Three-dimensional label-free imaging and analysis of Pinus pollen grains using optical diffraction tomography

Geon Kim,Sangyun Lee,Yongkeun Park,Seungwoo Shin

doi:10.1038/s41598-018-20113-w

Geon Kim, Sangyun Lee + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-20113-w

Copy DOI

Abstract

The structure of pollen grains is related to the reproductive function of the plants. Here, three-dimensional (3D) refractive index maps were obtained for individual conifer pollen grains using optical diffraction tomography (ODT). The 3D morphological features of pollen grains from pine trees were investigated using measured refractive index maps, in which distinct substructures were clearly distinguished and analyzed. Morphological and physiochemical parameters of the pollen grains were quantified from the obtained refractive index (RI) maps and used to quantitatively study the interspecific differences of pollen grains from different strains. Our results demonstrate that ODT can assess the structure of pollen grains. This label-free and rapid 3D imaging approach may provide a new platform for understanding the physiology of pollen grains.

Highlights

Pollen grains are the male gametophytes of seed plants and are essential to the life cycle of many plants that play a major role in ecosystems
quantitative phase imaging (QPI) does not rely on an exogenous labeling process, because the phase delay, which is equivalent to the multiplied product of the refractive index (RI) and the thickness of the sample, is determined by the inherent composition of the sample[19]
We demonstrated and obtained label-free imaging and analysis of the 3D structures of Pinus pollen grains

Summary

Discussion

We demonstrated and obtained label-free imaging and analysis of the 3D structures of Pinus pollen grains. We note that the present method can be combined with fluorescence imaging, to access both the morphological and molecular specific information about pollen grains and perform correlative image analysis[43,44,45,46]. Birefringence is another property that can be exploited to characterize pollen grains. It is likely that label-free identification of pollen structures using ODT will provide useful insights in understanding plant reproduction. We expect that use of ODT to identify allergenic pollen grains among airborne particles will allow early caution and prevention against allergic disorders, improving the health of communities[54,55,56]

Methods

Findings

Additional Information