Physiological effects of cutting on Secale cereale L. seedlings under freeze–thaw and alkaline salt stress

Abstract

Secale cereale L. (rye) as an overwinter forage usually harvested in the autumn, widely grows in the northeastern China, where the temperature varies widely from day to night. In this area, the crop is confronted with not only freeze–thaw stress, but also the soil salinization. In this study, the rye seedlings under alkaline salt (AS) stress were subjected to both cutting treatment (CT) after growing for 7 days and freeze–thaw (FT) stress（10/−5°C) after 6 days regrowth. The changes of soluble protein (SP), malondialdehyde (MDA), relative water content (RWC), catalase (CAT) and superoxide dismutase (SOD) activities in seedlings were studied to analyze the physiological effects of FT and AS stress with CT. The results indicated, under the combined stress, the enzyme activity and RWC decreased and the soluble protein and MDA content increased. Cutting treatment led to the accumulated of MDA, increase of enzyme activity and decrease of RWC in seedlings. The finding from the study indicates that the CT could aggravate the membrane peroxidation under the combined stress of FT and AS and enhance the osmotic adjustment ability of rye and activated the antioxidant enzyme system. The rye having been cut is more sensitive to the compound stress.