Tracking pollen tube and ovule development in vivo reveals rapid responses to pollination in Brassica napus.

Pollination and subsequent fertilization in most angiosperms are precursors of seed and fruit development. Thus, understanding the developmental processes can improve the management of plant reproductive success and food security. Indeed, the window between ovule fertilization and seed development is crucial for the accumulation of metabolites which determines ultimate seed quality and yield. Establishing detailed temporal maps of development to describe pollination to early seed development is therefore extremely valuable to provide context for molecular studies, plant breeding, and to refine crop management strategies for optimal seed quality. Here, we characterize aspects of post-pollination responses in the globally important crop plant Brassica napus (oilseed rape, canola) with a high-resolution time series of microscope images of the floral organs during the first 48 h post pollination. We demonstrate the rapid response to pollination in B. napus (c.v. Westar), with pollen tubes germinating and traversing the style within just 4 h. We also describe markers of early seed formation in response to fertilization in the synchronous development of ovule area and stigma length. Our results provide a series of temporal benchmarks for post-pollination floral morphology in B. napus, representing valuable reference points for studying and tracking pollination responses and early seed development.