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干旱胁迫下外源钙对石灰岩地区复羽叶栾树种子萌发的影响

蔡喜悦1,2,3,陈晓德1,2,3**,李朝政1,2,3,刘成1,2,3   

  1. (1三峡库区生态环境教育部重点实验室, 重庆 400715; 2重庆市三峡库区植物生态与资源重点实验室, 重庆 400715; 3西南大学生命科学学院, 重庆 400715)
  • 出版日期:2013-05-18 发布日期:2013-05-18

Effects of exogenous Ca2+ on the seed germination of Koelreuteria paniculata in limestone area of Southwest China under drought stress.

CAI Xi-yue1,2,3, CHEN Xiao-de1,2,3, LI Chao-zheng1,2,3, LIU Cheng1,2,3   

  1. (1Ministry of Education Key Laboratory of Ecoenvironments in the Three Gorges Reservoir Region, Chongqing 400715, China; 2Chongqing Key Laboratory of Plant Ecology and Resources Research in the Three Gorges Reservoir Region, Chongqing 400715, China; 3College of Life Science, Southwest University, Chongqing 400715, China)
  • Online:2013-05-18 Published:2013-05-18

摘要:

以石灰岩生态恢复优选树种复羽叶栾树种子为试材,采用聚乙二醇(PEG6000)设置0%(CK)、5%、15%、25%、30%模拟石灰岩山区不同干旱环境,以CaCl2设置0(CK)、15、20、25、30 mmol·L-1为外源钙离子梯度,模拟石灰岩地区的土壤高钙环境,研究不同浓度CaCl2、PEG及二者交互作用对种子萌发特征的影响.结果表明: 单纯CaCl2作用下,中低浓度的外源钙对复羽叶栾树种子萌发参数无显著影响,而高浓度的外源钙对种子萌发具有抑制作用,中低浓度CaCl2可以增加萌发后幼苗的鲜质量.PEG浓度从0%增至25%,各处理组的种子发芽率、发芽势、发芽指数及活力指数均与对照呈显著递减趋势,幼苗鲜质量明显减小.对各干旱处理组施加一定浓度的外源钙后,中低浓度的CaCl2可提高种子的萌发特性,而当CaCl2浓度达到30 mmol·L-1时,种子难以萌发.PEG浓度达到30%时,种子无萌发.施加一定的外源钙可以提高PEG胁迫下幼苗的鲜质量,使幼苗更加适应干旱缺水的环境.
 

Abstract: In this paper, different arid environments in the limestone area of Southwest China were simulated by using different concentrations (0%, 5%, 15%, 25%, and 30%) of PEG6000 (polyethylene glycol), and a gradient of exogenous Ca2+ (0, 15, 20, 25, and 30 mmol·L-1 of CaCl2) was installed to simulate the high calcium soil environments, aimed to study the effects of different concentration PEG6000, CaCl2, and their interactions on the seed germination characteristics of Koelreuteria bipinnata, one of the preferred species in the ecological restoration in limestone area. Under the action of CaCl2 alone, medium or low concentration exogenous Ca2+ had lesser effect on the seed germination parameters, but high concentration exogenous Ca2+ had inhibition effect on the seed germination. Medium or low concentration CaCl2 could increase the seedling fresh biomass. When the PEG6000 concentration increased from 0% to 25%, the seed germination rate, germination potential, germination index, and vigor index showed a significant decreasing trend, and the seedling fresh biomass decreased remarkably. When certain concentration of exogenous Ca2+ was exerted to the drought treatment groups, medium or low concentration CaCl2 improved the seed germination characteristics, which compensated the loss from drought stress to a certain degree. When the CaCl2 concentration was up to 30 mmol·L-1, the seeds were hard to germinate. Additionally, no seeds germinated under the condition of PEG with the concentration of 30%. It was suggested that applying definite concentration of exogenous Ca2+ could increase the seedling fresh biomass under PEG6000 stress, and make the seedlings more adapt to arid environment.