张海娇,
徐长山^,,
邵海玲,
乔金,
何惠敏,
郑博文
东北师范大学紫外光发射材料与技术教育部重点实验室, 长春 130024

作者简介: 张海娇(1992-),女,硕士研究生,研究方向为ZnO纳米粒子的生物效应,E-mail:1751853184@qq.com.

通讯作者: 徐长山,csxu@nenu.edu.cn ;

基金项目: 国家自然科学基金项目(No.11374046，No.11074030)


中图分类号: X171.5

Effects of Freezing Stress on the Distribution of Ca²⁺ and Na⁺ Ions in the Protoplast of Aloe vera Mesophyll Cells

Zhang Haijiao,
Xu Changshan^,,
Shao Hailing,
Qiao Jin,
He Huimin,
Zheng Bowen
Key Laboratory of UV-Emitting Materials and Technology, Ministry of Education, Northeast Normal University, Changchun 130024, China

Corresponding author: Xu Changshan,csxu@nenu.edu.cn ;

CLC number: X171.5

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摘要:低温和冻害是造成巨大农业损失和植物死亡的主要逆境因子。为揭示冷冻胁迫对植物细胞中离子分布的影响，选择芦荟细胞原生质体为受试材料，使用离子选择性微电极检测了经冷冻处理后的芦荟原生质体在低渗液中破裂时产生的Ca²⁺浓度脉冲信号，并同时检测Na⁺浓度脉冲信号作为对比。研究了冷冻温度、解冻时间和ZnO NPs处理等因素对冷冻胁迫下芦荟原生质体中Ca²⁺分布的影响。结果表明，与未经冷冻处理的原生质体相对比，经过冷冻处理的原生质体破裂后，其Ca²⁺脉冲信号前沿处发生明显的“凹陷”，这说明，原生质体中Ca²⁺分布出现分层现象，靠近细胞中心浓度较高而细胞膜附近浓度较低。这一分层现象在温度为-7 ℃时开始出现，原生质体解冻5 h后仍未消失。经过ZnO NPs预处理后再进行冷冻的原生质体，其Ca²⁺脉冲凹陷深度明显减小。而当用ZnO NPs处理解冻后的原生质体时，其Ca²⁺分层现象消失。冷冻胁迫下芦荟原生质体内Ca²⁺分布发生显著变化，表明原生质体内Ca²⁺分布变化与其抗寒反应存在一定关系。与Ca²⁺相反，Na⁺的分布几乎不受冷冻因素的影响。ZnO NPs处理对冷冻芦荟原生质体中Ca²⁺浓度分布分层有明显的缓解作用，表明一定浓度范围的ZnO NPs在缓解冷冻造成的Ca²⁺流动性下降，维持细胞Ca²⁺分布的调控能力方面，具有一定的积极影响。
关键词: 冷冻胁迫/
芦荟/
Ca²⁺分布/
离子选择性微电极/
离子浓度脉冲/
ZnO NPs

Abstract:Low temperature and frost damage are the main adverse factors that cause huge agricultural loss and plant death. To reveal the effects of freezing stress on the ion distribution in plant cells, Aloe vera mesophyll cell protoplasts were selected as test material and tested with ion-selective microelectrodes to examine the concentration pulse of Ca²⁺ produced when cryopreserved Aloe vera mesophyll cell protoplasts broke in hypotonic solution. At the same time Na⁺ concentration pulse was also recorded for comparison. The effects of freezing temperature, thawing time and ZnO NPs treatment on the distribution of Ca²⁺ in the protoplasts of Aloe vera mesophyll cell were studied. The results showed that, compared with the unfrozen protoplasts, there appeared a significant “depression” at the front edge of the Ca²⁺ pulse signal, indicating that the Ca²⁺ distribution in the protoplasts was stratified. Close to the cell center, the Ca²⁺ concentration was high and near the cell membrane, the Ca²⁺ concentration was low. This stratification emerged at -7 ℃ and did not disappear after 5 hours of thawing. For the Aloe vera mesophyll cell protoplasts treated with ZnO NPs before freezing, the depth of Ca²⁺ pulse depression was significantly reduced. And when thawed protoplasts were treated with ZnO NPs, the Ca²⁺ stratification completely disappeared. However, the distribution of Na²⁺ was not affected in all these circumstances. The changes of the distribution of Ca²⁺ in the protoplasts of Aloe vera mesophyll cell under freezing stress indicated that Ca²⁺ distribution has a certain relationship with the cold hardiness of plant cells. The treatment of ZnO NPs significantly alleviated the Ca²⁺ concentration distribution in the frozen aloe protoplasts, which showed that ZnO NPs of a certain concentration range had a positive effect on maintaining the Ca²⁺ fluidity and Ca²⁺ distribution in Aloe vera mesophyll cell.
Key words:freezing stress/
Aloe vera/
Ca²⁺ distribution/
ion selective microelectrode/
ion concentration pulse/
zinc oxide nanoparticle.