光照和氮交互作用对水曲柳幼苗生长、生物量和氮分配的影响

采用温室沙培方式,对水曲柳幼苗进行了不同光强（2个水平）和氮浓度（4个水平）处理,分析了其生长、生物量和氮分配对环境变化的响应.结果表明：与全光照处理相比,低光处理下水曲柳幼苗冠根比（S/R）和净氮吸收速率（NNUR）极显著提高（P<0.01）,但相对生长速率（RGR）和净同化速率（NAR）极显著下降（P<0.01）;低光处理下的幼苗根、茎、叶和整株生物量分别较全光照处理降低了36.8%（P<0.01）、1.7%、12.7%（P<0.05）和24.3%（P<0.01）;低光处理使幼苗分配到根系的氮比例明显下降,而叶片的分配比例增加.无论光强大小,氮对幼苗生长都具有十分明显的促进作用,而且幼苗S/R和叶片的氮分配比例都随氮供给浓度的增加而明显提高.光强和氮浓度对水曲柳幼苗的基径、S/R、RGR和生物量（根和叶）分配比例具有显著的交互作用（P<0.05）.     

不同养分水平对飞机草生长与生物量分配的影响

采用温室盆栽模拟实验研究了不同养分水平对外来入侵植物飞机草(Chromolaena odorata)的生长性状、生物量积累以及生物量分配格局的影响。实验共设置5 种养分浓度处理, 分别为Hoagland 标准营养液的10%、25%、50%、100%和200%溶液。结果表明: 养分水平对飞机草植株的生长性状以及生物量的积累、分配产生显著影响。随着养分水平的增加, 飞机草的总分枝数量、长度以及一级分枝数量、长度持续增加, 并且100%、200%处理还能促进二级分枝的萌发生长。飞机草的叶片数、总叶面积、总生物量以及茎、叶两器官生物量随养分水平的上升显著增加, 但株高、根生物量不受养分浓度变化的影响。根生物量比、根冠比随养分水平的提高显著下降, 叶生物量比则显著上升, 但茎生物量比在各养分浓度保持稳定。叶面积比、叶根比、RGR 亦随养分含量的上升显著增加。说明养分资源丰富的环境将促进飞机草的地上部生长, 而生物量分配格局的变化可能是其在入侵蔓延过程中适应养分异质性生境的重要生态策略。     

CO2浓度升高对两个种植密度下红桦生长和养分含量的影响

采用控制环境生长室,研究了CO2浓度升高对2个种植密度下红桦幼苗生长和氮(N)、磷(P)含量的影响。试验设置CO2浓度为350和700μmol.mol-12个水平,每个CO2浓度水平下又设密度28和84株.m-22个水平。结果表明:CO2浓度升高,红桦株高和叶面积指数(LAI)均增加,净同化率(NAR)值增加,叶质比(LMR)和比叶面积(SLA)均下降,但相对生长率(RGR)提高。CO2浓度增加,红桦幼苗茎枝、叶、根和总生物量提高,氮(N)、磷(P)含量降低,但单株N、P总吸收量均增加。CO2浓度升高,氮磷利用效率(NUE和PUE)提高,氮磷累积速率(NAcR和PAcR)显著增加。CO2浓度升高,红桦幼苗体内N、P浓度下降是由于生物量迅速增加引起的稀释效应造成的,而NUE和PUE的提高可以有效缓解CO2浓度升高后,亚高山和高山地区森林土壤中养分元素不足对森林生产力的限制。CO2浓度升高导致的植物生长的增加量会随植株密度的增加而降低,不同器官养分吸收量的增加量在低密度条件下比高密度条件下大得多,主要是因为高种植密度显著降低了植株各部位的干质量。     

浓度升高对两个种植密度下红桦生长和养分含量的影响

采用控制环境生长室,研究了CO₂浓度升高对2个种植密度下红桦幼苗生长和氮(N)、磷(P)含量的影响。试验设置CO₂浓度为350和700 μmol·mol^-12个水平,每个CO₂浓度水平下又设密度28和84株·m^-22个水平。结果表明：CO₂浓度升高,红桦株高和叶面积指数(LAI)均增加,净同化率(NAR)值增加,叶质比(LMR)和比叶面积(SLA)均下降,但相对生长率(RGR)提高。CO₂浓度增加,红桦幼苗茎枝、叶、根和总生物量提高,氮(N)、磷(P)含量降低,但单株N、P总吸收量均增加。CO₂浓度升高,氮磷利用效率(NUE和PUE)提高,氮磷累积速率(NAcR和PAcR)显著增加。CO₂浓度升高,红桦幼苗体内N、P浓度下降是由于生物量迅速增加引起的稀释效应造成的,而NUE和PUE的提高可以有效缓解CO₂浓度升高后,亚高山和高山地区森林土壤中养分元素不足对森林生产力的限制。CO₂浓度升高导致的植物生长的增加量会随植株密度的增加而降低,不同器官养分吸收量的增加量在低密度条件下比高密度条件下大得多,主要是因为高种植密度显著降低了植株各部位的干质量。     

不同供氮水平对水曲柳苗木生物量、氮分配及其季节变化的影响

在温室内以水曲柳苗木为材料进行砂培试验,探讨了4种不同氮素浓度处理(1、4、8和16mmol·L^-1)下的水曲柳苗木根系和叶片内氮分配以及对苗木生物量的影响．结果表明,氮素供给浓度显著影响苗木根系氮浓度和叶片氮浓度．随着供氮水平提高,苗木体内根系和叶片氮浓度明显提高．在生长初期(6月)和中期(7、8月),叶片中氮浓度分别高于根系9．40、9．55和4．21mg·g^-1,而在生长末期(9月)叶片中氮浓度低于根系;随着水曲柳幼苗生长发展,体内氮贮量呈明显上升趋势．9月份全株氮贮量比6月份平均增加了4倍．不同氮处理下水曲柳体内氮贮量明显不同．高氮处理下氮贮量平均为N1处理下4倍．氮贮量分配在不同部位有很大不同．分配到叶片中的比例在6月份最高,平均为43％．分配到根系中氮贮量比例随生长而增加,9月份根系氮贮量相对值最高,为81％．如果不考虑氮浓度和季节的作用,根系中分配的氮最多,其次为叶片,茎中最少．     

水曲柳幼苗根系对土壤养分和水分空间异质性的反应

通过沙培试验方法,研究了温室条件下水曲柳幼苗在施肥和浇水区,非施肥和非浇水区中根系生长,生物量分布,地下部分与地上部分关系,细根直径等特征。结果表明,土壤养分和水分的空间异质性对水曲柳幼苗根系生长和分布有明显影响。在施肥区和浇水区根系生长快,密度大,生物量高,而在非施肥和非浇水区根系生长受到抑制,根系密度小,生物量低,与非施肥区相比,施肥区细根直径下降,有利于根系对养分和水分的运输,但是在非浇水区     

两种热带木质藤本幼苗形态、生长和光合能力对光强和养分的响应

比较了两种不同攀援习性, 卷须缠绕种薄叶羊蹄甲(Bauhinia tenuiflora)和茎缠绕种刺果藤(Byttneria aspera), 木质藤本植物的形态、生长及光合特性对不同光强(4%、35%和全光照)和土壤养分(高和低)的响应。两种藤本植物大部分表型特征主要受光照的影响, 而受土壤养分的影响较小。弱光促进地上部分生长, 弱光下两种植物均具有较大的比叶面积(specific leaf area, SLA)、茎生物量比(stem mass ratio, SMR)和平均叶面积比(mean leaf area ratio, LARm)。高光强下, 两种植物的总生物量和投入到地下部分的比重增加, 具有更大的根生物量比(root mass ratio, RMR)、更多的分枝数、更高的光合能力( maximum photosynthetic rate, Pmax)和净同化速率(net assimilation rate, NAR), 综合表现为相对生长速率(relative growth rate, RGR)增加。两种藤本植物的Pmax与叶片含氮量的相关性均未达显著水平, 但刺果藤的Pmax与SLA之间呈显著的正相关, 而薄叶羊蹄甲的Pmax与SLA之间相关性不显著。在相同光照强度和土壤养分条件下, 卷须缠绕种薄叶羊蹄甲的RGR显著高于茎缠绕种刺果藤。薄叶羊蹄甲的RGR与NAR呈显著正相关, 其RGR与SLA、平均叶面积比(LARm)及Pmax之间相关性不显著。刺果藤的RGR与NAR呈显著的正相关, 而与SLA存在显著的负相关。上述结果表明, 与土壤养分相比, 光照强度可能是决定木质藤本分布更为重要的生态因子。卷须缠绕种薄叶羊蹄甲由于具有特化的攀援器官, 在形态上和生理上具有更大的可塑性, 这使得卷须缠绕种木质藤本在与其它植物的竞争中更具优势。     

氮素形态对黄檗幼苗三种生物碱含量的影响

通过改变水培溶液中NH 4-N和NO3--N的比例,探讨了氮素形态对黄檗幼苗主要药用成分小檗碱、药根碱及掌叶防己碱含量的影响。结果表明,小檗碱的含量与氮素形态有明显关系,在根和茎中都表现为NO3--N比例高更有利于小檗碱的积累。单纯的NO3--N供给最有利于药根碱在黄檗幼苗根中的积累,而处理46d后,NH4 -N/NO3--N为75/25和25/75时黄檗幼苗茎中的药根碱含量最高。黄檗幼苗根和茎中的掌叶防己碱含量对营养液中NH4 -N和NO3--N的比例反应类似,在处理46d后,掌叶防己碱含量由高到低所对应的NH4 -N/NO-3-N为25/75、50/50、75/25、0/100、100/0。处理33d后,黄檗幼苗根中的小檗碱、药根碱、掌叶防己碱含量随处理天数的增加呈下降趋势,而在茎中呈上升趋势。如果同时考虑氮素形态对黄檗幼苗生物量的影响,那么NH4 -N/NO3--N为0/100时其小檗碱产量(含量与生物量乘积)最高,而NH4 -N/NO-3-N为25/75时药根碱和掌叶防已碱的产量最高。     

林窗对岷江冷杉更新幼苗根系生物量积累与分配的影响

林窗对更新幼苗生物量积累和分配的影响在种群恢复中具有重要作用,尤其是暗针叶林更为突出。以川西亚高山岷江冷杉原始林林窗、林下的岷江冷杉更新幼苗为对象,研究其粗根和细根生物量的积累与分配过程及其异速生长关系。结果表明：随着岷江冷杉幼苗的生长,粗根、细根生物量均不断积累,但根系生物量中分配到粗根的比例逐渐增加、分配到细根的比例逐渐减少,粗根-细根间生物量的异速生长指数由等速生长转变为异速生长。林窗幼苗的细根生物量、粗根生物量和总根生物量中位数均小于林下幼苗,细根生物量分配比例大于林下幼苗;林窗还显著影响细根、粗根生物量随基径增粗的积累与分配过程,细根生物量分配比例随基径增粗的降幅大于林下幼苗;但林窗对粗根-细根生物量间的异速生长指数影响不显著。说明林窗干扰改变了岷江冷杉更新幼苗地下资源的分配方式,优化了资源配置。     

大气二氧化碳浓度与温度升高对红桦幼苗养分积累和分配的影响

利用封闭式生长室,研究了CO2浓度升高(环境CO2 350 μmol·mol-1,EC)、温度升高(环境温度 2 ℃,ET)以及二者同时升高(ECT)对川西亚高山红桦幼苗养分积累和分配的影响.结果表明:经过一个生长季, EC处理下红桦幼苗单株N、P、K积累比对照分别增加44%、45%和11%(P《0.05),ET处理下分别增加37%、76%和9%(P《0.05),ECT处理下分别增加24%、88%和20% (P《0.05).EC处理使N向红桦幼苗叶中分配的比例降低11.68%(P《0.05),向枝、茎、根中分配的比例分别增加2.95%、3.39%和5.34%(P》0.05);ET处理使N向叶中分配的比例增加11.09%(P《0.05),向枝、茎、根中分配的比例分别降低0.69%、10.35%和0.05%(P》0.05).ECT处理下N的分配格局与EC处理相似.3种处理下P和K在红桦幼苗中的分配变化差异较大,CO2浓度和温度升高可能促进植物养分的积累,改变养分在植物各器官间的分配.     

Stoichiometric patterns in foliar nutrient resorption across multiple scales

? Nutrient resorption is a fundamental process through which plants withdraw nutrients from leaves before abscission. Nutrient resorption patterns have the potential to reflect gradients in plant nutrient limitation and to affect a suite of terrestrial ecosystem functions. ? Here, we used a stoichiometric approach to assess patterns in foliar resorption at a variety of scales, specifically exploring how N?:?P resorption ratios relate to presumed variation in N and/or P limitation and possible relationships between N?:?P resorption ratios and soil nutrient availability. ? N?:?P resorption ratios varied significantly at the global scale, increasing with latitude and decreasing with mean annual temperature and precipitation. In general, tropical sites (absolute latitudes 相似文献   

喀斯特峰丛洼地不同类型森林养分循环特征

以中国西南喀斯特峰丛洼地为研究区域用标准木法和收获法对人工林、次生林、原生林3个不同类型森林的6个代表性群落的生物量、营养元素生物循环量及循环特征进行了研究。结果表明:(1)不同类型森林群落乔木各器官的养分含量大小顺序为:叶枝根干,林下植被层和凋落物层的养分含量比较高,其含量普遍高于乔木层各组分,仅次于乔木叶片;各组分中营养元素以K、Ca最高,P、Mg最低;(2)3种类型森林间乔木层的养分积累量总规律表现为原生林(4540.30 kg/hm~2)次生林(2107.09 kg/hm~2)人工林(719.51 kg/hm~2),分别占林分养分积累量的88.30%、79.57%和62.60%;(3)3种类型森林生态系统养分总贮量相差不大,均主要集中在土壤层在各层分配格局有所差异;营养元素的年吸收量和年归还量均为次生林原生林人工林,年吸收量分别为:418.80、271.17和148.79 kg hm~(-2)a~(-1);年归还量分别为:182.98、111.43和43.37 kg hm_(-2)a~(-1);(4)不同类型森林养分利用系数总规律为人工林(0.35)次生林(0.20)原生林(0.10);循环系数则相反,为原生林(0.48)次生林(0.46)人工林(0.30);而周转时间为原生林(37.32)人工林(18.63)次生林(13.93)。喀斯特峰丛洼地土层薄,养分贮存能力差,森林养分循环能力相对较弱,沿着强、中、弱干扰递减梯度,3种类型森林养分利用效率和循环能力呈增长趋势。     

Leaf nutrient dynamics and nutrient resorption: a comparison between larch plantations and adjacent secondary forests in Northeast China

Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China, resulting in a reduction in soil nutrient availability after a certain number of years following conversion. Nutrient resorption prior to leaf senescence was related to soil fertility, an important nutrient conservation strategy for plants, being especially significant in nutrient-poor habitats. However, the seasonal dynamics of leaf nutrients and nutrient resorption in response to secondary forest conversion to larch plantations is not well understood.Methods A comparative experiment between larch plantations (Larix spp.) and adjacent secondary forests (dominant tree species including Quercus mongolica, Acer mono, Juglans mandshurica and Fraxinus rhynchophylla) was conducted. We examined the variations in leaf nutrient (macronutrients: N, P, K, Ca and Mg; micronutrients: Cu and Zn) concentrations of these tree species during the growing season from May to October in 2013. Nutrient resorption efficiency and proficiency were compared between Larix spp. and the broadleaved species in the secondary forests.Important findings Results show that the seasonal variation of nutrient concentrations in leaves generally exhibited two trends, one was a downward trend for N, P, K, Cu and Zn, and another was an upward trend for Ca and Mg. The variations in foliar nutrient concentrations were mainly controlled by the developmental stage of leaves rather than by tree species. Resorption of the observed seven elements varied among the five tree species during leaf senescence. Nutrient resorption efficiency varied 6–75% of N, P, K, Mg, Cu and Zn, while Ca was not retranslocated in the senescing leaves of all species, and Mg was not retranslocated in Larix spp. Generally, Larix spp. tended to be more efficient and proficient (higher than 6–30% and 2–271% of nutrient resorption efficiency and resorption proficiency, respectively) in resorbing nutrients than the broadleaved species in the secondary forests, indicating that larch plantations had higher leaf nutrient resorption and thus nutrient use efficiency. Compared with Larix spp., more nutrients would remain in the leaf litter of the secondary forests, indicating an advantage of secondary forests in sustaining soil fertility. In contrast, the larch plantation would reuse internal nutrients rather than lose nutrients with litter fall and thus produce a positive feedback to soil nutrient availability. In summary, our results suggest that conversion from secondary forests to pure larch plantations would alter nutrient cycling through a plant-mediated pathway.     

缺苞箭竹密度对养分元素贮量、积累与分配动态的影响

研究了缺苞箭竹(Fargesiadenudate)-紫果云杉(Piceapurpurea)原始林下不同密度缺苞箭竹群落的养分元素贮量与分配动态以及养分元素在一个生长季节内的积累量。结果表明:地上、地下部分的N、P、K、Ca、Mg贮量均随着箭竹密度的增加而增大,养分元素贮量排序为:K>N>Ca>P>Mg。密度较大的箭竹群落(D1和D2)中,地上部分的N、P和K贮量大于地下部分,而密度较小的箭竹群落(D3)中P和K贮存于地下部分的比例较大,3个群落中的地下部分Ca和Mg贮量均大于地上部分,且地下部分的养分元素贮量的比例随着箭竹密度的增加而减少。养分元素的总积累量排序为:K>N>Ca>P>Mg,且地上部分和群落的总积累量随着箭竹密度的增加而增加,总积累率以D1群落最大,3个群落的养分元素积累率大小顺序为:Mg>Ca>P>N>K。地下部分(根系和鞭)养分元素贮量比例随着箭竹密度的增加而下降,而地上部分(叶、枝和竹杆)养分元素贮量比例随着箭竹密度增加而上升。密度对缺苞箭竹养分贮量、积累和分配动态有深刻影响。     

辽东山区落叶松人工林地上生物量和养分元素分配格局

落叶松是我国北方最主要的人工用材林树种,由于人工林树种单一、结构简单等原因,导致土壤养分循环出现失衡.研究落叶松生物量和养分元素分配规律,可以为落叶松人工林的合理经营和养分循环研究提供科学参考.本文以辽东山区19年生二代落叶松人工林(胸径12.8 cm,树高15.3 m,密度2308株·hm^-2)为对象,研究其地上各器官(干、枝、皮、叶)生物量、碳和养分元素含量(N、P、K、Ca、Mg、Fe、Mn、Cu、Zn)的积累规律和分配格局.结果表明：单株落叶松生物量为70.26 kg,林分水平落叶松生物量为162.16 t·hm^-2,各器官生物量差异显著,排序为：树干>树枝>树皮>树叶;单株落叶松养分积累量为749.94 g,林分水平落叶松养分积累量为1730.86 kg·hm^-2,其中,大量元素和微量元素的养分积累量均为树干显著高于树枝、树皮和树叶.全叶期每砍伐一棵落叶松(19年生),平均从系统中带出749.94 g养分元素;如果将树皮、树枝、树叶留在林地仅仅带走树干,带出的养分元素可减少40.7%.
     

Difference in nutrient accumulation patterns between diapause-destined and non-diapause-destined larvae of Hyphantria cunea

Nutrient accumulation is crucial in insect diapause preparation because insufficient nutrient accumulation can shorten the diapause period, interfere with diapause development completion, and decrease the probability of surviving the overwintering period. The amounts of lipids and carbohydrates stored in diapausing pupae of Hyphantria cunea (Drury) (Lepidoptera: Erebidae, Arctiinae) are greater than those in the non-diapausing pupae. In this study, we tested the hypothesis that diapause-destined (DD) and non-diapause-destined (NDD) larvae of H. cunea have different nutrient accumulation patterns in penultimate and final instars. The body mass, as well as lipid, carbohydrate, and soluble protein contents, and the efficiency of converting digested food and ingested food into body matter were greater in the DD penultimate and final instars than in the NDD penultimate and final instars. Larger amounts of lipids, carbohydrates, and proteins were absorbed by DD penultimate and final instars and the final instar development period in the DD larvae was prolonged relative to NDD larvae. The activities of fatty acid synthase and glycogen synthase of DD penultimate and final instars were significantly higher than those of NDD larvae. These results suggest that the changes in nutrient accumulation patterns between DD and NDD larvae occur in penultimate and final instars, and that the DD larvae increase their nutrient accumulation during diapause preparation by the combined effect of extending their final-instar development period and improving their digestive efficiency; they increase their lipid and carbohydrate stores by increasing the activities of fatty acid synthase and glycogen synthase in the fat body.     

Global‐scale patterns of nutrient density and partitioning in forests in relation to climate

Knowledge of nutrient storage and partitioning in forests is imperative for ecosystem models and ecological theory. Whether the nutrients (N, P, K, Ca, and Mg) stored in forest biomass and their partitioning patterns vary systematically across climatic gradients remains unknown. Here, we explored the global‐scale patterns of nutrient density and partitioning using a newly compiled dataset including 372 forest stands. We found that temperature and precipitation were key factors driving the nutrients stored in living biomass of forests at global scale. The N, K, and Mg stored in living biomass tended to be greater in increasingly warm climates. The mean biomass N density was 577.0, 530.4, 513.2, and 336.7 kg/ha for tropical, subtropical, temperate, and boreal forests, respectively. Around 76% of the variation in biomass N density could be accounted by the empirical model combining biomass density, phylogeny (i.e., angiosperm, gymnosperm), and the interaction of mean annual temperature and precipitation. Climate, stand age, and biomass density significantly affected nutrients partitioning at forest community level. The fractional distribution of nutrients to roots decreased significantly with temperature, suggesting that forests in cold climates allocate greater nutrients to roots. Gymnosperm forests tended to allocate more nutrients to leaves as compared with angiosperm forests, whereas the angiosperm forests distributed more nutrients in stems. The nutrient‐based Root:Shoot ratios (R:S), averaged 0.30 for R:S_N, 0.36 for R:S_P, 0.32 for R:S_K, 0.27 for R:S_Ca, and 0.35 for R:S_Mg, respectively. The scaling exponents of the relationships describing root nutrients as a function of shoot nutrients were more than 1.0, suggesting that as nutrient allocated to shoot increases, nutrient allocated to roots increases faster than linearly with nutrient in shoot. Soil type significantly affected the total N, P, K, Ca, and Mg stored in living biomass of forests, and the Acrisols group displayed the lowest P, K, Ca, and Mg.     

连栽第1和第2代杉木人工林养分循环的比较

森林生态系统的养分循环是生态系统的重要功能过程之一,直接影响着森林的生产力,很大程度上影响和制约着林地的肥力水平,而且人工林连栽地力衰退和生产力下降现象普遍存在,寻求杉木林连栽两代杉木人工林养分循环差异与连栽林分生产力下降的关系,无疑具有重要的现实意义。利用30多年连续定位的测定数据,分析了连栽第1、2代杉木人工林在物质生产养分利用有效性、生物地球化学循环、地球化学循环的差异。结果表明,杉木速生阶段,第2代林每生产1 t干物质需要的养分比第1代林多1.58-3.29 kg,干材生长阶段,第2代林每生产1t所需养分比第1代林多4.23-5.92kg;速生阶段生物地球化学循环的养分利用系数第2代林比第1代林分下降19.7%-22.8%,养分循环系数下降12.8%-15.6%,干材生长阶段养分利用系数比第1代林分下降35.3%-36.2%,养分循环系数下降23.2%-27.0%,养分周转利用的生物地球化学循环功能第2代林比第1代林差;由干材生长进入成熟阶段的生长期内,伴随水文学过程的养分地球化学循环中,第2代杉木人工林生态系统的养分积累的地球化学循环的能力下降,养分流失率是第1代林的2倍左右,养分的积累率还不到第1代林的60%,对森林地力的维持和林木生长都是不利的。从生态系统水平上定位研究,定量分析了杉木连栽两代人工林养分循环功能过程,研究成果为我国南方人工林持续经营措施的制定提供了理论指导和科学依据。     

Towards an understanding of the relations between tree nutrition,nutrient cycling and environment

The paper contains a discussion of the interrelations between the sciences used by managers of forest land to improve their management, in particular with respect to the plant nutrient economy of the forest ecosystems. Both site studies and studies of nutrient cycling have been carried out for long periods without proper consideration of tree nutrition. Therefore these studies contributed less to the understanding of the role of nutrients as regulators of processes in ecosystems than might have been expected. This situation has improved, especially within the last decade. In addition the necessity to manage forest land for environmental values as well as for forest yield requires new interdisciplinary approaches in the study of the roles of plant nutrients in the forest. Even more branches of biological and environmental sciences than those just mentioned must be involved.     

Global-scale patterns of nutrient resorption associated with latitude, temperature and precipitation

Aim   Nutrient resorption from senescing leaves is an important mechanism of nutrient conservation in plants, but the patterns of nutrient resorption at the global scale are unknown. Because soil nutrients vary along climatic gradients, we hypothesize that nutrient resorption changes with latitude, temperature and precipitation.
Location   Global.
Methods   We conducted a meta-analysis on a global data set collected from published literature on nitrogen (N) and phosphorus (P) resorption of woody plants.
Results    For all data pooled, both N resorption efficiency (NRE) and P resorption efficiency (PRE) were significantly related to latitude, mean annual temperature (MAT) and mean annual precipitation (MAP): NRE increased with latitude but decreased with MAT and MAP. In contrast, PRE decreased with latitude but increased with MAT and MAP. When functional groups (shrub versus tree, coniferous versus broadleaf and evergreen versus deciduous) were examined individually, the patterns of NRE and PRE in relation to latitude, MAT and MAP were generally similar.
Main conclusions   The relationships between N and P resorption and latitude, MAT and MAP indicate the existence of geographical patterns of plant nutrient conservation strategies in relation to temperature and precipitation at the global scale, particularly for PRE, which can be an indicator for P limitation in the tropics and selective pressure shaping the evolution of plant traits. Our results suggest that, although the magnitude of plant nutrient resorption might be regulated by local factors such as substrate, spatial patterns are also controlled by temperature or precipitation.