共查询到17条相似文献，搜索用时 125 毫秒
1.
多年施用氮肥对水曲柳人工林内生菌根真菌侵染及其根尖形态的影响 总被引：1，自引：0，他引：1
以水曲柳人工林1级根为研究对象,通过施氮肥处理,对不同季节和不同土壤深度根系取样,研究施用氮肥对根尖内生菌根真菌侵染率和形态与土壤N有效性、季节和土壤深度的关系.结果表明:1)施N肥处理导致水曲柳人工林1级根的菌根真菌侵染率显著降低11%,季节和土壤深度对1级根的侵染率影响显著,其中春季＞夏季＞秋季,土壤表层高于亚表层;2)施N肥导致1级根长度显著降低,季节和处理之间的交互作用影响1级根的直径和根长,季节、土层和处理3者的交互作用影响根长和比根长;3)与未侵染菌根真菌的1级根形态相比,菌根真菌侵染导致1级根平均直径未发生变化,长度略有降低,而比根长则显著减小.这种根系形态变化规律在不同处理、不同季节和不同土壤深度上表现一致. 相似文献
2.
第2代杉木林土壤有机碳、全氮对细根分布及形态特征的影响 总被引：1，自引：0，他引：1
以20年生杉木人工林为研究对象,分析了杉木细根的生长分布情况及形态学特征.结果表明:第2代杉木人工林的土壤有机碳与全氮主要分布在0～30 cm土壤中,随着土壤深度的增加而明显减少;杉木细根生物量在不同土壤层次问差异显著,随土壤深度的增加而显著减少,主要分布在0～15 cm的表层土壤中,占总量的50.35%,15～30 cm层占30.04%,30～45 cm层占19.61%;细根表面积在不同层次土壤间差异不显著,主要分布在0～30 cm层中,为2.86m2·m-3,占总量的79.88%;随着土壤深度的增加,杉木细根比根长增加不明显;土壤有机碳含量与杉木细根生物量、比根长和根表面积密度之间相关性均不显著;土壤全氮含量与杉木细根生物量和根表面积密度之间存在明显的正相关,与细根比根长存在不太明显的负相关. 相似文献
3.
马尾松细根与土壤养分含量研究 总被引：3，自引：0，他引：3
应用根钻法研究黔中12年生马尾松(Pinus massoniana)林下不同层次土壤(0～20 cm和20～40 cm)细根的分布情况及土壤养分含量的分布,并做了相关性分析.结果表明,马尾松细根单位面积生物量、根长密度及比根长在0～20 cm土层明显高于20～40 cm土层,在0～20 cm土层中单位面积根量是20～40 cm土层的3～6倍;土壤中养分含量也随着土壤深度的增加逐渐减少;马尾松根系生物量、根长密度及比根长与土壤中有效性养分存在显著正相关关系;细根生物量、根长密度与马尾松胸径呈显著正相关关系;养分含量对生物量、根长密度的综合影响存在显著线性相关性(R~2=0.903、0.917),土壤养分(0～20 cm、20～40 cm)对马尾松胸径存在显著或极显著线性相关关系(R~2=0.878、0.934),与树高线形相关性不明显. 相似文献
4.
对湘北地区6年生四川桤木(Alnus cremastogyne)人工林不同径级根系生物量分布、根长、比根长、根长密度的空间分布特征进行研究。结果表明:四川桤木人工林大根、中根、小根、细根生物量分别占林分根系生物量总和的55%、22%、14%、9%;约66%的根系生物量集中在0～30cm土层;不同径级根系根长变化趋势是:细根小根大根中根,比根长的变化趋势是:细根小根中根大根;各径级根长密度变化趋势各不相同:垂直方向上,在0～60cm土层,大根的根长密度随土层深度的增加先增后降,中根、小根、细根的根长密度随土层深度的增加而减小,水平方向上,在0～80cm距离,大根的根长密度随距树干距离的增加而减小,细根的根长密度随距树干距离的增加而增大,中根、小根的根长密度在距树干0～60cm内逐渐减小,而在距树干60～80cm又略有增加。 相似文献
5.
【目的】研究青海高寒区4种人工林的细根生物量及其养分储量时空变化特征,为该地区植被恢复和人工林经营提供理论依据。【方法】在青海高寒区选择白桦、青杨、华北落叶松和青海云杉4种典型人工纯林,2019年5—10月采集0～60 cm土层细根样品,测定细根生物量及其C、N、P含量,通过方差分析探究季节、树种和土层对细根生物量及其养分储量的影响。【结果】白桦、青杨、华北落叶松和青海云杉4种人工林0～60 cm土层的细根生物量分别为7.63、6.89、6.11和19.31 t·hm-2,青海云杉林细根生物量显著高于其他林分(P<0.05)。各林分细根生物量季节差异显著(P<0.05),均表现为秋季>夏季>春季。细根生物量主要分布在表层土壤,0～20 cm土层占比超过68%,随土层加深呈指数型降低。阔叶林细根的养分含量高于针叶林,阔叶林生长表现出较高的养分需求。各林分细根C含量表现为秋季>夏季>春季,N、P含量总体表现为夏季显著低于春季和秋季(P<0.05)。细根C、N和P含量总体上随土层加深而减小。青海云杉林细根C、N、P储量在各季节均... 相似文献
6.
黄土丘陵区燕沟流域人工刺槐林的细根空间分布特征 总被引：3，自引：0，他引：3
对黄土丘陵区燕沟流域10年生人工刺槐林的细根生物量、比根长、根长密度和根面积指数的空间分布特征,以及这些根系参数与土壤物理因子(土壤含水量、土壤温度和土壤密度)的关系进行研究。结果表明:1)人工刺槐林细根在0～180cm土层中随深度呈层次性衰减(a,b,c,d,e);其中,细根生物量、根长密度和根面积指数等随深度变化均可用负指数函数描述,根系集中分布在0～60cm土层,峰值都在0～20cm土层,该土层3项指标分别占各自0～60cm土层总量的42.72%,44.44%和47.14%;比根长随深度增加衰减趋势较弱,在80～140cm土层中出现反复,其随土层深度的变化可用三次多项式描述。2)细根生物量、根长密度和根面积指数等均随距树干基部的距离增加而减小,比根长在0～40cm随距树干距离增加而增加,在40～80cm达到最大值,120～160cm内最少。3)根系分布受环境因子影响,其影响程度依次为:土壤温度>土壤含水量>土壤密度,建立根系参数与土壤物理因子的多元线性回归模型,模型均达到95%以上显著水平。 相似文献
7.
连作杨树细根根序形态及解剖结构 总被引：3，自引：0，他引：3
[目的]针对连作杨树人工林细根形态和解剖结构,从根序视角探讨连作杨树人工林细根生长的代际差异及其与人工林生产力衰退的联系,以期揭示连作杨树人工林衰退机制.[方法]分别在杨树人工林Ⅰ和Ⅱ代林分设立标准地,采用改良全根取样法获得杨树细根(＜2 mm)并按根序进行分级,制作1～5级细根各根序石蜡切片.根系扫描仪结合分析软件获得各根序细根长度、直径,光学显微镜观察各根序细根剖面直径、皮层厚度、维管柱(中柱)直径等参数,并计算比根长、根组织密度、根长密度、维根比等.LSD分析1～5级根序形态参数的差异显著性,One-way ANOVA分析同一根序在不同代数间形态指标参数的差异显著性.[结果]杨树细根生物量表现为随根序增加而减小,且连作Ⅱ代人工林细根生物量分配高于Ⅰ代林,尤其在1,2级根序中更为显著(P＜0.05);连作导致杨树1,2级细根平均长度减少而3～5级根长度增加;直径虽然在不同根序细根间差异并不显著,但Ⅱ代林显著高于Ⅰ代林;杨树细根表面积、比根长和根长密度总体表现为1,2级根显著高于3,4级根(P＜0.05),但比根长在Ⅱ代林中差异不显著;连作导致杨树1,2级根表面积和根长密度显著增大,但比根长显著减小(P＜0.05);细根解剖特征表明,横剖面宽度随根序逐渐增大,中柱面积占横剖面的比例随根序增加而增大,1,2级细根总体呈现初生结构的特征,从3级根开始出现木栓层且皮层开始脱落.[结论]杨树1～5级根序细根形态和功能存在显著差异,1,2级细根仅具初生结构,是杨树的吸收根,3级以上细根出现木栓层从而变为输导根.连作导致杨树细根形态发生显著变化,且低级细根生物量显著增加,表明连作导致杨树人工林对地下部分的生长投入增大,这与养分匮乏生境中植物光合产物最优分配理论相一致.伴随细根死亡和周转,连作杨树人工林细根生物量分配格局将影响人工林地上部分生产力的形成. 相似文献
8.
9.
以徐州林场50年生侧柏人工林为研究对象,采用挖掘法获取土壤根系样品,探究林分密度对侧柏人工林不同根序细根形态的影响。结果表明:细根的直径和根长随着根序上升而显著增大,而比根长则随着根序的上升而显著减小。低林分密度(1 679株/hm2)与中林分密度(2 250株/hm2)相比显著减小了表层土壤1、2级细根的平均直径和平均根长,亚表层土壤3级细根的根长,显著增大了亚表层土壤2级细根的平均比根长;高林分密度(3074株/hm2)比中林分密度显著增大了2级根的平均比根长。与高林分密度相比,低林分密度显著减小了表层土壤1、2级细根的平均直径,增大了亚表层土壤5级细根的平均直径。 相似文献
10.
水曲柳落叶松混交林中细根空间分布 总被引：4，自引：0，他引：4
采用根钻取样方法对年生水曲柳落叶松混交林中细根空间分布状况进行了研究。结果表明,水曲柳落叶松地下生物量的空间分配差异显著。在林分水平上,水曲柳的根生物量密度高于落叶松(分别为4442.3和2234.9g/m3)。两树种在相邻区域中分配的细根生物量较高,表明种间根系竞争较弱。落叶松行间的水曲柳细根生物量密度和根长密度均高于水曲柳行间的落叶松细根,表明水曲柳地下部分具有较强能力。根系的空间分布有利于混交林中水曲柳的生长。图1表4参19。 相似文献
11.
Li Mei Youzhi Han Shuiqiang Yu Jianwei Shi Zhengquan Wang 《Frontiers of Forestry in China》2007,2(3):298-304
Fine root turnover plays important roles in carbon allocation and nutrient cycling in forest ecosystems. Seasonal dynamics
of fine roots is critical for understanding the processes of fine root turnover. From May to October 2002, soil core method
was used for estimating the seasonal pattern of fine root (diameter < 1 mm) parameters (biomass, specific root length (SRL)
and root length density (RLD)) in a Manchurian ash (Fraxinus mandshurica) plantation located at the Maoershan Experiment Station, Heilongjiang Province, northeast of China. The relationships of
fine root biomass, SRL and RLD with available nitrogen in soil, average soil temperature per month in 10 cm depth and soil
moisture content were analyzed. Seasonal variation of fine root biomass was significant (P < 0.05). The peak values of fine root biomass were observed both in spring and in autumn, but SRL and RLD were the highest
in spring and lowest in autumn. Specific root length and root length density were higher in spring and summer, which means
that fine root diameter was thinner. In autumn, both parameters decreased significantly due to secondary incrassation of fine
root diameter or the increase of tissue density. Seasonal dynamics of fine roots was associated with available nitrogen in
soil, soil temperature in 10 cm depth and moisture content. Fine root biomass has a significant relationship with available
NH4
+-N in soil. Available NO3
−-N in soil, soil temperature in 10-cm depth and moisture content have a positive correlation with fine root biomass, SRL and
RLD, although these correlations are not significant (P > 0.05). But the compound effects of soil available N, soil temperature and soil moisture content are significant to every
root parameter. The variations of these three root parameters in different seasons show different physiological and ecological
functions in different growing periods.
Translated from Scientia Silvae Sinicae, 2006, 42(9): 7–12 [译自: 林业科学] 相似文献
12.
Fine root turnover plays a key role in carbon(C) budgets and nutrients cycles in forest ecosystems.However,the difference between branch-order-based and diameter-based approaches in estimating fine root turnover is still unclear.We studied root biomass turnover based on multiplying root standing biomass by turnover rate(inverse of median root longevity) in two Chinese temperate tree species,Fraxinus mandshurica Rupr.and Larix gmelinii Rupr.The minirhizotron(MR) technique was used to estimate longevities for first and second order roots,and total roots(R total) apparent on the MR tube surface.The corresponding biomass for each root group was estimated by soil monolith.The difference in biomass turnover between R total and the sum of the first and second order roots was used to represent the discrepancy between diameter-and order-based approaches.First order roots had shorter life spans and higher biomass turnover rates than the second order roots in both species.Biomass turnover estimated by the order-based method for F.mandshurica and L.gmelinii were 155.4 g m-2 a-1 and 158.9 g m-2 a-1,respectively,in comparison with 99.5 g m-2 a-1 and 117.7 g m-2 a-1 estimated by the diameter-based method,indicating that the diameter-based approach underestimated biomass turnover.The most probable reason was that the order-based method enhanced separation of the heterogeneous root population into relatively homogenous root groups with varying turnover rates.We conclude that separating fine root pool into different branch orders can improve the accuracy of estimates for fine root turnover,as well as the understanding of the belowground C allocation and nutrient cycling at ecosystem level. 相似文献
13.
Stand age and fine root biomass, distribution and morphology in a Norway spruce chronosequence in southeast Norway 总被引：1，自引：0，他引：1
We assessed the influence of stand age on fine root biomass and morphology of trees and understory vegetation in 10-, 30-, 60- and 120-year-old Norway spruce stands growing in sandy soil in southeast Norway. Fine root (< 1, 1-2 and 2-5 mm in diameter) biomass of trees and understory vegetation (< 2 mm in diameter) was sampled by soil coring to a depth of 60 cm. Fine root morphological characteristics, such as specific root length (SRL), root length density (RLD), root surface area (RSA), root tip number and branching frequency (per unit root length or mass), were determined based on digitized root data. Fine root biomass and morphological characteristics related to biomass (RLD and RSA) followed the same tendency with chronosequence and were significantly higher in the 30-year-old stand and lower in the 10-year-old stand than in the other stands. Among stands, mean fine root (< 2 mm) biomass ranged from 49 to 398 g m(-2), SLR from 13.4 to 19.8 m g(-1), RLD from 980 to 11,650 m m(-3) and RSA from 2.4 to 35.4 m(2) m(-3). Most fine root biomass of trees was concentrated in the upper 20 cm of the mineral soil and in the humus layer (0-5 cm) in all stands. Understory fine roots accounted for 67 and 25% of total fine root biomass in the 10- and 120-year-old stands, respectively. Stand age had no affect on root tip number or branching frequency, but both parameters changed with soil depth, with increasing number of root tips and decreasing branching frequency with increasing soil depth for root fractions < 2 mm in diameter. Specific (mass based) root tip number and branching density were highest for the finest roots (< 1 mm) in the humus layer. Season (spring or fall) had no effect on tree fine root biomass, but there was a small and significant increase in understory fine root biomass in fall relative to spring. All morphological characteristics showed strong seasonal variation, especially the finest root fraction, with consistently and significantly higher values in spring than in fall. We conclude that fine root biomass, especially in the finest fraction (< 1 mm in diameter), is strongly dependent on stand age. Among stands, carbon concentration in fine root biomass was highest in the 30-year-old stand, and appeared to be associated with the high tree and canopy density during the early stage of stand development. Values of RLD and RSA, morphological features indicative of stand nutrient-uptake efficiency, were higher in the 30-year-old stand than in the other stands. 相似文献
14.
The responses of fine root mass, length, production and turnover to the increase in soil N availability are not well understood
in forest ecosystems. In this study, sequential soil core and ingrowth core methods were employed to examine the responses
of fine root (≤1 mm) standing biomass, root length density (RLD), specific root length (SRL), biomass production and turnover
rate to soil N fertilization (10 g N m−2 year−1) in Larix gmelinii (larch) and Fraxinus mandshurica (ash) plantations. N fertilization significantly reduced fine root standing biomass from 130.7 to 103.4 g m−2 in ash, but had no significant influence in larch (81.5 g m−2 in the control and 81.9 g m−2 in the fertilized plots). Similarly, N fertilization reduced mean RLD from 6,857 to 5,822 m m−2 in ash, but did not influence RLD in larch (1,875 m m−2 in the control and 1,858 m m−2 in the fertilized plots). In both species, N fertilization did not alter SRL. Additionally, N fertilization did not significantly
alter root production and turnover rate estimated from sequential soil cores, but did reduce root production and turnover
rate estimated from the ingrowth core method. These results suggested that N fertilization had a substantial influence on
fine root standing biomass, RLD, biomass production and turnover rate, but the direction and magnitude of the influence depended
on species and methods. 相似文献
15.
水曲柳苗木根系形态和解剖结构对不同氮浓度的反应 总被引：6，自引：0，他引：6
采用温室沙培方法,在不同氮浓度处理下,研究1年生水曲柳苗木整株根系和前3级根形态,以及前3级根形态与解剖结构的关系,探讨不同氮浓度导致细根形态变化的原因。结果表明:1)随着氮浓度的增加,整株根系的总面积、总长度和比根长增加,但是总的平均直径减小,前3级根也具有相同的变化规律。根表面积和比根长从低氮到高氮增加与直径和根长的变化有关。2)氮浓度引起直径和根长变化与解剖特征变化有密切关系。低氮条件下直径增加与横切面皮层细胞直径和皮层厚度的增加有关,而高氮条件下皮层细胞直径减小和皮层厚度缩窄有关。在纵切面上,根长度从低氮到高氮增加可能与细胞数量增加有关。研究结果对解释施肥导致细根形态变化原因具有重要意义。 相似文献
16.
Hooshang Majdi Laimi Truus Ulf Johansson Jan-Erik Nylund Håkan Wallander 《Forest Ecology and Management》2008
In the study reported here we examined the short-term effects (1–3 years) of slash retention (SR) and the long-term effects (13–15 years) of wood-ash application (A) on fine roots and mycorrhizae in a 40-year-old Norway spruce forest in southwest Sweden. Soil cores were used to obtain estimates of the biomass (g m−2) of roots in three diameter classes (<0.5, 0.5–1 and 1–2 mm), root length density (RLD), specific root length (SRL) and mycorrhizal root tip density (RTD). Fine root (<1 mm) length production and mortality, and mycelium production, were estimated using minirhizotron and mesh bag techniques, respectively. Compared with the control plots (C), the biomass of fine roots in diameter classes <0.5 mm and 0.5–1 mm was significantly higher in A plots, but lower in SR plots. In addition, RLD was significantly lower in the humus layer of SR plots than in the humus layers of C and A plots, but not in the other layers. None of the treatments affected the SRL. In all soil layers, the SR treatment resulted in significant reductions in the number of ectomycorrhizal root tips, and the mycelia production of fungi in mesh bags, relative to the C treatment, but the C and A treatments induced no significant changes in these variables. Fine root length production in the C, A and SR plots amounted to 94, 87 and 70 mm tube−1 during the 2003 growing season, respectively. Fine root mortality in treated plots did not change over the course of the study. We suggest that leaving logging residues on fertile sites may result in nitrogen mineralisation, which may in turn induce reductions in root biomass, and both root and mycelium production, and consequently affect nutrient uptake and the accumulation of organic carbon in soil derived from roots and mycorrhizae. 相似文献
17.
Changes in fine root production and longevity in relation to water and nutrient availability in a Norway spruce stand in northern Sweden 总被引：2，自引：0，他引：2
Majdi H 《Tree physiology》2001,21(14):1057-1061
Effects of irrigation and liquid fertilization on fine root (< 1 mm) production and longevity, and fine root (< 0.5-2 mm) biomass were studied in a Norway spruce (Picea abies (L.) Karst.) stand in northern Sweden. Fine root length production and longevity were measured by the minirhizotron technique at 0-10 cm depth in the following treatments: irrigation (I), liquid fertilization (IL) and control (C). Standing root biomass and root length density (RLD) were studied in the litter-fermented humus (LFH) layer and at depths of 0-10, 10-20 and 20-30 cm using soil cores in solid fertilized (F) and C plots. Minirhizotrons were installed in October 1994 and measurements recorded monthly from July to September 1995 and during the growing season in 1996. Soil cores were sampled in 1996. Fine root production increased significantly in IL plots compared with C plots, but the I treatment did not increase root production. Root mortality increased significantly in IL plots compared with C plots. Fine root longevity in IL plots was significantly lower compared with C and I plots. No significant difference was found between longevity of fine roots in I and C plots. Compared with C, F treatment increased fine root biomass in the LFH and mineral soil layers, and increased the amount of fine roots in mineral soil layers relative to the LFH layer. Furthermore, F increased RLD and the number of mycorrhizal root tips significantly. 相似文献