Annual and long-term fluctuations of the nematode fauna in a Swedish Scots pine forest soil

Samples from an old Scots pine forest at Ivantjärnsheden in the middle of Sweden were used to study predictability and patterns of variation of soil nematode communities. There were two annual sampling series (1974–75 and 1977–78) and one long-term series sampled in September ten times over a period of 25 years. The abundance and the composition of the fauna fluctuated rather considerably in both the annual and long-term series. In the annual series abundance and species composition varied in a way which can partly be explained by changes in temperature and moisture. Total nematode abundance was influenced by soil water contents as indicated by co-variations with precipitation. Although the variations in abundance and fauna composition were large no systematic changes could be detected during 25 years. The differences in faunal structure between the two annual series were greater than between the annual and the long-term series.In all series there was a distinct vertical stratification of the fauna. In the superficial moss and litter layers species belonging to Adenophorea (Plectus) dominated. In deeper layers members of Rhabditida (Acrobeloides) contributed a greater proportion of the fauna. Variations of the annual series indicate that coexistence of different nematode species is facilitated by differences in response to temperature and moisture. The abundance of fungal and bacterial feeders changed in a regular way. During the summer the proportions of fungal and bacterial feeders were almost equal, but during the wet and cold winter the proportion of bacterial feeders increased. Rapidly growing bacterial feeding species belonging to Rhabditida were common in late summer and early autumn, whereas the more slowly growing bacterial feeders belonging to Adenophorea were most abundant during the winter. Although the community fluctuated rather much the average values indicated a rather high degree of predictability and also a high similarity with nematode faunas of other pine forest soils.     

五针松疱锈病病原菌生活史的计算机模拟

利用计算机动画技术对红松疱锈病（ＰｉｍｕｓＫｏｒａｉｅｎｓｉｓｂｌｉｓｔｅｒｒｕｓｔ）病原菌茶生柱锈病（Ｃｒｏｎａｒｔｉｕｍｒｉｂｉｃｏｌａ）生活史进行了计算机模拟,概述了模拟的内容、方法、过程、特点等,并展望了这一技术的应用前景。     

松针多糖对小鼠腹腔巨噬细胞免疫调节作用的研究

本试验旨在研究松针多糖对正常状态及脂多糖(LPS)刺激状态下小鼠腹腔巨噬细胞的免疫调节作用。试验采用不同浓度的松针多糖作用于正常的和经LPS刺激的小鼠腹腔巨噬细胞,设空白对照组(加入100μL RPMI-1640培养基)、阳性对照组(加入100μL终浓度为5μg/m L的LPS)、松针多糖组(分别加入100μL 25、50、100、200μg/m L的松针多糖)和LPS+松针多糖组(加入与松针多糖组相同浓度的松针多糖和终浓度为5μg/m L的LPS,液体终体积为200μL)。噻唑蓝(MTT)比色法检测细胞活力,中性红吞噬试验检测巨噬细胞吞噬能力,Griess法检测一氧化氮(NO)的分泌量,酶联免疫吸附测定(ELISA)法检测巨噬细胞培养上清液中白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)、白细胞介素-10(IL-10)的分泌量。结果表明:1)对空白对照组相比,各松针多糖组巨噬细胞相对增殖率均显著或极显著提高(P0.05或P0.01),50、100和200μg/m L松针多糖组巨噬细胞中性红吞噬率显著或极显著提高(P0.05或P0.01),各LPS+松针多糖组巨噬细胞中性红吞噬率均极显著提高(P0.01),200μg/m L松针多糖组巨噬细胞NO分泌量极显著提高(P0.01),50、100和200μg/m L松针多糖组巨噬细胞TNF-α和IL-1β分泌量显著或极显著提高(P0.05或P0.01),50、100和200μg/m L松针多糖组巨噬细胞IL-10分泌量极显著降低(P0.01)。2)与阳性对照组相比,各松针多糖组巨噬细胞相对增殖率均极显著降低(P0.01),100和200μg/m L LPS+松针多糖组巨噬细胞中性红吞噬率极显著升高(P0.01),50、100和200μg/m L LPS+松针多糖组巨噬细胞NO分泌量极显著提高(P0.01),各LPS+松针多糖组巨噬细胞TNF-α分泌量显著或极显著提高(P0.05或P0.01),50、100和200μg/m L LPS+松针多糖组巨噬细胞IL-1β分泌量显著或极显著提高(P0.05或P0.01),100和200μg/m L LPS+松针多糖组巨噬细胞IL-10分泌量极显著降低(P0.01)。由此可见,松针多糖通过发挥其促炎作用调节巨噬细胞的免疫功能,进而增强机体抗疾病的能力。     

松材线虫伴生细菌与松树萎蔫病关系的初步研究

利用马尾松水培离体松枝作接种材料,接种消毒后的松材线虫、线虫虫体上分离到细菌分离物GD1以及两者的混合体。结果表明,单独接种消毒后的松材线虫蔌细菌分离物GD1均不能使松枝萎蔫,只有两者混合接种才能使松枝发病枯死。从而说明了松材线虫的伴生细菌对松树萎蔫病的发生起着重要的作用。     

Coarse woody debris dynamics in a post-fire jack pine chronosequence and its relation with site productivity

The long-term relationships between coarse woody debris (CWD) dynamics, soil characteristics and site productivity have, so far, received little attention. The objectives of the study were to describe CWD dynamics along a post-fire chronosequence (43–86 years after fire) in jack pine (Pinus banksiana Lamb.) stands, assess the importance of buried CWD in terms of soil available water holding capacity (AWHC), and investigate relationships between CWD, AWHC, nutrient retention and site productivity.

Twelve jack pine stands on sandy, mesic sites of glaciolacustrine origin were surveyed. Buried wood volume within the forest floor varied between 1 and 57 m³ ha⁻¹ (4–92% of total site CWD volume) and showed no relationship with time. Downed log mass accumulation followed a “U shaped” successional pattern with time since fire. Buried wood AWHC was negligible compared with that of the 0–20 cm mineral soil layer. The most productive sites were characterised by higher forest floor dry weight, effective CEC and water holding capacity in the mineral soil. Path analyses of relationships between organic matter content, CWD and forest floor CEC showed that CEC was conditioned by forest floor organic matter and buried wood content.     

火炬松69个组合组成的核心群体苗期生长表现

选择火炬松３７个亲本作正向同型与偶，产生６９个组合，经过１年苗期试验表明，组合间苗高生长差异极显著，有１６个组合的平均高显著或极显著地大于总体平均值，预示将来能够提供作下一代核心育种群体的选择。     

加勒比松林下坚尼草耐荫性试验报告

2年的试验结果表明，坚尼草在相对光照为30％－65％的加勒比松林下种植均能成活生长，以品系CIAT6299、CIAT6901的耐荫性最强，年均干草产量分别达11044kg/hm^2、8589kg/hm^2，比推广品种分别增产139.6%、86．4％。     

Study of structure and dynamics of Korean pine forest in the Xiaoxing’an Mountains

The thesis for the Doctorate consist of two parts. The first is to study on structure, dynamics and tree growth of natural Korean pine forest. The second is to research for tree architecture, growth and stand structure of artificial Korean pine (Pinus koraiensis) forests.The thesis compares the stand structure, process of regeneration, and various tree growth patterns between natural forests and artificial forests. Its purpose is to give a basis for forest management and silviculture. The study was carried out in Liangshui Experimental Forest Farm, which is located in the southern Xiaoxing’an Mountains.     

星鸦(Nucifraga caryocatactes)对集中放置红松球果的分散贮藏与临时贮点管理

星鸦(Nucifraga caryocatactes)对红松种子进行分散贮藏、重取、建立和更新临时贮点,这一过程的研究对丰富贮食行为理论很有意义。2017年10—11月,采用红外相机监测和样方调查的方法,分析凉水国家级自然保护区星鸦对集中堆放红松球果的贮食行为、临时贮点管理以及影响贮点生境选择的主要因素。结果表明:贮藏地星鸦的重取行为比例最高,为(55.42±1.34)%,移动行为占(25.74±6.24)%,贮藏行为占(11.08±2.69)%,且有争斗行为。星鸦贮点大小为(2.39±0.09)粒,密度为(1.82±0.11)个/m^2,贮藏深度为(1.55±0.03)cm。不同生境类型(F=7.471,P<0.05)及基质类型(F=3.205,P<0.05)的贮点密度具有显著差异。贮点数量、贮点更新率最高的是距离食物源最近的人工针叶林样地。贮食距离短、频繁更新贮点、冬季之前全部重取等行为特征,是星鸦对短暂爆发性集中食物源的适应。