Laboratory of Plant Systematics

Systematics and evolution of Balsaminaceae

Overwhelmed by the power of evolution, I was always interested in the fascinating search for evolutionary patterns between species. In 2002-2003, I started my research activities in the field of plant systematics at the Laboratory of Plant Systematics. After finishing my MSc-thesis on molecular systematics of Balsaminaceae, the Fund for Scientific Research Flanders (FWO-Vlaanderen) enabled me to continue this study as a PhD-student. Balsaminaceae are a family of predominantly annual and perennial herbs with flowers that are as beautiful as they are remarkable. Although the family contains more than 1000 species, only two genera (Impatiens and Hydrocera) are recognized. While Hydrocera is a monospecific genus from Indo-Malaysia, Impatiens is an extremely species-rich genus occurring in montane areas in the Old World tropics and subtropics. The highest diversity of Impatiens species is found in tropical Africa, Madagascar, South India, the eastern Himalayas, Southeast Asia, and Southwest China.

The main purpose of this project is to clarify the phylogenetic relationships within Balsaminaceae using both molecular and pollen morphological data.

The occurrence of hybridisation, high species radiation, an homoplastic nature of morphological characters (e.g. the number of sepals, length of spur, …) and transitional character states make Balsaminaceae a family that is difficult to investigate. Despite many attempts, until now, no successful classification of the family has been proposed. In order to obtain a clear and robust phylogeny, both chloroplast and nuclear markers from ca.120 Impatiens species will be sequenced.

 

 

 

 

Pollen morphology of Impatiens and Hydrocera

Although Balsaminaceae pollen has always been considered to be rather homogeneous, a preliminary palynological study revealed a large variation of pollen morphological features. Standard techniques will be used to acquire detailed SEM, TEM and LM observation of ca. 120 species.

Several characters that show phylogenetic significance include for instance the variation in sexine patterns, the shape of the pollen grains and the number of apertures. The considerable pollen morphological variation will also be used to evaluate the systematic relationships in the study group.