Nitric Oxide Alleviates Copper Toxicity in Germinating Seed and Seedling Growth of Lactuca sativa L.

Abstract

Copper has many metabolic functions in the plants. However, it can be toxic to plants where it reaches the excess level. The aim of the present study was to evaluate the role of nitric oxide treatments on lettuce seed germination under copper stress. Thus a factorial laboratory experiment with a completely randomized design was carried out at the Ataturk University. Treatments include different doses of copper (0, 50, 100, 150 and 200 µM of copper sulfate)and nitric oxide (0, 50, 100, 150, 200 and 300 µM of sodium nitroprusside). The results of this study monitored that high concentration of copper (100, 200 and 300 µM) had a significant effect on the germination percentage, germination rate, mean period of ultimate germination, seed vigor index, seedling fresh weight and  allometry coefficient, although the nitric oxide treatment (without copper) had not a significant effect on the seeds in comparing to the untreated ones. Copper treatment decreased the investigated parameters, but the simultaneous application of nitric oxide and copper had a positive impact. The results of this study suggested that nitric oxide treatments have been beneficial upon the seeds that treated with copper, but not upon the seeds that treated with water. In addition, the lower concentration of copper (50 µM) had a positive effect on the seed vigor index.