大气二氧化碳(CO_2)浓度和气温增高是全球气候变化的重要特征,本研究旨在揭示未来气候变化条件下生长的水稻,其种子活力是否受这两个重要环境因子的影响。利用稻田FACE(Free Air CO_2 Enrichment)系统,以常规水稻武运粳23为供试材料,设置对照(Ambient,环境空气)、CO_2浓度增高(比Ambient高200mumol/mol)、温度增高(比Ambient高2℃)和CO_2浓度与温度同时增高四个处理,成熟期收获种子进行实验室标准发芽实验。结果表明,与对照相比,单独CO_2浓度增加使成熟种子浸种24h浸出液电导率平均增加16.5%,但使种子露白率、发芽率、发芽势和发芽指数分别下降7.8%、10.0%、 17.4%和8.9%。相似地,单独温度增高或CO_2浓度和温度同时增高处理对上述参数影响的方向一致,但影响的幅度变小,多未达显著水平。与环境生长温度相比,高温环境下全生育期CO_2浓度升高使成熟种子浸种24h浸出液电导率、露白率、发芽率、发芽势和发芽指数的影响变小,表现在CO_2浓度与温度处理间存在一定程度的交互作用。种子发芽后芽和根系性状对高CO_2浓度或高温均无显著响应。以上结果说明,大气CO_2浓度增高200mumol/mol环境条件下,常规粳稻武运粳23成熟种子露白率、发芽率、发芽势和发芽指数等指标均明显下降,但在同时适度增温的生长环境下这种负面影响有减弱的趋势。
英文摘要:
The increases in atmospheric carbon dioxide concentration and air temperature are two important features of global climate change.The present study was conducted to reveal how rice seed vigor will be affected by these two important environmental factors when rice plants were grown under future environment conditions.By using the rice Free Air CO_2 Enrichment(FACE)system,an inbred japonica rice Wuyunjing 23 was grown under four different combinations of CO_2concentration and temperature treatments,i.e.ambient air(Ambient),elevated [CO_2](EC, Ambient+200mumol/mol,elevated temperature(ET,Ambient+2℃)and elevated[CO_2]+elevated temperature(EC +ET).At maturity,seeds were harvested and subjected to the standard germination trial in laboratory.The results indicated that compared with seeds obtained from ambient air,the seeds from EC plants showed higher value(+ 16.5%)in the electrical conductivity of deionized water in which seeds have been soaked for 24 hours.However,EC decreased the sprouting rate,germination rate,germination potential and germination index by 7.8%,10.0%,17.4% and 8.9%,respectively.The effects of ET and EC+ET on the above parameters followed the similar patterns,but in most cases the effects became smaller and were statistically insignificant.Compared with the ambient temperature, high temperature during growth reduced high CO_2 effects on the electrical conductivities of seed soaking solution, sprouting rate,germination rate,germination potential and germination index,which was shown by certain degree of interaction between CO_2 concentration and temperature.The characteristics of sprout and root of the germinated seed were not changed by CO_2 concentration or/and temperature increases during plant growth.The above results indicated that the sprouting rate,germination rate,germination potential and germination index of the seed of inbred japonica rice Wuyunjing 23 were significantly decreased when the seeds were produced in the high CO_2 concentration environment.But such negative effects of high CO_2 concentration on seed germination capacity of rice might be ameliorated by simultaneously moderate increase of air temperature during plant growth.