Two new 24-hydroxylated asterosaponins, sodium （20R,24S）-6α-O-（4-O-sodiumsulfato-β-D-quinovopyranosyl）-5α-cholest- 9（11）-en-3β,24-diol 3-sulfate （1） and sodium （20R,24S）-6α-O-β-O-methyl-β-D-quinovopyr...Two new 24-hydroxylated asterosaponins, sodium （20R,24S）-6α-O-（4-O-sodiumsulfato-β-D-quinovopyranosyl）-5α-cholest- 9（11）-en-3β,24-diol 3-sulfate （1） and sodium （20R,24S）-6α-O-β-O-methyl-β-D-quinovopyranosyl-（1→2）-β-D-xylopyranosyl- （1 → 3）-[3-D-glucopyranosyl]-5α-cholest-9（11）-en-3β,24-diol 3-sulfate （2）, were isolated from the starfish Culcita novaeguineae. Their structures were elucidated by extensive spectral analysis and chemical evidences.展开更多
Aims Plants control leaf phenology to maximize annual photosynthetic product.Although ferns play an important ecological role in many habitats,especially forests,their phenology traits have been poorly studied.Here,we...Aims Plants control leaf phenology to maximize annual photosynthetic product.Although ferns play an important ecological role in many habitats,especially forests,their phenology traits have been poorly studied.Here,we investigate the leaf phenology of two ferns of the forest understorey and analyse the relationship between the timing of leaf emergence and spore dispersal and the effect of between-year climatic variation.Methods We compared the leafing and sporing phenologies of two ferns with very large(>2 m),overwintering leaves:Culcita macrocarpa and Woodwardia radicans.We regularly monitored individuals of six popu-lations in the northwestern Iberian Peninsula during a 3-year study.We studied eight phenology variables:leafing start date,leafing end date,leaf expansion time,number of new leaves per individual,between-individual synchrony,within-individual synchrony,percentage of fertile leaves and spore release date.We also determined leaf mass per area(LMA)and gathered data on air temperature and humidity.Important findings Both C.macrocarpa and W.radicans produce few leaves(~2 leaves individual−1 year−1),which expand simultaneously for a very long period(from midwinter to early summer),are retained for more than 1 year(37 and 19 months,respectively)and have relatively high LMAs.Such traits,together with large leaf size,have also been found in seed plants from the forest understorey and represent adap-tations to this light-limited environment.Spores of both study ferns are simultaneously released in late winter,with little between-year variation caused by differences in air humidity.This remarkable similarity between species suggests that the convergence in tim-ing of leaf emergence favours the convergence in timing of spore dispersal.展开更多
基金the National Nature Science Foundation of China(No.20502035)the National High-Tech Research and Development Project(No.2006AA09Z423)
文摘Two new 24-hydroxylated asterosaponins, sodium （20R,24S）-6α-O-（4-O-sodiumsulfato-β-D-quinovopyranosyl）-5α-cholest- 9（11）-en-3β,24-diol 3-sulfate （1） and sodium （20R,24S）-6α-O-β-O-methyl-β-D-quinovopyranosyl-（1→2）-β-D-xylopyranosyl- （1 → 3）-[3-D-glucopyranosyl]-5α-cholest-9（11）-en-3β,24-diol 3-sulfate （2）, were isolated from the starfish Culcita novaeguineae. Their structures were elucidated by extensive spectral analysis and chemical evidences.
基金This research was supported by Xunta de Galicia Project PGIDT99PXI20301A.
文摘Aims Plants control leaf phenology to maximize annual photosynthetic product.Although ferns play an important ecological role in many habitats,especially forests,their phenology traits have been poorly studied.Here,we investigate the leaf phenology of two ferns of the forest understorey and analyse the relationship between the timing of leaf emergence and spore dispersal and the effect of between-year climatic variation.Methods We compared the leafing and sporing phenologies of two ferns with very large(>2 m),overwintering leaves:Culcita macrocarpa and Woodwardia radicans.We regularly monitored individuals of six popu-lations in the northwestern Iberian Peninsula during a 3-year study.We studied eight phenology variables:leafing start date,leafing end date,leaf expansion time,number of new leaves per individual,between-individual synchrony,within-individual synchrony,percentage of fertile leaves and spore release date.We also determined leaf mass per area(LMA)and gathered data on air temperature and humidity.Important findings Both C.macrocarpa and W.radicans produce few leaves(~2 leaves individual−1 year−1),which expand simultaneously for a very long period(from midwinter to early summer),are retained for more than 1 year(37 and 19 months,respectively)and have relatively high LMAs.Such traits,together with large leaf size,have also been found in seed plants from the forest understorey and represent adap-tations to this light-limited environment.Spores of both study ferns are simultaneously released in late winter,with little between-year variation caused by differences in air humidity.This remarkable similarity between species suggests that the convergence in tim-ing of leaf emergence favours the convergence in timing of spore dispersal.
