| 摘要: |
| 【目的】研究不同土壤镉污染对台湾桤木（Alnus formosana）和杂交相思（Acacia mangium×Acacia auriculiformis）2个结瘤固氮树种生长和光合参数的影响，并探讨施氮对2个树种土壤镉污染下的适应能力，为土壤环境镉污染的治理提供依据。【方法】采用盆栽方法，研究不同镉、氮处理（对照(CK)：0 mg/kg Cd2+，D1：30 mg/kg Cd2+，D2：60 mg/kg Cd2+，D3：120 mg/kg Cd2+，D1N1：30 mg/kg Cd2++0.4 g/kg CO(NH2)2，D1N2：30 mg/kg Cd2++0.8 g/kg CO(NH2)2）对台湾桤木和杂交相思2个树种生长及光合参数的影响。【结果】镉胁迫下台湾桤木和杂交相思苗高、地径、根茎叶及总生物量均随着镉添加量的增加而下降，而杂交相思苗高、地径受抑制程度要高于台湾桤木。30 mg/kg镉处理下施氮，台湾桤木及杂交相思苗高、地径、生物量虽然均低于CK无镉胁迫处理，但较不施氮的30 mg/kg镉处理均有所提高，并且杂交相思要比台湾桤木提高得更明显。高氮（0.8 g/kg）会降低氮对台湾桤木及杂交相思根的促进作用。台湾桤木及杂交相思Pn、Gs、Tr均随土壤镉添加量的增加呈下降趋势。在0~60 mg/kg镉胁迫处理时，光合主要受气孔因素限制，而在120 mg/kg镉胁迫处理时，限制因素为非气孔因素。在30 mg/kg镉胁迫下，施氮对2树种产生的影响存在一定差异，低氮（0.4 g/kg）更有利于台湾桤木Pn和Ci的提高，而高氮更好地促进了杂交相思Pn、Gs和Tr的提高。【结论】镉胁迫下台湾桤木较杂交相思具有更高的适应能力，而镉胁迫下施氮对杂交相思适应性的提高要明显优于台湾桤木。 |
| 关键词: 镉 氮 台湾桤木 杂交相思 结瘤固氮 木本植物 |
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| 基金项目:广西优良用材林资源培育重点实验室自主项目（15-A-02-02）；广西科技计划项目（桂科AB16380127）；广西林业科学研究院基本科研业务费项目（林科201601号）；广西林业科技项目（桂林科字［2016］第8号） |
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| Effects of cadmium and nitrogen on growth and photosynthesis of Alnus formosana and Acacia mangium×Acacia auriculiformis |
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TAN Zhangqiang,HAO Haikun,PENG Yuhua,et al
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| Abstract: |
| 【Objective】This study investigated the effects of soil heavy metals and N application on the growth and photosynthesis of 2 nodulation and nitrogen fixation trees of Alnus formosana and Acacia mangium×Acacia auriculiformis.【Method】The research carried an awnings pot soil experiment amd the effects of different cadmium (Cd) and nitrogen(N) levels (CK:0 mg/kg Cd2+,D1:30 mg/kg Cd2+,D2:60 mg/kg Cd2+,D3:120 mg/kg Cd2+,D1N1:30 mg/kg Cd2++0.4 g/kg CO(NH2)2,and D1N2:30 mg/kg Cd2++0.8 g/kg CO(NH2)2） on growth and photosynthesis were studied.【Result】In the soil without nitrogen,seedling height,ground diameter,root leaf and total biomass of Alnus formosana and Acacia mangium×Acacia auriculiformis descended with the increase of cadmium while the inhibition on seedling height and ground diameter of Acacia mangium×Acacia auriculiformis was higher than on Alnus formosana.In the soil with nitrogen,30 mg/kg cadmium treatment decreased seedling height,ground diameter and biomass compared with no nitrogen treatment,but those were higher than that of 30 mg/kg cadmium treatment without nitrogen.The changes in Alnus formosana were more significant than in Acacia mangium×Acacia auriculiformis.High nitrogen treatment (0.8 g/kg) reduced the promotion of root growth of Alnus formosana and Acacia mangium×Acacia auriculiformis.Pn,Gs and Tr of Alnus formosana and Acacia mangium×Acacia auriculiformis descended with the increase of cadmium level.Under 30 mg/kg cadmium stress,low nitrogen (0.4 g/kg) was more advantageous to improve Pn and Ci of Alnus formosana,and high nitrogen was more advantageous to improve Pn,Gs and Tr of Acacia mangium×Acacia auriculiformis.【Conclusion】Alnus formosana had high adaptation ability than Acacia mangium×Acacia auriculiformis under cadmium stress,while the adaptation of Acacia mangium×Acacia auriculiformis was improved more than Alnus formosana by adding nitrogen under cadmium stress. |
| Key words: cadmium nitrogen Alnus formosana Acacia mangium×Acacia auriculiformis nodulation and nitrogen fixation woody plant |
