Genotypic changes in protein synthesis in tomato during low and high temperatures and the alleviation of chilling and heat injury by calcium.

摘要

An experiment was conducted on tomato cultivars Strain-B, Media-A, Peto-86, Roma VF, Ace 55, Pearson Improve and Super marmande to study the differences in callus dry weight, seed germination, protein pattern and isoenzymes in response to low (10℃)and high (40℃) temperature. In a related experiment, the involvement of calcium (5.0 mM) in avoidance of stress injury was also studied. All the cultivars were affected by cold treatment and revealed averages of 49.57 and 28.7% of the control in callusdry weight and germination, respectively. Under low temperature, callus dry weight and seed germination of Super marmande were less affected (64.4 and 42.1% of the control, respectively). Strain-B was the highest sensitive variety (39.6 and 20.7% of thecontrol, respectively). Calcium significantly increased the performance of the cultivars under both 25 and 10℃. On average over the genotypes under cold treatment, calcium increased the dry weight of callus and percentage of germination by 7.59 and 9.4%, respectively. Heat stress significantly reduced callus dry weight and percentage of seed germination. Strain-B revealed the highest performance in callus dry weight and seed germination under high temperature. Low temperature induced the synthesis of10 new protein bands ranging from 71.32 to 16.64 Kd. Protein bands at molecular weight 35.95 Kd was induced only in the cold-tolerant cultivars. Isoenzyme analysis revealed the induction of one malate dehydrogenase band and the reduction of one esteraseband due to cold treatment. Heat stress suppressed one peroxidase band, one malate dehydrogenase band and 2 esterase bands.