马尾松苗木根系生长的养分-密度耦合效应
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摘要
旨在研究根系对种植密度、土壤养分及两者耦合的响应。采用盆栽试验,对比6种种植密度(1～6株/盆)和6种土壤养分条件下马尾松苗木根系生长特性。根系形态指标(根表面积、根长、根体积和根量)在种植密度或土壤养分单一条件下的生长规律与前人研究结果相似,表现为土壤养分高、种植密度小更宜根系生长。而在二者耦合条件下,在种植3株/盆以上密度时,高养分对部分指标反而有抑制作用。根系竞争强度表现为:中养分>高养分>低养分。根总量与土壤养分间的回归方程中以幂函数的相关系数最大(R2=0. 945)。在土壤养分-种植密度耦合效应中,种植密度对根系生长的影响力度更大,二者与根系指标间存在二元一次函数关系,土壤养分表现为正效应,种植密度为负效应。中等以上密度条件下,中等土壤养分更适宜马尾松根系生长。土壤养分增大能减弱根系间的竞争作用,种植密度增大能增强根系间的竞争作用,邻株根系间存在竞争以外的其它相互作用,将其假说为抑制效应—根系抑制邻株根系生长的结果。可用二元一次函数讨论适宜马尾松根系生长的种植密度和养分条件。
[Background] Root system plays key role in soil and water conservation,while coupling effect of planting density and soil nutrient on the root growth of plant remains unclear. Pinus massoniana is a dominant tree species in Guizhou province,and thus selected as study material in this study. This work aims to clarify 2 questions: 1) the response mechanism of P. massoniana seedlings roots to planting density and soil nutrients; and 2) the mechanism or effect of planting density-nutrient coupling among roots of P. massoniana seedlings. [Methods] The pot experiment was carried out in this study,6 planting densities( 1-6 Trees/pot) and 6 soil types( A0-A5) were set to explore the growth of P.massoniana roots, A0-A5 consisted of different ratio of layer A( leaching layer) and layer B( deposition layer),and their nutrients were in order: A0< A1< A2< A3< A4< A5. Root morphology indexes,including root length,root surface area,root volume,and root biomass,were analyzed by Expression 10000 XL 1. 0 and Win RHIZOC Pro 2004 b,and the data were processed using Microsoft Excel 2013 and SPSS 20. 0 software. [Results] Root surface area,root length,root volume and root biomass increased with the increase of soil nutrient,and were the maximum at planting density of 1 tree/pot. The total root length in the planting density 1 tree/pot was higher than that in planting density 6 trees/pot 30. 7%( A0),64. 5%( A1),51. 2%( A2),67. 3%( A3),54. 7%( A4) and 72. 2%( A5). The total root volume in planting density 1 tree/pot was higher than that in 6 trees/pot by 57. 2%( A0),55. 3%( A1) than,74. 1%( A2),47. 2%( A3),51. 2%( A4) and 65. 2%( A5). The competition intensity of roots in different soil nutrients showed as middle nutrient > high nutrient > low nutrient,and each nutrient had the highest competition index at planting density 6 trees/pot by 0. 502( A0),0. 641( A1),0. 737( A2),0. 623( A3),0. 753( A4) and 0. 629( A5). The correlation coefficient between total root length and soil nutrients was the largest( R2= 0. 945). Planting density had a greater impact on root growth than soil nutrients in the coupling effect of soil nutrient and planting density. There was a binary functional relationship between the two and the root system. The soil nutrient was positively correlated with root growth,and the positive correlation coefficient ranged in 0. 044 and1. 436. The planting density was negatively correlated with root growth,and the negative correlation coefficient was in(-34. 757) and(-1. 901). [Conclusions] Under medium and medium planting density conditions,medium soil nutrient is more suitable for root growth of P. massoniana. There are other interactions between the roots of adjacent plants,which are hypothesized as inhibitory effects,the results of plant roots inhibiting the growth of adjacent roots. Increased soil nutrients weaken competition between roots,and increased planting density increases competition among roots. The binary density function can be used to explain the planting density and nutrient conditions suitable for root growth of P.massoniana.
[Background] Root system plays key role in soil and water conservation,while coupling effect of planting density and soil nutrient on the root growth of plant remains unclear. Pinus massoniana is a dominant tree species in Guizhou province,and thus selected as study material in this study. This work aims to clarify 2 questions: 1) the response mechanism of P. massoniana seedlings roots to planting density and soil nutrients; and 2) the mechanism or effect of planting density-nutrient coupling among roots of P. massoniana seedlings. [Methods] The pot experiment was carried out in this study,6 planting densities( 1-6 Trees/pot) and 6 soil types( A0-A5) were set to explore the growth of P.massoniana roots, A0-A5 consisted of different ratio of layer A( leaching layer) and layer B( deposition layer),and their nutrients were in order: A0< A1< A2< A3< A4< A5. Root morphology indexes,including root length,root surface area,root volume,and root biomass,were analyzed by Expression 10000 XL 1. 0 and Win RHIZOC Pro 2004 b,and the data were processed using Microsoft Excel 2013 and SPSS 20. 0 software. [Results] Root surface area,root length,root volume and root biomass increased with the increase of soil nutrient,and were the maximum at planting density of 1 tree/pot. The total root length in the planting density 1 tree/pot was higher than that in planting density 6 trees/pot 30. 7%( A0),64. 5%( A1),51. 2%( A2),67. 3%( A3),54. 7%( A4) and 72. 2%( A5). The total root volume in planting density 1 tree/pot was higher than that in 6 trees/pot by 57. 2%( A0),55. 3%( A1) than,74. 1%( A2),47. 2%( A3),51. 2%( A4) and 65. 2%( A5). The competition intensity of roots in different soil nutrients showed as middle nutrient > high nutrient > low nutrient,and each nutrient had the highest competition index at planting density 6 trees/pot by 0. 502( A0),0. 641( A1),0. 737( A2),0. 623( A3),0. 753( A4) and 0. 629( A5). The correlation coefficient between total root length and soil nutrients was the largest( R2= 0. 945). Planting density had a greater impact on root growth than soil nutrients in the coupling effect of soil nutrient and planting density. There was a binary functional relationship between the two and the root system. The soil nutrient was positively correlated with root growth,and the positive correlation coefficient ranged in 0. 044 and1. 436. The planting density was negatively correlated with root growth,and the negative correlation coefficient was in(-34. 757) and(-1. 901). [Conclusions] Under medium and medium planting density conditions,medium soil nutrient is more suitable for root growth of P. massoniana. There are other interactions between the roots of adjacent plants,which are hypothesized as inhibitory effects,the results of plant roots inhibiting the growth of adjacent roots. Increased soil nutrients weaken competition between roots,and increased planting density increases competition among roots. The binary density function can be used to explain the planting density and nutrient conditions suitable for root growth of P.massoniana.
引文
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[10]叶立鹏.马尾松根系生长的营养空间特征及固土机制研究[D].贵阳:贵州大学,2013:1.YE Lipeng. Research on the nutrient spatial characteris-tics of growing root system of Pinus massoniana and themechanism of soil consolidation[D]. Guiyang:GuizhouUniversity,2013:1.
[11] III F S C,SHAVER G R. Individualistic growth re-sponse of tundra plant species to environmental manipu-lations in the field[J]. Ecology,1985,66(2):564.
[12] ROBINSON D. The responses of plants to non-uniformsupplies of nutrients[J]. New Phytologist,2006(127):635.
[13]任玫玫,杨华.长白山云冷杉林优势树种的竞争[J].应用生态学报,2016,27(10):3089.REN Meimei,YANG Hua. Competition of dominant treespecies in spruce and fir forests in Changbai Mountains[J]. Chinese Journal of Applied Ecology,2016,27(10):3089.
[14] BLISS K M,JONES R H. Are competitive in-teractionsinfluenced by spatial nutrient heterogeneity and root for-aging behavior?[J]. New Phytologist,2002(154):409.
[15] GRIME J P. Plant strategies and vegetation processes[J]. Biologia Plantrum,1979,23(4):254.
[16] EISSENSTAT D,CALDWELL M. Seasonal timing ofroot growth in favorable microsites[J]. Ecology,1988(69):870.
[17] GOLDBERG DE,RAJANIEMI T,GUREVITCH J,etal. Empirical approaches to quantifying interaction in-tensity:Competition and facilitation along productivitygradients[J]. Ecology,1999(80):1118.
[18] CAHILL J F Jr. Fertilization effects on interactions be-tween above-and belowground competition in an old field[J]. Ecology,1999(80):466.
[19] COOMES D A,GRUBB PJ. Impacts of root competitionin forests and woodlands:A theoretical framework andre-view of experiments[J]. Ecological Monographs,2000(70):171.
[20] SPELETA J F,DONOVAN L A. Fine root demographyand morphology in response to soil resources availabilityamong xeric and mesics and hill tree species[J]. Func-tional Ecology,2002(16):113.
[2]蔡鲁,朱婉芮,王华田,等.鲁中南山地6个造林树种根系形态的比较[J].中国水土保持科学,2015,13(2):83.CAI Lu,ZHU Wanrui,WANG Huatian,et al. Root mor-phology of six tree species in mountain area of middlesouth Shandong[J]. Science of Soil and Water Conser-vation,2015,13(2):83.
[3]王平,王天慧,周道玮,等.植物地上竞争与地下竞争研究进展[J].生态学报,2007,27(8):3489.WANG Ping,WANG Tianhui,ZHOU Daowei,et al. Re-search progress on plant ground competition and under-ground competition[J]. Acta Ecologica Sinica,2007,27(8):3489.
[4] WEIGELT A,JOLLIFFE P. Indices of plant competition[J]. Journal of Ecology,2003,91(5):14.
[5] CAMPBELL B D,GRIME J P. An experimental test ofplant strategy theory[J]. Ecology,1992,73(1):15.
[6]陈伟,薛立.根系间的相互作用:竞争与互利[J].生态学报,2004,24(6):1243.CHEN Wei,XUE Li. Root interactions:Competition andmutual benefit.[J]. Acta Ecologica Sinica,2004,24(6):1243.
[7] SNAYDON R W. Replacement or additive designs forcompetition studies?[J]. Journal of Applied Ecology,1991,28(3):930.
[8] KEDDY P A,TWOLAN-STRUTT L,WISHEU I C.Competitive effect and response rankings in 20 wetlandplants:Are they consistent across three environments?[J]. Journal of Ecology,1994,82(3):635.
[9] HE Yaping,FEI Shimin,CHEN Xiuming,et al. Effectsof simulated planting density resources on the growth ofJatropha curcas seedlings[J]. Sichuan Forestry Scienceand Technology,2010,31(6):1.
[10]叶立鹏.马尾松根系生长的营养空间特征及固土机制研究[D].贵阳:贵州大学,2013:1.YE Lipeng. Research on the nutrient spatial characteris-tics of growing root system of Pinus massoniana and themechanism of soil consolidation[D]. Guiyang:GuizhouUniversity,2013:1.
[11] III F S C,SHAVER G R. Individualistic growth re-sponse of tundra plant species to environmental manipu-lations in the field[J]. Ecology,1985,66(2):564.
[12] ROBINSON D. The responses of plants to non-uniformsupplies of nutrients[J]. New Phytologist,2006(127):635.
[13]任玫玫,杨华.长白山云冷杉林优势树种的竞争[J].应用生态学报,2016,27(10):3089.REN Meimei,YANG Hua. Competition of dominant treespecies in spruce and fir forests in Changbai Mountains[J]. Chinese Journal of Applied Ecology,2016,27(10):3089.
[14] BLISS K M,JONES R H. Are competitive in-teractionsinfluenced by spatial nutrient heterogeneity and root for-aging behavior?[J]. New Phytologist,2002(154):409.
[15] GRIME J P. Plant strategies and vegetation processes[J]. Biologia Plantrum,1979,23(4):254.
[16] EISSENSTAT D,CALDWELL M. Seasonal timing ofroot growth in favorable microsites[J]. Ecology,1988(69):870.
[17] GOLDBERG DE,RAJANIEMI T,GUREVITCH J,etal. Empirical approaches to quantifying interaction in-tensity:Competition and facilitation along productivitygradients[J]. Ecology,1999(80):1118.
[18] CAHILL J F Jr. Fertilization effects on interactions be-tween above-and belowground competition in an old field[J]. Ecology,1999(80):466.
[19] COOMES D A,GRUBB PJ. Impacts of root competitionin forests and woodlands:A theoretical framework andre-view of experiments[J]. Ecological Monographs,2000(70):171.
[20] SPELETA J F,DONOVAN L A. Fine root demographyand morphology in response to soil resources availabilityamong xeric and mesics and hill tree species[J]. Func-tional Ecology,2002(16):113.