Iron toxicity resistance strategies in tropical grasses:The role of apoplastic radicular barriers

作     者：Advanio Inacio Siqueira-Silva Camilla Oliveira Rios Eduardo Gusmao Pereira 

作者机构：Institute of Biological and Health SciencesFederal University of Vicosa (UFV)Campus Florestal Minas Gerais Brazil Federal University of Western Para (UFOPA)University Campus of JurutiPara Brazil Postgradute Program in Management and Conservation of Natural and Agrarian EcosystemsUFV Campus Florestal Florestal Minas Gerais Brazil 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2019年第31卷第4期

页      面：257-266页

核心收录：

学科分类：07[理学] 09[农学] 0903[农学-农业资源与环境] 0713[理学-生态学] 

基　　金：supported by Vale S.A. (No. ACA 5500023606/ 5900022781) the National Council for Scientific and Technological Development - CNPq (No. 311532/2017-9) the Minas Gerais Research Foundation - FAPEMIG 

主　　题：Paspalum densum Echinochloa crus-galli Apoplastic barrier Iron toxicity 

摘      要：The revegetation of mined areas poses a great challenge to the iron ore mining *** initial recovery process in degraded areas might rely on the use of Fe-resistant *** grasses, such as Paspalum densum and Echinochloa crus-galli, show different resistance strategies to iron toxicity; however, these mechanisms are poorly *** Fe-resistance mechanisms and direct iron toxicity as a function of root apex removal were investigated. To achieve this purpose, both grass species were grown for up to 480 hr in a nutrient solution containing 0.019 or 7 mmol/L Fe-EDTA after the root apices had been removed or maintained. Cultivation in the presence of excess iron-induced leaf bronzing and the formation of iron plaque on the root surfaces of both grass species, but was more significant on those plants whose root apex had been removed. Iron accumulation was higher in the roots, but reached phytotoxic levels in the aerial parts as well. It did not hinder the biosynthesis of chloroplastidic pigments. No significant changes in gas exchange and chlorophyll a fluorescence occurred in either grass when their roots were kept intact; the contrary was true for plants with excised root apices. In both studied grasses, the root apoplastic barriers had an important function in the restriction of iron translocation from the root to the aerial plant parts, especially in E. crus-galli. Root apex removal negatively influenced the iron toxicity resistance mechanisms(tolerance in P. densum and avoidance in E. crus-galli).