盐碱胁迫下沙地彰武松和樟子松苗木生理特性

Physiological characteristics of Pinus densiflora var.zhangwuensis and Pinus sylvestris var.mongolica seedlings on sandy lands under salt-alkali stresses

为了在北方沙漠化、盐碱化土地上推广应用沙地彰武松这一新的造林树种,客观评价彰武松的耐盐碱性及其耐盐碱机理,本文以4年生的彰武松和樟子松为试材,采用盆栽试验方法,研究NaCl、Na2CO3和NaHCO33种单盐胁迫及NaOH碱胁迫对苗木生长和叶片生理生化特性的影响.结果表明:盐碱胁迫下,彰武松苗木的受害级别较小,根系忍耐指数较大,叶片的过氧化氢酶(CAT)活性显著提高,最高为对照的22.6倍,丙二醛(MDA)含量没有显著提高,叶绿素(Chl)含量降幅较小,其叶片含水量(LWC)有所提高.樟子松则表现出与彰武松不同的变化规律,各处理MDA含量显著提高,CAT活性没有显著变化,Chl含量显著下降,LWC有所下降.说明彰武松的耐盐碱性高于樟子松.彰武松针叶内较高的Fe含量使其CAT活性和Chl含量较高,而Zn、Cu含量较高与其抗性强有关.

For the popularization of Pinus densiflora var.zhangwuensis,a new afforestation tree species on the desertified and salinized-alkalized lands in Northern China,and to evaluate the salinity-alkalinity tolerance of the tree species and to better understand the tolerance mechanisms,a pot experiment with 4-year old P.densiflora var.zhangwuensis and P.sylvestris var.mongolica was conducted to study their seedlings growth and physiological and biochemical indices under the effects of three types salt（NaCl,Na2CO3,and NaHCO3） stresses and of alkali（NaOH） stress.Under the salt-alkali stresses,the injury level of P.densiflora var.zhangwuensis was lower,and the root tolerance index was higher.The leaf catalase（CAT） activity increased significantly by 22.6 times at the most,as compared with the control;the leaf malondialdehyde（MDA） content had no significant increase;the leaf chlorophyll（Chl） content had a smaller decrement;and the leaf water content（LWC） increased slightly.P.sylvestris var.mongolica responded differently to the salt-alkali stresses.Its leaf CAT activity had less change,MDA content increased significantly,Chl content had significant decrease,and LWC decreased slightly.It was suggested that P.densiflora var.zhangwuensis had a greater salinity-alkalinity tolerance than P.sylvestris var.mongolica.The higher iron concentration in P.densiflora var.zhangwuensis needles enhanced the CAT activity and Chl content,whereas the higher concentrations of zinc and copper were associated with the stronger salinity-alkalinity tolerance.