研究论文
黄艺,李婷,姜学艳.锌对外生菌根植物苏格兰松幼苗锌积累和光合作用的影响[J].环境科学学报,2004,24(3):508-514
锌对外生菌根植物苏格兰松幼苗锌积累和光合作用的影响
- Effects of Zn on Zn accumulation and photosynthesis of ectomycorrhizal Pinus sylvestris seedlings
- 基金项目：国家自然科学基金资助(批准号:4421101)
- 作者
- 单位
- 黄艺
- 北京大学环境学院,北京 100871
- 李婷
- 北京大学环境学院,北京 100871
- 姜学艳
- 北京大学环境学院,北京 100871
- 摘要：在实验室条件下,对生长在锌(Zn)处理浓度为55mg·L-1和200mg·L-1下的外生菌根苏格兰松幼苗(Pinussylvestris)的锌积累和光合作用进行测定.处理4周后,两种浓度锌处理下菌根苗木Zn积累量分别为非菌根松苗的1.7倍和2.8倍,显示菌根没有减少植物对过量Zn的吸收 但200mg·L-1处理下菌根地上部分Zn与非菌根相同,说明菌根真菌可能通过调节Zn在植物内的分布积累减少重金属毒害.菌根真菌缓解了Zn对植物光合色素合成的影响,使菌根植物叶绿素含量比非菌根高12%和22%,其中叶绿素b都比非菌根的高12%.菌根真菌对Zn胁迫下的植物光合作用的影响,主要表现在缓解PSⅡ电子传递速率的减少,使Zn处理下菌根植物的PSⅡ电子传递速率比非菌根高33%和24%,但净光合强度与非菌根差异不显著.菌根还使Zn胁迫下的植物受伤呼吸减弱,在200mg·L-1Zn处理下比非菌根的呼吸耗氧低25%,减少了呼吸耗能,增加植物抵抗环境胁迫的能力.
- Abstract：Zn concentration, photosynthetic pigments, photosynthesis and respiration were measured for 4-week-old Pinus sylvestris seedlings associated with an ectomycorrhizal fungus （Suillus bovinus） under excessive Zn treatments grown in Perlite (55mg·L-1 and 200mg·L-1). Zn concentrations were 1.7 and 2.8 times higher in mycorrhizal than non-mycorrhizal seedlings. However, the Zn concentrations in roots of mycorrhizal plants were the same as in non-mycorrhizal ones. It indicated that mycorrhizal fungus did not protect its host plant from absorbing Zn, but limited excessive Zn translocation from roots to shoots. Ectomycorrhizal fungus also alleviated negative influence of excessive Zn on physiological process in the host plant. Content of chlorophyll was significantly higher in needles of mycorrhizal seedlings than in non-mycorrhizal seedlings under two Zn treatments; and Chlorophyll b was higher in mycorrhizal plants than in non-mycorrhizal ones. Contents of Chlorophyll a were not significantly different between the two Zn treatments. Furthermore, activity of PS II was higher in mycorrhizal seedlings; and CO2 consumption had no significant difference between mycorrhizal and non-mycorrhizal seedlings. At the addition of 200 mg（Zn）·L-1, respiration of mycorrhizal seedlings was lower than in non-mycorrhizal seedlings. The results showed that ectomycorrhizal fungi decreased energy consumption to alleviate Zn stress by decreasing maintenance respiration of its host plant.
- Key words：Zn ectomycorrhizal plant photosynthesis
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