Methods of wind pollination

Abstract, Biodiversity Science, 2017

The transfer of pollen in most seed plants relies on diverse pollination vectors. In comparison with animal pollination (zoophily), wind pollination (anemophily) has long been regarded as an inefficient mode and thus has received relatively little attention. However, the majority of gymnosperm species and over 10% of angiosperm species are wind pollinated, and the evolution of wind pollination from insect-pollinated ancestors has occurred at least 65 times in angiosperms. Furthermore, ambophily, a combination of wind and insect pollination, is also reported frequently. More refined methods are thus seriously needed to explore the existence and mechanisms of wind pollination in diverse ecosystems. In this paper, we explore the scope of anemophily research by describing the species and habitat diversities of wind-pollinated plants. In field experiments, we recommend using pollen traps (sticky slides or airborne particle samplers) to quantify airborne pollen, and conducting pollinator exclusion, bagging, and emasculation treatments to explore the reproductive contribution of anemophily and the possibilities of zoophily, autogamy, and apomixis. In constrained field conditions, researchers can bring relevant plant tissues back to the laboratory for experiments examining aerodynamics, i.e., measuring the settling velocity of pollen using stroboscopic photography or drop towers, calculating the pollination efficiency using wind tunnels, and evaluating the aerodynamics based on computer models in different simulated conditions. Furthermore, the abiotic and biotic factors (wind pollination syndromes) associated with anemophily should also be studied to explore the causes as well as the ecological and evolutionary consequences of wind pollination. The above methods cannot substitute for one another, as researchers should use them as a comprehensive unit when possible to reveal the details and mechanisms of wind pollination.

Key words: wind pollination, seed plants, pollen, field methods, aerodynamics