Differences in seed properties and germination between native and introduced populations of Triadica

• 作 者: Jialiang Zhang Evan Siemann Baoliang Tian Wei Huang Jianqing Ding
• 机 构: CAS Key Laboratory of Aquatic Botany and Watershed Ecology,Wuhan Botanical Garden,Chinese Academy of
• 出 处: 植物生态学报（英文版）
• 发表日期: 2020年1期
• 关键词: invasive plant germination seed volume gibberellins plant invasion

很多入侵植物的种子比原产地植物的种子萌发的更快,这可能有利于它们成功入侵.为了理解生物入侵过程,对入侵植物的入侵种群和原产地种群的种子特性和萌发特征同时进行评估极为必要.本研究中,我们以乌桕(Triadica sebifera)为研究对象探究种子萌发和种子特征的种内差异.我们利用采于2017年的乌桕种子,来自中国的12个原产地种群和美国的12个引入地种群,测定种子的物理性状(体积、重量、种皮硬度和种皮厚度)和化学特性[种仁的粗脂肪、可溶性蛋白质、糖、赤霉素(GA)和脱落酸(ABA)l,并在中国的温室中测定种子的发芽率和萌发时间.此外,我们在美国用采自2016和2017年的种子开展了研究地点(中国和美国)和种子采集年份(2016和2017年)对种子萌发影响的比较实验.来自引入地的种子要比来自原产地的种子萌发更快.种子的物理和化学特性测定结果表明:与原产地种子相比,引入地种子更大、种仁内含有的赤霉素浓度以及GA∶ABA比更高,但粗脂肪含量较低.种子重量、种皮硬度、种皮厚度、种仁脱落酸、可溶性蛋白质和糖含量在引入地和原产地之间没有显著差异.在中国和美国温室间的种子萌发率具有相关性,但种群的萌发率具有年际变化.我们的研究结果表明,体积较大和赤霉素含量较高的种子可能有助于快速萌发,这可能也有利于乌桕在引入地的入侵.“,”Aims Seeds of many invasive plants germinate more quickly than those of native species,likely facilitating invasion success.Assessing the germination traits and seed properties simultaneously for introduced and native populations of an invasive plant is essential to understanding biological invasions.Here,we used Triadica sebifera as a study organism to examine intraspecific differences in seed germination together with seed characteristics.Methods We measured physical(volume,mass,coat hardness and coat thickness of seeds)and chemical(crude fat,soluble protein,sugar,gibberellins[GA]and abscisic acid[ABA]of kernels)properties of T.sebifera seeds collected in 201 7 from 12 introduced(United States)populations and 12 native(China)populations and tested their germination rates and timing in a greenhouse experiment in China.Furthermore,we conducted an extra experiment in the United States using seeds collected in 2016 and 2017 to compare the effects of study sites(China vs.United States)and seed collection time(2016 vs.2017)on seed germination.Important Findings Seeds from the introduced range germinated faster than those from the native range.Physical and chemical measurements showed that seeds from the introduced range were larger,had higher GA concentrations and GA:ABA ratio,but lower crude fat concentrations compared to those from the native range.There were no significant differences in seed mass,coat hardness and coat thickness or kernel ABA,soluble protein or sugar concentrations between seeds from introduced vs.native ranges.Germination rates were correlated between United States and China greenhouses but germination rates for populations varied between collection years.Our results suggest that larger seeds and higher GA likely contribute to faster germination,potentially facilitating T.sebifera invasion in the introduced range.