Chemoattracted pollen tubes separated from randomly growing with new technique
Chemoattracted pollen tubes separated from randomly growing with new technique lead image
Pollen tubes in flowering plants are guided by intricate chemical signals and primarily serve to deliver sperm cells to ovules for fertilization. Chemotropic guidance can be seen in a petri dish, but the lack of a physical barrier between a plant’s pistil and ovary makes differentiating between random tubes and their chemoattracted counterparts difficult. This often leaves experimental outcomes open to subjective interpretation. A pair of researchers presents a new technique in Biomicrofluidics to address the difficulty that can evaluate the chemoattractant effect quantitatively.
The team demonstrated a new semi-in vitro assay that uses microslit channels to spatially separate the chemoattracted pollen tubes from randomly growing ones. Randomly growing pollen tubes have little chance of growing through such narrow channels. As chemoattractants diffuse through the slits, the chemical gradient allows for selecting the pollen tubes that are capable of responding to chemoattractants from a mixed population.
Depending on the size of the microslit channel, 80 to 100 percent of the randomly growing pollen tubes of the plant species Torenia fournieri were prevented from reaching the source of the attractant. The best selectivity occurred when the microslits measured approximately half the cylindrical diameter of the pollen tubes.
The microfluidic device is best suited for T. fournieri, according to the authors, and further work is needed to adapt the platform to other species, such as the model species Arabidopsis. In addition to the assay’s potential for developing a high-throughput to evaluate the activity of pollen tube attractants, the group noted that similar assays might one day help elucidate other forms of chemotropic cell growth, such as neuronal cell axon formation.
Source: “Quantitative assessment of chemotropism in pollen tubes using microslit channel filters,” by Naoki Yanagisawa and Tetsuya Higashiyama, Biomicrofluidics (2018). The article can be accessed at https://doi.org/10.1063/1.5023718 .
