植物的根从土壤中吸收水分和养分,并将其运输至地上部供植物生长发育所需.内皮层是包围根部维管系统的最内层的细胞层,其分化而产生凯氏带和木栓层2个重要的质外体屏障.其中,木栓层近年被发现其在植物水分、养分根部径向运输的意义甚至不亚于凯氏带.内皮层分化在植物响应广泛的非生物胁迫和生物胁迫的过程中也起到至关重要的作用,特别内皮层中的凯氏带和木栓层通过自身的改变来响应环境变化,以提高对环境的适应力.因此,本文综述了近年来内皮层分化可塑性的最新研究进展,重点阐述了凯氏带和木栓层与环境胁迫、矿质元素吸收,以及生物胁迫的关系,以期为内皮层的可塑性在植物生理功能调控的理论与实践中提供参考.

【Objective】This research revealed the physiological growth and Pb absorption and accumulation of Three Cherry Pepper from Tochigi,Japan.【Method】Lead were added to the culture soil with different concentrations(291,541,791,1041,1541,2041,2541,3041and 3541mg/kg)(the background was 41mg/kg),and the physiological indicators,including height and biomass of plants,activities of CAT,POD,SOD,MDA content,net photosynthetic rate(Pn),accumulation of Pb in different tissues(roots,stems,leaves and fruits)were measured.Piecewise function describing changes of plant height and dry matter along with soil Pb content was established.Soil pollution degrees were classified based on activities of CAT,POD,SOD,MDA and Pn.Direct and comprehensive correlation analysis between CAT,POD,SOD,MDA,Pnand Pb content was conducted as well.【Result】(1)The average height and individual biomass of pepper significantly decreased as the increase of Pb concentration,especially when the concentration of Pb was more than 1200mg/kg.(2)The contents of CAT,POD,SOD,MDA and Pnin seedlings increased firstly then decreased with the increase of Pb concentration.Pb had the greatest impact on POD and SOD,followed by CAT,MDA and Pn.The relevant coefficient of Pb to the five physiological indicators was0.992 with extreme significant difference(P=0.01).Cluster and discriminant analysis also revealed the differences.(3)The contents of Pb in roots,stems,leaves and fruits all increased as the increase of Pb concentration with different accumulation peaks.The transfer coefficient of Pb was highest when Pb concentration was 541mg/kg,then decreased as the increase of Pb concentration.The contents of Pb in roots increased faster than stems,leaves and fruits,indicating that roots were the major tissue for Pb absorption.【Conclusion】The physiological indicators of Three Cherry Pepper were affected by Pb concentrations.Pb enriched in roots,stems,leaves of Three Cherry Pepper,which can be used to reduce soil lead contamination.The highest Pb transfer coefficient occurred when the Pb concentration was 541mg/kg.