不同花生品种对旱涝胁迫的响应及生理机制

为评价花生对旱、涝胁迫的响应,本试验以4个旱、涝耐性差异明显的花生品种为材料,运用温室防雨盆栽方法,在苗期、花针期分别进行正常灌溉(对照)、干旱(7d,叶片萎蔫)、根部淹涝(土面水深2 cm,时间1d、3d、7d)和整株淹涝(水深至苗顶,时间1d、3d、7d)的处理,测定地上部及根系生物量、根冠比、根系活力、叶片超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量。结果表明,苗期、花针期干旱均抑制地上部生长,提高根冠比;苗期干旱降低根系生物量,而花针期增加。2个时期淹涝均促进地上部生长、抑制根系生长、降低根冠比,并随淹水加深、延时而加重。旱、涝条件下根系活力均降低,SOD、MDA呈上升趋势。遭受相同时间(7d)的水分胁迫后,危害程度以干旱重于淹涝,花针期重于苗期。基于生物量、生理指标变化的综合分析进一步表明,4个花生品种的旱、涝耐性差异很大,湘花55号耐旱性强、耐涝性弱,豫花15号耐旱性弱、耐涝性强,中花4号耐旱、涝性均最弱,中花8号耐旱、涝性均最强。

Responses of different peanut cultivars to drought and waterlogging stress and physiological mechanism

To evaluate the responses of peanut to drought and waterlogging stresses, biomass of shoot and root, root-shoot ratio, root activity, SOD activity and MDA content in leaves at seedling and flowering-pegging stages were determined. A pot experiment with four different drought-waterlogging tolerance cultivars was conducted in rainproof greenhouse. Four water treatments were carried out as follows: normal irrigation (CK), drought (7d, leaf wilting), root waterlogging (1d, 3d and 7d, 2cm of water-depth over soil surface) and whole plant waterlogging (1d, 3d and 7d, water-depth over the canopy of plant). The results showed that drought stress decreased shoot dry biomass (SDB) and increased root-shoot ratio (RSR) at seedling and flowering-pegging stages, reduced root dry biomass (RDB) at seedling stage whereas elevated at flowering-pegging stage. Waterlogging stress accelerated SDB, reduced RDB and RSR at both stages, and the effects of it aggravated with increase of water level and progress of time. For all cultivars, root activity decreased, but SOD activity and MDA content in leaf increased under drought and waterlogging conditions. After same time (7d) of water stresses, damage suffering from drought was much heavier than that from waterlogging, while that at flowering-pegging stage was much heavier than at seedling stage. Comprehensive analysis based on changing of biomass and physiological indexes further revealed that there was large difference in drought and waterlogging tolerance among cultivars: Xianghua 55 had higher tolerance to drought and lower to waterlogging, Yuhua 15 had lower tolerance to drought and higher to waterlogging, Zhonghua 4 had the lowest tolerance to the two stresses, while Zhonghua 8 had the highest.