Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China.P.forrestii tree numbers have greatly decreased due to deforestation,over-utilization and habitat degradation.Here we cl...Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China.P.forrestii tree numbers have greatly decreased due to deforestation,over-utilization and habitat degradation.Here we clarify P.forrestii community types,structure,species diversity,seedling recruitments and growth trends.We identified four P.forrestii community types:(1)Pseudotsuga forrestii-Quercus guyavifolia-Acer davidii evergreen coniferous and broad-leaved mixed forest;(2)Pseudotsuga forrestii-Pinus yunnanensis-Quercus guyavifolia evergreen coniferous and broad-leaved mixed forest;(3)Pseudotsuga forrestii evergreen coniferous forest;(4)Pseudotsuga forrestii-Abies georgei var.smithii evergreen coniferous forest.P.forrestii forests are characterized by both warm temperate and temperate affinities.Simpson diversity,Pielou evenness,Shannon-Wiener diversity indices ranged from 0.75 to 0.76,0.74-0.81,and 1.62-1.93,respectively,with no significant differences among the four forest types.The forest stratification was multilayered.The canopy layer was generally 10-25 m tall,with the emergent layer reached 25-42 m.DBH and age structures of P.forrestii showed multimodal distributions.Its maximum age P.forrestii was 570 years with a DBH of 143 cm.The growth of annual ring width of P.forrestii was slow,and generally decreased with age,whereas the basal area at the breast height increased with age.Established seedlings/saplings were mainly found in unstable micro-habitats.Regeneration of P.forrestii depends on moderate natural disturbances.Finally,we provide recommendations for P.forrestii conservation.展开更多
Forrestiacids C(1)and D(2),a pair of C-25 epimeric triterpene–diterpene adducts were isolated from the needles and twigs of the vulnerable conifer Pseudotsuga forrestii.This unprecedented class of compounds might be ...Forrestiacids C(1)and D(2),a pair of C-25 epimeric triterpene–diterpene adducts were isolated from the needles and twigs of the vulnerable conifer Pseudotsuga forrestii.This unprecedented class of compounds might be generated via an intermolecular Michael addition reaction of a rearranged 6/6/5/5-fused spiro-lanostene with an abietene.Their structures were established by spectroscopic data and X-ray crystallography.The adducts showed inhibitory activities against the ATP-citrate lyase(ACL)and acetyl-CoA carboxylase 1(ACC1),two rate-limiting enzymes in the de novo lipogenesis pathway.展开更多
基金This study received financial support from the Science and Technology Department of Yunnan University,China(2019YNU002)Major Program for Basic Research Project of Yunnan Province,China(202101BC070002)the Special Foundation for National Science and Technology Basic Resources Investigation of China(2019FY202300).
文摘Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China.P.forrestii tree numbers have greatly decreased due to deforestation,over-utilization and habitat degradation.Here we clarify P.forrestii community types,structure,species diversity,seedling recruitments and growth trends.We identified four P.forrestii community types:(1)Pseudotsuga forrestii-Quercus guyavifolia-Acer davidii evergreen coniferous and broad-leaved mixed forest;(2)Pseudotsuga forrestii-Pinus yunnanensis-Quercus guyavifolia evergreen coniferous and broad-leaved mixed forest;(3)Pseudotsuga forrestii evergreen coniferous forest;(4)Pseudotsuga forrestii-Abies georgei var.smithii evergreen coniferous forest.P.forrestii forests are characterized by both warm temperate and temperate affinities.Simpson diversity,Pielou evenness,Shannon-Wiener diversity indices ranged from 0.75 to 0.76,0.74-0.81,and 1.62-1.93,respectively,with no significant differences among the four forest types.The forest stratification was multilayered.The canopy layer was generally 10-25 m tall,with the emergent layer reached 25-42 m.DBH and age structures of P.forrestii showed multimodal distributions.Its maximum age P.forrestii was 570 years with a DBH of 143 cm.The growth of annual ring width of P.forrestii was slow,and generally decreased with age,whereas the basal area at the breast height increased with age.Established seedlings/saplings were mainly found in unstable micro-habitats.Regeneration of P.forrestii depends on moderate natural disturbances.Finally,we provide recommendations for P.forrestii conservation.
基金supported by grants from the National Natural Science Foundation of China(Nos.21937002,81773599,21772025)。
文摘Forrestiacids C(1)and D(2),a pair of C-25 epimeric triterpene–diterpene adducts were isolated from the needles and twigs of the vulnerable conifer Pseudotsuga forrestii.This unprecedented class of compounds might be generated via an intermolecular Michael addition reaction of a rearranged 6/6/5/5-fused spiro-lanostene with an abietene.Their structures were established by spectroscopic data and X-ray crystallography.The adducts showed inhibitory activities against the ATP-citrate lyase(ACL)and acetyl-CoA carboxylase 1(ACC1),two rate-limiting enzymes in the de novo lipogenesis pathway.
