Abstract: In order to investigate the allelopathy of Peganum multisectum(Maxim.) Bobr.on perennial ryegrass(Lolium perenne L.),the effects of aqueous extract in different concentrations from P.multisectum were studied on the seed germination,seedling growth,and physiological-biochemical manifestation of perennial ryegrass using solution and pot-soil culture methods.The results show that the aqueous extract from P.multisectum significantly inhibited the activities of α-amylase and ATPase during seed germination and the mitosis in the meristem tissue of root tips but increased IAAoxidase activity of perennial ryegrass,and decreased the seed germination rate,germination index,root length,aboveground height,and dry weight;those inhibitory effects were enhanced along with the increased concentration of aqueous extract and negatively correlative with perennial ryegrass planting densities.Watering perennial ryegrass seedlings with the aqueous extract of P.multisectum increased the contents of O₂^·-,H₂O₂,and malondialdehy-de (MDA),catelase(CAT) activities,and intercellular carbon dioxide concentration of perennial ryegrassleaves,decreased glutathion(GSH) contents,net photosynthetic rate,stomatal conductance,and transpiration rate;the activities of superoxide dismutase(SOD),peroxidase(POD) and ascorbate peroxidase(APX) and ascorbic acid(ASA) content increased initially and then decreased with the increasing of aqueous extract concentration.The kinetic data of chlorophyll fluorescence revealed that,when the aqueous extract concentration increased,the minimal fluorescence(Fo) of perennial ryegrass leaves increased,the maximum fluorescence(Fm),PSⅡ potential fluorescence efficiency(Fv/Fo),PSⅡ maximum fluorescence efficiency(Fv/Fm),the actual photochemical efficiency of PSⅡ(ΦPSⅡ),and photochemical quenching(qP) decreased,and the non-photo chemical quenching(NPQ) increased at the beginning and then decreased,which indicated the leaf photosynthetic system was injured.

Key words: Peganum multisectum(Maxim.) Bobr., Perennial ryegrass, Allelopathy, Photosynthesis, Chlorophyll fluorescence parameter

摘要： 为探讨多裂骆驼蓬(Peganum multisectum (Maxim.) Bobr.)对多年生黑麦草(Lolium perenne L.)的化感效应,采用溶液培养和盆栽土培法研究了不同浓度多裂骆驼蓬水浸液对多年生黑麦草种子萌发和幼苗生长的影响及其生理生化表现。结果表明,多裂骆驼蓬水浸液显著抑制多年生黑麦草萌发种子的α-淀粉酶和ATP酶活性及根尖细胞的有丝分裂,提高吲哚乙酸氧化酶活性,使种子萌发率和萌发指数及幼苗根长、株高和干重下降,这种抑制效应随水浸液浓度提高而增强,并与多年生黑麦草的种植密度呈负相关。在多年生黑麦草植株生长过程中浇灌多裂骆驼蓬水浸液提高了其叶片的超氧阴离子(O₂^·-)、H₂O₂和丙二醛(MDA)含量;超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性及抗坏血酸(ASA)含量随着水浸液浓度提高先升后降,过氧化氢酶(CAT)活性升高,谷胱甘肽(GSH)含量及光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)降低,胞间CO₂浓度(Ci)升高。叶绿素荧光动力学资料显示,叶片初始荧光(Fo)随多裂骆驼蓬水浸液浓度提高而增加,最大荧光(Fm)、PSⅡ潜在光化学效率(Fv/Fo)、最大光化学效率(Fv/Fm)、光合电子传递量子效率(ΦPSⅡ)和光化学狡灭系数(qP)降低,非光化学狡灭系数(NPQ)先升后降,表明叶片光合机构受到伤害。

关键词: 多裂骆驼蓬, 多年生黑麦草, 化感作用, 光合作用, 叶绿素荧光参数