Florescence and pollen germination in Lagerstroemia caudate

Key words: 
• botany /
• Lagerstroemia caudate /
• flowering habit /
• pollen germination /
• pollen storage

Abstract: In order to study the flowering habit and the conditions for pollen germination and storage of Lagerstroemia caudate，the processes of flower opening and pollen viability of Lagerstroemia caudate were observed over a 30 d period. Pollen germination was also tested using orthogonal test of PEG 4000，boric acid，CaCl2，and sucrose. Results showed that at 3:30 sepals of L. caudate started to diverge，at 6:00 petals flattened up，at 6:30 the anther diverged，and at 06:30 the stigma secreted a large amount of mucus. The highest rate of in vitro pollen germination which could reach 96.28% was with sucrose （100 gL-1） + boric acid （30 mgL-1） + CaCl2 （30 mgL-1） + PEG 4000 （150 gL-1）. Pollen germination in the indoor natural environment decreased sharply from 87% to 65% in 2 d with the pollen losing vigor in 6 d. The best preservation temperature for dry pollen was 4 ℃，in which temperature the dry pollen viability could keep 30%，with dry pollen losing its vigor in 30 d. Thus，as a basis for breeding，if L. caudate was used as a female parent in hybridization，the stamens must be removed before 6:30，and the best pollination time would be at 7:30.［Ch，2 fig. 2 tab. 15 ref.］