碱胁迫对白柳根系生长及光合特征参数的影响  

Effects of alkali stress on root growth and photosynthetic characteristic parameters of white willow(Salix alba L.)

作　　者：王晓 冉馨 高小宽[2] 梁海永[1] 黄晓茜 刘炳响[1,3] WANG Xiao;RAN Xin;GAO Xiaokuan;LIANG Haiyong;HUANG Xiaoxi;LIU Bingxiang(College of Forestry,Hebei Agricultural University,Baoding 071000,China;College of Life Science,Hengshui University,Hengshui 053000,China;Hebei Urban Forest Health Technology Innovation Center,Baoding 071000,China)

机构地区：[1]河北农业大学林学院,河北保定071000 [2]衡水学院生命科学系,河北衡水053000 [3]河北省城市森林健康技术创新中心,河北保定071000

出　　处：《甘肃农业大学学报》2021年第6期119-126,共8页Journal of Gansu Agricultural University

基　　金：河北省野生柳树资源评价、筛选及抗寒品种选育项目(17226320D-4)。

摘　　要：【目的】探究白柳(Salix alba L.)在碱胁迫下根系及光合特性的调控机制.【方法】以树龄1 a白柳插条为试材,通过水培的方式模拟在不同pH的碱处理(mNa_(2)CO_(3)∶mNaHCO_(3)=1∶1)下,持续处理20 d后白柳根系的生长状况、光合作用及叶绿素荧光对碱胁迫的响应.【结果】随碱胁迫加剧,白柳的平均根数、平均根长和生根指数显著降低,受害症状表现明显;叶片净光合速率(P_(n))、蒸腾速率(E)、气孔导度(G_(s))总体呈逐渐下降趋势;胞间CO_(2)浓度(C_(i))呈先降后升的趋势,其中溶液pH<8.5时,叶片P_(n)下降主要受气孔因素限制,当pH>8.5时,P_(n)下降主要由非气孔因素限制,且E的下降幅度明显大于Pn;碱胁迫下白柳快速叶绿素荧光诱导动力学曲线(OJIP曲线)变为OKJIP曲线,溶液pH>8.0时,I、P点荧光值显著下降且出现明显拐点K;光系统II(PSII)反应中心量子产额和能量分配比率明显变化(φPo、Ψo和φEo受到抑制,φDo得到促进);性能指数及推动力(PI_(ABS)、PI_(CSm)和DF_(CSm))呈明显下降趋势,说明碱胁迫使PSII反应中心部分失活、供体侧与受体侧功能受到损害.【结论】白柳可通过调节P_(n)与E的下降幅度在一定程度上确保自身对蒸腾耗水的利用能力,以提高φDo等方式来应对碱胁迫,表现出一定的自我调节适应能力.【Objective】To explore the regulatory mechanism of the root system and photosynthetic characteristics of white willow in alkali stress environment.【Method】One-year white willow cuttings were used as experimental materials.Through the method of hydroponics to simulate the alkali treatment with different pH values(mNa_(2)CO_(3)∶mNaHCO_(3)=1∶1),the root growth status,photosynthesis and chlorophyll fluorescence responses to alkali stress were studied after 20 days of continuous alkali treatment.【Result】With the increase of alkali stress,the average root number,average root length and rooting index of white willow decreased significantly,and the victimization symptoms were obvious.The net photosynthetic rate(P_(n)),transpiration rate(E)and stomatal conductance(gs)of leaves overall decreased gradually.The intercellular CO_(2) concentration(C_(i))showed a trend of decreasing first and then increasing.When the solution pH<8.5,the decrease of P_(n) in leaves is mainly restricted by the stomata.When pH>8.5,the decrease of Pn is mainly limited by non-stomatal factors,and the decrease amplitude of E is significantly greater than that of P_(n).Due to the alkali stress environment,the OJIP curve of white willow turns into an OKJIP curve.When the pH value is greater than 8.0,the fluorescence values of I and P points decreased significantly and the inflection point K appeared obviously.The quantum yield and energy distribution ratio of the PSII reaction center have changed significantly(φPo,Ψo and φEo are suppressed,and φDo get promotion).The performance index and driving force(PI_(ABS),PI_(CSm) and DF_(CSm))showed a significant downward trend,indicating that alkali stress caused partial inactivation of PSII reaction center,and the functions of donor side and recipient side are damaged.【Conclusion】White willow can ensure its own ability to use transpiration water consumption to a certain extent by adjusting the decrease amplitude of P_(n) and E,and adopt methods such as increasing φDo to cope with the alk

关 键 词：白柳 碱胁迫 根系生长 光合特征 叶绿素荧光动力学 

分 类 号：S792.12[农业科学—林木遗传育种]