低温胁迫下西番莲叶片的生理反应及超微结构变化

摘要

In this paper,we reported the physiological and cell ultra-structure changes in leaves of one-year old Passiflora edulis cane under - 6°C cold stress treatment. Our results demonstrated that;(l)Relative e-lectrical conductivity (REC),contents of MDA and H2O2 in leaves of room temperature treatment group increased under - 6°C cold stress,but REC and MDA contents in leaves of cold-hardening treatment group declined 24. 79% and 49. 29%,respectively,after 12 hours or 72 hours treatment comparing to room temperature treatment group. (2)The content of H2O2 in room temperature treatment group increased 1. 20 folds at 48 hours treatment comparing to 0 hour treatment and increased 1. 14 folds at 48 hours treatment comparing to cold-hardening treatment group. (3)Proline content was detected to increase during treatment and the content of cold-hardening treatment group increased 15. 48% than that of room temperature treatment group after 72 hours treatment. (4)Cold-hardening treatment group enhanced cold tolerance in P.Edulis through activiting antioxidative system, such as, POD, CAT, SOD. The activities of the three enzymes were showed to reach peak after 12 hours (POD) and 24 hours (CAT,SOD) of treatment,then decreased. (5) We observed phenomena as chloroplast granas tumidness, karyothecas disappearing and plas-malemma invagination in room temperature treatment group under the electronic microscope. These symptoms were not very obvious at 24~48 hours of treatment, but turned to be serious after 72 hours cold stress. The degree of cold hurting to chloroplasts in cold-hardening treatment group were lighter than that in room temperature treatment group. The results obtained from this study hinted that cold-hardening treatment could help to increase cold endurance for P. Edulis.%以西番莲扦插苗为实验材料,比较预冷处理和常温处理(对照)情况下,西番莲叶片对-6℃低温胁迫的生理反应及叶肉细胞的超微结构变化,以探讨预冷处理对西番莲的抗寒作用及其机理.结果显示:(1)常温处理组在-6℃低温胁迫处理后,西番莲叶片的质膜相对透性、MDA含量随着低温处理时间的延长而逐渐增加,而预冷处理组这两个指标在处理期间都比常温处理组低；(2)常温处理组叶片H2O2含量在48 h时达到峰值后出现下降,而预冷处理组的H2O2含量都低于对照,在48 h时对照的H2O2含量比预冷锻炼的高1.14倍；(3)常温处理组的脯氨酸含量在24 h内增加以后出现下降,而预冷处理组在处理期间逐渐增加且高于对照；(4)常温处理组的POD活性在12h时最高,CAT、SOD活性在24 h时最高,以后出现下降.预冷处理组提高了3个酶的活性,其中POD在12h时是对照的2.73倍,CAT、SOD活性在24 h时比对照分别提高18.7％和42.7％.(5)超微结构研究显示,预冷处理组在低温胁迫72 h时虽出现叶绿体片层肿胀、核膜消失、质膜内陷等症状,但叶绿体伤害症状轻于常温处理.研究表明,低温预冷处理能够提高西番莲的抗寒性.