摘 要

为了掌握不同无性系杨树对重金属Pb的抗性以及富集状况，筛选适宜的杨树无性系修复土壤Pb污染，本研究在南京林业大学下蜀林场温室内对110杨、3804杨和895杨进行了盆栽Pb处理试验，共设置了4种处理，分别是对照、Pb500（土壤中的Pb含量为500mg/kg）、Pb1000（土壤中的Pb含量为1000mg/kg）和 Pb2000（土壤中的Pb含量为2000mg/kg）。调查了三种杨树无性系苗木在不同浓度Pb处理下的生长、生理以及重金属富集状况，主要结果如下：

（1）在Pb处理下，895杨苗高和地径的生长明显好于110杨和3804杨，且在Pb2000处理下苗高和地径增量最大；110杨的地下部分生物量较大，895杨的地上部分和总生物量较大。

（2）在Pb处理下，110杨各器官的N含量较高，895杨各器官的K含量较高；Pb处理对三种无性系杨树苗木P含量的影响总体较小；Pb处理对苗木地上部分的K含量影响总体较小，但是可以促进根系中的K含量提高。

（3）Pb处理下三种杨树无性系苗木体内的Pb含量都明显高于对照，且基本上是随着Pb处理浓度的提高而提高，其中地下部分的变化趋势尤为明显。

（4）三种杨树无性系苗木地下部分Pb富集量总体高于地上部分。就地上部分而言，895杨在Pb2000处理下的Pb富集量最大；就地下部分而言，110杨在Pb1000处理下的Pb富集量最大；就总量而言，110杨在Pb1000处理下的Pb富集量最大。

关键词：杨树；重金属Pb；富集状况；生长状况

Study on absorption and accumulation of heavy metal Pb in poplar seedlings

ABSTRACT

In this paper, we studied the resistance and accumulation status of different clones of poplar which including clone 110, clone 3804 and clone 895 to heavy metal Pb, and provided materials for screening suitable poplar clones to repair the soil Pb pollution. In this experiment, pot experiments were carried out in the greenhouse of Xiashu Forest Farm of Nanjing Forestry University. The growth status and physiological changes of three clones seedlings under different heavy metal Pb treatments were observed. Four treatments were set up, which including control, Pb500 (500g/kg of Pb in soil), Pb1000 (1000mg/kg of Pb in soil) and Pb2000 (2000mg/kg of Pb in soil). The main results were as follows.

Under the Pb treatment, the growth of height and diameter of clone 895 was significantly better than that of clone 110 and clone 3804. The increment of clone 895 seedling height and ground diameter under Pb2000 treatment were the greatest. The underground part of clone 110 had larger biomass. The aboveground part and total biomass of clone 895 were larger.

Under the Pb treatment, N content in organs of clone 110 was higher, K content in organs of clone 895 was higher. The effect of the Pb treatment on P content of three clones of poplar seedlings was relatively small. The effect of Pb treatment on K content in aboveground part of seedlings was relatively small. But the Pb treatment could promote the increase of K content in roots.

The content of Pb in seedlings of three poplar clones treated with Pb was significantly higher than that of the control. Basically, Pb content increased with the increase of the concentration of Pb treatment, and the change trend of underground part was particularly obvious.

The accumulation of Pb in underground part of three poplar clones was higher than that in aboveground part. For the aboveground part, the Pb accumulation in clone 895 treated with Pb2000 was the highest. For the underground part, the Pb accumulation in clone 110 treated with Pb1000 was the highest. For the total part, the Pb accumulation in clone 110 treated with Pb1000 was the highest

Key words: Poplar; Heavy metal Pb; Accumulation status; Growth status

目 录

前 言 - 1 -

1综 述 - 2 -

1.1杨树的基本情况.. ..- 2 -

1.1.1杨树的自然分布 - 2 -

1.1.2杨树的形态特征 - 2 -

1.1.3杨树的用途 - 2 -

1.1.4研究现状 - 2 -

1.2杨树在重金属处理下的生理变化研究 - 5 -

1.2.1光合作用 - 5 -

1.2.2铅胁迫对植物养分含量的影响 - 5 -

1.3杨树在重金属处理下的生长状况研究 - 5 -

1.4杨树苗期对重金属的富集状况研究 - 6 -

1.5结语 - 6 -

2研究材料与方法 - 8 -

2.1试验材料 - 8 -

2.2试验方法 - 8 -

2.2.1试验设计 - 8 -

2.2.2测定方法 - 8 -

3结果与分析 - 10 -

3.1不同处理对杨树苗木生长的影响 - 10 -

3.1.1对苗高的影响 - 10 -

3.1.2对地径的影响 - 10 -

3.1.3对生物量的影响 - 11 -

3.2不同处理对杨树苗木养分含量的影响 - 12 -

3.2.1对N含量的影响 - 12 -

3.2.2对P含量的影响 - 13 -

3.2.3对K含量的影响 - 13 -

3.3杨树苗木对Pb的富集状况 - 14 -

3.3.1植物体内的Pb含量 - 14 -

3.3.2不同杨树无性系的Pb转移系数 - 15 -

3.3.3不同无性系杨树苗木的Pb富集量 - 16 -

4结 论 - 17 -

致 谢 - 18 -

参考文献 - 19 -

前 言

杨树属于杨柳科杨属，是中国江苏北部常见的落叶阔叶速生树种，应用广泛，适用性强，具有较高的经济效益和生态效益。我国土壤受重金属污染的面积约为2.5×10⁷hm²，受重金属污染的粮食每年达1.2×10⁷t左右。我国一般采用传统的物理和化学方法对土壤污染进行修复，会因经济条件或技术问题难以实施，目前大多数处于未修复状态^[1]。利用植物的富集作用去除污染土壤中超标重金属的修复技术具有操作简单、能快速且大面积实施的优点，是一项十分有前途的修复技术^[1,2] 。在木本植物盆栽模拟实验中，黄会一^[3]研究了11 种木本植物在重金属镉胁迫下，植物各器官对Cd的积累效率，结果表明木本植物对土壤中Cd的吸收能力较高，但种间有显著差异，其中富集能力较强的树种是杨树，表明杨树在重金属污染土壤修复中具有很大的潜力。

本文采用室内盆栽土培试验方法研究了3种无性系杨树（110杨、895杨、3804杨）在重金属Pb处理下的生长和生理响应情况，通过研究，掌握不同无性系杨树对重金属Pb的抗性以及富集状况，为筛选适宜的杨树无性系修复土壤Pb污染提供素材。