Evaluation of Chenopodium botrys Resistance to Salinity Stress during Early Growth Stage

چکیده مقاله

Salinity is a major abiotic stress that affected nearly 20% of the world’s cultivated lands. Germination is a critical phase during plant growth, because seedling establishment affects the plant vigor during other growth phases and so plant density. Choosing plants that have more resistant to salinity (such as Chenopodiaceae) is an appropriate strategy for crop production in areas affected by salt stress. Chenopodium botrys (synonyms: Botrydium botrys, Dysphania botrys and Teloxys botrys) is a strongly aromatic annual plant in Chenopodi aceae with an incense like fragrance. To the best of our knowledge, so far the response of this plant to salinity stress has not been evaluated during germination stage. Therefore, we monitored the effects of different levels of salinity stress (0, 50, 100, 150, 200, 250, 300 and 350 mMol induced by NaCl) on germination indices of Chenopodium botrys. Seeds were germinated at room temperature (~ 25 oC), in 9 cm diameter Petri-dishes with one Whatman No. 1 filter paper moistened with 5 ml of distilled water or the appropriate solutions. Germinated seeds (radicle length ~2 mm) were counted daily for 10 days and finally the germination percentage and seedling length were determined. Then seedlings were dried in oven at 75ºC for 48 hours to determine their dry weight. The germination percentage ascertained for 0, 50, 100, 150, 200, 250, 300 and 350 mM of NaCl was 100, 76, 65, 52, 25, 14, 0 and 0%, respectively. The seedling length varied from 4.90 to 4.01, 2.20, 1.52, 0.35, 0, 0.51 and 0 cm for 0, 50, 100, 150, 200, 250, 300 and 350 mM of NaCl respectively. Similarly, seedling dry weight was significantly reduced when salt severity increased above 150 mM. Overall, results revealed that Chenopodium botrys has a considerable tolerance to salinity up to 150 mM salt concentration during early growth stage. Salinity affects seeds germination and seedling growth either by creating an osmotic potential external to the seed preventing water uptake, or through the toxicity of Na+ and Cl− ions for germinating seed. Reduction of storage substrates decomposition and disturbance in synthesis of storage proteins are two other main deterrent impacts of salinity on seed germination.