UV-B辐射增强对麻花艽叶片光合作用及相关生理参数的影响

采用20 W和40 W的UV-B灯辐射增强处理,测定分析了UV-B辐射增强对麻花艽(Gentiana straminea Maxim)叶片净光合速率及相关生理参数的影响. 结果显示:2008年8月3日,研究区大气温度从09:00开始上升,到14:00达到最高点,叶温和大气饱和水气压变化与气温变化趋势相似;光合有效辐射强度从07:00开始上升,至13:00达到最高,之后下降;麻花艽叶片净光合作用速率(P_n)、气孔导度(G_s)、胞间CO₂浓度(C_i)、蒸腾速率(E)和水分利用效率在对照下最高,在40 W UV-B辐射下最低;P_n在08:00—10:00最高,G_s在07:00—08:00最高,C_i在日出及日落时最高,E在09:00—13:00及14:00—18:00最高,水分利用效率在日出后最高;P_n与G_s,叶片温度,大气温度,光合有效辐射和大气饱和水气压亏缺呈正相关,与C_i呈负相关,与光合有效辐射强度的相关系数较高. P_n在光合有效辐射强度为0～800 μmol/(m2·s)时随光合有效辐射强度增加而增加,在2 200～3 000 μmol/(m2·s)时变化不大;G_s和E随光合有效辐射强度的增加而增加;C_i在光合有效辐射强度为0～800 μmol/(m2·s)时,随光合有效辐射强度的增加而呈下降趋势;水分利用效率在光合有效辐射强度为0～800 μmol/(m2·s)时随光合有效辐射强度的增加而呈增加的趋势,在800～3 000 μmol/(m2·s)时呈下降趋势. 说明UV-B辐射增强将使高寒草甸植物叶片P_n,G_s,C_i,E和水分利用效率降低.      

Synthesis of Li-doped bismuth oxide nanoplates,Co nanoparticles modification,and good photocatalytic activity toward organic pollutants

Abstract

Lithium-doped bismuth oxide nanoplates with the thickness of 50–150?nm and tetragonal bismuth oxide, monoclinic lithium bismuthate phases have been synthesized via a simple hydrothermal process using lithium acetate and sodium bismuthate as the raw materials. Cobalt nanoparticles modified lithium-doped bismuth oxide nanoplates hybrids were obtained by an in situ photo-deposition route. The cobalt nanoparticles-modified nanoplates hybrids display significantly enhanced photocatalytic activity toward gentian violet compared with the nanoplates. Gentian violet solution can be totally degraded by the hybrids within 60?min under ultraviolet–visible light irradiation. The superior photocatalytic activity of the cobalt nanoparticles modified nanoplates hybrids originates from the superior charge transfer capacity and the energy band structure of the hybrids. The excellent photocatalytic performance makes the cobalt nanoparticles modified nanoplates hybrids a promising candidate as the photocatalyst for wastewater treatment.