General Testing salt tolerance of quinoa, tomato and New Zealand spinach on rhizosheets
In the first work package of the SALAD project we are testing the salt tolerance of three crops on a rhizosheet experimental set up. The investigated species – tomato, quinoa and New Zealand spinach – are grown on filter paper in plastic bags at various levels of salinity. The growth of the root apparatus is studied through pictures and images analyses. At the end of the experiment the sodium concentration of the used filter paper is measured to monitor salt accumulation around the roots (preliminary results are reported in Figure 1).
The information collected with these experiments will provide a first screening of salinity tolerance of different varieties of the tested species, with the most promising ones to be further analysed under greenhouse and field conditions.
The species investigated in this part of the SALAD project are tomato (Solanum lycopersicum), quinoa (Chenopodium quinoa), and New Zealand spinach (Tetragonia tetragonioides). The three crops are currently not at the same stage of development and awareness among the general public, with quinoa crops already extensively screened on their performance in saline conditions, tomato showing very promising quality improvements of the fruits under saline conditions, and New Zealand spinach still is at an early stage of research.
High salinity can be lethal to plants, which is why plant roots tend to exclude salt when they take up water. Unfortunately, this process causes the excluded salts to accumulate in the soil around the roots. When irrigated with salt water or when growing in saline soils, this build-up of salt causes plant roots to “feel” a much higher salt concentration than the bulk soil salinity.
The rate at which salt accumulates around roots is dependent on the environment, but also differs among species and varieties of the same plant. The rhizosheet experiment investigates how our salt-tolerant plants cope with accumulating salt, and why some varieties can perform better than others in saline environments. Figure 2 shows a particular of young plantlets of New Zealand spinach (left) & quinoa (right) growing in the rhizosheet experimental set up and figure 3 describes the experimental set up of the two species.
The rhizosheet protocol in this experiment is based on the protocol for tomato described by Perelman et al. (2020) “Tracing root-felt sodium concentrations under different transpiration rates and salinity levels” Plant Soil 447:55-71 https://doi.org/10.1007/s11104-019-03959-5