Sunlit mesocosms designed for pollen confinement and risk assessment of transgenic crops

To minimize concerns about the ecological consequences of wind and insect dispersal of pollen and the potential of gene flow from experimental genetically modified (GM) crops to compatible relatives, we have modified outdoor sunlit open top chambers (OTCs) for use with GM plants. We have redesigned 21 cylindrical OTCs, commonly used to study the effects of atmospheric pollutants, by adding (1) a pollen filter at the top of each unit to minimize the possibility of the escape of GM pollen; with pollen filters in place, the OTCs are referred to as mesocosms, (2) an evaporative cooler to help mitigate elevated temperatures during the summer months, and (3) an automated watering system that eliminates the need to enter a mesocosm for irrigation during pollination, thereby minimizing potential pollen escape and entry of insect pollinators. Each sunlit mesocosm contains three large plastic pots (each with 1.2-m² surface area) that simulate field plots and that contain a constructed plant community. For example, the community may consist of a GM and a non-GM cultivar of canola (Brassica napus), compatible weedy relatives, and non-compatible species that may be found in mesic disturbed areas such as roadsides or ditches beyond crop fields. The sunlit mesocosms provide a well-replicated outdoor testing system that confines pollen and that can be used to precede or supplement field tests that evaluate the potential ecological consequences of transgenic crops. The mesocosms are proposed as test systems in which transgenic crops and other plants (e.g., biofuel crops) that have been proposed to be grown in new geographies, or plants that produce novel compounds, may be studied to evaluate their potential effects on plant communities. The pollen confinement and insect exclusion features of our mesocosms may also minimize exposure of sensitive humans and insect pollinators to pollen and cellular debris from other plant parts.