银纳米颗粒对黄菖蒲早期生长和生理特征的影响

N-AgNPs（银纳米颗粒）暴露对湿地植物的生长发育有重要影响，而N-AgNPs对大型湿地植物黄菖蒲（Iris pseudacorus）的影响尚不清楚.选取湿地植物黄菖蒲为受试物种，采用室内土培法分析柠檬酸钠包覆的N-AgNPs对黄菖蒲早期生长和生理特征的影响.结果表明:①不同ρ（N-AgNPs）〔分别为0、5、10、15、20 mg/L，依次记为N0（对照）、N5、N10、N15、N20〕处理和作用时间均会影响黄菖蒲生长和生物量积累.培养初期（0~14 d），N5、N10处理会抑制黄菖蒲生长，而N15、N20处理会促进黄菖蒲生长；培养后期（14~35 d），不同ρ（N-AgNPs）处理均抑制黄菖蒲生长.整个培养期内（0~35 d），N5、N10处理均抑制黄菖蒲地上、地下生物量积累，而N20处理会促进黄菖蒲地上、地下生物量积累.②不同ρ（N-AgNPs）处理均降低了黄菖蒲叶绿素含量，提高了PSⅡ（光系统Ⅱ）反应中心的光能转换效率，降低了光氧化损伤的发生率；N5、N10、N15处理下黄菖蒲叶片PSⅡ功能反应中心的开放度降低、光合电子传递速率（ETR）变慢；N5和N20处理下黄菖蒲叶片光合电子传递活性（qP）增大，而N10和N15处理下光合电子传递活性降低.③各ρ（N-AgNPs）处理均显著降低了黄菖蒲叶片中的丙二醛含量，膜脂过氧化作用减弱；同时，增加了黄菖蒲叶片中w（脯氨酸），对黄菖蒲产生较强的胁迫.研究显示，随着培养浓度的增加，ρ（N-AgNPs）对黄菖蒲生物量累积的影响由抑制作用变为促进作用；各ρ（N-AgNPs）处理均会降低黄菖蒲的叶绿素含量、增加w（脯氨酸），对黄菖蒲的生长产生胁迫. 

Effect of Silver Nanoparticle on the Early Growth and Physiological Characteristics of Iris pseudacorus

In recent years, silver nanoparticles (N-AgNPs) are increasingly used as antimicrobial additives in consumer products and may lead to their release in the environment. However, the behavior of silver nanoparticles in the environment is still unknown. Understanding the adverse impact of silver nanoparticles in plants has emerged as one of the most interesting fields of plant research. N-AgNPs significantly affect the growth of wetland plants. However, more knowledge about the effects of N-AgNPs on Iris pseudacorus is needed. Indoor cultivation was used to study the effects of N-AgNPs, which was covered by sodium citrate at boiling temperature to reduce aqueous AgNO₃, on the early growth and physiological characteristics of I. pseudacorus. The result showed that:(1) N-AgNPs (the concentration of N-AgNPs were set at 0, 5, 15, 20 mg/L, respectively, and were marked as N0, N5, N15, N20 correspondingly) inhibited the growth of I. pseudacorus in N5 and N10 groups, but accelerated the growth of I. pseudacorus in N15 and N20 groups at the beginning of the incubation. All N-AgNPs treatments restrained the growth of I. pseudacorus with the increase of cultivation time. N-AgNPs inhibited the aboveground and belowground biomass accumulation of I. pseudacorus in N5 and N10 groups, but accelerated the aboveground and belowground biomass accumulation of I. pseudacorus in N20 groups during the incubation. (2) N-AgNPs input reduced the content of the chlorophyll in I. pseudacorus's leaves. The PSⅡ reaction center of light energy conversion efficiency of PSⅡphotosynthesis reaction centers upped along with the increase of the concentration of N-AgNPs, reducing the risk of light oxidative damage. The open degree of PSⅡ photosynthesis reaction centers decreased, showing a slower photosynthetic electron transport rate in N5, N10 and N15 groups. The photosynthetic electron transport activity (qP) increased in N5 and N20 groups, but it decreased in N10 and N15 groups. (3) N-AgNPs input significantly reduced the content of MDA in I. pseudacorus's leaves, weakening the membrane lipid peroxidation. N-AgNPs input significantly increased the content of proline in I. pseudacorus's leaves, which suggested that the input of N-AgNPs could increase the stress on the growth of I. pseudacorus. The results showed that N-AgNPs inhibited the biomass accumulation of I. pseudacorus at the beginning of the incubation, but accelerated the biomass accumulation of I. pseudacorus with the increase of cultivation time. N-AgNPs input reduced the content of the chlorophyll but increased the content of proline in I. pseudacorus's leaves. It is suggested that the input of N-AgNPs could increase the stress on the growth of I. pseudacorus.