Short description of research activities in CRC 990:
Populations of invasive panicoid grasses Paspalum conjugatum and Centotheca lappacea spread across tropical transformation systems in Harapan and Bukit Duabelas in Jambi province (Sumatra). In both landscapes, C. lappacea and P. conjugatum often co-occur in oil palm and rubber plots, whereas rather shady jungle rubber seems to be more beneficial for Centotheca than for Paspalum. In this survey we investigate biological factors favoring dispersal success (invasiveness) of grasses, with main focus on their reproductive strategies.
We assess the mode of reproduction via microscopic investigation of megasporogenesis and development of embryo sac and pollen. Flow cytometry (FCSS) enables to determine reproductive pathways of mature seeds, as well as chromosomal ploidy levels of leaf tissues. In addition to the above-mentioned karyological and embryological methods, we perform investigations on population genetic structure inferred from fingerprinting techniques (e.g., AFLP). Population sub-structuring or distribution of different cytotypes will be correlated to biotic and abiotic differences among the transformation systems.