细根

In the 20 yr forest, 304. 6gm〓 C and 11. 6gm〓 N are inputted to the soil. In the 80 yr forest, 502. 3gm〓 C and 17. 2gm〓 N are inputted to the soil. In the climax forest, 430.3gm〓 C and 11. 9gm〓 N are inputted to the soil. Along with forest succession, the C inputted to the soil B layer by fine root increases because of the deepening of root depth distribution.

白桦山杨幼林、白桦山杨成熟林与原始阔叶红松林中，细根每年向林地周转的碳量分别为304.6gm〓、502.3gm〓、430.3gm〓，氮量分别为11.6gm〓、17.2gm〓、11.9gm〓；其中，随着演替的进行，由于根系分布的加深，细根每年向土壤B层周转的碳量会逐渐增加。

Following girdling and HWA infestation, very fine root biomass declined by 20–40% in 2 years, which suggests hemlock root mortality in the girdling treatment, and a reduction in hemlock root production in the HWA treatment.

围绕和偶遇之后，非常细根生物量下降20%~ 40%，这表明在2年的死亡率的根叶围绕的处理，并减少生产中的铁根单治疗。

The organic materials and N fertilizer application decreased the ratio of dry matter distribution in ligneous roots and increased in fine roots.

三种类型根系中，施肥对细根刺激作用大于木质根，其中氮肥对生长根的作用较大，而有机物料则主要影响吸收根的生长。

In two secondary forests, Populus davidiana fine root decomposition rate was faster than Betula platyphylla's.

在白桦山杨幼林和成熟林中，山杨的细根分解均比白桦细根快。

Along with forest succession, the percentage of C and N turnover through fine root to the root, soil and the belowground increases gradually and then decreases.

由高海拔到低海拔根系生物量逐渐增加，而细根的生物量则没有明显的变化规律，细根占根系总生物量的范围为11％～24％。

In order to assess the change of triploid populus tomentoza pulp plantation long-term-site productivity, The paper studied on effects of aboveground litterfall, fine root turnover and wet dust precipitation in nutrient cycling of triploid populus tomentoza pulp plantations at different ages,namely 2a、4a、5a、6a.It studied influence of different factors on decomposition of leaf、tree bark and twig of triploid populus tomentoza to select the operations to accelerate the decomposition and nutrient release. Finally, it studied influence of different intercrops on plantation site productivity and the relationship of intercrops and triploid populus tomentoza to select suitable intercrops. The main results as follows:(1)The aboveground litterfall of triploid populus tomentoza increased along with age from 216.03±59.7gm~(-2) at 3a to 482.38±101.3gm~(-2) at 7a, The N returned by litterfall wasl8.38±2.46kg.hm~(-2)a~-121.63±2.25kg.hm~(-2a~-139.51±4.61kg.hm~(-2a~-138.89±4.89kg.hm~(-2a~(-1) at 3a、5a、6a、7a respectively. The P returned by litterfall was 5.80±0.62kg.hm~(-2)a~(-1)、8.16±0.94kg.hm~(-2)a~(-1), 11.31±1.33kg.hm~(-2)a~(-1)、11.76±1.37kg.hm~(-2)a~(-1) at 3a、5a、6a、7a respectively. The nutrient returned by fine root turnover increased along with age, too. The N returned by fine root turnover was 3.85±0.41kghm~(-2)a~(-1)、5.22±0.63kghm~(-2)a~(-1),7.62±0.89kghm~(-2)a~(-1),9.17±1.22kghm~(-2)a~(-1) at 3a、5a、6a、7a respectively. The P returned by fine root turnover was 0.73±0.07kghm~(-2)a~(-1)、1.69±0.09kghm~(-2) a~(-1)、1.92±0.31kghm~(-2)a~(-1)、1.96±0.21kghm~(-2)a~(-1) at 3a、5a、6a、7a respectively. The leaf was the principal pathway to return nutrient to soil among litterfall, fine root turnover and wet dust precipitation. The proportion of returned N by leaf was 74.84%、71.96%、78.58%、75.03% at 3a、5a、6a、7a respectively,The proportion of returned P by leaf was 85.93%、80.31%、83.04%、83.23% at 3a、5a、6a、7a respectively. Therefore, it is important to protect and utilize the leaf in order to maintenance and enhance the long-term-site productivity of triploid populus tomentoza pulp plantation.

本文采取时序研究法，以3a、5a、6a、7a共4个不同年龄的三倍体毛白杨纸浆林为对象，研究了地上凋落物、细根周转、湿沉降在林分N、P营养元素循环中的作用及不同年龄林分N、P营养元素循环的特征，以评价三倍体毛白杨纸浆林长期立地生产力的变化；采取网袋法研究了不同因素对落叶、树皮、树枝分解的影响，以确定加快其分解、促进养分释放的措施：同时研究了不同间作物对林地影响、林木与间作物之间关系，以选择能维持立地生产力的合适的间作物种类等内容，得到以下结论：(1)随着年龄的增加，三倍体毛白杨地上凋落物的数量从3a的216.03±59.7gm~(-2)增加到7a的482.38±101.3gm~(-2)，通过凋落物归还的N分别为：3a时为18.38±2.46kg.hm~(-2)a~(-1)，5a时为21.63±2.25kg.hm~(-2)a~(-1)，6a时为39.51±4.61kg.hm~(-2)a~(-1)，7a时为38.89±4.89kg.hm~(-2)a~(-1)，归还的P分别为：3a时为5.80±0.62kg.hm~(-2)a~(-1)，5a时为8.16±0.94kg.hm~(-2)a~(-1)，6a时为11.31±1.33kg.hm~(-2)a~(-1)，7a时为11.76±1.37kg.hm~(-2)a~-1随着年龄的增加，通过细根周转归还的养分也在增加，归还的N分别为：3a时3.85±0.41kghm~(-2a~(-1)，5a时5.22±0.63kghm~(-2)a~(-1)，6a时7.62±0.89kghm~(-2)a~(-1)，7a时9.17±1.22kghm~(-2)a~-1归还的P分别为：3a时0.73±0.07kghm~(-2a~(-1)，5a时1.69±0.09kghm~(-2)a~(-1)，6a时1.92±0.31kghm~(-2)a~(-1)，7a时1.96±0.21kghm~(-2)a~-1从地上凋落物、细根周转、湿沉降三种不同途径归还林地养分所占的比例来看，地上凋落物中的落叶是归还养分主要途径，年龄在3a、5a、6a、7a时，通过落叶归还的N所占比例分别为74.84%、71.96%、78.58%和75.03%，归还的P所占比例分别为85.93%、80.31%、83.04%和83.23%。

Herbs annual or perennial. Roots fibrous or woody; primary root with few secondary rootlets or rhizomes and with few fleshy adventitious rootlets.

一年生或多年生草本根纤维状的或木质；主根具很少次生细根或根状茎和具很少肉质的不定的细根。

Rhizome erect or obliquely ascending, short, 0.5-3 cm, slender, with numerous white rootlets, sometimes with underground stolons; roots elongating, producing new individuals.

根状茎直立或斜升，短，0.5-3厘米，纤细，具多数白色细根，有时具地下匍匐茎；根拉长，生产新个体。

The compensation effect of water stress only was observed in the percentage distribution values in fine roots of RAWS plants, which kept significantly higher than that of CK during rewatereing. However, there apparently was an after-effect of water stress, as revealed by the delayed recovery of almost all of the three parameters in RAWS plants.

水分胁迫解除期间，细根获得同化物百分比仍保持在显著高于对照水平，表明水分胁迫对细根具有一定的补偿效应；尽管茎尖、粗根、韧皮部、木质部获得的同化物绝对量、相对量及分配系数均在复水后5天内完全恢复，但它们起始恢复的时间大多与复水并不同步，而是表现出一定程度的滞后，表明水分胁迫对这些器官同化物分配过程具有后效作用。

Unfortunately, accurately quantifying below-ground C fluxes and estimating fine root longevity are still elusive. One of reasons is because we do not know the proportions of shortlived vs. long-lived root pools or the distribution of fine root longevity within these pools.

但是，准确量化地下C通量以及估计细根寿命仍然是目前研究中的难点，其原因之一是因为我们无法确定不同寿命细根间的数量比例关系，抑或说不清楚细根寿命符合何种统计分布。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。