Diving into Salt Tolerance of Germinating Crops Open Access
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As sea level continues to rise, saltwater intrusion is threatening agricultural fields. The traditional 3-year crop rotation of the Lower Easter Shore of Maryland is not tolerant to high salinity levels. This study aims to better understand crop seed response to saltwater intrusion and determine which crops are better equipped to tolerate increases in salinity. Saltwater intrusion is dangerous to crops in two ways: osmotic toxicity and ionic toxicity. In this study, these two negative effects were examined by germinating crop species in a range of osmotic pressures. Polyethylene glycol 8000 (PEG) was mixed with deionized water to create solutions of ten different osmotic pressures. Solutions of PEG do not contain the ionic toxicity but they do have osmotic toxicity. The same ten osmotic pressures were then created with sodium chloride (NaCl) and deionized water solutions, which contain osmotic and ionic toxicity. Crop seeds were germinated in petri dishes on filter paper saturated in the different PEG and NaCl concentrations and incubated under a diurnal pattern. Six species were used: barley, sorghum, rapeseed, wheat, standard soy, and salt tolerant soy. Germination was monitored and larger seeds (standard soy, and salt-tolerant soy) were weighed throughout germination. Findings were analyzed by comparing final percent germination to osmotic pressure in PEG and NaCl. Percent weight increase and percent germination were plotted against time for the PEG and NaCl experiments with standard soy and salt tolerant soy. It was found that barley, wheat, and sorghum showed some osmotic tolerance but little ionic tolerance. Patterns across species also emerged. Seeds in lower (more negative) osmotic pressures showed a significant delay in germination, and those in the lowest potentials showed no germination. Greater and earlier water uptake was associated with higher germination success.