Low-temperature stress has a significant effect on plant physiology, inducing growth hindrance and reducing yields. This study aimed to explore the effect of low-temperature stress [control (20/15 °C), 15/12 °C (LT1) and 10/8 °C (LT2) during day/night] on plant growth, enzyme activities, proline and H₂O₂ content, DNA methylation, and genome template stability (GTS) as well as chlorophyll content in pepper cultivars (AK, KD, YC, and TK). Based on the results, low-temperature stress significantly decreased the plant dry biomass, CAT activity, and chlorophyll content in pepper cultivars but had a slight impact on AK cultivar. The highest proline content (46%) was detected in the AK cultivar under LT1 compared to the control, but its lowest content (18.9%) was observed in the TK cultivar. Furthermore, the lowest and the highest hydrogen peroxide content under LT1 were found in the AK and TK cultivars (8.5% and 13.0%, respectively) compared to the control. Based on the results, low-temperature stress decreased GTS in all cultivars, but the highest GTS rate was observed in the AK cultivar, and this was paralleled by having the highest plant dry biomass, enzyme activity, and proline content compared to the other cultivars. Low-temperature stress increased the DNA full methylation ratio in all pepper cultivars, whereas the AK cultivar was less affected compared to the other cultivars. These results suggest that pepper cultivars' responses differ under low-temperature stress, and the AK cultivar showed greater tolerance to low-temperature stress compared to the other cultivars by having the highest GTS, POD, and CAT activities, as well as chlorophyll and proline content. Furthermore, proline was more effective compared to antioxidant enzyme activities in countering the harmful effects of cold stress in pepper.

低温胁迫对植物生理有显着影响，会导致生长障碍和减产。本研究旨在探讨低温胁迫[控制（20/15°C）、15/12°C（LT1）和10/8°C（LT2）白天/夜间]对植物生长、酶活性的影响, 脯氨酸和 H ₂ O ₂辣椒品种（AK、KD、YC 和 TK）中的含量、DNA 甲基化和基因组模板稳定性 (GTS) 以及叶绿素含量。结果表明，低温胁迫显着降低了辣椒品种的植物干生物量、CAT活性和叶绿素含量，但对AK品种的影响较小。与对照相比，在 LT1 下的 AK 品种中检测到最高的脯氨酸含量 (46%)，但在 TK 品种中观察到最低含量 (18.9%)。此外，与对照相比，在 AK 和 TK 栽培品种中发现了 LT1 下最低和最高的过氧化氢含量（分别为 8.5% 和 13.0%）。根据结果​​，低温胁迫降低了所有品种的 GTS，但在 AK 品种中观察到的 GTS 率最高，同时具有最高的植物干生物量，酶活性和脯氨酸含量与其他品种相比。低温胁迫增加了所有辣椒品种的 DNA 全甲基化率，而与其他品种相比，AK 品种受到的影响较小。这些结果表明，辣椒品种在低温胁迫下的反应不同，与其他品种相比，AK 品种对低温胁迫的耐受性更高，GTS、POD 和 CAT 活性最高，以及叶绿素和脯氨酸内容。此外，与抗氧化酶活性相比，脯氨酸在对抗辣椒冷应激的有害影响方面更有效。而与其他品种相比，AK 品种受到的影响较小。这些结果表明，辣椒品种在低温胁迫下的反应不同，与其他品种相比，AK 品种对低温胁迫的耐受性更高，GTS、POD 和 CAT 活性最高，以及叶绿素和脯氨酸内容。此外，与抗氧化酶活性相比，脯氨酸在对抗辣椒冷应激的有害影响方面更有效。而与其他品种相比，AK 品种受到的影响较小。这些结果表明，辣椒品种在低温胁迫下的反应不同，与其他品种相比，AK 品种对低温胁迫的耐受性更高，GTS、POD 和 CAT 活性最高，以及叶绿素和脯氨酸内容。此外，与抗氧化酶活性相比，脯氨酸在对抗辣椒冷应激的有害影响方面更有效。