Page 91 - 《广西植物》2026年第7期
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7 期 于淼等: 根区亚低温下外源 GABA 对山定子幼苗根系线粒体功能的影响 1 1 8 7
∗
YU Miaoꎬ WANG Aiguoꎬ ZHAO Yiluꎬ MA Huaiyu
( Horticulture College of Shenyang Agricultural Universityꎬ Shenyang 110866 )
Abstract: During the early growth season in cold fruit ̄producing regions of northern Chinaꎬ low temperatures in the
root ̄zone restrict the recovery of root function and the growth and development of above ̄ground tissues. In response to
the climatic characteristics of early spring in Northeast China’s cold ̄temperate fruit production areas — namelyꎬ rapid
temperature recovery with large fluctuations and relatively delayed soil warmingꎬ this study aimed to explore the
regulatory mechanism of exogenous γ ̄aminobutyric acid (GABA) on mitochondrial function in root ̄zone of one ̄year
M. baccata under sublow ̄temperatureꎬ using M. baccata seedlings as experimental materialꎬ and the seedlings were
 ̄1
subjected to a root ̄zone sublow ̄temperature treatment at 5 ℃ and applied exogenous GABA (10 mmolL ) or its
 ̄1
metabolic inhibitorꎬ vigabatrin ( VGBꎬ 0. 1 mmol L )ꎬ respectively. Mitochondrial membrane permeabilityꎬ
cytochrome c/ a valueꎬ respiratory metabolic pathwaysꎬ energy substance contentsꎬ and antioxidant enzyme activities in
roots were measured at 0ꎬ 2ꎬ 4ꎬ 6ꎬ 12 and 24 h after treatments. The results were as follows: (1) Compared with the
controlꎬ 5 ℃ sublow ̄temperature significantly increased mitochondrial membrane permeabilityꎬ decreased the
cytochrome c/ a valueꎬ and enhanced total respiration rateꎬ activities of the cytochrome pathway (CP) and alternative
pathway (AP)ꎬ and induced upregulation of the alternative oxidase gene ( AOX) expression. (2) Compared with
sublow ̄temperature treatment aloneꎬ exogenous GABA treatment significantly improved mitochondrial membrane
stability and c/ a valueꎬ promoted CP respiration and its contribution rateꎬ inhibited AP respiration and AOX gene
expressionꎬ while maintaining higher adenosine triphosphate ( ATP) content and energy charge level and reducing
adenosine monophosphate ( AMP) accumulation. (3) Exogenous GABA treatment also increased the activities of
superoxide dismutase (SOD)ꎬ peroxidase (POD)ꎬ catalase (CAT) and ascorbate peroxidase (APX)ꎬ decreased
malondialdehyde (MDA) contentꎬ and enhanced root vigor. (4) VGB treatment aggravated mitochondrial membrane
damage and energy metabolic disorderꎬ and inhibited antioxidant enzyme activities. In conclusionꎬ exogenous GABA
effectively alleviates root ̄zone sublow ̄temperature stress injury in M. baccata roots by protecting mitochondrial
membrane integrityꎬ optimizing respiratory pathway allocationꎬ maintaining cellular energy homeostasis and enhancing
antioxidant capacityꎬ and this effect depends on an intact GABA metabolic pathway. These findings provide a
theoretical basis for improving cold tolerance of M. baccata roots and are of great significance for breeding cold ̄
resistant apple rootstocks.
Key words: root ̄zone sublow ̄temperatureꎬ Malus baccata seedlingꎬ γ ̄aminobutyric acid ( GABA)ꎬ mitochondrial
functionꎬ respiratory metabolismꎬ energy metabolismꎬ antioxidant enzyme
山 定 子 ( Malus baccata ) 是 一 种 蔷 薇 科 株生长受阻ꎮ 因此ꎬ如何提高山定子根系对根区
(Rosaceae)苹果属( Malus Mill.) 的植物ꎬ以其发达 亚低温的适应能力ꎬ是保障苹果产业可持续发展
的根系和极强的耐寒性而著称ꎬ是我国东北冷凉 的关键之一ꎮ 关于山定子的耐寒性ꎬ前人已从生
苹果产区广泛应用的抗寒砧木ꎮ 山定子作为苹果 理生化及分子层面开展了研究ꎮ 如山定子在低温
嫁接砧木ꎬ不仅能增强接穗品种的抗逆性ꎬ而且还 胁迫下能通过积累可溶性糖、脯氨酸等渗透调节
能调控树体生长势ꎬ影响果实品质和产量ꎬ在苹果 物质ꎬ增强细胞膜的稳定性ꎬ同时激活抗氧化酶系
生产中具有不可替代的重要地位ꎮ 然而ꎬ东北地 统以 清 除 过 量 活 性 氧 ( reactive oxygen speciesꎬ
区早春的气候特征表现为气温回升迅速且波动剧 ROS)ꎬ减轻氧化损伤( Gharechahi et al.ꎬ 2014ꎻ李
烈ꎬ而土壤温度的上升则相对缓慢ꎬ这种根区温度 金涛等ꎬ2025)ꎮ 近年来ꎬ随着研究的深入ꎬ线粒体
与气温的非同步变化导致根系长期处于 5 ℃ 左右 作为细胞能量代谢和逆境响应的中心ꎬ其在山定
的亚低温环境ꎬ造成根系吸收功能下降、代谢紊 子抗寒中的作用日益受到关注ꎮ 线粒体作为呼吸
乱ꎬ进而影响地上部萌芽抽梢ꎬ严重时导致整个植 作用的主要场所(陈楠楠和薛一涛ꎬ2022)ꎬ为细胞

