ZnO-NPs+SiO2-NPs提高洋桔梗幼苗抗温度胁迫能力的研究

Enhancement of temperature stress resistance in Eustoma grandiflorum seedlings by ZnO-NPs and SiO2-NPs

关键词:  氧化锌纳米粒子(ZnO-NPs), 二氧化硅纳米粒子(SiO₂-NPs), 洋桔梗幼苗, 抗氧化酶活性, 基因表达

Key words:  zinc oxide nanoparticles(ZnO-NPs), silicon dioxide nanoparticles(SiO₂-NPs), Eustoma grandiflorum seedlings, antioxidant enzyme activity, gene expression

摘要:

温度是影响花卉生长发育的重要因子。氧化锌纳米粒子(ZnO-NPs)和二氧化硅纳米粒子(SiO₂-NPs)在增强植物抗逆性方面展现出潜力。为明确ZnO-NPs+SiO₂-NPs预处理对洋桔梗在温度胁迫下的调控机制,该研究以洋桔梗幼苗为材料,首先采用正交试验设计 [L₉(3⁴)],通过ZnO-NPs和SiO₂-NPs在不同浓度、配比及喷施次数下对洋桔梗幼苗生长的影响,筛选最优喷洒方案,然后预处理幼苗,并分别进行 42 ℃(24 h)高温和 4 ℃(24 h)低温胁迫,测定生理指标及相关抗逆基因表达。结果表明:(1)当纳米粒子总浓度为0.03%(m/V),ZnO-NPs:SiO₂-NPs 配比为1:2(V/V),叶面喷施 2 次时,幼苗生长最佳。(2)ZnO-NPs+SiO₂-NPs预处理提高了正常生长条件下叶片叶绿素含量; 降低了42 ℃和4 ℃胁迫下的相对电导率、丙二醛(MDA)含量和过氧化氢(H₂O₂)含量; 提高了超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性。(3)ZnO-NPs+SiO₂-NPs预处理上调了 Mn-SOD、Cu/Zn-SOD、Fe-SOD、CAT 和 POD 基因的表达水平。(4)42 ℃胁迫下,ZnO-NPs+SiO₂-NPs预处理促进了热休克蛋白90基因(HSP90)的表达和4 ℃胁迫下冷调节基因(COR413)的表达。综上认为,适宜的ZnO-NPs+SiO₂-NPs预处理通过促进抗氧化酶活性的升高及相关抗逆基因的表达来增强洋桔梗幼苗对温度胁迫的抗性。该研究揭示了ZnO-NPs+SiO₂-NPs预处理增强洋桔梗抗温度胁迫的分子机制,并为纳米材料在花卉抗逆研究中提供了理论依据。

Abstract:

Temperature is a crucial environmental factor affecting the growth and development of flowers. Zinc oxide nanoparticles(ZnO-NPs)and silicon dioxide nanoparticles(SiO₂-NPs)have demonstrated significant potential in enhancing plant stress resistance. To elucidate the regulatory mechanism of ZnO-NPs+SiO₂-NPs pretreatment on Eustoma grandiflorum under temperature stress, this study employed E. grandiflorum seedlings as materials and adopted an orthogonal experimental design [L₉(3⁴)]. Initially, the effects of ZnO-NPs+SiO₂-NPs on the growth of E. grandiflorum seedlings under different concentrations, proportions, and spraying times were investigated to screen the optimal spraying scheme. Subsequently, the seedlings were pretreated and subjected to high temperature(42 ℃ for 24 h)and low temperature(4 ℃ for 24 h)stress treatments, respectively. Physiological indicators and related stress-resistant gene expression were measured. The results were as follows:(1)When the total concentration of nanoparticles was 0.03%(m/V), the proportion of ZnO-NPs to SiO₂-NPs was 1:2(V/V), and the seedlings were sprayed twice on the leaves, the seedling growth was optimal.(2)The ZnO-NPs + SiO₂-NPs pretreatment increased the chlorophyll content of the leaves under normal growth condition, reduced relative electrical conductivity, malondialdehyde(MDA)content, and hydrogen peroxide(H₂O₂)accumulation under 42 ℃ and 4 ℃ stresses; enhanced the activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD).(3)ZnO-NPs+SiO₂-NPs pretreatment upregulated the expression levels of Mn-SOD, Cu/Zn-SOD, Fe-SOD, CAT, and POD genes.(4)Under 42 ℃ stress, ZnO-NPs+SiO₂-NPs pretreatment promoted the expression of heat shock protein 90 gene(HSP90); under 4 ℃ stress, it upregulated the expression of cold-regulated gene(COR413). In summary, suitable ZnO-NPs+SiO₂-NPs pretreatment effectively improves the growth status of E. grandiflorum seedlings and enhances their resistance to temperature stress by promoting increases in antioxidant enzyme activities and the expressions of related stress-resistant genes. This study reveals the molecular mechanism by which ZnO-NPs+SiO₂-NPs pretreatment enhances the resistance of E. grandiflorum to temperature stress, and provides a theoretical basis for the application of nanomaterials in flower stress-resistant research.