荒漠草原建群种及其枯落物的C、N、P生态化学计量特征

以希拉穆仁草原建群种羊草(Leymuschinensis)、短花针茅(Stipa breviflora Griseb)、芨芨草(Achnatherum splendens nevski)及其枯落物为研究对象,通过测定其C、N、P质量分数,并计算生态化学计量比,分析建群种养分限制格局及养分再吸收规律。结果表明:①植物叶片的C、N、P质量分数均值分别为398.74、24.41、1.55 g/kg,枯落物的为362.53、14.79、1.17 g/kg,3种植物叶片的C、N、P质量分数与其枯落物的差异显著(P<0.05)。②植物在枯落之前会将养分转移,防止养分的流失,N、P的养分再吸收效率范围分别在13.51%~77.49%、2.65%~49.51%,N的回流率大于P,进而使其具备了较强的适应干旱环境的能力。③3种植物叶片的N/P、C/N、C/P变化范围分别在11.81~21.70、15.76~16.59、195.47~273.37,枯落物的变化范围分别在7.72~17.05、17.71~64.46、215.43~487.46,3种植物叶片与枯落物的N/P、C/P差异显著(P<0.05)。④植物叶片N/P均值为16.95,枯落物N/P均值为12.31,说明植物的生长主要受P的限制。研究结果可为荒漠草原提供草地管理指导。

Ecological Stoichiometry Characteristics of C,N and P of Constructive Species and Litter in Desert Steppe

Different plant and litter of Leymuschinensis,Stipa breviflora Griseb and Achnatherum splendens nevski in the Xilamuren desert grassland were studied.The purpose was to characterize the effects of veretation type on plant and litter carbon(C),nitrogen(N)and phosphorus(P)and C∶N∶P ecological stoichiometic.The C,N and P contents of plant and litter were measured,and the ecological stoichiometric ratio was calculated.Analysis on nutrient limitation and nutrient reabsorption of main species was conducted in this area.The average plant C,N and P contents are 398.74,24.41 and 1.55 g/kg,respectively.And the average litter C,N and P contents are 362.53,14.79 and 1.17 g/kg,respectively.The content C,N and P of three plants varied significance litter(P<0.05).Plant transferred nutrient before they wither to prevent nutrient loss.The nutrients resorption efficiencies of N and P are different,ranging in 13.51%-77.9%,and 2.65%-49.51%,respectively.Among them,N is larger than P.It also further illustrates have a strong adaptability to arid environment.The ranges of N/P,C/N and C/P of three plants are 11.81-21.7,15.76-16.59,and 195.47-373.37,respectively.The ranges of litters are 7.72-17.05,17.71-64.46,and 215.43-487.46,respectively.While N/P and C/P in three plants are significantly related litter(P<0.05).The average plant N/P is 16.95,and the litter is 12.31.The plants are restricted by phosphors(P).