叶面喷施纳米硅提高水稻叶片镉固持量的机理  

Mechanism of increasing Cd retention in rice leaves through foliar application of nano-silicon

作　　者：师展 王科积 刘涛 黄化刚 余海英 SHI Zhan;WANG Ke-ji;LIU Tao;HUANG Hua-gang;YU Hai-ying(College of Resource,Sichuan Agricultural University,Chengdu,Sichuan 611130,China)

机构地区：[1]四川农业大学资源学院,四川成都611130

出　　处：《植物营养与肥料学报》2024年第12期2366-2379,共14页Journal of Plant Nutrition and Fertilizers

基　　金：四川省重点研发计划项目(2023YFN0023);国家现代农业水稻产业技术体系岗位科学家项目(CARS-01)。

摘　　要：【目的】叶面施硅(Si)是镉(Cd)污染农田水稻安全生产中广泛应用的一种措施,但其对Cd的阻控效果因种植环境、水稻品种的不同而存在显著差异。从叶片生理及分子响应的角度探究叶面喷施纳米Si对不同水稻品种Cd积累分配的影响,为合理施用叶面阻控剂提供科学依据。【方法】选择叶面喷施纳米Si后,水稻糙米Cd含量显著降低的雅恢2816和宜香优2115,以及糙米Cd含量无显著变化的Y两优1号为供试材料,进行盆栽试验。供试土壤添加CdCl2·2.5H2O,并加水高出土面3~4 cm陈化30天,平衡后的土壤有效Cd含量为1.07 mg/kg。供试纳米Si制剂含Na2SiO3·9H2O 2.5 mmol/L。每个品种设置施Si和不施Si两个处理,施Si处理于水稻抽穗期和灌浆期分别叶面喷施纳米Si制剂50 mL/盆。灌浆期采集倒1、2、3片叶样品,用于生理指标分析。成熟期采集茎秆、倒1~3片叶、籽粒样品,分析Cd积累量分配,叶片Cd的亚细胞分布,细胞壁Cd固持能力及相关基因的表达量。基于细胞壁等温吸附和吸附动力学试验,分析细胞壁Cd的吸附特征。【结果】3个水稻品种地上部各器官Cd的分布均表现为茎秆>籽粒>叶片,叶面喷施纳米Si对水稻地上部Cd的积累总量无显著影响,但影响Cd在水稻茎、叶及籽粒中的分配。叶面喷施纳米Si后,Y两优1号叶片Cd的分配比例降低,糙米Cd含量与对照相比无显著变化;而雅恢2816和宜香优2115叶片Cd的分配比例增加,尤其以倒二叶Cd含量和积累量的增加最为显著,为对照的1.3~2.5倍,糙米Cd含量显著降低,降幅分别为21%和32%。叶面喷施纳米Si显著增加了雅恢2816和宜香优2115倒二叶细胞壁的Cd含量及分配比例,动力学分析结果表明,细胞壁Cd的饱和吸附量分别增加13.72%和42.81%,且细胞壁羟基官能团(-OH)的相对峰面积分别提高43.99%和74.21%;但对于Y两优1号而言,叶面喷施纳米Si后上述生理特征均无显著变化。果胶是3个水稻�【Objectives】Foliar application of silicon(Si)has emerged as a widely adopted practice to ensure the safe production of rice in cadmium(Cd)-contaminated farm lands.However,its efficacy varies significantly across different planting environments and rice varieties.We investigated the underlying reasons for the variations observed among rice varieties in terms of their leaf physiology and molecular responses,which contribute to differences in their performance following foliar application of nano-silicon.【Methods】Based on previous research,a pot experiment was conducted using the rice cultivars Yahui 2816 and Yixiangyou 2115,which exhibited significant reductions in brown rice Cd content following foliar spraying of nano-Si,and Y liangyou 1,which showed no significant decrease in brown rice Cd content with foliar Si application,as the test materials.CdCl2·2.5H2O was added to the soil,and water was then poured to a depth of 3-4 cm above the soil surface.This mixture was allowed to equilibrate for 30 days,resulting in a soil with an equilibrium Cd concentration of 1.07 mg/kg.The nano-Si preparation contained 2.5 mmol/L of NaSiO3·9H2O.For each rice cultivar,two treatments were established:one with Si application and one without.In the Si treatment,nano-Si preparation was sprayed onto the rice leaves at the heading and filling stages,with each pot receiving 50 mL of the solution.During the grain filling stage of rice,samples of the first,second,and third leaves from the top were collected for physiological analysis.During the mature stage,samples of stems,the first to third leaves from the top,and seeds were collected to analyze the distribution of Cd accumulation,the subcellular distribution of Cd in leaves,the Cd retention capacity of cell walls,and the expression levels of related genes.The adsorption characteristics of Cd on cell walls were analyzed based on isothermal adsorption and adsorption kinetics experiments.【Results】The distribution ratio of Cd in various organs of the three rice cultivars was

关 键 词：稻米镉含量 纳米硅肥 叶片镉固持量 细胞壁羟基官能团 果胶合成基因OsGAUT1 果胶合成基因OsGAUT4 

分 类 号：X53[环境科学与工程—环境工程] X173[农业科学—作物学] S511