CAJ | 학술논문

以浙江天童常绿阔叶林、常绿针叶林和落叶阔叶林为对象,通过对叶片和凋落物C:N:P比率与N、P重吸收的研究,揭示3种植被类型N、P养分限制和N、P重吸收的内在联系.结果显示:1)叶片C:N:P在常绿阔叶林为758:18:1,存常绿针叶林为678:14:1,在落叶阔叶林为338:11:1;凋落物C:N:P在常绿阔叶林为777:13:1,常绿针叶林为691:14:1,落叶阔叶林为567:14:1;2)常绿阔叶林和常绿针叶林叶片与凋落物C:N均显著高于落叶阔叶林;叶片C:P在常绿阔叶林最高,常绿针叶林中等,落叶阔叶林最低,常绿阔叶林和常绿针叶林凋落物C:P显著高于落叶阔叶林:叶片N:P比也是常绿阔叶林最高、常绿针叶林次之,落叶阔叶林最低,但常绿阔叶林凋落物N:P最低;3)植被叶片N、P含量间(N为x,P为y)的Ⅱ类线性回归斜率显著大于1(p＜0.05),表明叶片P含量的增加可显著提高叶片N含量;凋落物N、P含量的回归斜率约等于1,反映了凋落物中单位P含量与单位N含量间的等速损耗关系;4)常绿阔叶林N重吸收率显著高于常绿针叶林与落叶阔叶林,落叶阔叶林P重吸收率显著高于常绿阔叶林和常绿针叶林.虽然植被的N:P指示常绿阔叶林受P限制,落叶阔叶林受N限制,常绿针叶林受N、P的共同限制,但是N、P重吸收研究结果表明:受N素限制的常绿阔叶林具有高的N重吸收率,受P限制的落叶阔叶林并不具有高的P重吸收率.可见,较高的N、P养分转移率可能不是植物对N、P养分胁迫的一种重要适应机制,是物种固有的特征.
이절강천동상록활협림、상록침협림화락협활협림위대상,통과대협편화조락물C:N:P비솔여N、P중흡수적연구,게시3충식피류형N、P양분한제화N、P중흡수적내재련계.결과현시:1)협편C:N:P재상록활협림위758:18:1,존상록침협림위678:14:1,재락협활협림위338:11:1;조락물C:N:P재상록활협림위777:13:1,상록침협림위691:14:1,락협활협림위567:14:1;2)상록활협림화상록침협림협편여조락물C:N균현저고우락협활협림;협편C:P재상록활협림최고,상록침협림중등,락협활협림최저,상록활협림화상록침협림조락물C:P현저고우락협활협림:협편N:P비야시상록활협림최고、상록침협림차지,락협활협림최저,단상록활협림조락물N:P최저;3)식피협편N、P함량간(N위x,P위y)적Ⅱ류선성회귀사솔현저대우1(p＜0.05),표명협편P함량적증가가현저제고협편N함량;조락물N、P함량적회귀사솔약등우1,반영료조락물중단위P함량여단위N함량간적등속손모관계;4)상록활협림N중흡수솔현저고우상록침협림여락협활협림,락협활협림P중흡수솔현저고우상록활협림화상록침협림.수연식피적N:P지시상록활협림수P한제,락협활협림수N한제,상록침협림수N、P적공동한제,단시N、P중흡수연구결과표명:수N소한제적상록활협림구유고적N중흡수솔,수P한제적락협활협림병불구유고적P중흡수솔.가견,교고적N、P양분전이솔가능불시식물대N、P양분협박적일충중요괄응궤제,시물충고유적특정.
Aims Little is known about constrained ratios of carbon, nitrogen, and phosphorus (C:N:P) in terrestrial ecosystems. Our objective was to examine the C:N:P stoichiometry and its relationship with N and P resorption in evergreen broad-leaved forests (EBLF), evergreen coniferous forests (CF) and deciduous broad-leaved forests (DF) at the regional scale.Methods The study was conducted in Tiantong National Forest Park (29°52' N, 121°39' E), Zhejiang Province, eastern China. To estimate foliar and litter C:N:P ratios and N and P resorption efficiencies, we quantified the C, N and P concentrations in leaf and litterfall in EBLF, CF and DF. We used type II regression slopes (reduced major axis, RMA) to determine whether C:N:P stoichiometry varied across gradients of forest production and nutrients. Important findings The C:N:P ratios in EBLF, CF and DF were 758:18:1, 678:14:1 and 338:11:1 in fresh leaves and 777:13:1, 691:14:1 and 567:14:1 in litterfall, respectively. The foliar C:N ratio was highest in CF, intermediate in EBLF and lowest in DF, while the foliar C:P and N:P ratios were highest in EBLF, intermediate in CF and lowest in DF. In contrast, the litterfall C:N and C:P ratios were higher in EBLF than in CF and DF, and there were no significant differences of N:P ratio among forests. The type II regression slope for N vs. P in leaves of overall plants was statistically >1, suggesting an increasing investment of N with increasing of P in fresh leaves. In contrast, the slope for N vs. P in litterfall approximated 1. N resorption in EBLF was significantly higher than in CF and in DF, but the highest P resorption was observed in DF. Although foliar N:P ratios indicated that EBLF was P limited, DF was N limited and CF was both N and P limited, the nutrient resorption efficiency did not respond with relatively high N resorption in EBLF and high P resorption in DF. We concluded that the relative higher resorption of N andP before leaf abscission could be an inherent property of plants, but was not a mechanism thought to have evolvedto conserve nutrients in environments with limited N or P supply.