Ecological role of physical dormancy in seeds of Oxytropis racemosa in a semiarid sandland with unpredictable rainfall  

作　　者：Dandan Hu Jerry M.Baskin Carol C.Baskin Xuejun Yang Zhenying Huang 

机构地区：[1]State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,No.20 Nanxincun,Xiangshan,Haidian District,Beijing 100093,P.R.China [2]University of Chinese Academy of Sciences,No.19(A)Yuquan Road,Shijingshan District,Beijing 100039,P.R.China [3]Department of Biology,University of Kentucky,Lexington,KY 40506,USA [4]Department of Plant and Soil Sciences,University of Kentucky,Lexington,KY 40546,USA

出　　处：《Journal of Plant Ecology》2018年第4期542-552,共11页植物生态学报（英文版）

基　　金：This research was supported by the Key Basic Research and Development Plan of P.R.China(2016YFC050080502);the National Natural Science Foundation of P.R.China(31370705,31570416).

摘　　要：Aims Seed dormancy and the soil seed bank are crucial to plant regeneration strategy,especially in semiarid ecosystems with unpredictable precipi-tation.the aim of this study was to investigate how seed dormancy is controlled by environmental factors and how it is correlated with the soil seed bank and regeneration of the perennial legume Oxytropis race-mosa,a dominant perennial herb in Mu Us Sandland of semiarid China.Methods Germination and imbibition experiments on fresh intact and scarified seeds of O.racemosa were used to identify physical dormancy(PY)in seeds of this species.Soil seed bank dynamics,timing of seedling emer-gence and the fate of buried seeds in the natural habitat were investigated.Important Findings PY was broken by mechanical scarification or wet heat/ice water cycles but not solely by dry heat or wet heat treatment.the soil seed bank exhibited seasonal changes in the number of seeds,which was highest in September and lowest in July.Seeds buried at different sand depths gradually lost dormancy;20-42%of the seeds remained dormant after 20 months of burial.Dormancy break occurs grad-ually throughout the year.Our results indicate that O.racemosa exhibits hardcoatedness heterogeneity that spreads germination of a seed cohort between seasons and years in the semiarid environ-ment,where the amount of precipitation during the growing season is highly variable.

关 键 词：Oxytropis racemosa physical dormancy seedling emergence soil moisture soil seed bank soil temperature unpredictable rainfall 

分 类 号：X51[环境科学与工程—环境工程]