6个不同种源任豆树幼苗对干旱胁迫的生理响应

Physiological Responses to Drought Stress of Zeniain signis Chun Seedlings with Six Provenances

任豆树是喀斯特地区具有重要生态和经济价值的保护植物,其树叶可作为饲料,然而不同种源任豆树耐旱性鲜有研究。本研究以广西6个不同地理种源(大新、乐业、上林、忻城、龙胜、南丹)的1年生任豆树幼苗为试验材料,采用盆栽人工控水模拟自然干旱胁迫条件,测定不同干旱胁迫阶段任豆树幼苗叶片的相对含水量、脯氨酸、可溶性糖、丙二醛(MDA)含量变化及超氧化物歧化酶(SOD)和过氧化物酶(POD)活性变化,并采用隶属函数法对不同种源任豆树的抗旱性进行综合评价。结果表明:随着干旱胁迫时间的延长,6个种源任豆树幼苗叶片相对含水量逐渐减少而可溶性糖含量逐渐增加;游离脯氨酸含量在大新和乐业种源呈持续上升趋势,上林、忻城和龙胜种源呈升—降—升的趋势,而南丹种源在4d时下降后持续上升;MDA含量在大新、上林、忻城和龙胜种源呈升—降—升的趋势,乐业种源呈降—升—降的趋势,而南丹种源则在4d时降低后持续升高;SOD活性在大新种源呈升—降—升的趋势,乐业种源在4d时升高后持续下降,上林和龙胜种源持续上升,忻城和南丹则呈降—升—降的趋势;POD活性除南丹持续上升外,其他种源均呈升—降—升的趋势,且除龙胜在4d时达到最大值外均在12d时达到最大值。根据隶属函数法综合评价不同种源任豆树耐旱能力大小为龙胜>大新>乐业>上林>南丹>忻城。

Zeniain signis Chun, which is an important protected tree endemic to Karst area with leaves used for fodder, has important ecological and economic value in south China. However, little was known about the drought resistance capability of Z. signis from different provenances. The experiment was conducted with one-year Z. signis seedlings leaves from 6 provenances (Daxin, Leye, Shanglin, Xincheng, Longsheng, Nandan) in Guangxi, the physiological parameters of leaf relative water content, free proline content, soluble sugar content, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity and peroxidase (POD) activity were measured under artificial simulated natural drought stress environment. The results showed that with the prolongation of drought stress, the leaf relative water content decreased while the soluble sugar content increased in all the six provenances;the free proline content showed an increasing trend in Daxin and Leye, an up-down-up trend in Shanglin, Xincheng and Longsheng, and a decreasing at 4 d then increasing trend in Nandan;the MDA content showed an up-down-up trend in Daxin, Shanglin, Xincheng and Longsheng, a down-up-down trend in Leye, and a decreasing at 4 d then increasing trend in Nandan;the SOD activity showed an up-down-up trend in Daxin, an increasing at 4 d then decreasing trend in Leye, an increasing trend in Shangling and Longsheng, and a down-up- down trend in Xincheng and Nandang;the POD activity showed an increasing trend in Nandan, and an up-down-up trend in the others which the POD activity maximum were appeared at 12 d except Longsheng (4 d). According to the comprehensive evaluation of membership function method, the drought tolerances of six Z. signis provenances were showing as followed: Longsheng>Daxin> Leye>Shanglin>Nandan>Xincheng.