干旱预处理改变花生苗期对后干旱胁迫的生理响应.docVIP

稿件编号：stxb201611112296 ?2-含量；抗氧化酶SOD、CAT活性降低，其中POD活性降低最为明显，并在复水后恢复到与对照相同水平或低于对照。与正常水分的对照相比，干旱胁迫显著降低叶片光合速率（PN）、最大光合势能（PC）、最大光量子产量（YQ），但重复干旱处理在重复干旱胁迫时期和复水后PN、PC和YQ均高于干旱处理。预干旱胁迫导致光合和气孔导度滞后面积、滞后率（HP和Hg）增加，经过预干旱胁迫后，重复干旱显著降低光合和气孔导度滞后面积和滞后率。预干旱胁迫提高植株在重复干旱胁迫下叶片含水量，减轻重复干旱对植株造成的生理伤害，在光合作用上提高对重复干旱的抵御能力，并在复水后快速恢复到正常水分条件下植株生长水平，减少干旱对植株的不利影响。因此，预干旱胁迫促使花生幼苗具备适应或可记忆初始胁迫的能力，重复干旱胁迫时表现更为迅速和强烈的生理防御和快速的生理恢复机制。 关键词：重复干旱胁迫；光合滞后；花生；抗氧化酶；气孔导度滞后；胁迫记忆 Previous drought alters physiological responses to subsequent drought stress in peanut seedlings QIN Feifei*, CI Dunwei Shandong Peanut Research Institute, Qingdao 266100，China Abstract: A pot experiment was performed in a rain shelter. The aim of this study was to explore the possible physiological responses or roles of pre-drought priming to/in damage alleviation of subsequent severe drought stress in peanut seedlings. Three treatments were designed as follows: control (75% of field water capacity), drought stress without pre-drought treatment (D, 35%), and subsequent drought stress with pre-drought treatment (DD, 35%). Compared with the D treatment, pre-drought priming increased the leaf relative water content and reduced proline accumulation in the DD treatment when seedlings experienced subsequent drought stress. In addition, MDA and O2?- contents and activities of antioxidant enzymes including superoxide dismutease (SOD), catalase (CAT), and peroxidase (POD) decreased in response to the DD treatment and recovered to the level of the control, or lower, following rewatering. Drought decreased photosynthetic rate (PN), photosynthetic capacity (PC), and maximum quantum yield of PSII (YQ). However, PN, PC, and YQ in the DD treatment were higher than those in the D treatment when seedlings experienced a second drought stress. The hysteresis area and hysteresis rate of leaf photosynthesis (HP) and stomatal conductance (Hg) decreased significantly in response to the DD treatment following repetitive drought and rewatering. In conclusion, pre-drough