The outermost layer of the pollen of angiosperms, which represent more than 80 percent of all plant species,1 is covered in a sticky substance known as pollenkitt. The adhesive properties of pollenkitt allows pollen to adhere to plant and insect surfaces, promoting pollination.2 These adhesive properties are known to be affected by relative humidity3, 4 and temperature, causing the refractive index (RI) to change. We propose a label-free method based on in-line digital holographic microscopy (DHM) to quantify the RI of pollenkitt of common angiosperms, using the morning glory flower (Ipomoea caricia) as an example. We track the RI with (1) local temperature and (2) pollen ageing. This method can also be expanded to quantify the refractive index of pollenkitt of other species.
|