ABSTRACT

Two applications of cryogenic protocols are cryotherapy and cryopreservation for virus cleaning and germplasm storage. They are based on exposing explants to ultra-low temperature (−196°C) in liquid nitrogen. Ultra-low temperature in cryogenics implies abiotic stress, leading to the production of reactive oxygen species (ROS), which are the main reason for the low survival and death of explants. Hydrogen peroxide (H₂O₂) is an important ROS produced by stress. Enzymatic antioxidants like catalase (CAT) and peroxidase (POX) are essential for avoiding damage due to H₂O₂, which is a primary signal against stress. Salicylic acid (SA) is involved in tolerance to stress-like cryogeny. Information about the relationship between SA-cryogeny-antioxidant enzymatic activity is scarce. The objective was to evaluate the induction of cryogeny tolerance by SA associated with antioxidant activities like CAT, POX, and H₂O₂ and proline accumulation in tissue, during cryogenic protocols in two clones of potato (Solanum tuberosum L.). SA-induced cryogenic tolerance in both clones, mediated by reducing CAT enzymatic activity, higher H₂O₂ content, proline accumulation and higher water potential before cryogeny. Enhanced CAT and POX activities after cryogeny were related to decreased H₂O₂ content and higher survival. Results suggest the signalling role of H₂O₂ in the induction of tolerance to cryogenic stress.

摘要

低温协议的两个应用是用于病毒清洁和种质储存的冷冻疗法和冷冻保存。它们基于将外植体暴露在液氮中的超低温（-196°C）中。低温中的超低温意味着非生物胁迫，导致产生活性氧（ROS），这是外植体存活率低和死亡的主要原因。过氧化氢（H ₂ O ₂）是应激产生的重要活性氧。过氧化氢酶 (CAT) 和过氧化物酶 (POX) 等酶促抗氧化剂对于避免 H ₂ O _{2造成的损害至关重要}，这是对抗压力的主要信号。水杨酸 (SA) 与对压力样低温的耐受性有关。关于 SA-低温-抗氧化酶活性之间关系的信息很少。目的是评估在两个马铃薯 ( Solanum tuberosum L.)的低温方案中，SA 诱导的低温耐受性与抗氧化活性（如 CAT、POX 和 H ₂ O _{2和组织中脯氨酸积累）相关。}SA 诱导的两个克隆的低温耐受性，通过降低 CAT 酶活性、更高的 H ₂ O ₂含量、脯氨酸积累和低温前更高的水势介导。低温后 CAT 和 POX 活性增强与 H 降低有关₂ O ₂含量高，成活率高。结果表明H ₂ O ₂在诱导低温胁迫耐受中的信号传导作用。