西藏东南部色季拉山主要类型森林叶片和枯落物养分含量特征
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摘要
为阐明不同生长年限森林叶片和不同分解程度枯落物养分含量特征,为植物-土壤养分循环研究提供科学依据。以藏东南色季拉山几种典型森林植被(雪山杜鹃(Rhododendron aganniphum)、海拔4000 m和3900 m区域急尖长苞冷杉(Abies georgei var. smithii)、川滇高山栎(Quercus aquifolioides))为研究对象,分析了1年生和2年生植物叶片及不同分解程度枯落物有机碳(OC)、全氮(TN)、全磷(TP)和全钾(TK)含量。结果表明:色季拉山森林叶片和枯落物OC含量表现为2年生叶片>1年生叶片>未分解枯落物(ND)>半分解枯落物(SD)>完全分解枯落物(CD),即老叶片以C积累为主,而枯落物OC含量随分解程度的增加而下降,叶片OC平均含量(68.5%)显著高于中国平均水平(45.5%);叶片N、P、K含量表现为1年生>2年生,即新叶以N、P、K等营养物质的吸收积累为主。枯落物TN含量低于中国森林的平均水平(12.03 g/kg),而TP含量显著高于中国森林平均水平(0.74 g/kg),枯落物TN和TP以SD最高,即分解初期表现为净固定,而后期则呈净释放,TK含量随分解程度的增加而增加,表现为K的净固定;叶片C∶N,C∶P和C∶K表现为2年生>1年生,枯落物C∶N,C∶P和C∶K随着分解程度的增加而显著降低;叶片N∶P处于较低水平(6.08),显著低于全球平均水平(16.0),表现出明显的N限制营养型;研究结果为科学阐明藏东南森林生态系统植被-土壤养分循环研究提供了数据支撑。
The contents and dynamics of nutrients in leaves and litter are important for plant-soil nutrient cycling in forest ecosystems. Forests are one of the most important terrestrial ecosystems in southeastern Tibet, where the litter layer develops in an alpine climate. In this study we investigated the contents and stoichiometry of the most important nutrients(carbon, nitrogen, phosphorus, and potassium) in relation to the leaf age and stage of forest litter decomposition on Sejila Mountain(elevation approximately 3400—4150 m) in southeastern Tibet. We measured the organic carbon(OC), total nitrogen(TN), total phosphorus(TP), and total potassium(TK) contents in 1-a-old and 2-a-old leaves, and at different stages of litter decomposition(non-decomposed [ND], semi-decomposed [SD], and completely decomposed [CD]), in typical forest types(Rhododendron aganniphum, Abies forrestii, and Quercus aquifolioides). The OC contents of the leaf and litter showed the following rank order: 2-a-old leaf> 1-a-old leaf> ND> SD> CD(65.71%, 71.29%, 60.58%, 41.15%, and 29.86%, respectively). The litter OC content decreased with an increasing litter decomposition. The leaf OC contents were higher than the average for China(45.5%). The leaf OC contents were significantly higher in the coniferous forest than in the broad-leaved forest, and those in both forest types were higher in older leaves than in new leaves(72.89% and 58.32% for 1-a-old leaves, and 78.31% and 64.29% for 2-a-old leaves, in the coniferous and broad-leaved forests, respectively). The contents of N, P, and K in the leaf were higher in the 1-a-old leaves than in the 2-a-old leaves. The TN content of the 1-a-old leaves was higher in the broad-leaved forest(11.23 g/kg) than in the coniferous forest(10.55 g/kg), whereas the TN content of the 2-a-old leaves in the coniferous forest(9.39 g/kg) was higher than that in the broad-leaved forest(7.15 g/kg). The TN and TP contents of litter were highest in the SD forest, which indicated that net fixation occurred during initial decomposition, whereas complete decomposition resulted in a net release of nitrogen and phosphorus. The litter TK content was elevated with increased decomposition, and thus showed net fixation during the decomposition process. The litter TN contents were lower than the average for Chinese forests(12.03 g/kg), and the average values were 6.59, 8.24, and 9.55 g/kg for ND, SD, and CD forests, respectively. The litter TP contents were higher than the average for Chinese forests(0.74 g/kg), and the average values were 1.17, 2.49, and 1.87 g/kg for ND, SD, and CD forests, respectively. The litter TK contents were 2.19, 3.33, and 4.67 g/kg for ND, SD, and CD forests, respectively. The leaf C∶N, C∶P, and C∶K ratios were higher in the 2-a-old leaves than in the 1-a-old leaves; the ratios at each leaf age were 87.81 and 60.79 for C∶N, 539.25 and 375.49 for C∶P, and 139.15 and 101.20 for C∶K, respectively. The litter C∶N, C∶P, and C∶K ratios were decreased with increased decomposition. The ND, SD, and CD ratios were 90.20, 43.36, and 35.68 for C∶N; 520.34, 167.60, and 159.13 for C∶P; and 297.73, 129.97, and 64.42 for C∶K, respectively. The leaf N∶P ratios were low(6.09 and 4.76), and significantly lower than the global average(16.0), which was indicative of nitrogen limitation. The litter N∶P ratios for ND, CD, and SD were 5.86, 4.51, and 3.90, respectively. The results provide valuable information on plant-soil nutrient cycling in forest ecosystems in southeastern Tibet.
The contents and dynamics of nutrients in leaves and litter are important for plant-soil nutrient cycling in forest ecosystems. Forests are one of the most important terrestrial ecosystems in southeastern Tibet, where the litter layer develops in an alpine climate. In this study we investigated the contents and stoichiometry of the most important nutrients(carbon, nitrogen, phosphorus, and potassium) in relation to the leaf age and stage of forest litter decomposition on Sejila Mountain(elevation approximately 3400—4150 m) in southeastern Tibet. We measured the organic carbon(OC), total nitrogen(TN), total phosphorus(TP), and total potassium(TK) contents in 1-a-old and 2-a-old leaves, and at different stages of litter decomposition(non-decomposed [ND], semi-decomposed [SD], and completely decomposed [CD]), in typical forest types(Rhododendron aganniphum, Abies forrestii, and Quercus aquifolioides). The OC contents of the leaf and litter showed the following rank order: 2-a-old leaf> 1-a-old leaf> ND> SD> CD(65.71%, 71.29%, 60.58%, 41.15%, and 29.86%, respectively). The litter OC content decreased with an increasing litter decomposition. The leaf OC contents were higher than the average for China(45.5%). The leaf OC contents were significantly higher in the coniferous forest than in the broad-leaved forest, and those in both forest types were higher in older leaves than in new leaves(72.89% and 58.32% for 1-a-old leaves, and 78.31% and 64.29% for 2-a-old leaves, in the coniferous and broad-leaved forests, respectively). The contents of N, P, and K in the leaf were higher in the 1-a-old leaves than in the 2-a-old leaves. The TN content of the 1-a-old leaves was higher in the broad-leaved forest(11.23 g/kg) than in the coniferous forest(10.55 g/kg), whereas the TN content of the 2-a-old leaves in the coniferous forest(9.39 g/kg) was higher than that in the broad-leaved forest(7.15 g/kg). The TN and TP contents of litter were highest in the SD forest, which indicated that net fixation occurred during initial decomposition, whereas complete decomposition resulted in a net release of nitrogen and phosphorus. The litter TK content was elevated with increased decomposition, and thus showed net fixation during the decomposition process. The litter TN contents were lower than the average for Chinese forests(12.03 g/kg), and the average values were 6.59, 8.24, and 9.55 g/kg for ND, SD, and CD forests, respectively. The litter TP contents were higher than the average for Chinese forests(0.74 g/kg), and the average values were 1.17, 2.49, and 1.87 g/kg for ND, SD, and CD forests, respectively. The litter TK contents were 2.19, 3.33, and 4.67 g/kg for ND, SD, and CD forests, respectively. The leaf C∶N, C∶P, and C∶K ratios were higher in the 2-a-old leaves than in the 1-a-old leaves; the ratios at each leaf age were 87.81 and 60.79 for C∶N, 539.25 and 375.49 for C∶P, and 139.15 and 101.20 for C∶K, respectively. The litter C∶N, C∶P, and C∶K ratios were decreased with increased decomposition. The ND, SD, and CD ratios were 90.20, 43.36, and 35.68 for C∶N; 520.34, 167.60, and 159.13 for C∶P; and 297.73, 129.97, and 64.42 for C∶K, respectively. The leaf N∶P ratios were low(6.09 and 4.76), and significantly lower than the global average(16.0), which was indicative of nitrogen limitation. The litter N∶P ratios for ND, CD, and SD were 5.86, 4.51, and 3.90, respectively. The results provide valuable information on plant-soil nutrient cycling in forest ecosystems in southeastern Tibet.
引文
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[7] Mooshammer M,Wanek W,Schnecker J,Wild B,Leitner S,Hofhansl F,Bl?chl A,H?mmerle L,Frank A H,Fuchslueger L,Keiblinger K M,Zechmeister-Boltenstern S,Richter A.Stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter.Ecology,2012,93(4):770- 782.
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[13] 吴统贵,陈步峰,肖以华,潘勇军,陈勇,萧江华.珠江三角洲3种典型森林类型乔木叶片生态化学计量学.植物生态学报,2010,34(1):58- 63.
[14] Zhao H,Xu L,Wang Q F,Tian J,Tang X L,Tang Z Y,Xie Z Q,He N P,Yu G R.Spatial patterns and environmental factors influencing leaf carbon content in the forests and shrublands of China.Journal of Geographical Sciences,2018,28(6):791- 801.
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[16] 王晶苑,王绍强,李纫兰,闫俊华,沙丽清,韩士杰.中国四种森林类型主要优势植物的C∶N∶P化学计量学特征.植物生态学报,2011,35(6):587- 595.
[17] Aerts R,Chapin Ⅲ F S.The mineral nutrition of wild plants revisited:a re-evaluation of processes and patterns.Advances in Ecological Research,1999,30:1- 67.
[18] Wright I J,Reich P B,Cornelissen J H C,Falster D S,Garnier E,Hikosaka K,Lamont B B,Lee W,Oleksyn J,Osada N,Poorter H,Villar R,Warton D I,Westoby M.Assessing the generality of global leaf trait relationships.New Phytologist,2005,166(2):485- 496.
[19] 普穷,边巴多吉.西藏色季拉山冷杉林土壤养分特征研究.安徽农业科学,2010,38(19):10127- 10128,10266- 10266.
[20] 谢柯香,文仕知,何功秀,邵明晓,郭文平,颜家雄.闽楠人工林枯落物养分季节动态变化.中南林业科技大学学报,2013,33(6):113- 116.
[21] 唐仕姗,杨万勤,王海鹏,熊莉,聂富育,徐振锋.中国森林凋落叶氮、磷化学计量特征及控制因素.应用与环境生物学报,2015,21(2):316- 322.
[22] Aponte C,García L V,Maraňón T.Tree species effect on litter decomposition and nutrient release in Mediterranean oak forests changes over time.Ecosystems,2012,15(7):1204- 1218.
[23] 王斌,郑思俊,朱义,巨波,赵慧娟,张群,崔心红.上海市大莲湖池杉林三种优势植物枯落物分解动态.生态学杂志,2013,32(3):577- 582.
[24] Manzoni S,Trofymow J A,Jackson R B,Porporato A.Stoichiometric controls on carbon,nitrogen,and phosphorus dynamics in decomposing litter.Ecological Monographs,2010,80(1):89- 106.
[25] Aerts R,de Caluwe H.Nutritional and plant-mediated controls on leaf litter decomposition of Carex species.Ecology,1997,78(1):244- 260.
[26] Wu H T,Lu X G,Yang Q,Jiang M,Tong S Z.Early-stage litter decomposition and its influencing factors in the wetland of the Sanjiang Plain,China.Acta Ecologica Sinica,2007,27(10):4027- 4035.
[27] Laganière J,Paré D,Bradley R L.How does a tree species influence litter decomposition?Separating the relative contribution of litter quality,litter mixing,and forest floor conditions.Canadian Journal of Forest Research,2010,40(3):465- 475.
[28] 秦仕忆,喻阳华,邢容容,王璐.喀斯特高原山地区水源涵养林土壤及凋落物的生态化学计量特征.林业资源管理,2017,(5):66- 73.
[29] Almagro M,Martínez-Mena M.Exploring short-term leaf-litter decomposition dynamics in a Mediterranean ecosystem:dependence on litter type and site conditions.Plant and Soil,2012,358(1/2):323- 335.
[30] H?ttenschwiler S,J?rgensen H B.Carbon quality rather than stoichiometry controls litter decomposition in a tropical rain forest.Journal of Ecology,2010,98(4):754- 763.
[31] Wang Y P,Law R M,Pak B.A global model of carbon,nitrogen and phosphorus cycles for the terrestrial biosphere.Biogeosciences,2010,7(7):2261- 2282.
[2] Xu X F,Thornton P E,Post W M.A global analysis of soil microbial biomass carbon,nitrogen and phosphorus in terrestrial ecosystems.Global Ecology and Biogeography,2013,22(6):737- 749.
[3] 陆耀东,薛立,曹鹤,谢腾芳,王相娥.去除地面枯落物对加勒比松(Pinus caribaea)林土壤特性的影响.生态学报,2008,28(7):3205- 3211.
[4] Berg B.Litter decomposition and organic matter turnover in northern forest soils.Forest Ecology and Management,2000,133(1/2):13- 22.
[5] Smith P.Land use change and soil organic carbon dynamics.Nutrient Cycling in Agroecosystems,2008,81(2):169- 178.
[6] 刘霞,周涛,吴昊,徐培培,罗惠,曹乐瑶.中国森林凋落物分解速率的空间格局及主控因子:基于最优线性混合模型.北京师范大学学报(自然科学版),2018,54(4):553-560.
[7] Mooshammer M,Wanek W,Schnecker J,Wild B,Leitner S,Hofhansl F,Bl?chl A,H?mmerle L,Frank A H,Fuchslueger L,Keiblinger K M,Zechmeister-Boltenstern S,Richter A.Stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter.Ecology,2012,93(4):770- 782.
[8] Kang H Z,Zhuang H L,Wu L L,Liu Q L,Shen G R,Berg B,Man R Z,Liu C J.Variation in leaf nitrogen and phosphorus stoichiometry in Picea abies across Europe:an analysis based on local observations.Forest Ecology and Management,2011,261(2):195- 202.
[9] Wu T G,Yu M K,Wang G G,Dong Y,Cheng X R.Leaf nitrogen and phosphorus stoichiometry across forty-two woody species in Southeast China.Biochemical Systematics and Ecology,2012,44:255- 263.
[10] 任书杰,于贵瑞,姜春明,方华军,孙晓敏.中国东部南北样带森林生态系统102个优势种叶片碳氮磷化学计量学统计特征.应用生态学报,2012,23(3):581- 586.
[11] 张万林,张蓓,杨传金,梅浩,戴前石.西藏自治区森林枯落物碳储量估算.中南林业调查规划,2013,32(4):12- 15.
[12] 鲍士旦.土壤农化分析(第三版).北京:中国农业出版社,2000.
[13] 吴统贵,陈步峰,肖以华,潘勇军,陈勇,萧江华.珠江三角洲3种典型森林类型乔木叶片生态化学计量学.植物生态学报,2010,34(1):58- 63.
[14] Zhao H,Xu L,Wang Q F,Tian J,Tang X L,Tang Z Y,Xie Z Q,He N P,Yu G R.Spatial patterns and environmental factors influencing leaf carbon content in the forests and shrublands of China.Journal of Geographical Sciences,2018,28(6):791- 801.
[15] 司高月,李晓玉,程淑兰,方华军,于贵瑞,耿静,何舜,于光夏.长白山垂直带森林叶片-凋落物-土壤连续体有机碳动态——基于稳定性碳同位素分析.生态学报,2017,37(16):5285- 5293.
[16] 王晶苑,王绍强,李纫兰,闫俊华,沙丽清,韩士杰.中国四种森林类型主要优势植物的C∶N∶P化学计量学特征.植物生态学报,2011,35(6):587- 595.
[17] Aerts R,Chapin Ⅲ F S.The mineral nutrition of wild plants revisited:a re-evaluation of processes and patterns.Advances in Ecological Research,1999,30:1- 67.
[18] Wright I J,Reich P B,Cornelissen J H C,Falster D S,Garnier E,Hikosaka K,Lamont B B,Lee W,Oleksyn J,Osada N,Poorter H,Villar R,Warton D I,Westoby M.Assessing the generality of global leaf trait relationships.New Phytologist,2005,166(2):485- 496.
[19] 普穷,边巴多吉.西藏色季拉山冷杉林土壤养分特征研究.安徽农业科学,2010,38(19):10127- 10128,10266- 10266.
[20] 谢柯香,文仕知,何功秀,邵明晓,郭文平,颜家雄.闽楠人工林枯落物养分季节动态变化.中南林业科技大学学报,2013,33(6):113- 116.
[21] 唐仕姗,杨万勤,王海鹏,熊莉,聂富育,徐振锋.中国森林凋落叶氮、磷化学计量特征及控制因素.应用与环境生物学报,2015,21(2):316- 322.
[22] Aponte C,García L V,Maraňón T.Tree species effect on litter decomposition and nutrient release in Mediterranean oak forests changes over time.Ecosystems,2012,15(7):1204- 1218.
[23] 王斌,郑思俊,朱义,巨波,赵慧娟,张群,崔心红.上海市大莲湖池杉林三种优势植物枯落物分解动态.生态学杂志,2013,32(3):577- 582.
[24] Manzoni S,Trofymow J A,Jackson R B,Porporato A.Stoichiometric controls on carbon,nitrogen,and phosphorus dynamics in decomposing litter.Ecological Monographs,2010,80(1):89- 106.
[25] Aerts R,de Caluwe H.Nutritional and plant-mediated controls on leaf litter decomposition of Carex species.Ecology,1997,78(1):244- 260.
[26] Wu H T,Lu X G,Yang Q,Jiang M,Tong S Z.Early-stage litter decomposition and its influencing factors in the wetland of the Sanjiang Plain,China.Acta Ecologica Sinica,2007,27(10):4027- 4035.
[27] Laganière J,Paré D,Bradley R L.How does a tree species influence litter decomposition?Separating the relative contribution of litter quality,litter mixing,and forest floor conditions.Canadian Journal of Forest Research,2010,40(3):465- 475.
[28] 秦仕忆,喻阳华,邢容容,王璐.喀斯特高原山地区水源涵养林土壤及凋落物的生态化学计量特征.林业资源管理,2017,(5):66- 73.
[29] Almagro M,Martínez-Mena M.Exploring short-term leaf-litter decomposition dynamics in a Mediterranean ecosystem:dependence on litter type and site conditions.Plant and Soil,2012,358(1/2):323- 335.
[30] H?ttenschwiler S,J?rgensen H B.Carbon quality rather than stoichiometry controls litter decomposition in a tropical rain forest.Journal of Ecology,2010,98(4):754- 763.
[31] Wang Y P,Law R M,Pak B.A global model of carbon,nitrogen and phosphorus cycles for the terrestrial biosphere.Biogeosciences,2010,7(7):2261- 2282.