Impact of Heat Stress on Tomato Pollen Development

In this study, a heat treatment system of tomatoes (cv. Money Maker ) was developed. An infrared heating element was hanging over tomato plants to generate a temperature gradient at different height of the plants. Using the temperature control on the heating element, heat treatments from 25-38/40 degree were applied beginning when tomato plants started to bear the first flower buds. Results show that above 35 degree heat treatments would result in bleaching of leaves in short term and those plants started to dry after longer period of treatments, no flowers survived such heat conditions. When setting the temperature at below 30 degree, some flowers were developed to full maturity. However, constant heating, even at below 30 degree still had negative impacts on leaves closer to the heating element which is due to dehydration more than heat. In vitro pollen germination assay was used to evaluate the impact of heat/drying on developing viable pollens. Incubator experiments were conducted to set day/night temperature regions to treat tomato ‘Micro-Tom’. Pollens from these plants were used to pollinated ‘Money Maker’ to assess the impact of heat stress on pollen viability in vivo. Setting-up this heat system is the first step for us to collect pollen cells at various developmental stages for a single cell proteomics/genomics study. The project is supported by NIFA-AFRI Exploratory Award 2015-11680.