摘要
研究了人工模拟淹水胁迫对两年生栓皮栎(Quercusvariabilis)和枫杨(Pterocaryastenoptera)树苗的影响。经过70d的淹水处理两种植物的存活率均为100%。淹水对两种植物生理生态过程的早期影响是快速降低了二者的最大净光合速率(Pmax)、气孔导度(Gs)、最大光化学量子效率(Fv/Fm)。经过7d的淹水处理后,受淹栓皮栎的最大净光合速率是对照的39%,枫杨是对照的42%;受淹栓皮栎的气孔导度是对照的38.8%,枫杨是对照的71.9%;水淹5d后,枫杨和栓皮栎的最大光化学量子效率分别为0.694和0.757。但经过最初的下降后,枫杨的最大净光合速率、气孔导度和最大光化学量子效率逐渐恢复,而栓皮栎的则持续下降。到淹水70d时栓皮栎的最大净光合速率下降了94.1%,最大光化学量子效率的平均值为0.537。在试验过程中,枫杨产生了有利于吸收氧气的不定根和肥大的皮孔,而栓皮栎没有产生不定根。随淹水时间的增加枫杨的叶绿素含量与对照没有显著差异;而栓皮栎的叶绿素含量在第33d后大幅降低,Chla/Chlb的比值下降。淹水后第10d和第70d测定的清晨水势,受淹栓皮栎比对照高,而受淹枫杨比对照低,因此淹水导致的叶片水势的变化可能与树种相关。以上的试验结果表明受淹的栓皮栎的光合机构运转受到了严重影响,因此栓皮栎应属于对淹水较敏感的树种。从两种植物受淹水胁迫的形态和生理变化看,枫杨比栓皮栎更耐淹,更适合库塘消落区生境。
Background and Aims Cork oak （ Quercus variabilis ） and China wingnut （ Pterocarya stenoptera ） are important species in the subtropical riparian and drawdown areas of reservoirs and ponds in China. Methods We investigated the effect of waterlogging on morphological and physiological characteristics of these species. We measured the maximum net photosynthesis rate （Pmax）, stomatal conductance （Gs）, Chla fluorescence maximum quantum efficiency （ Fv/Fm ）, chlorophyll content and water potential on different days during a period of waterlogging.
Key Results Throughout a 70-day waterlogged period, the survival rates of seedlings of the two species were 100%. The earliest effects of waterlogging were significantly decreased Pmax, Gs and Fv/Fm. On the 5th day of waterlogging, Fv/Fm of cork oak and China wingnut decreased to 0.694 and 0.757, respectively. On the 7th day, significant reduction of Pmax（cork oak, 39% of control; China wingnut, 42%） and Gs（cork oak, 38.8% of control; China wingnut, 71.9% ） were observed. With prolonged waterlogging, Pmax, Gs and Fv/Fm recovered gradually to control values in China wingnut, but not in cork oak where values decreased continuously. On the 70th day, Pmax of cork oak was reduced by 94.1% of control and Fv/Fm was only 0.537. Waterlogged China wingnut seedlings developed hypertrophied lenticels and adventitious roots at their stem base and exhibited no visible symptoms of injury （neither mortality, leaf chlorosis, leaf necrosis, leaf abscission nor reduced chlorophyll content）. However, cork oak showed leaf necrosis with waterlogging. The chlorophyll content of cork oak steadily declined from the 33rd day and the Chla/Chlb ratio also deceased. Predawn leaf water potential was higher in waterlogged cork oak seedlings compared to the control on the 10th and 70th days, but lower in waterlogged China wingnut seedlings. This indicated that water potential changes under waterlogging are species specific.
Conclusions All results show that cork oak exhibits damage to its photosynthetic apparatus under waterlogging. In contrast, although the photosynthetic apparatus of China wingnut is initially affected, it can recover, indicating that China wingnut seedlings can tolerate prolonged soil waterlogging better than cork oak seedlings. We conclude that it is more suitable to plant China wingnut in the drawdown areas of reservoirs and ponds than cork oak.
出处
《植物生态学报》
CAS
CSCD
北大核心
2006年第6期960-968,共9页
Chinese Journal of Plant Ecology
基金
中国科学院知识创新工程重要方向课题(KSCX2-SW-109)
国务院三峡工程建设委员会项目(SX2002-006和SX2004-011)
关键词
栓皮栎
枫杨
库塘消落区
模拟淹水
生理生态过程
Quercus variabilis, Pterocarya stenoptera, Drawdown area of reservoirs and ponds, Simulated waterlogging, Eco-physiological processes
