| 摘要: |
| 【目的】研究土壤重金属Cd对珍稀树种桢楠（Phoebe zhennan）幼树生长和生理特性的影响，分析桢楠对Cd的耐受性。【方法】以3.5年生桢楠幼树为试验材料，采用盆栽控制试验，试验共设置6个Cd处理，施Cd量分别为0，10，20，30，40，50 mg/kg，将每个处理的施Cd量以CdCl2形式分5次施入，待处理结束后测定植株的生长及抗性生理指标。【结果】（1）Cd胁迫下桢楠幼树叶缘出现枯萎现象，且随着Cd胁迫的加重其叶缘枯萎面积逐渐增大，顶芽萌发展开时间推迟，株高净生长量、地径净生长量、顶芽长、春梢长均呈下降趋势。（2）随着Cd含量的增加，H2O2和MDA含量总体呈增加趋势，SOD、POD和CAT活性呈先升后降趋势。（3）随着Cd含量的增加，脯氨酸（Pro）和可溶性糖（SS）含量呈增加趋势，可溶性蛋白质（SP）含量在Cd含量为30 mg/kg时增至最大，此后随Cd胁迫程度的进一步加重有所降低。（4）随着Cd含量的增加，植株春季萌芽中生长素（IAA）、细胞分裂素（CTK）含量无显著变化，但二者比值（IAA/CTK）在Cd含量为50 mg/kg时显著高于CK；赤霉素（GA3）含量呈下降趋势。（5）随着Cd含量的增加，桢楠幼树地上部和地下部Cd含量均显著增大，可知桢楠幼树对Cd的富集量与施Cd量呈正相关，但Cd转移效率较低，在同一施Cd水平下，桢楠幼树地下部Cd含量均明显高于地上部。【结论】Cd胁迫会明显抑制桢楠幼树的生长，干扰其生理过程，且当施Cd量≥20 mg/kg时，Cd对桢楠的影响尤为突出，说明桢楠对Cd的耐受性较弱，并且富集Cd的主要部位是植株根系，因此桢楠不适宜在Cd污染严重的地段种植并用于土壤修复。 |
| 关键词: 桢楠 Cd胁迫 抗性生理 土壤修复 |
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| 基金项目:四川省“十三五”农作物育种攻关项目（2016NZ0098-10）；四川省教育厅重点项目（13ZA0246） |
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| Responses of growth and resistant physiology of Phoebe zhennan saplings to cadmium stress |
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TIE Dexiangi,HU Hongling,CHEN Hong,et al
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| Abstract: |
| 【Objective】This study investigated the effects of soil heavy metal cadmium (Cd) on growth and physiological characteristics of rare species Phoebe zhennan saplings and analyzed the tolerance of P. zhennan to Cd.【Method】The saplings of 3.5-year-old P. zhennan were selected for potted control experiment with a total of 6 Cd treatments (0,10,20,30,40,and 50 mg/kg).In each treatment,Cd was applied in the form of cadmium chloride (CdCl2) for 5 times,and the growth and resistance physiological indexes of treated plants were determined after treatments.【Result】(1) Under Cd stress,the edge of P. zhennan leaves showed withering.With the increase of Cd stress,the blight area increased gradually,the time of apical bud expanding was delayed,and the length of apical bud and spring shoots,the net increment of height and ground diameter showed downward trends.(2) With the increase of Cd content,the contents of H2O2 and MDA increased,while the activities of SOD,POD and CAT increased first and then decreased.(3) With the increase of Cd content,the contents of proline (Pro) and soluble sugar (SS) increased.The content of soluble protein (SP) increased to the maximum when Cd content was 30 mg/kg,and then decreased with the enhancement of Cd stress.(4) With the increase of Cd content,there was no significant change in contents of auxin (IAA) and cytokinin (CTK) in the spring buds of plants,but the IAA/CTK ratio was significantly higher than that of CK in the treatment of 50 mg/kg.The content of gibberellin (GA3) showed a downward trend.(5) With the increase of Cd content,Cd contents in the aboveground and underground parts of P. zhennan saplings increased significantly,indicating that Cd enrichment was positively correlated with Cd amount.The transfer efficiency of Cd was low.At same treatment level, Cd content in the underground part was significantly higher than that in the aboveground part.【Conclusion】Cd stress significantly inhibited the growth of P. zhennan saplings and interfered with physiological process.When Cd amount was 20 mg/kg and above,the effect of Cd on P. zhennan was particularly prominent,indicating the tolerance of P. zhennan to Cd was weak and the main enrichment part was roots.It is concluded that P. zhennan cannot be planted in sites with serious Cd pollution for soil remediation. |
| Key words: Phoebe zhennan cadmium stress resistance physiology soil remediation |
