不同种源非洲桃花心木对寒害的生理响应

Physiological Responses to Cold Stress in Different Provenances of Khaya senegalensis

2012年1月,广东省经历了2次低温天气.本研究分别于2次降温后（3 ～10℃）和正常温度下（＞10℃）采集广州和肇庆2片试验林的非洲桃花心木叶片,测定相对电导率（REC）、丙二醛（MDA）含量、脯氨酸（Pro）含量、超氧化物歧化酶（SOD）活性和过氧化物酶（POD）活性5个指标,分析了27个种源对寒害的生理响应模式.结果表明,2次降温均显著提高了非洲桃花心木的REC、Pro含量、SOD和POD活性.相比首次降温,第2次降温后,Pro含量、SOD和POD活性进一步提高,而REC则有所降低,表明植株在2次降温后进一步启动了自身的保护系统.该研究应用耐寒隶属函数值对27个种源进行综合评价,初步选出来自马里（种源10#,20#,22#）和布基纳法索（种源30#,31#,32#）的6个耐寒表现优异的种源.

In January 2012,the temperature dropped strongly for two times in Guangdong province.To evaluate the variation of cold tolerance among provenances of Khaya senegalensis,the leaf samples were collected from the test stand in Guangzhou and Zhaoqing under the cold conditions （3-10 ℃） and normal condition （〉 10 ℃）.The relative electrical conductivity （REC）,the malondialdehyde （MDA） contents,the proline contents and the activities of superoxide dismutases （SOD） and peroxidases （POD） were measured in 27 provenances.The results showed that the REC,the proline contents,the SOD and POD activities were increased under cold stress.Furthermore,the SOD activity,the POD activity and the proline content of the samples at second cold time were much higher compared to the ones at the first cold time,while the MDA content were similar and the REC were lower.It＇s implied that the protecting system was further activated to stabilize the membranes when the plants were exposed to the second cold stress.Six cold-resistant provenances from Burkina Faso （the provenance No.30#,31# and 32#） and Mali （the provenance No.10#,20#,22#） of the 27 provenances were selected according to the subordinate function values of the cold resistance.