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锰矿区废弃地重金属污染土壤下栾树和杜英的光合生理响应研究

Studies on Photosynthetic Physiological Response of Koelreuteria Paniculata Laxm and Elaeocarpus Decipens under Heavy Metal Polluted Soil of Slag Wastelands of Manganese Mine

【作者】 周仁飞

【导师】 李雄华;

【作者基本信息】 中南林业科技大学 , 生态学, 2010, 硕士

【摘要】 利用木本植物进行生态恢复与重建是以丘陵山地为主的南方重金属矿区废弃地生态治理的一种重要方法。研究在重金属胁迫条件下一些树种的光合特性,并揭示其适应机制,对于正确选择矿区废弃地生态修复的树种,治理土壤重金属污染和进行生态恢复具有十分重要的意义。本研究采用五种方案进行盆栽试验(对照CK:100%自然土;W1:25%矿区废弃地土壤+75%自然土;W2:50%矿区废弃地土壤+50%自然土;W3:75%矿区废弃地土壤+25%自然土;W4:100%矿区废弃地土壤),对比研究锰矿区重金属污染土壤下有广阔利用前景的乡土树种-栾树(Koelreuteria paniculata Laxm)和杜英(Elaeocarpus decipens)光合生理生态的响应、两树种净光合速率与各因子相关性及重金属胁迫对植物生长的影响进行研究,以揭示栾树、杜英地上部分的生理生态响应对策。结果表明:1.7月份日变化进程中,4种不同处理(W1、W2、W3、W4)下,栾树的W1、W2和W4的净光合速率日变化呈双峰曲线,CK和W3则呈单峰曲线;杜英(除W4)净光合速率日变化均呈双峰曲线,杜英的净光合速率日均值高于栾树。对栾树来说,4种不同处理(W1、W2、W3、W4),随着重金属土壤浓度的增加,各处理净光合速率日均值分别是对照的66%、87%、106%、117%。对杜英来说,4种不同处理的净光合速率日均值均低于对照,分别是对照的73%、83%、72.7%、57%。重金属处理降低了两树种的气孔导度和蒸腾速率日变化幅度。栾树W1和W4处理加大了胞间C02浓度日变化幅度,而W2、W3处理减少了其日变化幅度;杜英而言,W1、W2、W4处理加大了胞间CO2浓度日变化幅度,W3减少了其日变化幅度。2.对两树种夏秋两季的净光合速率进行了研究,结果表明:两树种的夏季净光合速率平均值高于秋季,秋季各处理间净光合速率平均值的大小关系发生了变化。夏季,栾树W3净光合速率平均值最大,为4.7μmol·m-2·s-1,且只有W3的平均值高于对照的4.1μmol·m-2·s-1,W1最小,为2.36μmol·m-2·s-1;秋季,W2平均值最大,为2.56μmol·m-2·s-1,W3最小,为2.12μmol·m-2·s-1,均高于对照的1.72μmol·m-2·s-1。夏季,杜英W2处理净光合速率平均值最大,为4.52μmol·m-2·s-1,W4最小,为3.59μmol·m-2·s-1,各处理平均值均低于对照的6.04μmol·m-2·s-1;秋季,W1净光合速率平均值最大,为2.36μmol·m-2·s-1,W4最小,为1.73μmol·m-2·s-1,且各处理平均值均低于对照的3.05μmol·m-2·s-1。3.栾树净光合速率与土壤各重金属元素(Mn、Cu、Zn、Pb、Ni、Co、Cd)含量的相关性都不显著,杜英净光合速率与土壤Pb、Cd、Cu含量呈显著负相关。影响两树种净光合速率的环境因子不同。栾树净光合速率与叶片全N及叶绿素含量呈显著负相关,与叶片Mn、Zn元素含量呈显著正相关;杜英净光合速率与叶片N、P、K、Mg、Ca、Fe、Mn、Zn含量及叶绿素含量的相关关系均未达到显著水平。4.栾树的株高增长率均低于杜英。夏季栾树(除W3)各处理的株高增长率都高于秋季;各处理平均地径增长量大小顺序W3>W4>CK>W2>W1,说明低浓度下对地径增长有抑制作用,而高浓度下反而促进地径的增长。杜英生长快,且长势良好,夏季株高增长率均远高于秋季;各处理的平均地径增长量大小顺序是CK>W2>W1>W3>W4,均低于对照,不同重金属土壤掺和浓度下对地径增长有一定的抑制作用,且随着浓度的增加抑制作用越明显。5.各重金属元素中锰元素的损失量最大,各处理与其试验初相比,两树种均是W2损失得最大,W1损失最小。试验末期栾树各处理土壤锰含量按顺序分别为试验初的62.9%、21.34%、50.33%、43.38%;杜英各处理土壤锰含量按顺序分别为试验初的63.45%、21.1%、41.2%、41.66%。造成锰元素损失的主要原因是降水和浇灌及植物的吸收。杜英对Mn、Pb元素的吸收富集能力高于栾树,而栾树对Cu、Zn元素的吸收富集能力高于杜英。

【Abstract】 Using woody plants for ecological restoration and reconstruction for southern heavy metal slag wasteland which are mainly hills and mountains is an important method. Studying on heavy metal stress on the photosynthetic characteristics of some species, and revealing their adaptive mechanisms, it is of great significance to choosing the correct species for restoration of the slag wasteland、controlling heavy metal pollution of the soil and ecological restoration. By using the slag wasteland soil in Xiangtan Manganese Mine, five different mixed soil treatments by which potted plant tests are conducted, five treatments are as follows:(CK:100% untreated soil; Wl:25% slag wasteland soil+75% untreated soil; W2:50% slag wasteland soil+50% untreated soil; W3:75% slag wasteland soil+25% untreated soil; W4:100% slag wasteland soil). This paper focuses on the impacts of heavy metal polluted soil in slag wastelands of manganese mine on photosynthetic physiological reactions、relevances among Pn and all factors、and inhibits on the growth by comparative study of Koelreuteria paniculata Laxm and Elaeocarpus decipens which have many promising uses so as to reveal physiological and ecological responses of the overground part of the two species. The results showed that:1. The diural net photosynthetic rate of W1、W2 and W4 treatments of Koelreuteria paniculata Laxm in July varies with double peak curves, while the diural net photosynthetic rate of the contrast(CK) and W3 varies with single peak curve. The diural net photosynthetic rate of Elaeocarpus decipens (except W4 treatment) varies with double peak curves. The daily average net photosynthetic rate (Pn) of Elaeocarpus decipens is higher than that of Koelreuteria paniculata Laxm in July. For Koelreuteria paniculata Laxm, the daily average net photosynthetic rate (Pn) of each treatment (W1、W2、W3、W4) is 66%,87%,106%,117% compared to the contrast and increases with the concentration of heavy metals in the soil. While for Elaeocarpus decipens, the daily average rates of (Pn) are 73%,83%,72.7%,57% compared to the contrast and raises when the soil heavy metal concentration increases, and then decreases. Impacts of soil heavy metal concentrations on Koelreuteria paniculata Laxm are relatively smaller than that of Elaeocarpus decipens. Heavy metal treatments make the range of diural variation of (Gs) and (Tr) decrease of both two species. For Koelreuteria paniculata Laxm, Wl and W4 treatments make the range of diural variation of (Ci) increase, while W2 and W3 treatments make it decrease. For Elaeocarpus decipens, W1、W2 and W4 treatments make the range of diural variation of (Ci) increase, while W3 make it decrease.2. Focused on net photosynthetic rate (Pn) of the two species in Summer and Autumn, the results showed that the average net photosynthetic rate (Pn) of both two species in Summer are higher than in Fall, and the relationship among all treatments (W1、W2、W3、W4) of the average net photosynthetic rate (Pn) has changed in Autumn. For Koelreuteria paniculata Laxm in Summer, the average value of Pn of W3 is the largest, that is 4.74μmol·m-2·s-1, only the value of Pn of W3 is bigger than the contrast, W1 is the minimum, that is 2.36μmol·m-2·s-1, While in Autumn, the average value of Pn of W2 is the largest which is 2.56μmol·m-2·s-1, W3 is the minimum which is 2.12μmol·m-2·s-1, the value of Pn of all treatments are higher than the contrast which is1.72μmol·m-2·s-1. For Elaeocarpus decipens in Summer, the average value of Pn of W2 is the maximum, that is 4.52μmol·m-2·s-1, while W4 is the minimum, that is 3.59μmol·m-2·s-1, the value of Pn of all treatments are lower than the contrast which is 6.04μmol·m-2·s-1; In Autumn, the average value of Pn of W1 is the largest which is 2.36μmol·m-2·s-1, while W4 is the minimum which is 1.73μmol·m-2·s-1, the value of Pn of all treatments are lower than the contrast which is3.05μmol·m-2·s-1.3. For Koelreuteria paniculata Laxm relevances among Pn and heavy metals Mn、Cu、Zn、Pb、Ni、Co、Cd contents in soil all fail to meet the significant level; while relevances among Pn and Pb、Cd and Cu contents in soil reach negative significant level of Elaeocarpus decipens. Relevances among Pn and N、Chlorophyll contents in leaves reach significant negative level, while Pn among Zn and Mn contents in leaves of Koelreuteria paniculata Laxm reach positive significant level; For Elaeocarpus decipens, Relevances Pn among N、P、K、Mg、Ca、Fe、Mn、Zn and Chlorophyll contents in leaves all fail to meet the significant level.4. Survival rate and height growth rate of Koelreuteria paniculata Laxm are lower than those of Elaeocarpus decipens. height growth rate of Koelreuteria paniculata Laxm each treatment (exceptW3) is higher than that in fall; the average diameter growth in order is W3>W4>CK>W2>W1, W1 and W2 are less than the contrast, while W3 and W4 are larger than the contrast. It means that low concentration inhibits diameter growth, while high concentration promotes it.Elaeocarpus decipens grow fast and grow well, height growth rate in summer is far more higher than that in autumn. The average diameter growth in order is CK> W2> W1> W3> W4, all treatments are lower than the contrast, heavy metal treatments in the soil inhibits diameter growth, and with the increase in the concentration of heavy metal, the inhibitory effect gets more obvious.5. Among all the heavy metals, content of Mn losses the most. Compared with its in the early stage of experiment, for both of the two species, W2 lost the most Mn content, W1 lost the least, at the end stage of the experiment, Mn content in the soil of each treatment of Koelreuteria paniculata Laxm in order is 62.9%,21.34%, 50.33%,43.38% of its early stage; For Elaeocarpus decipens, Mn content in the soil of each treatment in order is 63.45%,21.1%,41.2%,41.66% of its early stage. The causes of so much loss in Mn content are mainly due to rainfall、irrigation and absorption of the plants. Elaeocarpus decipens has better capacity to absorb Mn and Pb elements than Koelreuteria paniculata Laxm, while Koelreuteria paniculata Laxm absorbs more Cu and Zn elements than Elaeocarpus decipens.

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