Physiochemical Responses and Ecological Adaptations of Peach to Low-Temperature Stress: Assessing the Cold Resistance of Local Peach Varieties from Gansu, China

Abstract

In recent years, extreme weather events have become increasingly frequent, and low winter temperatures have had a significant impact on peach cultivation. The selection of cold-resistant peach varieties is an effective solution to mitigate freezing damage. To comprehensively and accurately evaluate the cold resistance of peaches and screen for high cold resistance among Gansu local resources, nine different types of peach were selected as test resources to assess physiological, biochemical, and anatomical indices. Subsequently, 28 peach germplasms were evaluated using relevant indices. The semi-lethal temperature (LT50) was calculated by fitting the change curve of the electrolyte leakage index (ELI) with the Logistic equation; this can be used as an important index for identifying and evaluating the cold resistance of peach trees. The LT50 values ranged from −28.22 °C to −17.22 °C among the 28 tested resources; Dingjiaba Liguang Tao exhibited the lowest LT50 value at −28.22 °C, indicating its high level of cold resistance. The LT50 was positively correlated with the ELI and malondialdehyde (MDA) content with correlation coefficients of 0.894 and 0.863, respectively, while it was negatively correlated with the soluble sugar (SS), soluble protein (SP), and free proline (Pro) contents with correlation coefficients of −0.894, −0.721, and −0.863, respectively. The thicknesses of the xylem, cork layer, cork layer ratio (CLR) and thickness/cortex thickness (X/C) showed negative correlations (−0.694, −0.741, −0.822, −0.814, respectively). Finally, the membership function method was used to evaluate cold resistance based on the ELI, MDA, Pro, SP, SS, CLR, and xylem thickness/cortex thickness (X/C) indices. The average membership degree among all tested resources ranged from 0.17 to 0.61. Dingjiaba Liguang Tao emerged prominently in terms of high-cold-resistance (HR) membership value (0.61).

Exogenous Spermidine Alleviated Low-Temperature Damage by Affecting Polyamine Metabolism and Antioxidant Levels in Apples

“…Soluble sugars, soluble proteins, and proline can regulate cell osmotic potential, maintain turgor, protect the normal functions of various enzymes and cell membrane structures in plant tissues, and reduce the damage caused by stress [ 37 ]. Niu et al found that the content of osmotic adjustment substances was positively correlated with cold resistance in peaches [ 38 ], which is similar to the results of this study. With a decrease in temperature, the content of soluble sugar and proline increased slowly, and the soluble protein peaked at −20 °C.…”

Physio-Biochemical Insights into the Cold Resistance Variations among Nectarine (Prunus persica (L.) Batsch var. nectarina) Cultivars

“…In March 2023, sampled shoots were divided into six groups, and separately placed in a high and low temperature alternating test chamber (Guangzhou Xingtuo [11,12], respectively. After treatment for 24 h, shoots were picked out, kept at room temperature for 2 h, and then the middle parts of shoots (excluding flower and leaf buds) were subjected to the determination of electric conductivity.…”

“…Moreover, cold stress can impair cell membrane permeability, disturb ionic and phytohormone homeostasis, and induce electrolyte leakage (EL) [10]. Therefore, the activities of antioxidant enzymes (such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)) [11], accumulations of osmoregulatory substances (including proline (PRO), soluble sugar (SS), soluble protein (SP) and so on), contents of the marker of cell membrane damage malondialdehyde (MDA)) [12] and endogenous phytohormones (such as gibberellin acid (GA 3 ), indoleacetic acid (IAA) and abscisic acid (ABA)) [13,14] and EL are often used as important indexes for plant cold resistance evaluations [15][16][17].…”