Graft Recovery in Tomato Seedlings

Plant grafting is the process of surgically combining separate plant parts so that they grow as a single individual one. It commonly involves joining a genotypically distinct root system (‘rootstock’) with a shoot (‘scion’). In tomatoes, graft combinations can increase resistance to soil-borne diseases, shoot vigor, tolerance to abiotic stresses, and crop yield (Moreno et al. 2019). Yet our knowledge of the mechanisms underlying successful grafts is limited. Further knowledge about the timing of graft reconnection is beneficial for the overall understanding of these processes. Previously, radiolabeled C-11 was used as a tracer to track phloem transport in tomato seedlings, and it was found that the phloem was fully reconnected after 5 days (Frank and Tai 2018 (unpublished)). To replicate the conditions of that study, tomato seedlings were grown in a hydroponics setup and phloem reconnection was observed using fluorescence microscopy. The fluorescent dye carboxyfluorescein (CFDA) was used to track phloem transport and observe reconnection. CFDA is phloem mobile due to its structural similarity to sucrose (Martens et al. 2019) In addition, reconnection was observed in seedlings in soil and compared with those grown in the hydroponics setup. The reconnection of the phloem was determined by the presence of fluorescence in the roots compared to a control to account for autofluorescence. The plants were imaged on days 3, 4, 5, and 6 after grafting.

My Experience

This summer I have learned valuable skills concerning lab techniques, scientific writing skills, and working in a lab environment. It has been amazing to learn about the other interesting projects going on in the lab, as well as learning about the reasoning behind my own project. I was introduced to a variety of areas of research in plant biology that have broadened my view. After taking the bioinformatics course, I have a newfound appreciation for the work that goes into analyzing and sorting data. Overall, this research opportunity has been a very rewarding experience that has allowed me to grow as a person.