Aims Foliar herbivory and water stress may affect floral traits attractive to pollinators.Plant genotypes may differ in their responses to the interplay between these factors,and evolution of phenotypic plasticity cou...Aims Foliar herbivory and water stress may affect floral traits attractive to pollinators.Plant genotypes may differ in their responses to the interplay between these factors,and evolution of phenotypic plasticity could be expected,particularly in heterogeneous environments.We aimed at evaluating the effects of simulated herbivory and experimental drought on floral traits attractive to pollinators in genetic families of the annual tarweed Madia sativa,which inhabits heterogeneous environments in terms of water availability,herbivore abundance and pollinator abundance.Methods In a greenhouse experiment with 15 inbred lines from a M.sativa population located in central Chile(Mediterranean-type climate),we measured the effects of apical bud damage and reduced water availability on:number of ray florets per flower head,length of ray florets,flower head diameter,number of open flower heads per plant,flowering plant height and flowering time.Important Findings Apical damage and water shortage reduced phenotypic expression of floral traits attractive to pollinators via additive and non-additive effects.Plants in low water showed decreased height and had fewer and shorter ray florets,and fewer and smaller flower heads.Damaged plants showed delayed flowering,were less tall,and showed shorter ray florets and smaller flower heads.The number of ray florets was reduced by damage only in the low water treatment.Plant height,flowering time and number of flower heads showed among-family variation.These traits also showed genetic variation for plasticity to water availability.Ray floret length,flower head size and time to flowering showed genetic variation for plastic responses to apical damage.Plasticity in flowering time may allow M.sativa to adjust to the increased aridity foreseen for its habitat.Because genetic variation for plastic responses was detected,conditions are given for evolutionary responses to selective forces acting on plastic traits.We suggest that the evolution of adaptive floral plasticity in M.sativa in this ecological scenario(heterogeneous environments)would result from selective forces that include not only pollinators but also resource availability and herbivore damage.展开更多
利用6条ISSR引物对内蒙古西伯利亚杏资源圃内选择的30个早花个体和37个晚花个体进行遗传多样性分析,共扩增出94个位点,其中多态性位点为92个。早花群体等位基因数(Na)为1.8936,有效等位基因数(Ne)为1.4579,多态性位点数为89.36%,Nei...利用6条ISSR引物对内蒙古西伯利亚杏资源圃内选择的30个早花个体和37个晚花个体进行遗传多样性分析,共扩增出94个位点,其中多态性位点为92个。早花群体等位基因数(Na)为1.8936,有效等位基因数(Ne)为1.4579,多态性位点数为89.36%,Nei's基因多样性指数(H)为0.2716,Shannon多样性指数(I)为0.4148。晚花群体依次Na为1.9681,Ne为1.4594,PPB%为96.81%,H为0.2795,I为0.4306。西伯利亚杏晚花群体比早花群体具有更高的遗传多样性。早晚花群体间的遗传分化系数(Gst)为0.0308,总遗传变异的3.08%存在于群体间,96.92%存在于群体内,AMOVA分析也得到了相似结果,群体间的遗传变异是7%,群体内的变异为93%。早晚花群体间的基因流(Nm)为15.7585,群体间有很强的基因流。用NTSYS聚类软件对早晚花67个体进行了聚类,在相似系数0.652处聚成了晚花和早花两类;用Gen Al Ex软件进行主成分分析时,也聚成了晚花和早花两类。研究结果表明,西伯利亚杏晚花群体比早花群体具有更高的遗传多样性,早晚花群体间存在一定的遗传分化。展开更多
基金Fondo de Desarrollo Científico y Tecnológico(Chile)(3040036 to W.G.L.).
文摘Aims Foliar herbivory and water stress may affect floral traits attractive to pollinators.Plant genotypes may differ in their responses to the interplay between these factors,and evolution of phenotypic plasticity could be expected,particularly in heterogeneous environments.We aimed at evaluating the effects of simulated herbivory and experimental drought on floral traits attractive to pollinators in genetic families of the annual tarweed Madia sativa,which inhabits heterogeneous environments in terms of water availability,herbivore abundance and pollinator abundance.Methods In a greenhouse experiment with 15 inbred lines from a M.sativa population located in central Chile(Mediterranean-type climate),we measured the effects of apical bud damage and reduced water availability on:number of ray florets per flower head,length of ray florets,flower head diameter,number of open flower heads per plant,flowering plant height and flowering time.Important Findings Apical damage and water shortage reduced phenotypic expression of floral traits attractive to pollinators via additive and non-additive effects.Plants in low water showed decreased height and had fewer and shorter ray florets,and fewer and smaller flower heads.Damaged plants showed delayed flowering,were less tall,and showed shorter ray florets and smaller flower heads.The number of ray florets was reduced by damage only in the low water treatment.Plant height,flowering time and number of flower heads showed among-family variation.These traits also showed genetic variation for plasticity to water availability.Ray floret length,flower head size and time to flowering showed genetic variation for plastic responses to apical damage.Plasticity in flowering time may allow M.sativa to adjust to the increased aridity foreseen for its habitat.Because genetic variation for plastic responses was detected,conditions are given for evolutionary responses to selective forces acting on plastic traits.We suggest that the evolution of adaptive floral plasticity in M.sativa in this ecological scenario(heterogeneous environments)would result from selective forces that include not only pollinators but also resource availability and herbivore damage.
文摘利用6条ISSR引物对内蒙古西伯利亚杏资源圃内选择的30个早花个体和37个晚花个体进行遗传多样性分析,共扩增出94个位点,其中多态性位点为92个。早花群体等位基因数(Na)为1.8936,有效等位基因数(Ne)为1.4579,多态性位点数为89.36%,Nei's基因多样性指数(H)为0.2716,Shannon多样性指数(I)为0.4148。晚花群体依次Na为1.9681,Ne为1.4594,PPB%为96.81%,H为0.2795,I为0.4306。西伯利亚杏晚花群体比早花群体具有更高的遗传多样性。早晚花群体间的遗传分化系数(Gst)为0.0308,总遗传变异的3.08%存在于群体间,96.92%存在于群体内,AMOVA分析也得到了相似结果,群体间的遗传变异是7%,群体内的变异为93%。早晚花群体间的基因流(Nm)为15.7585,群体间有很强的基因流。用NTSYS聚类软件对早晚花67个体进行了聚类,在相似系数0.652处聚成了晚花和早花两类;用Gen Al Ex软件进行主成分分析时,也聚成了晚花和早花两类。研究结果表明,西伯利亚杏晚花群体比早花群体具有更高的遗传多样性,早晚花群体间存在一定的遗传分化。