关键词: 水曲柳, 根序, 去叶, 光合产物, 源汇关系

Abstract: To clarify the variation characteristics of flowering phenology of Lagerstroemia indica in urban gardens, to explore factors impacting its flowering phases and to provide guidance to disposition in planting, cultivated individuals of the species in southern Sichuan were observed every week in 2011-2014. The difference of phenological events was analyzed at individual level and population level, and the effects of plant size and weather factors on flowering phenology were also discussed. The results showed that the period of flowering at individual level began in early June to middle September and ended in October, lasting for 8-137 d, and most individuals had a 60-90 d flowering duration. The proportion of blooming plants and the phonological characteristics varied in different years. The shortest duration of flowering was 106 d in 2014, while the longest duration was 130 d in 2012. Similar temporal pattern of flowering plant number was recorded in different years, and the first flowering phase was significantly correlated to flowering duration. Basal diameter had a significant effect on flowering phenology. The individuals with big size bloomed earlier and lasted for longer time. Peak flowering phase of L. indica often occurred from July to September. The number of flowering individuals was positively correlated to the average air temperature in previous month, but had no significant correlation to current air temperature and rainfall. Being affected by weather and other factors, flowering phenology differed obviously among various years, showing some regular patterns as well. Diversified flowering phenology at individual level was beneficial to maintaining high ornamental value at population level, and selection of big size plants in gardens could obtain stable flowering effects.

Key words: Fraxinus mandshurica, root order, defoliation, source-sink relationship, photosynthate production