Volume 35 Issue 1
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XIE Mingming, GUO Sujuan, SONG Ying, ZHANG Li, SUN Huijuan. Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima[J]. Journal of Zhejiang A&F University, 2018, 35(1): 60-67. doi: 10.11833/j.issn.2095-0756.2018.01.008
Citation: XIE Mingming, GUO Sujuan, SONG Ying, ZHANG Li, SUN Huijuan. Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima[J]. Journal of Zhejiang A&F University, 2018, 35(1): 60-67. doi: 10.11833/j.issn.2095-0756.2018.01.008
shu

Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima

doi: 10.11833/j.issn.2095-0756.2018.01.008

  • Key Laboratory for Silviculture and Conservation of the Ministry of Education, Beijing Forestry University, Beijing 100083, China

  • Received Date: 2017-01-20
  • Rev Recd Date: 2017-03-04
  • Publish Date: 2018-02-20
  • To confirm the spatial distribution and seasonal dynamics of fine roots in the non-timber forest products breeding and cultivation practice base for Castanea mollissima (chestnut) of Beijing Forestry University in Qianxi, Hebei Province, the monthly dynamics and spatial distribution characteristics of fine root length density and dry weight density in a six-year-old chestnut plantation for the 0-20, 20-40, and 40-60 cm soil layers were studied using the soil coring method. Soil cores with a diameter of 8 cm were taken each month during the growing period (from April to October) about 50 and 100 cm away from the chestnut tree stem. Results showed that the fine root length density with a monthly average value of 1 274.9 m·m-3 had two growth peaks. Compared to the previous month, June and October both had significant difference (P < 0.05), which increased 203.0 m·m-3 and 524.6 m·m-3 separately. The fine root dry weight density had a monthly average value of 184.7 g·m-3 and two growing periods from April to June and from September to October. The fine root dry weight density in October was 39.5 g·m-3 higher compared to that in September (P < 0.05). The value of the fine root length density and dry weight density reached a maximum and changed with the seasons most noticeably in the vertical direction of the 20-40 cm soil layer (P < 0.05). Also, the fine root length density and dry weight density in the horizontal direction about 100 cm were greater than those about 50 cm (P < 0.05). This study indicated that spatial distribution and seasonal dynamics of fine roots likely resulted from spatial soil properties and the growth rule of C. mollissima.
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  • [1]
    CHEN Lili, YUAN Zhiyou, MU Xingmin, et al. A review of fine root productive of forest [J]. J Northwest For Univ, 2015, 30(3): 70-75.
    [2]
    XI Benye, WANG Ye, JIA Liming, et al. Property of root distribution of triploid Populus tomentosa and its relation to root water uptake under the wide-and-narrow row spacing scheme [J]. Acta Ecol Sin, 2011, 31(1): 47-57.
    [3]
    OSMONT K S, SIBOUT R, HARDTKE C S. Hidden branches: developments in root system architecture [J]. Ann Rew Plant Biol, 2007, 58(58): 93-113.
    [4]
    SCHMIDT W. Root systems biology [J]. Front Plant Sci, 2014, 5(5): 215. doi: 10.3389/fpls.2014.00215.
    [5]
    ZHANG Xiaoquan, WU Kehong, MURACH D. A review of methods for fine-root production and turnover of trees [J]. Acta Ecol Sin, 2000, 20(5): 875-883.
    [6]
    VOGT K A, VOGT D J, PALMIOTTO P A, et al. Review of root dynamics in forest ecosystems grouped by climate, climatic forest type and species [J]. Plant Soil, 1995, 187(2): 159-219.
    [7]
    YANG Hongqiang, FAN Weiguo. Advances in research of apple root system architecture and it's regulation [J]. Acta Hortic Sin, 2012, 39(9): 1673-1678.
    [8]
    ZHANG Jinsong, MENG Ping. Spatial distribution characteristics of fine roots of pomegranate tree [J]. J Nanjing For Univ Nat Sci Ed, 2004, 28(4): 89-91.
    [9]
    YUN Lei, BI Huaxing, MA Wenjing, et al. Spatial distribution characteristics of root system of walnut trees in the walnut-peanut intercropping system in the loess region of western Shanxi [J]. J Northeast For Univ, 2010, 38(7): 67-70.
    [10]
    GAO Chenxi, LIU Hangkong, HAN Mingyu, et al. Growth dynamic and characteristics of root distribution of dwarfing self-rooted rootstock apply nursery [J]. J Northwest A&F Univ Nat Sci Ed, 2016, 44(5): 170-176.
    [11]
    PENG Jingjing, GUO Sujuan, WANG Jing, et al. Effect of different pruning intensity on leaf traits and photosynthetic characteristics of Chinese chestnut with different plant densities [J]. J Northeast For Univ, 2014, 42(11): 47-50.
    [12]
    GUO Sujuan, LI Guanghui, LÜ Wenjun, et al. Influence of manganese on growth, physiological effects of chestnut seedlings [J]. Plant Nutr Fert Sci, 2012, 18(6): 1530-1536.
    [13]
    ZHOU Feng, GUO Shujuan, XIE Peng, et al. Megasporogenesis and development of female gametophyte in Chinese chestnut (Castanea mollissima) cultivar 'Yanshanzaofeng' [J]. Int J Agric Biol, 2014, 16(5): 1001-1005.
    [14]
    BLOCK R M A, REES K C J V, KNIGHE J D. A review of fine root dynamics in populus, plantations [J]. Agrofor Syst, 2006, 67(1): 73-84.
    [15]
    JACKSON R B, CANDELL J, EHLERI J R, et al. A global analysis of root distributions for terrestrial biomes [J]. Oecologia, 1996, 108(3): 389-411.
    [16]
    SONG Xiaolin, WU Pute, ZHAO Xining, et al. Distribution characteristic of soil moisture and roots in rain-fed old apple orchards with water-fertilizer pit on the Loess Plateau [J]. Trans Chin Soc Agric Eng, 2016, 32(7): 121-128.
    [17]
    DI Nan, XI Benye, PINTO J R, et al. Root biomass distribution of triploid Populus tomentosa under wide-and narrow-row spacing planting schemes and its responses to soil nutrients [J]. Chin J Plant Ecol, 2013, 37(10): 961-971.
    [18]
    SHI Jianwei, WANG Mengben, CHEN Jianwen, et al. The spatial distribution and seasonal dynamics of fine roots in a mature Caragana korshinskii plantation [J]. Acta Ecol Sin, 2011, 31(3): 726-733.
    [19]
    CRAINE J M. Competition for nutrients and optimal root allocation [J]. Plant Soil, 2006, 285(1/2): 171-185.
    [20]
    SONG Yueqin, ZHAI Mingpu, JIA Liming, et al. Fine root dynamics of different aged triploid Populus tomentosa pulp forests during growth period [J]. Chin J Ecol, 2010, 29(9): 1696-1720.
    [21]
    JIAN Shengqi, ZHAO Chuanyan, FANG Shumin, et al. Distribution of fine root biomass of main planting tree species in Loess Plateau, China [J]. Chin J Appl Ecol, 2014, 25(7): 1905-1911.
    [22]
    TIAN Shoule, SHEN Guangning, XU Lin, et al. Effects of different water-saving irrigation modes on chestnut growth and fruiting in drought hilly land [J]. Chin J Appl Ecol, 2012, 23(3): 61-66.
    [23]
    ZHANG Liangde, XU Xuexuan, HU Wei, et al. Spatial distribution of fine roots of a Robinia pseudoacacia plantation in Yangou watershed in the hilly region of Loess Plateau [J]. Sci Silv Sin, 2011, 47(11): 31-36.
    [24]
    FEBRUARY E C, HIGGINS S I. The distribution of tree and grass roots in savannas in relation to soil nitrogen and water [J]. South Afr J Bot, 2010, 76(3): 517-523.
    [25]
    YANG Xiuyun, HAN Youzhi, ZHANG Yunxiang. Effects of horizontal distance on fine root biomass and seasonal dynamic in Larix principis-rupprechtil plantation [J]. J Plant Ecol, 2008, 32(6): 1277-1284.
    [26]
    JANSSENS P, DIELS J, VANDERBORGHT J, et al. Numerical calculation of soil water potential in an irrigated 'Conference' pear orchard [J]. Agric Water Manage, 2015, 148: 113-122.
    [27]
    LI Lusheng, ZHAO Xining, GAO Xiaodong, et al. Influences of stand age on root patterns in a rain-fed jujube (Ziziphus jujube) plantation of Loess Plateau in China [J]. Trans Chin Soc Agric Eng, 2015, 31(20): 140-146.
    [28]
    GAN Zhuoting, LIU Wenzhao. Distribution of the fine roots of different aged apple trees in Weibei rained tableland of the Loess Plateau [J]. Acta Ecol Sin, 2008, 28(7): 3401-3407.
    [29]
    LI Nan, LIAO Kang, CHENG Xiaolong, et al. Correlation and growth dynamic state of growth and development in root and aboveground organ of Korla fragrant pear [J]. J Xinjiang Agric Univ, 2013, 36(2): 131-135.
    [30]
    PREGITZER K S, ZAK D R, MZAIASZ J, et al. Interactive effectives of atmospheric CO2 and soil-N availability on fine roots of populous tremuloides [J]. Ecol Appl, 2000, 10(1): 18-33.
    [31]
    SOKALSKA D I, HAMAN D Z, SZEWCZUK A, et al. Spatial root distribution of mature apple trees under drip irrigation system [J]. Agric Water Manage, 2009, 96(6): 917-924.
    [33]
    XIE Peng, GUO Sujuan, LÜ Wenjun. Comparison analysis on mineral elements of different shoots in Chinese chestnut 'Yanshanzaofeng' during flowering and young fruit period [J]. J Northeast Agric Univ, 2014, 45(4): 41-45.
    [34]
    LI Guanghui, GUO Sujuan, ZOU Feng, et al. Dynamic changes and regression analysis of leaf and soil nutrients of Castanea mollissima [J]. J Cent South Univ For Technol, 2012, 32(9): 41-46.
    [35]
    WANG Yanping, XU Tan, ZHU Wanrui, et al. Seasonal dynamics of quantitative and morphological traits of poplar fine roots and their differences between successive rotation plantations [J]. Chin J Appl Ecol, 2016, 27(2): 395-402.
    [36]
    GAN Zhuoting, ZHOU Zhengchao, LIU Wenzhao. Vertical distribution and seasonal dynamics of fine root parameters for apple trees of different ages on the Loess Plateau of China [J]. Agric Sci China, 2010, 9(1): 46-55.
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Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima

doi: 10.11833/j.issn.2095-0756.2018.01.008
  • Key Laboratory for Silviculture and Conservation of the Ministry of Education, Beijing Forestry University, Beijing 100083, China
  • Received Date: 2017-01-20
  • Rev Recd Date: 2017-03-04
  • Publish Date: 2018-02-20

Abstract: To confirm the spatial distribution and seasonal dynamics of fine roots in the non-timber forest products breeding and cultivation practice base for Castanea mollissima (chestnut) of Beijing Forestry University in Qianxi, Hebei Province, the monthly dynamics and spatial distribution characteristics of fine root length density and dry weight density in a six-year-old chestnut plantation for the 0-20, 20-40, and 40-60 cm soil layers were studied using the soil coring method. Soil cores with a diameter of 8 cm were taken each month during the growing period (from April to October) about 50 and 100 cm away from the chestnut tree stem. Results showed that the fine root length density with a monthly average value of 1 274.9 m·m-3 had two growth peaks. Compared to the previous month, June and October both had significant difference (P < 0.05), which increased 203.0 m·m-3 and 524.6 m·m-3 separately. The fine root dry weight density had a monthly average value of 184.7 g·m-3 and two growing periods from April to June and from September to October. The fine root dry weight density in October was 39.5 g·m-3 higher compared to that in September (P < 0.05). The value of the fine root length density and dry weight density reached a maximum and changed with the seasons most noticeably in the vertical direction of the 20-40 cm soil layer (P < 0.05). Also, the fine root length density and dry weight density in the horizontal direction about 100 cm were greater than those about 50 cm (P < 0.05). This study indicated that spatial distribution and seasonal dynamics of fine roots likely resulted from spatial soil properties and the growth rule of C. mollissima.

XIE Mingming, GUO Sujuan, SONG Ying, ZHANG Li, SUN Huijuan. Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima[J]. Journal of Zhejiang A&F University, 2018, 35(1): 60-67. doi: 10.11833/j.issn.2095-0756.2018.01.008
Citation: XIE Mingming, GUO Sujuan, SONG Ying, ZHANG Li, SUN Huijuan. Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima[J]. Journal of Zhejiang A&F University, 2018, 35(1): 60-67. doi: 10.11833/j.issn.2095-0756.2018.01.008
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  • 根系是植物吸收土壤水分和养分的重要营养器官，并通过自身周期性的衰老死亡和分解作用参与土壤生态过程[1]。根系的空间分布决定了林木吸收土壤水分和营养空间的大小[2]。林木新根数量、长度和有效吸收面积等决定了根系吸收水分和养分的能力[3-4]。而直径≤2 mm的根，由于吸收表面积大、生理活性强等特点，在水分和养分吸收上发挥着重要的作用[5]。VOGT等[6]研究表明：在植物生长季中，粗根变化不明显，细根的变化较为明显。对于经济林来说，根系是果树栽培的基础。果园改土、灌溉、施肥等基本栽培措施都要通过根系对地上部分产生影响[7]。根系对于提高果实品质也有影响。目前，对果树根系进行了大量研究，张劲松等[8]对太行山低山丘陵区石榴Punica granatum吸水根的研究表明：石榴吸水根在垂直方向上主要集中在0~80 cm，水平方向上主要集中在0~100 cm。云雷等[9]对晋西黄土区核桃Juglans regia-花生Arachis hypogaea复合系统核桃根系的研究表明，核桃根系垂直方向上主要集中在0~60 cm，水平方向上主要集中在距核桃1.5 m的区域内。高琛稀等[10]对1年生矮化自根砧苹果Malus pumila苗木的研究表明：地下根系在6月和9月生长旺盛，7月和8月死亡较多。这一系列的研究对指导果树施肥和灌溉发挥了重要的作用。板栗Castanea mollissima原产中国，在中国分布范围较广，是中国重要的木本粮食作物之一，其抗病能力强、果实含糖量高、糯性强和易剥离等优点，深受广大消费者喜爱。提高板栗的产量和品质是许多学者比较关心的问题，而目前的研究主要集中在修剪、施肥、授粉等方面[11-13]，对板栗根系的研究却鲜有报道。因此，本研究通过对板栗细根季节性动态及空间分布特征的研究，以期为生产中确定合理的施肥和灌溉制度，提高果树产量和质量提供科学依据。

1.   材料与方法

    1.1.   试验样地概况

  • 研究区域位于河北省迁西县北京林业大学经济林(板栗)育种与栽培实践基地。该地区地势平坦，属于东部季风暖温带半湿润气候，年平均气温为10.9 ℃，最冷月(1月)平均气温-6.5 ℃，最热月(7月)平均气温25.4 ℃，年平均降水量为744.7 mm，主要集中在7月和8月。全年日照时数为2 581.5 h，无霜期为176 d。试验地成土母质为片麻岩，土壤质地为沙壤土，土壤类型为褐土。试验地土壤理化性质见表 1。

    土层深度/cm 容重/(g·m-3) 总孔隙度/% pH值 有机质/(g·kg-1) 碱解氮/(mg·kg-1) 有效磷/(mg·kg-1) 速效钾/(mg·kg-1)
    0~20 1.51 43.07 6.48 6.11 51.42 22.53 157.61
    20 ~40 1.42 46.37 6.68 6.55 46.55 18.72 125.51
    40 ~60 1.47 44.41 7.59 5.56 38.85 16.58 123.12

    Table 1.  Physical and chemical properties of the soils at the experiment site

    • 1.2.   研究方法

    1.2.1.   根系取样

  • 研究对象是位于示范园内的6年生板栗，林带内植株密度为2 m × 3 m(株距为2 m，行距为3 m)，平均树高2.4 m，平均地径6.6 cm，采用中等强度的管理措施。在研究区域内设置3个40 m × 40 m的标准地，选择标准木(接近平均树高和平均地径的树木)21株·样地-1。采用连续根钻法，土钻内径为8 cm，于2016年4-10月生长季内，每月10-15日选择样本3株·样地-1，以样本为中心，东西南北4个方向为取样区，距树干50 cm，100 cm处钻取土芯，分3层(0~20，20~40，40~60 cm)取样。试验为期6个月，共计分析7次样品。

    • 1.2.2.   根系分析

  • 根样取回后先在水中浸泡，然后用水冲洗，过100目筛使根系与土壤等分离，重复数次。本研究采用传统的根系分类方法[14]，将直径≤2 mm的根系归为板栗细根。然后将洗净的根系放在清水中，用镊子捡取所有的细根。根据细根的外形、颜色、弹性区别死根和活根。装入自封袋内放入冰箱内低温保存。本研究只统计活细根的特征，活细根用Epson Twain Pro根系扫描仪扫描获取图像。扫描时将根系放在透明塑料板上，用镊子将各条根系充分展开，扫描后的图像用WinRhizo根系分析系统进行分析。分析后的活根置于80 ℃的烘箱中烘干至恒量，用电子天平称量(精确到0.001 g)。以此来估算生物量。

    • 1.2.3.   根系指标计算

  • 根长密度(m·m-3)=L/[πr2h·10-4]；根质量密度(g·m-3)=m土芯/[πr2h·10-4]。其中：L为土芯根长；m土芯为土芯根质量；r为土钻半径，为4 cm；h为土层深，为20 cm。

    • 1.3.   统计方法

  • 使用SPSS 20.0软件进行数据统计分析，采用单因素方差分析(one-way ANOVA)和Duncan法比较不同土层深度、不同距离的差异性及不同月份的差异性，应用Excel 2007进行图表制作。

2.   结果与分析

    2.1.   板栗细根空间分布特征

  • 从4-10月板栗细根根长密度和根质量密度的总平均值来看(表 2)，随着土层的变化，细根根长密度和根质量密度均表现出明显的变化趋势。在0~60 cm土层中，总细根根长密度为3 824.6 m·m-3，其中20~40 cm土层中最多，占总细根根长密度的43.03%。细根的总根质量密度在0~60 cm土层为554.2 g·m-3，与细根的根长密度相同，在20~40 cm土层中也是最多的，占总细根根质量密度的45.35%。细根根长密度和根质量密度的最大值均出现在距树干100 cm处的20~40 cm土层中。方差分析表明：随着土层的加深，细根的根长密度和根质量密度的变化差异显著(P＜0.05)。

    土层深度/cm 根长密度/(m·m-3) 根质量密度/(g·m-3)
    50 cm 100 cm 50 cm 100 cm
    0~20 1 352.8 ± 82.3 a 1 174.7 ± 65.0 b* 194.4 ± 10.5 a 141.4 ± 9.7 b*
    20~40 1 246.5 ± 76.4 a 2 044.6 ± 124.3 a* 211.8 ± 14.7 a 290.8 ± 18.4 a*
    40~60 824.0 ± 72.5 b 1 006.9 ± 98.3 c* 140.2 ± 8.4 b 129.7 ± 7.3 b
    说明：数值为平均值±标准差。同列不同小写字母表示同一列不同土层细根差异显著(P < 0.05)，*表示相同土层距树干不同距离细根差异显著(P < 0.05)。

    Table 2.  Spatial distribution characteristics of fine root of Castanea mollissima

    板栗细根在水平距离上也表现出一定的分布特征。通过对这2个水平距离的细根进行统计分析，结果表明(表 2)：在相同的土层处，这2个水平距离的细根根长密度差异显著，而细根的根质量密度除40~60 cm土层外，都差异显著(P＜0.05)。在同一水平距离处，随土层的变化差异显著，尤其在100 cm的变化更为明显，其中100 cm处的20~40 cm土层中细根根长密度和根质量密度都明显高于其他层(P＜0.05)。而在50 cm处，0~20 cm土层和20~40 cm土层的细根差异不明显。

    • 2.2.   板栗细根根长密度的季节变化

  • 在0~60 cm土层中，板栗细根根长密度的季节变化范围为88.4~4 166.3 m·m-3，细根根长密度的月平均值为1 274.9 m·m-3。其中10月细根根长密度最大，4月细根根长密度最小。板栗在生长季中，细根根长密度有2次生长高峰，分别是6月和10月，10月增长最多，为524.6 m·m-3。

    从图 1可以看出：20~40 cm土层的细根根长密度季节性变化最明显。在这一土层中，距树干50 cm和100 cm处的细根根长密度的季节性变化都显著(P＜0.05)，但它们的变化趋势不相同。在距树干100 cm处，细根根长密度的最大值出现在10月，且显著高于其他各月份(P＜0.05)，最小值是4月。在距树干50 cm处，细根根长密度的最大值出现在5月，最小值出现在7月。方差分析结果表明：5月的细根根长密度，除与6月差异不明显外，都显著高于其他月份(P＜0.05)。

    Figure 1.  Seasonal dynamics of fine root length density of Castanea mollissima at different locations

    距树干50 cm处，细根根长密度呈波动变化，6月的细根根长密度最大，且明显大于其他月份(P＜0.05)。在7月，细根根长密度有明显的下降，相比6月减少了904.4 m·m-3。距树干100 cm处，细根根长密度的变化不同于距树干50 cm处的，在7月和10月有2个生长高峰，其中10月细根根长密度最大。方差分析表明：10月的细根根长密度显著大于其他月份(P＜0.05)。

    • 2.3.   板栗细根根质量密度的季节变化

  • 板栗细根根质量密度随着季节的变化也产生相应的变化。在0~60 cm的土层中，其生长季的波动范围为29.9~498.1 g·m-3，细根根质量密度的月平均值为184. 0 g·m-3。在生长过程中，细根的根质量密度有2个生长阶段，分别是4-6月和10月，其中4-6月生长相对较少，10月生长较为旺盛，与9月相比增长了39.5 g·m-3。

    在不同的土层中，细根根质量密度的季节性变化有所不同(图 2)。与细根根长密度相同，20~40 cm的细根根质量密度相对较大，且变化较明显。在这一土层中，距树干50 cm处的细根根质量密度在5月有明显的增加，其中5月和6月的细根根质量密度明显大于其他月份(P＜0.05)。距树干100 cm处，细根根质量密度在7月增加明显。方差分析表明：10月的细根根质量密度除与9月差异不明显外，都显著大于其他月份(P＜0.05)。

    Figure 2.  Seasonal dynamics of fine root biomass density of Castanea mollissima at different locations

    距树干50 cm处，细根根质量密度季节变化明显，其中6月细根根质量密度显著大于其他月份(P＜0.05)。距树干100 cm处，整体上细根根质量密度是呈上升趋势的。与距树干50 cm不同，细根根质量密度在7月明显上升。10月和6月与其他月份相比差异均达显著水平(P＜0.05)。

3.   讨论

    3.1.   板栗细根的空间分布特征

  • 根系在空间分布上受多方面影响，除树种遗传因素外，还在很大程度上受土壤空间异质性影响。根系通过根长密度和生物量的改变来适应不同的条件，这是根系适应土壤空间异质性的策略[15]。长期以来，人们对细根分布研究仅局限于生物量[16-17]，而细根在生长中受各种生态因子的影响，反映细根功能的各个指标也会随之发生变化[18]。CRAINE[19]的研究发现：根长密度能反映树体对水分和养分的吸收能力，在反映根系生理生态功能方面比根质量密度更有价值。因此，本研究还考虑到细根的根长密度这一指标，发现这2个指标在空间分布上有所不同。研究中发现，在垂直方向上，20~40 cm的土层中细根根长密度和根质量密度较多。而有研究表明，土壤表层0~20 cm处细根较多，且随着土层深度的增加，根系数量减少[20-21]。这与本研究结果不一致。他们的研究对象大多数属于浅根性树种，本研究中板栗属于经济林，根系分布范围较深。田寿乐等[22]在半干旱半湿润山地果园的研究表明：20~40 cm土层是板栗根系的富集区。此外，试验地土壤性质差异也会导致根系分布差异。表 1可以看出：在20~40 cm土层中，总孔隙度和有机质质量分数相对较高。在适宜的土壤水分条件下，孔隙度越大，越有利于细根的生长[23]。土壤有机质质量分数对细根也有显著影响。为了获取更多的有机质，细根通常趋向于养分质量分数高的区域[24]。

    目前，关于细根在水平方向的分布，有不同的结论。有研究表明：细根分布与距树干位置有关[25]。但也有一些研究表明：细根分布与距树干位置没有显著关系[26]。李陆生等[27]和甘卓亭等[28]的研究发现：幼龄林根系在水平方向上随径向距离增大而降低，成熟林则没有显著关系。本研究发现：整体上，距树干100 cm的细根根长密度和根质量密度大于距树干50 cm的，各个月份和不同土层之间也存在差异，这与土壤的垂直变化和板栗的生长规律有关。

    • 3.2.   板栗细根的季节性变化

  • 对于经济林来说，根系的作用尤为质量要，能吸收水分和养分，并调控地上部分的果实产量，与地上部分相辅相成。由于自身生长特性以及受到环境因素的影响，地上部分和地下部分呈交替生长的规律，即地上部分生长旺盛时，地下部分生长缓慢，地上部分生长迟缓时，地下部分生长旺盛[8, 29]。土壤水分与养分在垂直上的差异，使得在不同季节，甚至是同一季节不同层的细根发生变化[30]。0~20 cm土层处于表层，水热条件受季节变化影响较大。距树干50 cm处，4-6月细根根长密度和根质量密度都呈上升趋势，而距树干100 cm处，细根根长密度和根质量密度基本上呈下降趋势。这是由于在这段时间降雨较少，气候干旱，地表温度逐渐升高，而50 cm处位于树冠内，100 cm处位于树冠外，导致这2个距离产生了不同的变化趋势。在生长季前期，地上部分枝条和叶片生长旺盛，冠幅不断扩大，而根系也随之扩张，林分逐渐郁闭。在7月和8月，试验地区降雨增多，进入雨季，此时距树干100 cm位于树冠线边缘，树冠对于降水的再分配及降水的化学性质，改变了树冠下土壤湿度及化学性质，同时这个距离的光照条件相对较好，细根向有利的营养空间聚集，以获取水分和养分[31]，使这一距离的细根根长密度和根质量密度逐渐上升。

    20~40 cm土层中，板栗根系的季节性变化主要与营养生长和生殖生长的矛盾有关。根据对研究区域板栗的生长特征研究，其物候期可以分为叶芽萌发期(4月)、展叶期(5月)、授粉期(6月初)、坐果期(6月中旬)、幼果期(7月)、果实膨大期(8月)、果实成熟期(9月)和落叶期(10月)[32]。在展叶期(5月)，细根根质量密度和根长密度明显增大。由于在这段时间，板栗主要进行营养生长，根系横向生长和纵向生长同时进行。在6月板栗进入生殖生长期，此时细根根长密度增加明显而根质量密度没有变化，这一时期地上部分需要大量营养供应，根系主要通过纵向伸长来获取更多的养分和水分。进入到幼果期(7月)，果实营养物质积累少，营养生长和生殖生长的矛盾得到缓和，叶片逐渐成熟，光合作用增强[33]，因此细根根长密度下降而根质量密度上升。在8月(果实膨大期)和9月(果实成熟期)，板栗对氮、磷、钾的营养的需求较高[34]，细根根长密度不断增大。进入到生长季末(10月)，地上部分生长基本结束，地下部分生长旺盛，细根根长密度大幅度增加，但是研究中发现细根根质量密度变化不明显，这主要是由于在根系横向生长的过程中，一部分细根进入到了下一个径级，而本研究并未考虑其他径级的根系。在40~60 cm土层距树干50 cm和100 cm处交替增长，因为这一层次的土壤受外界影响较小，土壤几乎是同质性的，细根的季节变化主要与树种本身根系生长特点有关。

4.   结论与展望

  • 板栗细根垂直分布差异明显，20~40 cm土层中细根根长密度和根质量密度最大。水平方向上，距树干100 cm处的细根根长密度和根质量密度大于50 cm处。板栗细根表现出明显的季节波动性，其中20~40 cm土层的细根季节变化较明显。根长密度在6月和10月有2个生长高峰，根质量密度在10月增长较多，5月和6月也有增长。板栗细根的空间分布和季节变化与土壤分布差异和树种生长规律密切相关。

    影响根系变化和分布的因素是多种多样的，不同根序[35]以及不同年龄[36]等的根系变化和分布都有所不同。这方面的研究还有待于更为深入和全面的探讨。

Reference (36)

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