【作者】 游秀花；

【导师】 柯玉琴； 罗涛；

【作者基本信息】 福建农林大学 ， 生物工程， 2008， 硕士

【摘要】 本研究采用溶液培养法和盆栽方法分别研究了榕树（Ficus microcarpa L.f）、樟树（Cinnamomum camphora（L.）Presl）和芒果（Mangifera indica Linn）种子和1年生幼苗对重金属镉（Cd）胁迫的生长和生理生化反应。设置的Cd浓度梯度分别为0.3、1.0、10.0、20.0 mg/kg(以Cd²⁺计),同时设置对照（CK）。研究结果如下:1、Cd处理对3种树种种子发芽具有低浓度下的激活效应和高浓度下的抑制效应,且3种种子胚根伸长的抑制率随着Cd浓度的增大呈增大的趋势,抑制效应大小顺序为樟树＜榕树＜芒果。另外,Cd胁迫浓度与种子发芽率、根伸长抑制率之间普遍存在显著的回归关系。2、Cd胁迫下,芒果的细胞膜透性增大,且随浓度的增大呈上升的趋势;榕树和樟树则表现为低浓度（1mg/kg）时细胞膜透性减小,高浓度时细胞膜透性增大,榕树增大的幅度比樟树大。3、Cd胁迫下,3种幼苗的光合系统也受影响,榕树和芒果幼前苗叶片叶绿素含量和净光合速率随着Cd处理浓度的增加呈现下降趋势,芒果下降的幅度比榕树大;樟树在Cd胁迫下幼苗叶片叶绿素含量和净光合速率变化不大。而3种幼苗叶片叶绿素a/b值均比对照高,但与浓度主效应的差异不显著。4、Cd胁迫下,3种幼苗的自由基清除系统受到严重影响。低浓度（Cd浓度≤10 mg/kg）的Cd在一定程度上刺激了樟树和榕树的过氧化氧酶（CAT）和过氧化物酶（POD）的活性,表明这两种树种具有一定抵御Cd伤害的能力,但是随着处理浓度的增加,两种酶活性开始下降,说明两树种对Cd的抵御能力是有一定限度的。Cd胁迫下芒果的CAT和POD的活性表现为下降的趋势。5、Cd胁迫下,芒果的幼苗植株细而矮,生物量累积少;榕树的地茎、苗高和生物量累积随Cd胁迫浓度的增加变化不大,而樟树却略有增大。6、用隶属函数法进行综合评定,3种树种的抗Cd胁迫能力强弱顺序为:樟树＞榕树＞芒果。本论文以3种福州市常见的常绿阔叶乔木树种的种子与1年生幼苗为试材,研究其在不同浓度Cd胁迫下的生理生态效应,探讨和比较不同树种抗Cd胁迫的差异,综合评定其抗Cd胁迫能力的强弱,为福州市园林绿化树种选择提供理论依据,从而更好地发挥园林绿化植物在改善生态环境中的作用。更多还原

【Abstract】 The reaction in growth,and physiology and biochemistry of Ficus microcarpa L.f,Cinnamomum camphora（L.） Presl,Mangifera indica Linn and the one-year -old seedlings to the stress of Cd were studied with the methods of solution and pot culture.Each species was treated with different concentration gradient,namely,0.3, 1,10 and 20 mg/kg(pure Cd²⁺) in turn,and meanwhile control group（CK） was set as well.The results were as follows:（1） The Cd treatment had an activation effect on the seed germination of these three tree species under low concentrations and an inhibition effect under high concentrations.The inhibition rate of embryonic root extension increased with the increase of Cd concentration,and the order was Cinnamomum camphora（L.） Presl＜Ficus microcarpa L.f.＜Mangifera indica Linn.In addition,the regressive relationship between Cd concentration and seed germination,and between Cd concentration and inhibition rate of the root was significant.（2） Under the stress of Cd,the cell permeability of Mangifera indica Linn increased,having an upward trend with the increase of the concentration;as for Ficus microcarpa L.f.and Cinnamomum camphora（L.） Presl,their cell permeability decreased when the concentration of Cd＜1 mg/kg,and increased with higher concentration,in addition,the increasing amplitude of Ficus microcarpa L.f.was bigger than Cinnamomum camphora（L.） Presl.（3） Under the stress of Cd,the photosynthetic systems of the 3 species were affected.The chlorophyll contents of the leaves and net photosynthetic rate of the seedlings of Mangifera indica Linn and Ficus microcarpa L.f.displayed a downward trend with the increase of Cd concentration,and the decreasing amplitude of Mangifera indica Linn was bigger than that of Ficus microcarpa L.f..While the chlorophyll contents of the leaves and net photosynthetic rate of the seedlings of Cinnamomum camphora（L.） Presl changed little.Besides,a/b values of these three tree species were all more than that of CK,however,the difference between a/b value and the concentration main effect was insignificant.（4） Under the stress of Cd,the free radical scavenging system was seriously affected.The activity of peroxidase（POD） and catalase（CAT） of Cinnamomum camphora（L.） Presl and Ficus microcarpa L.f.was stimulated to some extent by the Cd of low concentration,which showed that the two tree species had the capacity to prevent being hurt by Cd.However,their enzyme activity began to drop with the increase of concentration,which reflected that the capacity to resist Cd was limited.As for Mangifera indica Linn,its POD and CAT activity decreased under the stress of Cd.（5） Under the stress of Cd,the seedlings of Mangifera indica Linn were more slender and shorter,and had less biomass;while the root stem,seedling height and biomass of Cinnamomum camphora（L.） Presl changed more than Ficus microcarpa L.f.did,and Ficus microcarpa L.f.changed quite a little with the increase of Cd concentration.（6） According to the comprehensive evaluation by subordination function method,the stress-resistance to Cd of the three tree species was in the order of Cinnamomum camphora（L.） Presl＞Ficus microcarpa L.f.＞Mangifera indica Linn.With the seeds of three common evergreen broad-leaved tree species in Fuzhou and one-year-old seedlings as the test materials,their physiological and ecological effects on the stress of Cd with different concentrations were studied,and the differences in stress-resistance to Cd of different tree species were discussed and compared,besides,their capacity in stress-resistance to Cd was comprehensively evaluated as well in this paper,in order to provide theoretical basis for the selection of garden tree species in Fuzhou and thus the garden tree species could better play their part in improving the ecological environment.更多还原