Factors influencing the phenology of Ursinia cakilefolia DC., an ephemeral from Namaqualand

Abstract

The aim of this study was to investigate the effect of temperature and sowing date on the phenology of Ursinia cakilefolia, a Namaqualand ephemeral species. Seeds were sown on different dates and plants were subjected to various temperature treatments. Sowing date had a distinct effect on the growth and phenology of the plants. From the results it seems that temperature plays an important role in the timing of phenological stages. However, the effect of temperature differed between sowing dates. The plant's response to temperature is apparently modified by the prevailing photoperiod, although it may also be due to an endogenous rhythm. Generally it seems as if plants require cold temperatures from sowing until the initiation of flower buds, after which the plants need heat for anthesis and further development.