6种绿化灌木叶片PS Ⅱ的耐盐性研究及综合评价

Salt tolerance of PS Ⅱ in leaves of six kinds of evergreen shrubs and comprehensive evaluation

为了改变盐碱地植被种类单一的现状,筛选出更加耐盐的城市绿化树种,以黑龙江常用的紫丁香、白丁香、暴马丁香、连翘、茶条槭和金银忍冬这6种绿化树种为试验材料,利用快相叶绿素荧光技术,观测了其叶片光系统Ⅱ(PSⅡ)对盐胁迫的快速响应特性,并对其叶片PSⅡ的耐盐性进行了评价。结果表明:在较低浓度的盐(<50mmol.L-1的NaCl)胁迫下,6种灌木叶片的叶绿素荧光参数没有明显的变化;当盐浓度大于50 mmol.L-1时,随着盐浓度的升高,6种灌木叶片中的Fv/Fm、Fv/Fo、φPo、φEo、Ψo和ETo/RC值均逐渐降低,而VJ、Mo、φDo和DIo/RC值均增加,这表明大于50 mmol.L-1的盐胁迫会抑制6个灌木树种叶片的PSⅡ功能,具体表现在于PSⅡ受体侧的电子传递受阻;但是,不同树种对盐胁迫的适应机制和耐受性的表现不同,其中金银忍冬和茶条槭的叶绿素荧光参数在盐胁迫下的变化幅度较小,与其它4种灌木相比,其PSⅡ反应中心具有较强的耐盐性,而暴马丁香、连翘和紫丁香的PSⅡ反应中心对盐胁迫较为敏感。文中还运用模糊隶属函数法对6种绿化灌木叶片PSⅡ的耐盐性进行了综合评判,结果表明其耐盐性的强弱顺序为:金银忍冬>茶条槭>白丁香>暴马丁香>连翘>紫丁香。

In order to change the single vegetation type at saline-alkali land, to select out urban greening species with better salt tolerance. Taking six common afforestation species in Heilongjiang as materials, including Syringa oblata, S. oblata var. alba, S. reticular var. mandshurica, Forsythia suspense （Thunb.） Vahl, Acer ginnala and Lonicera maackii （Rupr.）, characteristics of fast responses of PS II in leaves under salt stress were investigated by using the fast fluorescence transients techniques, and their salt tolerance capacity were evaluated. The results show that the chlorophyll fluorescence parameters in leaves of six kinds of shrubs have not significant differences under low salt concentration （ 〈 50 mmol·L^-1NaCl）. However, the parameters ofFv/Fm、Fv/Fo、φPo、φEo、Ψo and ETo/RC are decreased gradually with salt concentration rising, when salt concentration is above 50 mmol ·L^-, while the parameters of Vj, Mo, φDo and DlJRC are increased, which shows that reactions of PS II in 6 kinds of shrubs under salt stress over 50 mmol ·L-1 are inhibited, because electron transport in the receptor side of PS II is impeded. However, different species have different adaptive mechanism and tolerance under salt stress. The change ranges of the chlorophyll fluorescence parameters are smaller in A. ginnala and L. maackii （Rupr.） Maxim, PS II reaction centers of which have stronger salt tolerance capacity than that of the other shrubs, and PS II in S. oblata, S. reticular var. mandshurica, and F. suspense （Thunb.） Vahl are more sensitive to salt stress. The salt tolerance capacity in PS II of the urban afforestation shrubs was evaluated by using fuzzy membership function method, and the order of the shrubs based on salt tolerance from stron.g to weak is L. maackii （Rupr.）Maxim., A. ginnala, S. oblata var. alba, S. reticular var. mandshurica, F. suspense （Thunb.） Vahl, S. oblata.