雜交杏李種質的抗寒性鑒定及生理機制解析

中圖分類號：S662.3 文獻標志碼：A 文章編號：1009-9980（2025）07-1397-1

Abstract：【Objective】ThePrunussalicina ×P. armeniaca hybridisanovel interspecifichybrid derived from the crossbetween plum（ P. salicina） and apricot（ P. armeniaca），renowned forits exceptional fruit quality and economic value. P. salicina ×P. armeniacahybridtreesarewidelyplantedin Xinjiang， where they are known as the climatically marginal zone for economic cultivation due to its harsh cold winters characterized by prolonged subzero temperatures. In recent years，recurrent freezing injurieshave severely constrained the sustainable development of P. salicina ×P. armeniaca hybrid plantations，positioning low-temperature stress as a critical abiotic factor limiting its cultivation.However， systematic investigations into cold tolerance evaluation and physiological response mechanisms of this nybrid Iruit crop remain scarce. inIs stuay aimea to evaiuate ine coia toierance capacity o1 P. saucina × P. armeniaca hybrid germplasms and elucidate the physiological mechanisms underlying genotype-specific responses to low-temperature stress， thereby facilitating the breeding of cold-resistant varieties. 【Methods】 Ten P. salicina ×P. armeniaca hybrid genotypes comprising six commercial cultivars and four elite lines selected through our previous efforts were used for this study.In the winter of 2023， their annual dormant branches were colected and were subjected to controlled low-temperature treatments a t-10，-15，-20，-25 and -30^°C for 12h ，respectively. The relative electrical conductivity （REC） at different temperatures was measured immediately，and the half-lethal temperature （ LT₅₀ was calculated by combining the logistic equation to identify their cold tolerance.Furthermore，comparative physiological analysis was conducted on two strong cold-tolerant genotypes （Weiwang and XL9） and two cold-sensitive cultivars （Konglongdan and Weidi）. The malondialdehyde （MDA） content was measured using thiobarbituric acid method. The determination of soluble sugar （SS） content was carried out using the anthrone method.The proline （Pro） content was determined using the indene ketone colorimetric method. In addition， the superoxide anion （O₂^-）? ） content，hydrogen peroxide （H₂O₂） ）content， superoxide dismutase （SOD） activity， and peroxidase （POD） activity were determined using commercial reagent kits purchased from Suzhou Mengxi Biomedical Technology Co.，Ltd.Finally， their cold tolerance was comprehensively evaluated through membership function analysis.【Results】With the decreasing of cold treatment temperature， the relative conductivity of the annual dormant branches of 10 P. salicina ×P. armeniaca hybrid genotypes gradually increased， with LT₅₀ values ranging from - to ，and the fit of the logistic equation for each genotype was R² between 0.822 and 0.996.Based on these data， their cold tolerance is divided into three levels： strong cold tolerance （ LT₅₀lt; -30^°C ， including Weiwang and XL9）， moderate cold tolerance （-30^°C50lt;-25^°C ， including Fengweihuanghou， Fengweimeigui and XL8），and low temperature sensitivity （LT₅₀gt;-25^°C ， including Weihou，Weidi， Konglongdan， XL7and XL10）. Two strong cold-tolerant genotypes （Weiwang and XL9） and low-temperature sensitive genotypes （Konglongdan and Weidi） were selected to comparatively analyze the physiological response mechanism to low-temperature stress. Physiological responses diverged significantly between cold-tolerant and sensitive genotypes. In Weiwang and XL9，antioxidant enzymes （SOD and POD） and osmolytes （SS and Pro） displayed coordinated regulation，peaking at intermediate temperatures （ -20^°C to -25^°C ）before declining， suggesting adaptive stress mitigation. Conversely， sensitive genotypes exhibited progressive oxidative damage， evidenced by linearly increasing O₂^- ， H₂O₂ ，and MDA levels （up to 195.4% increase in H₂O₂ at -30^°C ）， coupled with declining SS （ 44.2% reduction） and Pro contents，which indicated the oxidative damage they suffered increased gradually and the cell osmotic balance was disrupted. Additionally， SOD and POD activity of Konglongdan and Weidi fluctuated significantly.Membership function analysis confirmed the cold tolerance hierarchy： XL9gt; Weiwang gt; Konglongdan gt; Weidi，aligning with LT₅₀ rankings.【Conclusion】 LT₅₀ serves asa reliable indicator for cold tolerance evaluation in P. salicina ×P. armeniaca hybrids. The superior cold tolerance of Weiwang and XL9 primarily stems from enhanced antioxidant capacity and osmotic adjustment in dormant branches. These findings provide valuable germplasm resources for cold-tolerant breeding programs and offer theoretical guidance for the introduction and cultivation of P. salicina ×P. armeniaca hybrids in cold-prone regions.

Key words： Prunus salicina ×P. armeniaca hybrid; Low temperature stress; Cold tolerance; Physiological response;Membership function analysis;Comprehensive evaluation

雜交杏李（Prunussalicina ×P. armeniaca）是通過李和杏種間雜交而選育的新型果樹，果實外觀（如果實大小）和品質（如含糖量）顯著優于傳統杏、李品種，被譽為\"21世紀水果新驕子\"。目前，我國主栽的雜交杏季品種，如味帝、恐龍蛋等，均為從國外引進品種，栽培面積約2萬 hm² ，其中近一半分布在新疆地區。新疆地處我國西北，屬于氣候偏冷的經濟林栽培邊緣地區，冬季極端低溫持續時間長，凍害頻繁]。近年來，新疆氣溫屢創新低，雜交杏李遭受大面積凍害，造成了嚴重的經濟損失。低溫已成為制約雜交杏李生長發育最主要的環境因素之一。因此，鑒定現有雜交杏李品種（系）的抗寒性，篩選抗寒種質，對培育具有自主知識產權的抗寒杏李優良品種具有重要意義。

抗寒親本的選擇是培育抗寒優良品種的關鍵。植物在低溫脅迫下，細胞膜是受損的原初部位，相對電導率（REC）能夠準確反映細胞膜的受損程度[4-5]。目前，通過測定REC并擬合Logistic方程計算半致死溫度 以評價果樹抗寒性的方法已廣泛應用于葡萄、鮮食棗、百香果以及扁桃等經濟林果的研究中。此外，脯氨酸（Pro）、可溶性糖（SS）等滲透調節物質含量，及超氧化物歧化酶（SOD）、過氧化物酶（POD）等抗氧化酶活性，也在一定程度上反映了植株的抗寒水平[10-12]。然而，植物的抗寒能力受多因素調控，單一指標評價存在局限性。隸屬函數法通過綜合多項指標進行評價，結果更為可靠[13-15]。王季姣等同時結合 LT₅₀ 和隸屬函數法對75份釀酒葡萄進行抗寒性評價，成功篩選出抗寒能力最強的種質。……