Plant flowers transmit various bio-agents through air

Abstract

Growing air pollution, known as “April snow”, by fluffy catkins from plant flowering was frequently observed during the Spring time in China. Current efforts mainly focus on controlling catkin release, while their public health and environmental impacts are unknown. Here, using culturing, microscopic and sequence methods we found that the flying catkins carry a significant amount of bio-agents (bacteria, fungal, viruses, and pollens), e.g., up to 6.33×104 bacterial and 7.46×105 fungal cells per catkin. Abundant pollens from plants were also found riding on the flying catkins. For collected fluffy catkins, bacterial Paracoccus, Massilia, fungal Ophiocordyceps, Arthrocladiella, pollen Robina, Pickeringia, Pinus, and viral family Genomoviridae, to name a few, were found to be dominant. With infection and allergic potentials, the detected microbial structures on the fluffy catkins were different from those of local air, varying from one location to another. Being not just white pollution, flying plant fluffy catkins were discovered here also acting as a cloud of biological agents, and further actions need to be taken urgently to understand and limit their environmental and ecological consequences.