Tolerance of increased salinity by tomato is of great importance to the tomato processing industry, where increased conductivity of up to 6 dS m-1 is used to increase specific yield components. A new line of miniature dwarf tomato, Lycopersicon esculentum Mill. cv. Micro Tom, was evaluated for photosynthetic response to elevated salinity. Tomatoes were grown in solution batch culture and subjected to constant salt treatments of 2.4 (control), 7.6, 12.8, or 18 dS m-1. Weekly photosynthetic measurements were made beginning week 4 on the most recent fully open leaf or leaf opposite a fruit. Net photosynthesis decreased across all salt treatments over the last six weeks of sampling. As salinity level increased, net photosynthesis decreased compared to the control. The 18 dS m-1 treatment reduced net photosynthesis relative to 12.8 and 7.6 dS m-1. Although salinity increased succulence, limitations to net photosynthesis were due to diminished utilization of intercellular CO2, rather than reduced internal CO2 concentration or stomatal conductance.
If the inline PDF is not rendering correctly, you can download the PDF file here.