Spray Application of Selected Substances Increases Cold Endurance of Broccoli (Brassica oleraceae var. italica) Seedlings

Abstract

The vegetable crop broccoli is rich in nutrients and its economic significance continues improving. The present research was conducted to determine effects of externally applied glucose, NaCl, the antibiotic lecilline and active oxygen on cold endurance of broccoli seedlings. The cultivar 'Tutku' was used as the plant material. In order to determine the survival rate broccoli seedlings both at cotyledon and true-leaf stages were sprayed with these substance and then exposed to temperatures of -7.5 degrees C, -10 degrees C, -12.5 degrees C and -15 degrees C. Results showed that seedlings at true-leaf stage were more resistant to freezing temperatures compared to seedlings at the cotyledon stage. Viability ratios were over LT(50) both in cotyledon and true-leaf stages at -7.5 and -10 degrees C. We determined that glucose increased LT(50) limit to -12.5 degrees C at the cotyledon stage. Also, the antibiotic lecilline and active oxygen increased LT(50) limit to -12.5 degrees C in both growth stages.