海南岛4个热带阔叶树种前5级细根的形态、解剖结构和组织碳氮含量

doi:10.3724/SP.J.1258.2011.00955

摘要/Abstract

摘要：

细根具有复杂的分支系统, 以根序(root order)为取样单元的细根生理生态学研究正在成为根系生态学研究领域的重要内容。该研究以海南岛尖峰岭4个热带阔叶树种海南蕈树(Altingia obovata)、厚壳桂(Cryptocarya chinensis)、山杜英(Elaeocarpus sylvestris)和黄桐(Endospermum chinense)为研究对象, 测定了1-5级细根的形态、解剖结构和组织碳(C)、氮(N)含量, 旨在探讨这些根系特征之间的联系。研究表明: 4个树种的细根形态差异较大, 但在树种水平上直径、根长和组织密度均随着根序的升高而增加, 比根长则随着根序的升高而降低; 低级根(前2级根或前3级根)具有皮层组织, 是典型的吸收根, 而高级根皮层组织消失, 是典型的运输和储藏根; 影响直径大小最重要的因子是皮层厚度, 它可以解释细根直径变异的97%, 而维管束直径仅能解释细根直径变异的70%; 根组织N和C浓度受维管束-根直径比(维根比)的影响, 随着维根比增加, 组织N浓度显著降低, 组织C浓度显著升高。4个树种细根的C/N比的变异受组织N浓度的影响程度为76%, 而受C浓度的影响程度不足10%。上述结果表明, 细根的形态特征、解剖结构和组织化学含量之间存在着紧密联系, 这为我们理解根系结构与功能变异提供了重要依据。

关键词: 解剖, 形态, 根序, 组织化学, 热带树种

Abstract:

Aims Knowledge of fine root morphology, anatomy and tissue chemistry is critical to understanding root functions (e.g., longevity), but little is known about these root traits and their relationships in woody plants. We investigated root morphology, anatomy and tissue chemistry of the first five orders in four tropical tree species (Altingia obovata, Cryptocarya chinensis, Elaeocarpus sylvestris and Endospermum chinense) in Jianfengling of Hainan Island, China. Our objectives were to: 1) examine how root morphology (diameter, length, specific root length (SRL) and tissue density), anatomy (cortex thickness and stele to root diameter ratio (V/R)) and tissue chemistry (N and C content) changes with root branch orders and 2) reveal the relationships between anatomical structures and root diameter or tissue N or C concentrations in the four tree species.
Methods Tree roots of the four species were sampled in August 2009, and root samples were sorted into different orders. Root morphology of the first five orders was analyzed by the Win-RHIZO system. Root tissue C and N concentrations in roots of each order were analyzed by the Vario MACRO Element Analyzer. Individual roots in each order were made into paraffin slices stained by safranin and fast green to observe root anatomical structures and to calculate cortical thickness, stele diameter and V/R.
Important findings From the first to fifth order, root diameter, length and tissue density as well as stele diameter and V/R increased, and SRL and cortex thickness decreased in all species. The first two or three orders exhibited primary development with an intact cortex and lower V/R ratio, whereas higher order roots showed secondary development with no cortex and higher V/R ratio. Correlation analysis indicated that cortex thickness can explain 97% of the variations of root diameter and 70% of stele diameter. In all species, tissue N concentration decreased and tissue C concentrations increased with ascending root order. Moreover, C/N ratio in roots was mainly affected by tissue N rather than tissue C concentrations. These results suggest that there are systematic differences in root morphology, anatomy and tissue chemistry among different orders, and root morphology and tissue chemistry are closely linked to root anatomical traits such as cortex thickness in these tropical tree species.

Key words: anatomy, morphology, root orders, tissue chemistry, tropical tree species

许旸, 谷加存, 董雪云, 刘颖, 王政权. 海南岛4个热带阔叶树种前5级细根的形态、解剖结构和组织碳氮含量. 植物生态学报, 2011, 35(9): 955-964. DOI: 10.3724/SP.J.1258.2011.00955

XU Yang, GU Jia-Cun, DONG Xue-Yun, LIU Ying, WANG Zheng-Quan. Fine root morphology, anatomy and tissue nitrogen and carbon contents of the first five orders in four tropical hardwood species in Hainan Island, China. Chinese Journal of Plant Ecology, 2011, 35(9): 955-964. DOI: 10.3724/SP.J.1258.2011.00955

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链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2011.00955

https://www.plant-ecology.com/CN/Y2011/V35/I9/955

图/表 6

图1 海南岛尖峰岭热带森林海南蕈树(Alob)、厚壳桂(Crch)、山杜英(Elsy)和黄桐(Ench)前5级根的细根形态指标(平均值±标准误差)。同一树种不同字母表示根序间的差异显著(p < 0.05)。

Fig. 1 Fine root morphology of Altingia obovata (Alob), Cryptocarya chinensis (Crch), Elaeocarpus sylvestris (Elsy) and Endospermum chinense (Ench) among the first five orders in tropical forest of Jianfengling, Hainan Island, China (mean ± SE). Within each panel, mean values sharing different letters indicate significant difference with species at p < 0.05 level.

图2 海南岛尖峰岭热带森林海南蕈树(Alob)、厚壳桂(Crch)、山杜英(Elsy)和黄桐(Ench)前5级根的细根解剖结构(平均值±标准误差)。同一树种不同字母表示根序间的差异显著(p < 0.05)。

Fig. 2 Fine root anatomy of Altingia obovata (Alob), Cryptocarya chinensis (Crch), Elaeocarpus sylvestris (Elsy) and Endospermum chinense (Ench) among the first five orders in tropical forest of Jianfengling, Hainan Island, China (mean ± SE). Within each panel, mean values sharing different letters indicate significant difference with species at p < 0.05 level.

图3 海南岛尖峰岭热带森林海南蕈树(Alob)、厚壳桂(Crch)、山杜英(Elsy)和黄桐(Ench)细根直径与维管束直径(A)和皮层厚度(B)的相关关系。

Fig. 3 Correlations of fine root diameter with stele diameter (A) and cortex thickness (B) in Altingia obovata (Alob), Cryptocarya chinensis (Crch), Elaeocarpus sylvestris (Elsy) and Endospermum chinense (Ench) in tropical forest of Jianfengling, Hainan Island, China.

图4 海南岛尖峰岭热带森林海南蕈树(Alob)、厚壳桂(Crch)、山杜英(Elsy)和黄桐(Ench)前5级根的细根氮碳浓度(平均值±标准误差)。同一树种不同字母表示根序间的差异显著(p < 0.05)。

Fig. 4 Fine root nitrogen and carbon contents of Altingia obovata (Alob), Cryptocarya chinensis (Crch), Elaeocarpus sylvestris (Elsy) and Endospermum chinense (Ench) among the first five orders in tropical forest of Jianfengling, Hainan Island, China (mean ± SE). Within each panel, mean values sharing different letters indicate significant difference with species at p < 0.05 level.

图5 海南岛尖峰岭热带森林海南蕈树(Alob)、厚壳桂(Crch)、山杜英(Elsy)和黄桐(Ench)细根维根比与根组织氮(A)和碳浓度(B)的相关关系。

Fig. 5 Correlations of root tissue N (A) and root tissue C (B) with stele to root diameter ratio in Altingia obovata (Alob), Cryptocarya chinensis (Crch), Elaeocarpus sylvestris (Elsy) and Endospermum chinense (Ench) in tropical forest of Jianfengling, Hainan Island, China.

图6 海南岛尖峰岭热带森林海南蕈树(Alob)、厚壳桂(Crch)、山杜英(Elsy)和黄桐(Ench)细根碳氮比与根组织氮(A)和碳浓度(B)的相关关系。

Fig. 6 Correlations of C/N ratio of fine roots with root tissue N (A) and root tissue C (B) in Altingia obovata (Alob), Cryptocarya chinensis (Crch), Elaeocarpus sylvestris (Elsy) and Endospermum chinense (Ench) in tropical forest of Jianfengling, Hainan Island, China.

参考文献 36

[1]	Burton AJ, Pregitzer KS, Ruess RW, Hendrick RL, Allen MF (2002). Root respiration in North American forests: effects of nitrogen concentration and temperature across biomes. Oecologia, 131, 559-568. URL PMID
[2]	Chang WJ ( 常文静), Guo DL ( 郭大立) (2008). Variation in root diameter among 45 common tree species in temperate, subtropical and tropical forests in China. Journal of Plant Ecology (Chinese Version) (植物生态学报), 32, 1248-1257. (in Chinese with English abstract)
[3]	Eissenstat DM, Yanai RD (1997). The ecology of root lifespan. Advances in Ecological Research, 27, 2-59.
[4]	Esau K (1977). Anatomy of Seed Plants 2nd edn. Wiley, New York. 215-255.
[5]	Espeleta JF, West JB, Donovan LA (2009). Tree species fine-root demography parallels habitat specialization across a sandhill soil resource gradient. Ecology, 90, 1773-1787. URL PMID
[6]	Fitter AH (1985). Functional significance of root morphology and root system architecture. In: Fitter AH, Atinson D, Read DJ, Usher MB eds. Ecological Interaction in Soil Plant Microbes and Animals. Special Bulletin Number 4 of British Ecological Society. Blackwell Scientific Publication, Oxford. 87-106.
[7]	Fitter AH (1996). Characteristics and functions of root systems. In: Waisel Y, Eshel E, Kafkafi U eds. Plant Roots: the Hidden Half 2nd edn. Dekker, New York. 1-20.
[8]	Guo DL, Mitchell RJ, Hendricks JJ (2004). Fine root branch orders respond differentially to carbon source-sink manipulations in a longleaf pine forest. Oecologia, 140, 450-457. DOI URL PMID
[9]	Guo DL, Mitchell RJ, Withington JM, Fan PP, Hendricks JJ (2008a). Endogenous and exogenous controls of root life span, mortality and nitrogen flux in a longleaf pine forest: root branch order predominates. Journal of Ecology, 96, 737-745. DOI URL
[10]	Guo DL, Xia MX, Wei X, Chang WJ, Liu Y, Wang ZQ (2008b). Anatomical traits associated with absorption and mycorrhizal colonization are linked to root branch order in twenty-three Chinese temperate tree species. New Phytologist, 180, 673-683. DOI URL
[11]	Hishi T (2007). Heterogeneity of individual roots within the fine root architecture: causal links between physiological and ecosystem functions. Journal of Forest Research, 12, 126-133. DOI URL
[12]	Jia SX ( 贾淑霞), Zhao YL ( 赵妍丽), Ding GQ ( 丁国泉), Sun Y ( 孙玥), Xu Y ( 许旸), Wang ZQ ( 王政权) (2010). Relationship among fine-root morphology, anatomy, tissue nitrogen concentration and respiration in different branch root orders in Larix gmelinii and Fraxinus mandshurica. Chinese Bulletin of Botany (植物学报), 45, 174-181. (in Chinese with English abstract)
[13]	Lambers H, Chapin FS III, Pons TL (1998). Plant Physiological Ecology. Springer, New York.
[14]	Li A, Guo DL, Wang ZQ, Liu HY (2010). Nitrogen and phosphorus allocation in leaves, twigs, and fine roots across 49 temperate, subtropical and tropical tree species: a hierarchical pattern. Functional Ecology, 24, 224-232.
[15]	Liu J ( 刘佳), Xiang WH ( 项文化), Xu X ( 徐晓), Chen R ( 陈瑞), Tian DL ( 田大伦), Peng CH ( 彭长辉), Fang X ( 方晰) (2010). Analysis of architecture and functions of fine roots of five subtropical tree species in Huitong, Hunan Province, China. Chinese Journal of Plant Ecology (植物生态学报), 34, 938-945. (in Chinese with English abstract)
[16]	Liu JL ( 刘金梁), Mei L ( 梅莉), Gu JC ( 谷加存), Quan XK ( 全先奎), Wang ZQ ( 王政权) (2009). Effects of nitrogen fertilization on fine root biomass and morphology of Fraxinus mandshurica and Larix gmelinii: a study with in-growth core approach. Chinese Journal of Ecology (生态学杂志), 28, 1-6. (in Chinese with English abstract)
[17]	Liu Y ( 刘颖), Gu JC ( 谷加存), Wei X ( 卫星), Xu Y ( 许旸), Wang ZQ ( 王政权) (2010). Variations of morphology, anatomical structure and nitrogen content among first-order roots in different positions along branch orders in tree species. Chinese Journal of Plant Ecology (植物生态学报), 34, 1336-1343. (in Chinese with English abstract)
[18]	Lux A, Luxova M, Abe J, Morita S (2004). Root cortex: structural and functional variability and responses to environmental stress. Root Research, 13, 117-131.
[19]	Mei L ( 梅莉), Wang ZQ ( 王政权), Cheng YH ( 程云环), Guo DL ( 郭大立) (2004). A review: factors influencing fine root longevity in forest ecosystems. Acta Phytoecologica Sinica (植物生态学报), 28, 704-710. (in Chinese with English abstract)
[20]	Norby RJ, Jackson RB (2000). Root dynamics and global change: seeking an ecosystem perspective. New Phytologist, 147, 3-12.
[21]	Pregitzer KS, DeForest JL, Burton AJ, Allen MF, Ruess RW, Hendrick RL (2002). Fine root architecture of nine north American trees. Ecological Monographs, 72, 293-309. DOI URL
[22]	Pregitzer KS, Kubiske ME, Yu CK, Hendrick RL (1997). Relationships among root branch order, carbon, and nitrogen in four temperate species. Oecologia, 111, 302-308. URL PMID
[23]	Pregitzer KS, Laskowski MJ, Burton AJ, Lessard VC, Zak DR (1998). Variation in sugar maple root respiration with root diameter and soil depth. Tree Physiology, 18, 665-670. URL PMID
[24]	Qiu J ( 邱俊), Gu JC ( 谷加存), Jiang HY ( 姜红英), Wang ZQ ( 王政权) (2010). Factors influencing fine root longevity of plantation-grown Pinus sylvestris var. mongolica. Chinese Journal of Plant Ecology (植物生态学报), 34, 1066-1074. (in Chinese with English abstract) DOI URL
[25]	Reich PB, Walters MB, Ellsworth DS (1997). From tropics to tundra: global convergence in plant functioning. Proceedings of the National Academy of Sciences of the United States of America, 94, 13730-13734. URL PMID
[26]	Valenzuela-Estrada LR, Vera-Caraballo V, Ruth LE, Eissenstat DM (2008). Root anatomy, morphology, and longevity among root orders in Vaccinium corymbosum(Ericaceae). American Journal of Botany, 95, 1506-1514. URL PMID
[27]	Vogt KA, Grier CC, Gower ST, Sprugel DG, Vogt DJ (1986). Overestimation of net root production: A real or imaginary problem? Ecology, 67, 577-579.
[28]	Wang XR ( 王向荣), Wang ZQ ( 王政权), Han YZ ( 韩有志), Gu JC ( 谷加存), Guo DL ( 郭大立), Mei L ( 梅莉) (2005). Variations of fine root diameter with root order in Manchurian ash and Dahurian larch plantations. Acta Phytoecologica Sinica (植物生态学报), 29, 871-877. (in Chinese with English abstract)
[29]	Wang ZQ ( 王政权), Guo DL ( 郭大立) (2008). Root ecology. Journal of Plant Ecology (Chinese Version) (植物生态学报), 32, 1213-1216. (in Chinese)
[30]	Wang ZQ, Guo DL, Wang XR, Gu JC, Mei L (2006). Fine root architecture, morphology, and biomass of different branch orders of two Chinese temperate tree species. Plant and Soil, 288, 155-171.
[31]	Wells CE, Glenn DM, Eissenstat DM (2002). Changes in the risk of fine-root mortality with age: a case study in peach,Prunus persica(Rosaceae). American Journal of Botany, 89, 79-87. URL PMID
[32]	Wei X ( 卫星), Liu Y ( 刘颖), Chen HB ( 陈海波) (2008). Anatomical and functional heterogeneity among different root orders of Phellodendron amurense. Journal of Plant Ecology (Chinese Version) (植物生态学报), 32, 1238-1247. (in Chinese with English abstract)
[33]	Withington JM, Reich PB, Oleksyn J, Eissenstat DM (2006). Comparisons of structure and life span in roots and leaves among temperate trees. Ecological Monographs, 76, 381-398.
[34]	Wu C ( 吴楚), Fan ZQ ( 范志强), Wang ZQ ( 王政权) (2004). Effect of phosphorus stress on chlorophyll biosynthesis, photosynthesis and biomass partitioning pattern of Fraxinus mandchurica seedlings. Chinese Journal of Applied Ecology (应用生态学报), 15, 935-940. (in Chinese with English abstract) URL PMID
[35]	Xia MX, Guo DL, Pregitzer KS (2010). Ephemeral root modules in Fraxinus mandshurica. New Phytologist, 188, 1065-1074.
[36]	Yu SQ ( 于水强), Wang ZQ ( 王政权), Shi JW ( 史建伟), Quan XK ( 全先奎), Mei L ( 梅莉), Sun Y ( 孙玥), Jia SX ( 贾淑霞), Yu LZ ( 于立忠) (2007). Estimating fine root longevity of Fraxinus mandshurica and Larix gmelinii using mini-rhizotrons. Journal of Plant Ecology (Chinese Version) (植物生态学报), 31, 102-109. (in Chinese with English abstract)