c began to wilt, with low root activity. As a result, the stem was thinner than the plants grown under 15 c . The results showed that P. maximowiczii grew well under long day and low temperature, and short day induced plants into dormancy, while temperature above 20 c influenced the growth and development adversely.