A new C-glycosylflavone, named panzhihuacycaside (1), was isolated from the leaves of Cycas panzhihuaensis L. Zhou et S. Y. Yang (Cycadaceae) along with 2,3-dihydrohinokiflavone (2), 5,5',7,7', 4',4'&#...A new C-glycosylflavone, named panzhihuacycaside (1), was isolated from the leaves of Cycas panzhihuaensis L. Zhou et S. Y. Yang (Cycadaceae) along with 2,3-dihydrohinokiflavone (2), 5,5',7,7', 4',4''-hexahydroxy-(2',8')-biflavone (3), vanillic acid (4), P-sitosterol (5) and daucosterol (6). Their structures were elucidated by spectral and chemical evidence.展开更多
Cycas panzhihuaensis L.Zhou & S.Y.Yang(Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China.Although the wild C.panzhihuaensis population from ...Cycas panzhihuaensis L.Zhou & S.Y.Yang(Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China.Although the wild C.panzhihuaensis population from Panzhihua Cycad Natural Reserve is well protected and its genetic diversity has been well assessed,the genetic characteristics of populations outside the nature reserve,which face larger risks of extinction,remain unknown.Furthermore,the population genetics and historical dynamics of this endemic and endangered species have not been examined across its entire range.In this study,to analyze the genetic diversity,phylogeographical structure and demographic history of C.panzhihuaensis from all its seven known locations,we sequenced and compared molecular data from chloroplastic DNA(psbA-trnH,psbM-trnD,and trnS-trnG),single-copy nuclear genes(PHYP,AC5,HSP70,and AAT) from 61 individuals,as well as 11 nuclear micro satellite loci(SSR) from 102 individuals.We found relatively high genetic diversity within populations and high genetic differentiation among populations of C.panzhihuaensis,which is consistent with the patterns of other Asian inland cycads.Although no significant phylogeographical structure was detected,we found that small and unprotected populations possess higher genetic diversity and more unique haplotypes,which revises our understanding of diversity within this species and deserves due attention.Analysis of demographic dynamics suggest that human activity might be the key threat to C.panzhihuaensis.Based on the genetic characterization of C.panzhihuaensis,we propose several practical guidelines for the conservation of this species,especially for the populations with small sizes.展开更多
在攀枝花苏铁(Cycas panzhihuaensis L.Zhou et S.Y.Yang)自然群体中,雌雄株在数量上基本相等,但雄株的无性系产量是雌株的1.31倍,小孢子叶球的数量是大孢子叶球的2.21倍,呈现偏雄现象。小孢子叶球散粉次序是从轴基部向顶部和从小孢子...在攀枝花苏铁(Cycas panzhihuaensis L.Zhou et S.Y.Yang)自然群体中,雌雄株在数量上基本相等,但雄株的无性系产量是雌株的1.31倍,小孢子叶球的数量是大孢子叶球的2.21倍,呈现偏雄现象。小孢子叶球散粉次序是从轴基部向顶部和从小孢子叶的基部向顶部进行的,散粉高峰出现在午后,风传花粉浓度在2.55m内随着距离增加而迅速下降,而在2.55m以外维持在一个较低的水平上。在大孢子叶球内发现有两种蚂蚁和一种蜚蠊类昆虫在活动,没有发现这些昆虫对大孢子叶球的破坏,小孢子叶球则几乎没有昆虫探访。清晨在大孢子叶叶片上出现许多水样液滴,可能起着将大孢子叶叶片上沉积的花粉传递至胚珠的作用。研究表明,在攀枝花苏铁的传粉过程中,风是将花粉从小孢子叶球传至大孢子叶球的唯一媒介,大孢子叶球内活动的昆虫和大孢子叶叶片上的液滴同样起着传粉媒介作用,但不排除风传花粉一步到位的可能性。展开更多
文摘A new C-glycosylflavone, named panzhihuacycaside (1), was isolated from the leaves of Cycas panzhihuaensis L. Zhou et S. Y. Yang (Cycadaceae) along with 2,3-dihydrohinokiflavone (2), 5,5',7,7', 4',4''-hexahydroxy-(2',8')-biflavone (3), vanillic acid (4), P-sitosterol (5) and daucosterol (6). Their structures were elucidated by spectral and chemical evidence.
基金This work was supported by the National Key R&D Program of China(2017YF0505200).The authors thank Fangming Zhang for her assistance with plant sampling,and Xiuyan Feng,Rui Yang and Yujuan Zhao for their help and discussion of data analyses.
文摘Cycas panzhihuaensis L.Zhou & S.Y.Yang(Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China.Although the wild C.panzhihuaensis population from Panzhihua Cycad Natural Reserve is well protected and its genetic diversity has been well assessed,the genetic characteristics of populations outside the nature reserve,which face larger risks of extinction,remain unknown.Furthermore,the population genetics and historical dynamics of this endemic and endangered species have not been examined across its entire range.In this study,to analyze the genetic diversity,phylogeographical structure and demographic history of C.panzhihuaensis from all its seven known locations,we sequenced and compared molecular data from chloroplastic DNA(psbA-trnH,psbM-trnD,and trnS-trnG),single-copy nuclear genes(PHYP,AC5,HSP70,and AAT) from 61 individuals,as well as 11 nuclear micro satellite loci(SSR) from 102 individuals.We found relatively high genetic diversity within populations and high genetic differentiation among populations of C.panzhihuaensis,which is consistent with the patterns of other Asian inland cycads.Although no significant phylogeographical structure was detected,we found that small and unprotected populations possess higher genetic diversity and more unique haplotypes,which revises our understanding of diversity within this species and deserves due attention.Analysis of demographic dynamics suggest that human activity might be the key threat to C.panzhihuaensis.Based on the genetic characterization of C.panzhihuaensis,we propose several practical guidelines for the conservation of this species,especially for the populations with small sizes.
文摘在攀枝花苏铁(Cycas panzhihuaensis L.Zhou et S.Y.Yang)自然群体中,雌雄株在数量上基本相等,但雄株的无性系产量是雌株的1.31倍,小孢子叶球的数量是大孢子叶球的2.21倍,呈现偏雄现象。小孢子叶球散粉次序是从轴基部向顶部和从小孢子叶的基部向顶部进行的,散粉高峰出现在午后,风传花粉浓度在2.55m内随着距离增加而迅速下降,而在2.55m以外维持在一个较低的水平上。在大孢子叶球内发现有两种蚂蚁和一种蜚蠊类昆虫在活动,没有发现这些昆虫对大孢子叶球的破坏,小孢子叶球则几乎没有昆虫探访。清晨在大孢子叶叶片上出现许多水样液滴,可能起着将大孢子叶叶片上沉积的花粉传递至胚珠的作用。研究表明,在攀枝花苏铁的传粉过程中,风是将花粉从小孢子叶球传至大孢子叶球的唯一媒介,大孢子叶球内活动的昆虫和大孢子叶叶片上的液滴同样起着传粉媒介作用,但不排除风传花粉一步到位的可能性。
