Live cell and immuno-labeling techniques to study gravitational effects on single plant cells

Silicone Chambers for Pollen Tube Imaging in Microstructured In Vitro Environments

Live cell imaging at high resolution of pollen tubes growing in vitro requires an experimental setup that maintains the elongated cells in a single optical plane and allows for controlled exchange of growth medium. As a low-cost alternative to lithography-based microfluidics, we developed a silicone-based spacer system that allows introducing spatial features and flexible design. These growth chambers can be cleaned and reused repeatedly.

Internally Controlled Methods to Quantify Pollen Tube Growth and Penetration Defects in Arabidopsis thaliana

Double-fertilization in angiosperms requires precise communication between the male gametophyte (pollen), the female tissues, and the associated female gametophyte (embryo sac) to facilitate efficient fertilization. Numerous small molecules, proteins, and peptides have been shown to impact double-fertilization through the disruption of pollen germination, pollen tube growth, pollen tube guidance, or pollen tube penetration of the female tissues. The genetic basis of signaling events that lead to successful double-fertilization has been greatly facilitated by studies in the model organism Arabidopsis thaliana, which possesses a relatively simple reproductive physiology and a widely available T-DNA mutant seed collection. In this chapter, we detail methods for determining the effects of single gene loss-of-function mutations on pollen behavior through the creation of an internally controlled fluorescent hemizygous complement line. By transforming a single copy of the disrupted gene back into the homozygous mutant background, a precise endogenous control is generated due to the fact that pollen containing equal ratios of mutant and complemented pollen can be collected from a single flower. Using this experimental design, we describe multiple assays that can be performed in series to assess mutant pollen defects in germination, pollen tube elongation rate, and pistil penetration, which can be easily quantified alongside a "near-wildtype" complemented counterpart.