黄土丘陵沟壑区植被恢复演替过程中根系行为特征
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摘要
根系的结构与生态功能特征称为根系行为特征,研究根系行为特征对黄土区植被恢复具有重要意义。采用非线性计算方法,采集黄土区4种典型退耕植被群落根系、土壤样品,分析根系形态特征、基于径级的根长分形维数、根系生态位指数与土壤有机碳的关系。结果显示:根长密度、根生物量、根系直径随着退耕演替的发展存在缓慢增大趋势。退耕演替发展的2—21年中,根系平均分维数由2.77显著减小至2.59(P<0.05),生态位指数由3.75显著增大至9.37(P<0.05)。根系的生态功能性对丰富土壤有机碳具有极显著的影响效果,根系分维数与生态位指数呈极显著负相关(P<0.01),即根系的结构特征直接决定了根系综合生态功能,表现为结构越复杂,功能性越强。
Restoration of vegetation can also play a role in reducing soil erosion and improving the soil environment in the Chinese Loess Region. The vegetation recovery process, however, is slow and complicated, and the succession of vegetation can occur over the extended period. The root system is sensitive to the soil environmental response as it directly contacts the soil and plays an important role in the succession process of vegetation communities. The study of root system behavior in different succession stages can reveal the associated changes in the root structure and functional characteristics of plant community roots. The structure and ecological function of the root system are called root behavior characteristics, which is important to study for vegetation restoration in the Loess area. In this study, soil and root samples of 4 different vegetation communities(Artemisia capillaris, A. sacrorum, Bothriochloa ischaemun, and Lespedeza davurica) were collected in 2015 in Wangmaogou watershed of Wuding River. Each vegetation communities was arranged in two plots, and then 3—5 quadrants were established in each kind of plot. The inner diameter of 9 cm root drilling was collected vertically down to 50 cm, all the roots were picked out of the soil sample inside the root drill, and the soil and root samples were finally separately placed into a bag, which was sealed and brought back to the laboratory. The root samples were washed with water and divided into four diameter grades: 0>D≥0.5 mm,0.5>D≥ 1 mm,1>D ≥2 mm,and 2> D≥5 mm. Then, the root samples were scanned with a scanner. Finally, the root system parameters of length, surface area, tips, and diameters were determined. In the study of root ecology, a complex problem is how to reflect the ecological function of the root system through the characteristics of the root structure, that is, the mechanism of interaction between the soil interface and the acquisition of resources based on the characteristics of the root system. However, the problems of various plant communities under different soil site conditions and climates are considerably different, which could reflect the underground ecosystem, and the related research is particularly complex and difficult. Therefore, we analyzed the structure and functional recovery, the correlation, and effect on soil organic carbon of the root system of the plant community of returning farmland using nonlinear ecological simulation technology in the Chinese Loess Region. The results showed that root length densities(RLDs), root biomass, and root diameter increased slowly with the development of succession. The RLD of different diameter classes was mainly affected by species richness and coverage, and the root system distribution in different successional stages was uneven. The average fractal dimension of roots decreased from 2.77 to 2.59, and the niche index increased from 3.75 to 9.37(both P<0.05) in the 2—21 years of succession development. The ecological function of the root system significantly affected the soil organic carbon, and there was a significant negative correlation between the fractal dimension of the roots and the niche index(P<0.01). Therefore, the structural characteristics of the root system directly determined its comprehensive ecological function and, therefore, the more complex the structure, the stronger the functionality.
Restoration of vegetation can also play a role in reducing soil erosion and improving the soil environment in the Chinese Loess Region. The vegetation recovery process, however, is slow and complicated, and the succession of vegetation can occur over the extended period. The root system is sensitive to the soil environmental response as it directly contacts the soil and plays an important role in the succession process of vegetation communities. The study of root system behavior in different succession stages can reveal the associated changes in the root structure and functional characteristics of plant community roots. The structure and ecological function of the root system are called root behavior characteristics, which is important to study for vegetation restoration in the Loess area. In this study, soil and root samples of 4 different vegetation communities(Artemisia capillaris, A. sacrorum, Bothriochloa ischaemun, and Lespedeza davurica) were collected in 2015 in Wangmaogou watershed of Wuding River. Each vegetation communities was arranged in two plots, and then 3—5 quadrants were established in each kind of plot. The inner diameter of 9 cm root drilling was collected vertically down to 50 cm, all the roots were picked out of the soil sample inside the root drill, and the soil and root samples were finally separately placed into a bag, which was sealed and brought back to the laboratory. The root samples were washed with water and divided into four diameter grades: 0>D≥0.5 mm,0.5>D≥ 1 mm,1>D ≥2 mm,and 2> D≥5 mm. Then, the root samples were scanned with a scanner. Finally, the root system parameters of length, surface area, tips, and diameters were determined. In the study of root ecology, a complex problem is how to reflect the ecological function of the root system through the characteristics of the root structure, that is, the mechanism of interaction between the soil interface and the acquisition of resources based on the characteristics of the root system. However, the problems of various plant communities under different soil site conditions and climates are considerably different, which could reflect the underground ecosystem, and the related research is particularly complex and difficult. Therefore, we analyzed the structure and functional recovery, the correlation, and effect on soil organic carbon of the root system of the plant community of returning farmland using nonlinear ecological simulation technology in the Chinese Loess Region. The results showed that root length densities(RLDs), root biomass, and root diameter increased slowly with the development of succession. The RLD of different diameter classes was mainly affected by species richness and coverage, and the root system distribution in different successional stages was uneven. The average fractal dimension of roots decreased from 2.77 to 2.59, and the niche index increased from 3.75 to 9.37(both P<0.05) in the 2—21 years of succession development. The ecological function of the root system significantly affected the soil organic carbon, and there was a significant negative correlation between the fractal dimension of the roots and the niche index(P<0.01). Therefore, the structural characteristics of the root system directly determined its comprehensive ecological function and, therefore, the more complex the structure, the stronger the functionality.
引文
[1] 张雷明,上官周平.黄土高原土壤水分与植被生产力的关系.干旱区研究,2002,19(4):59- 63.
[2] 程积民.黄土区植被的演替.土壤侵蚀与水土保持学报,1999,5(5):58- 61.
[3] 李鹏,李占斌,澹台湛.黄土高原退耕草地植被根系动态分布特征.应用生态学报,2005,16(5):849- 853.
[4] Sindh?j E,Hansson A C,Andrén O,K?tterer T,Marissink M,Pettersson R.Root dynamics in a semi-natural grassland in relation to atmospheric carbon dioxide enrichment,soil water and shoot biomass.Plant and Soil,2000,223(1/2):255- 265.
[5] Osman N,Barakbah S S.Parameters to predict slope stability—soil water and root profiles.Ecological Engineering,2006,28(1):90- 95.
[6] Mamo M,Bubenzer G D.Detachment rate,soil erodibility,and soil strength as influenced by living plant roots.Part Ⅰ:laboratory study.Transactions of the ASAE,2001,44(5):1167- 1174.
[7] Mamo M,Bubenzer G D.Detachment rate,soil erodibility,and soil strength as influenced by living plant roots.Part Ⅱ:field study.Transactions of the ASAE,2001,44(5):1174- 1181.
[8] Wells C E,Glenn D M,Eissenstat D M.Changes in the risk of fine- root mortality with age:a case study in peach,Prunus persica (Rosaceae).American Journal of Botany,2002,89(1):79- 87.
[9] 黄林,周立江,王峰,黄茹,田锋,齐代华,唐元会.红壤丘陵区典型植被群落根系生物量及碳储量研究.水土保持学报,2009,23(6):134- 138.
[10] 徐少君,曾波,类淑桐,苏晓磊.三峡库区几种耐水淹植物根系特征与土壤抗水蚀增强效应.土壤学报,2011,48(1):160- 167.
[11] 韦兰英,上官周平.黄土高原白羊草、沙棘和辽东栎细根比根长特性.生态学报,2006,26(12):4164- 4170.
[12] Hendrick R I,Pregitzer K S.The demography of fine roots in a northern hardwood forest.Ecology,1992,73(3):1094- 1104.
[13] Pregitzer K S.Woody plants,carbon allocation and fine roots.New Phytologist,2003,158(3):421- 424.
[14] Fransen B,de Kroon H,Berendse F.Root morphological plasticity and nutrient acquisition of perennial grass species from habitats of different nutrient availability.Oecologia,1998,115(3):351- 358.
[15] 冯长根,李后强,祖元刚.非线性科学的理论,方法和应用.北京:科学出版社,1997:2- 21.
[16] Morávek Z,Fiala J.Fractal dynamics in the growth of root.Chaos,Solitons & Fractals,2004,19(1):31- 34.
[17] Wang Z,Liu G B,Xu M X,Zhang J,Yang W,Li T.Temporal and spatial variations in soil organic carbon sequestration following revegetation in the hilly Loess Plateau,China.CATENA,2012,99:26- 33.
[18] Liu Y,Yu D S,Wang N,Shi X Z,Warner E D,Zhang H D,Qin F.Impacts of agricultural intensity on soil organic carbon pools in a main vegetable cultivation region of China.Soil and Tillage Research,2013,134:25- 32.
[19] Zhao B H,Li Z B,Li P,Xu G C,Gao H D,Cheng Y T,Chang E H,Yuan S L,Zhang Y,Feng Z H.Spatial distribution of soil organic carbon and its influencing factors under the condition of ecological construction in a hilly-gully watershed of the Loess Plateau,China.Geoderma,2017,296:10- 17.
[20] 周正朝,上官周平.子午岭次生林植被演替过程的土壤抗冲性.生态学报,2006,26(10):3270- 3275.
[21] 韦兰英,上官周平.黄土高原不同演替阶段草地植被细根垂直分布特征与土壤环境的关系.生态学报,2006,26(11):3740- 3748.
[22] 常恩浩,李鹏,张铁钢,肖列,徐国策,赵宾华,张祎.旱季雨季对黄土丘陵退耕区植被根系分布及水分利用的影响.农业工程学报,2016,32(24):129- 138.
[23] Turcotte D L.Fractals and fragmentation.Journal of Geophysical Research,1986,91(B2):1921- 1926.
[24] 胡建忠,郑佳丽,沈晶玉.退耕地人工植物群落根系生态位及其分布特征.生态学报,2005,25(3):481- 490.
[25] Waisel Y,Eshel A,Kafkafi U.Plant Roots,the Hidden Half.New York:Marcel Dekker,1991:3- 25.
[26] Eissenstat D M.Costs and benefits of constructing roots of small diameter.Journal of Plant Nutrition,1992,15(6/7):763- 782.
[27] Hao H M,Lu R,Liu Y,Fang N F,Wu G L,Shi Z H.Effects of shrub patch size succession on plant diversity and soil water content in the water-wind erosion crisscross region on the Loess Plateau.CATENA,2016,144:177- 183.
[28] 常恩浩,李鹏,刘莹,徐国策,柯浩成,刘琦,李雄飞.黄土丘陵区油松林细根在坡面的空间分布特征.水土保持研究,2016,23(5):28- 34.
[29] 梅莉,王政权,韩有志,谷加存,王向荣,程云环,张秀娟.水曲柳根系生物量、比根长和根长密度的分布格局.应用生态学报,2006,17(1):1- 4.
[30] Erktan A,Mccormack M L,Roumet C.Frontiers in root ecology:recent advances and future challenges.Plant & Soil,2018(1/2):1- 9.
[31] 常杰,陈刚,葛滢.植物形态结构定量研究的新方法——分形模拟.植物学通报,1996,13(2):57- 62.
[32] Weemstra M,Mommer L,Visser E J W,van Ruijven J,Kuyper T W,Mohren G M J,Sterck F J.Towards a multidimensional root trait framework:a tree root review.New Phytologist,2016,211(4):1159- 1169.
[33] Kramer-Walter K R,Bellingham P J,Millar T R,Smissen R D,Richardson S J,Laughlin D C.Root traits are multidimensional:specific root length is independent from root tissue density and the plant economic spectrum.Journal of Ecology,2016,104(5):1299- 1310.
[34] de la Riva E G,Maraňón T,Pérez-Ramos I M,Navarro-Fernández C M,Olmo M,Villar R.Root traits across environmental gradients in Mediterranean woody communities:are they aligned along the root economics spectrum?Plant and Soil,2018,424(1/2):35- 48.
[35] Rewald B,Raveh E,Gendler T,Ephrath J E,Rachmilevitch S.Phenotypic plasticity and water flux rates of Citrus root orders under salinity.Journal of Experimental Botany,2012,63(7):2717- 2727.
[36] Gambetta G A,Fei J,Rost T L,Knipfer T,Matthew M A,Shackel K A,Walker M A,McElrone A J.Water uptake along the length of grapevine fine roots:developmental anatomy,tissue-specific aquaporin expression,and pathways of water transport.Plant Physiology,2013,163(3):1254- 1265.
[2] 程积民.黄土区植被的演替.土壤侵蚀与水土保持学报,1999,5(5):58- 61.
[3] 李鹏,李占斌,澹台湛.黄土高原退耕草地植被根系动态分布特征.应用生态学报,2005,16(5):849- 853.
[4] Sindh?j E,Hansson A C,Andrén O,K?tterer T,Marissink M,Pettersson R.Root dynamics in a semi-natural grassland in relation to atmospheric carbon dioxide enrichment,soil water and shoot biomass.Plant and Soil,2000,223(1/2):255- 265.
[5] Osman N,Barakbah S S.Parameters to predict slope stability—soil water and root profiles.Ecological Engineering,2006,28(1):90- 95.
[6] Mamo M,Bubenzer G D.Detachment rate,soil erodibility,and soil strength as influenced by living plant roots.Part Ⅰ:laboratory study.Transactions of the ASAE,2001,44(5):1167- 1174.
[7] Mamo M,Bubenzer G D.Detachment rate,soil erodibility,and soil strength as influenced by living plant roots.Part Ⅱ:field study.Transactions of the ASAE,2001,44(5):1174- 1181.
[8] Wells C E,Glenn D M,Eissenstat D M.Changes in the risk of fine- root mortality with age:a case study in peach,Prunus persica (Rosaceae).American Journal of Botany,2002,89(1):79- 87.
[9] 黄林,周立江,王峰,黄茹,田锋,齐代华,唐元会.红壤丘陵区典型植被群落根系生物量及碳储量研究.水土保持学报,2009,23(6):134- 138.
[10] 徐少君,曾波,类淑桐,苏晓磊.三峡库区几种耐水淹植物根系特征与土壤抗水蚀增强效应.土壤学报,2011,48(1):160- 167.
[11] 韦兰英,上官周平.黄土高原白羊草、沙棘和辽东栎细根比根长特性.生态学报,2006,26(12):4164- 4170.
[12] Hendrick R I,Pregitzer K S.The demography of fine roots in a northern hardwood forest.Ecology,1992,73(3):1094- 1104.
[13] Pregitzer K S.Woody plants,carbon allocation and fine roots.New Phytologist,2003,158(3):421- 424.
[14] Fransen B,de Kroon H,Berendse F.Root morphological plasticity and nutrient acquisition of perennial grass species from habitats of different nutrient availability.Oecologia,1998,115(3):351- 358.
[15] 冯长根,李后强,祖元刚.非线性科学的理论,方法和应用.北京:科学出版社,1997:2- 21.
[16] Morávek Z,Fiala J.Fractal dynamics in the growth of root.Chaos,Solitons & Fractals,2004,19(1):31- 34.
[17] Wang Z,Liu G B,Xu M X,Zhang J,Yang W,Li T.Temporal and spatial variations in soil organic carbon sequestration following revegetation in the hilly Loess Plateau,China.CATENA,2012,99:26- 33.
[18] Liu Y,Yu D S,Wang N,Shi X Z,Warner E D,Zhang H D,Qin F.Impacts of agricultural intensity on soil organic carbon pools in a main vegetable cultivation region of China.Soil and Tillage Research,2013,134:25- 32.
[19] Zhao B H,Li Z B,Li P,Xu G C,Gao H D,Cheng Y T,Chang E H,Yuan S L,Zhang Y,Feng Z H.Spatial distribution of soil organic carbon and its influencing factors under the condition of ecological construction in a hilly-gully watershed of the Loess Plateau,China.Geoderma,2017,296:10- 17.
[20] 周正朝,上官周平.子午岭次生林植被演替过程的土壤抗冲性.生态学报,2006,26(10):3270- 3275.
[21] 韦兰英,上官周平.黄土高原不同演替阶段草地植被细根垂直分布特征与土壤环境的关系.生态学报,2006,26(11):3740- 3748.
[22] 常恩浩,李鹏,张铁钢,肖列,徐国策,赵宾华,张祎.旱季雨季对黄土丘陵退耕区植被根系分布及水分利用的影响.农业工程学报,2016,32(24):129- 138.
[23] Turcotte D L.Fractals and fragmentation.Journal of Geophysical Research,1986,91(B2):1921- 1926.
[24] 胡建忠,郑佳丽,沈晶玉.退耕地人工植物群落根系生态位及其分布特征.生态学报,2005,25(3):481- 490.
[25] Waisel Y,Eshel A,Kafkafi U.Plant Roots,the Hidden Half.New York:Marcel Dekker,1991:3- 25.
[26] Eissenstat D M.Costs and benefits of constructing roots of small diameter.Journal of Plant Nutrition,1992,15(6/7):763- 782.
[27] Hao H M,Lu R,Liu Y,Fang N F,Wu G L,Shi Z H.Effects of shrub patch size succession on plant diversity and soil water content in the water-wind erosion crisscross region on the Loess Plateau.CATENA,2016,144:177- 183.
[28] 常恩浩,李鹏,刘莹,徐国策,柯浩成,刘琦,李雄飞.黄土丘陵区油松林细根在坡面的空间分布特征.水土保持研究,2016,23(5):28- 34.
[29] 梅莉,王政权,韩有志,谷加存,王向荣,程云环,张秀娟.水曲柳根系生物量、比根长和根长密度的分布格局.应用生态学报,2006,17(1):1- 4.
[30] Erktan A,Mccormack M L,Roumet C.Frontiers in root ecology:recent advances and future challenges.Plant & Soil,2018(1/2):1- 9.
[31] 常杰,陈刚,葛滢.植物形态结构定量研究的新方法——分形模拟.植物学通报,1996,13(2):57- 62.
[32] Weemstra M,Mommer L,Visser E J W,van Ruijven J,Kuyper T W,Mohren G M J,Sterck F J.Towards a multidimensional root trait framework:a tree root review.New Phytologist,2016,211(4):1159- 1169.
[33] Kramer-Walter K R,Bellingham P J,Millar T R,Smissen R D,Richardson S J,Laughlin D C.Root traits are multidimensional:specific root length is independent from root tissue density and the plant economic spectrum.Journal of Ecology,2016,104(5):1299- 1310.
[34] de la Riva E G,Maraňón T,Pérez-Ramos I M,Navarro-Fernández C M,Olmo M,Villar R.Root traits across environmental gradients in Mediterranean woody communities:are they aligned along the root economics spectrum?Plant and Soil,2018,424(1/2):35- 48.
[35] Rewald B,Raveh E,Gendler T,Ephrath J E,Rachmilevitch S.Phenotypic plasticity and water flux rates of Citrus root orders under salinity.Journal of Experimental Botany,2012,63(7):2717- 2727.
[36] Gambetta G A,Fei J,Rost T L,Knipfer T,Matthew M A,Shackel K A,Walker M A,McElrone A J.Water uptake along the length of grapevine fine roots:developmental anatomy,tissue-specific aquaporin expression,and pathways of water transport.Plant Physiology,2013,163(3):1254- 1265.