Biochemical responses of two tomato cultivars by cold treatment

Cold stress is the main cause of reduced tomato yield in subtropical regions, especially in the seedling stage. Most current studies on cold stress have focused on the response of tomato shoots to cold stress. The aim of this study was to show the biochemical responses of the roots of two tomato-cultivars (Lycopersicon esculentum Mill.) Called CaljN۳ and Peto Meck (PM) under cold treatment in greenhouse conditions in factorial completely randomized design under controlled conditions with three replications. The results showed that application of six-day cold stress increased the activity of phenylalanine ammonia lyase (PAL) and total phenol content in the roots of CaljN۳ cultivar, However, in PM cultivar, cold reduced PAL enzyme activity by ۱۸.۶% and significantly increased total phenol content by ۳۳۷%. With the application of cold stress in both cultivars, the activity of polyphenol oxidase (PPO) was significantly increased, which was significantly higher (۲۶۰.۶%) in CaljN۳ cultivar. Thus, despite the increase in PAL enzyme in CaljN۳ cultivar, due to a significant increase in PPO enzyme, we saw a decrease in roots phenolic pool under cold stress, while, in PM cultivar, due to a ۱۶۵% increase in PAL enzyme in leaves, we saw a significant increase in the accumulation of soluble phenolic compounds in the root, which may act as an adaptation mechanism to overcome oxidative stress due to low temperature in this cultivar

کلیدواژه ها:

Polyphenol oxidase ، Phenylalanine ammonia lyase ، Total phenol ، Adaptation