| It is well known that carbon(C),nitrogen(N),phosphorous(P)are not only the important nutrients of the grassland ecological system productivity,but also the primary nutrients of plant growth and survival in many natural environments.In order to know stoichiometry of plant leaves in alpine meadow,we choosed 42 common spe-cies to study the stoichiometric charactertics of carbon(C),nitrogen(N),phosphorous(P)for mature leaves and sencesed leaves,and NRE(Nitrogen resorption efficiency)and NUE(Nitrogen use efficiency)of all 42 plant species and among three plant functional groups.The results showed:1.The contents of C,N and P for mature leaves ranged in 34.60～49.99%,1.25～3.72%and 0.17～0.66%,with mean being 42.78%,2.21%,and 0.30%,respectively.C/N,C/P and N/P of mature leaves ranged from 10.94 to 32.16,from 66.18 to 270.18,and from 3.68 to 15.56,with mean being 20.52,156.79 and 7.91,respectively.2.The contents of C,N and P for leaf litter ranged in 33.05～56.66%,0.37～2.84%and 0.07～0.37%,with mean being 42.29%,1.17%,and 0.21%,respectively.C/N,C/P and N/P of leaf litter ranged from 16.55 to 127.92,from 113.72 to 696.46,and from 2.06 to 20.04,with mean being 43.83,229.14 and 5.89,respectively.3.As compared with other results,the stoichiometric characteristics of C,C/N,C/P and N/P for mature leaves were lower,while both N and P were higher.There was no differences in C content between mature leaves and leaf litter,while N,P and N/P were significantly lower in leaf litter than in mature leaves(P<0.05);in contrast,both C/N and C/P were higher in leaf litter than in mature leaves.4.C concentration did not correlate between mature leaves and leaf litter(r=0.154,P<0.05),but N concentration and P concentration in mature leaf and leaf litter correlated well,respectively(r=0.756,P<0.0001;r=0.661,P<0.0001);Similarly,C/N,C/P and N/P in mature leaves and leaf litter correlated well,respectively(r ＝0.624,P<0.0001;r =0.609,P<0.0001;r=0.778,P<0.0001).5.The contents of N in mature leaves among Legumes,Graminoids,Forbs with mean being 31.89 mg.g-1,19.94 mg.g-1 and 20.73 mg.g-1,respectively;The contents of N in leaf litters among the three plant functional groups are 21.48 mg.g-1,9.18 mg.g-1 and 10.00 mg.g-1,respectively.6.NRE of 42 plant species in our research is 48.16%;among three plant functional groups,NRE of graminoids is highest(64.96%),legumes and forbs are 32.78%and 46.18%,respectively.7.NUE of 42 plant species in our research is 103.18 g.g-1;The NUE of Legumes,Graminoids and Forbs ranged in 38.22～64.91g.g-1,90.41～254.32 g.g-1 and 44.11～174.66 g.g-1,respectively;with mean being 48.43 g·g-1,156.08 g·g-1 and 98.02 g·g-1,respectively.8.There was a strong positive correlation between mature leave and leaf litter of N concentration,and disproportionately more remained nutrient in leaf litter as live leaf nutrient concentrations increased,that is to say,nutrient resorption efficiencies decreased with an increase of mature leaf concentrations.9.There was a strong nagative correlation between N concentration in mature leaves and NUE,and NUE decreased more as live leaf nutrient concentrations increased.10.There was a strong positive allometric relationship between NRE and NUE across 42 plant species and among three plant functional groups.Our results suggested the contents of C in mature leaves were lower,and N and P concentration were higher in our study area;Different plant functional groups has different adaptation strategies characteristics,stuy plant adaptation characteristics in plant communities based on functional group is very important and meaningful. |
