The duration of priming, elimination and maintenance of low temperature stress memory response to periodic chilling risk in pepper (Capsicum annuum L.)

Abstract

Pepper (Capsicum annuum L.) as often out-of-season vegetable is cultivated in greenhouse along with the large difference between night and day. To cope with repeated and frequent low temperature stress, pepper often adopt a memory response by remembering one past recurring stress, and enable survival of a harsher chilling stress that may arise later. Here, we wanted to determine how continuous and intermittent low temperature stress affect the priming and elimination of low temperature memory of pepper plants, as well as the response to subsequent stress and their capacity to remember low temperature information. The results showed that the continuous low temperature induced the priming of low temperature memory and improved cold resistance of pepper, and the storage of low temperature information in pepper plants could be maintained for at least 12 h, but not longer than 36 h. The results of rewarming for 3–5 d after 3 d of low temperature priming at 5 °C and then triggering low temperature stimulus for 1–2 d showed that rewarming for 3 d to trigger the stimulus again could still prime the low temperature memory, but the duration of low temperature memory was almost completely eliminated after rewarming for 5 d. Our study also unveiled that low temperature memory of pepper continued for 3–4 d under low temperature stress. Overall, these findings unraveled that the priming, elimination and maintenance of low temperature memory was associated with the duration of low temperature treatment and rewarming, and the low temperature memory in pepper was not enhanced with the extension of low temperature treatment, but the low temperature memory in pepper would be completely eliminated with the extension of rewarming.