泡桐幼苗对铝胁迫的生理响应

【目的】研究铝胁迫下泡桐幼苗的生理变化,为泡桐幼苗逆境生长的抗性提供帮助。【方法】选取3年生9501泡桐和白花泡桐的根作为供试材料,采用砂培胁迫的方式研究在铝胁迫处理30 d和60 d条件下对照组以及0.3、0.6、0.9、1.2和2.4 mmol/L浓度在铝胁迫条件下2种泡桐幼苗的全氮和叶绿素等以及超氧化物歧化酶活性等生理指标的变化规律。【结果】随着铝处理浓度的升高,泡桐幼苗中的全氮、全钾、钙和锌元素含量均呈现下降趋势,磷元素含量随胁迫浓度增加逐渐增长,上述元素除0.3 mmol/L均与对照组差异显著,硫、铁、铜元素含量各胁迫浓度间差异不显著;同时,两种泡桐幼苗的叶绿素含量与对照组相比差异先增后减;丙二醛、可溶性糖、过氧化物酶的含量和电导率不断增加,显著高于对照组;游离脯氨酸含量则呈现逐渐递减的规律,显著低于对照组;超氧化物歧化酶活性在胁迫30 d时递增,60 d时先增后减。上述生理指标在除0.3 mmol/L处理与对照组差异显著(P <0.05)。【结论】泡桐幼苗在铝胁迫条件下各营养元素吸收过程受阻、生长受限,生理指标出现显著降低,泡桐幼苗的铝毒可适浓度为0.3 mmol/L,通过对铝胁迫条件下泡桐的各项生理指标比较分析得出,9501泡桐的铝胁迫抗性优于白花泡桐。

Physiological responses of Paulownia fortunei root seedlings under aluminum stress

【Objective】The physiological changes of Paulownia fortunei root seedlings under aluminum stress were studied to help the resistance of P.fortunei root seedlings to stress growth.【Method】The roots of 3-year old P.fortunei-9501 and P.fortunei sinensis were selected as the tested materials.The control group and the 0.3,0.6,0.9,1.2 and 2.4 mmol/L were studied under the conditions of aluminum stress treatment for 30 days and 60 days.The changes of physiological indexes such as total nitrogen and chlorophyll and superoxide dismutase activities of two species of P.fortune root seedlings.【Result】With the increasing of aluminum stress concentration,the total nitrogen,total potassium,calcium and zinc in the root seedlings of P.fortunei showed a downward trend,and the phosphorus increased with the increase of stress concentration.The above elements except 0.3 mmol/L the differences in the control group were significantly,and the differences in stress concentrations between sulfur,iron increased first and then decreased and copper were not significant.At the same time,the chlorophyll content of the two P.fortunei root seedlings had significantly differences with the control group;malondialdehyde,soluble sugar,peroxidase content and the conductivity increased continuously,and the difference with the control group gradually increased;the free proline content showed a gradual decreasing discipline,and the difference with the control group gradually increased;superoxide dismutase increased at 30 days of stress,first increased after 60 days after subtraction,the difference with the control group gradually increased in 30 days,and increased and then decreased in 60 days.The above physiological and biochemical indexes were significantly different from the control group except 0.3 mmol/L(P<0.05).【Conclusion】The overall index indicated that the absorption of nutrients in P.fortunei root seedlings was inhibited and growth restricted under aluminum stress,and the physiological and biochemical indexes were significantly decreased.The suitable concentration of aluminum toxicity in P.fortune root seedlings was 0.3 mmol/L.According to the comparative analysis of various physiological indexes of P.fortunei,the aluminum stress resistance of P.9501was better than that of P.fortunei.