Seasonal Variation in Plant Growth and Inflorescence Composition in Begonia semperflorens

Abstract

SummaryTo identify the factors affecting inflorescence development of Begonia semperflorens, seasonal changes in plant growth and inflorescence composition were investigated. Experiments were started in March, May, July, and September. Branched plants and unbranched ones were used to clarify competition for assimilates between inflorescences and vegetative parts.The plant growth rate was evaluated by the rate of leaf emergence, derived by calculation of 5-day means of the plastochron index. The plant growth rate was higher in summer. The growth rate of unbranched plants, which had fewer competing sinks, was higher than that of branched plants.The inflorescence composition was recorded as the highest order of visible flowers and the number of biparous branches. The former seemed to be mainly controlled by temperature and the latter by the amount of photosynthetic assimilates available to the inflorescence.

Correlation of microsporangial and megasporangial differentiation along racemes of Phytolacca americana L. (Phytolaccaceae)

“…Pollination patterns along sorghum panicles regulated the weight of caryopses (Heiniger et al, 1993) in that the first flowers to be pollinated produced the heaviest fruits. Other variables influencing inflorescence development have been found to br water availability (Dampty & Aspinall, 1976;Marc & Palmer 1976), temperature (Hayashi et al, 1990) and competition for resources (Pinthus & Belcher, 1994;Slafer & Swain, 1994). Even inflorescence size has regulatory capability as in Sagitturia, where larger inflorescences produced more microsporangiate than megasporangiate flowers (Kaul, 1979).…”