Development and characterization of microsatellite loci in western larch (Larix occidentalis Nutt.)

Western larch (Larix occidentalis Nutt.) is an important ecological and commercial species in the Pacific Northwest. We isolated nine microsatellite loci with variable polymorphism ranging from five to 19 alleles per locus. Observed and expected heterozygosities averaged 0.42 and 0.64 and ranged from 0.11 to 0.83 and from 0.48 to 0.80, respectively. These markers, along with those already existing, will be useful for the species' gene resource management activities.     

川西山地主要人工林种群根系生物量与生产力

采用标准地法,对四川西部山地主要人工林的根系进行了研究,结果表明(1)用D2H估测单株林木根系生物量的适合模型均以幂函数模型为最佳,所筛选统计模型的相关系数较高,在0.94～0.99之间;(2)根系总生物量大小排序为日本落叶松＞峨眉冷杉＞四川红杉＞川西云杉,分别为37.832、24.907、18.320t/hm2和15.982 t/hm2,各级根的生物量占总根量的比例各不相同;(3)根系生物量集中在分布土层0.00～40.00cm,川西云杉占97.88%,四川红杉占96.78%,峨眉冷杉占95.65%,日本落叶松占99.72%;尤其在0.00～20.00cm土层分布的根最多,分别占77.13%,77.13%,65.02%和80.66%;在0.00～20.00cm,20.00～40.00cm和40.00～60.00cm的各层根系生物量分配比例,川西云杉为34121,四川红杉为2461,峨眉冷杉为1571,日本落叶松为63141;(4)川西云杉、四川红杉、峨眉冷杉和日本落叶松人工林种群根系的生物量密度分别为10.782t/(hm2·m),8.230t/(hm2·m),14.546 t/(hm2·m)和13.211 t/(hm2·m);(5)川西云杉、四川红杉、峨眉冷杉和日本落叶松人工林种群根系生产力分别为0.57、0.83、0.71 t/(hm2·a)和1.64 t/(hm2·a).     

用地统计学方法对落叶松人工纯林表层细根生物量的估计

 采用地统计学的变异函数分析方法定量研究了落叶松（Larix olgensis）纯林表层（0～10 cm）细根的空 间异质性特征,利用地统计学的克里格内插法结合定积分,对落叶松纯林表层细根（<2 mm）的生物量进 行了估测。结果表明：1）6种林龄（14～40 年）的落叶松人工纯林表层细根的变异函数曲线理论模型均 为球状模型,空间变异主要是由结构性因素引起,且空间自相关程度均属中等以上（空间结构比>25%）。 14、19、22、26、32、40年生的落叶松纯林表层细根的空间变异尺度分别为1.76、3.40、1.02、4.12、 3.37和5.58 m。在所研究的林龄范围内,随林龄的增长,落叶松纯林表层细根的空间变异尺度近似呈直线 增长（p =0.074 4）。2）非参数统计的成对样本符号检验结果表明,变异函数分析结果基础上的克里格 内插法适用于落叶松纯林表层细根生物量的估计。利用此估计值,拟合其与位置坐标值之间的多元回归关 系均为二元十次余弦级数多项式。利用此多项式,通过定积分的方法（积分区间为整块样地的大小）,估 计出14、19、22、26、32、40年生的落叶松纯林表层细根生物量分别为1.097 3、1.434 0、1.185 4、 0.974 3、1.682 6、1.255 6 Mg• hm-2。3）在本次调查的林龄范围内（14～40年）,落叶松纯林表层细 根的现存量近似相等（α=0.037 3）,土壤表层单株细根生物量与林龄之间呈极显著的指数增长关系（α =0.002）。4）采用地统计学的克里格空间插值,结合多元回归和定积分的方法,可以实现落叶松人工林 表层细根生物量的准确估计。     

黑龙江省长白落叶松八齿小蠹虫体及坑道的真菌类群

采集落叶松八齿小蠹成虫、幼虫、蛹,以及母坑道、子坑道、蛹室的韧皮组织和蓝变组织。采用马丁氏培养基和PDA综合培养基对各虫态体表、体内、坑道内真菌进行分离培养,统计真菌检出率。对获得的真菌菌株通过形态学和分子生物学相结合的方法进行鉴定。在落叶松八齿小蠹虫体内外和坑道内共分离出真菌24种,其中子囊菌7种,担子菌2种,无性型真菌15种。从各虫态体表共分离出真菌21种,从体内共分离出真菌6种,24种真菌在坑道内均有检出。其中,Ceratocystis fujiensis为检出率较高的蓝变真菌。     

Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe

Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland‐dominated forest‐steppe area and small forest patches in a grassland‐dominated area. We found increasing climate sensitivity and decreasing first‐order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland‐dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland‐dominated area, the increase was much greater than in the forest‐dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure.     

Effects of host abundance on larch budmoth outbreaks in the European Alps

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基于随机效应的兴安落叶松材积生长模拟

基于黑龙江省带岭林业局大青川林场80株人工兴安落叶松解析木数据和Logistic生长模型,分别考虑单木效应和样地效应,利用S-PLUS软件中的NLME过程拟合非线性材积生长模型,采用赤池信息准则(AIC)、贝叶斯信息准则(BIC)、对数似然值和似然比检验等模型评价指标对不同模型的精度进行比较.结果表明：当考虑单木效应影响时,b₁、b₂、b₃（分别代表Logistic模型中的渐进、尺度和形状的随机参数）同时作为随机参数时模型拟合效果最好; 当考虑样地效应影响时,b₁作为随机参数时模型拟合效果最好.基于单木效应和样地效应的混合模型的拟合精度高于基本模型（Logistic生长模型）,考虑单木效应影响的混合模型的精度高于考虑样地效应影响的模型.模型检验结果表明,随机效应模型不但能反映单木材积的总体平均变化趋势,还能反映个体之间的差异;随机效应模型通过校正随机参数值能提高模型的预测精度.     

三种温带树种非结构性碳水化合物的分配

树体中的非结构性碳水化合物(NSC)浓度、含量及其分配反映了树木整体的碳供应状况, 是决定树木生长和存活的关键因子, 也是构建树木碳平衡模型的关键参数。温带树种的NSC尚缺乏系统研究。该文测定了特性各异的3种温带树种在生长盛期的NSC及其组分的浓度和含量以及分配格局的种间种内变异。结果表明, NSC及其组分的浓度在树种和组织之间差异显著, 可溶性糖、淀粉和总NSC浓度分别在0.65-8.45、1.96-5.95和3.00-13.90 g·100 g^-1 DM之间波动。NSC及其组分含量的大小依次为: 兴安落叶松(Larix gmelinii) >蒙古栎( Quercus mongolica) >红松( Pinus koraiensis), 其中叶和根中的浓度较高。树干中的NSC及其组分浓度的纵向变化不显著, 但其心材与边材之间的浓度差异却随树种和NSC组分而异, 表现为心边材的可溶性糖浓度差异不显著, 但其淀粉和总NSC浓度差异显著。不同直径根系的NSC及其组分浓度在2种针叶树种中差异不显著, 但在蒙古栎中差异显著。蒙古栎将可溶性糖主要投资到地上生长, 而2种针叶树将更多的可溶性糖投资到根系生长。淀粉的主要储存库为树干, 其在树体内的分布格局与可溶性糖正相反, 因而使总NSC在树根和树枝中的分配趋于较平衡状态。在树干中, 除了2种针叶树的可溶性糖库以边材为主外, 心材是淀粉和总NSC的主要储存库。在树根中, 粗根是NSC及其组分的优势储存库。该研究中3种温带树种的NSC及其组分的浓度和含量的种间和种内变化, 反映了这些树种的生长对策和体内碳源汇强度的差异。     

Resin duct size and density as ecophysiological traits in fire scars of Pseudotsuga menziesii and Larix occidentalis

Background and Aims

Resin ducts (RDs) are features present in most conifer species as defence structures against pests and pathogens; however, little is known about RD expression in trees following fire injury. This study investigates changes in RD size and density in fire scars of Douglas fir (Pseudotsuga menziesii) and western larch (Larix occidentalis) as a means to evaluate the ecophysiological significance of traumatic resinosis for tree defence and survival.

Methods

Transverse and tangential microsections were prepared for light microscopy and image analysis in order to analyse axial and radial RDs, respectively. Epithelial cells of RDs and fusiform rays associated with radial RDs were also examined. RDs were compared between normal xylem and wound xylem at four different section heights along the fire-injured stem.

Key Results

Following fire injury, P. menziesii axial RDs narrowed by 38–43 % in the first year after injury, and the magnitude of this change increased with stem height. Larix occidentalis axial RDs widened by 46–50 % in the second year after injury. Radial RDs were of equivalent size in P. menziesii, but widened by 162–214 % in L. occidentalis. Fusiform rays were larger following fire injury, by 4–14 % in P. menziesii and by 23–38 % in L. occidentalis. Furthermore, axial RD density increased in both species due to the formation of tangential rows of traumatic RDs, especially in the first and second years after injury. However, radial RD density did not change significantly.

Conclusions

These results highlight traumatic resinosis as a species-specific response. Pseudotsuga menziesii produce RDs of equivalent or reduced size, whereas L. occidentalis produce wider RDs in both the axial and radial duct system, thereby increasing resin biosynthesis and accumulation within the whole tree. Larix occidentalis thus appears to allocate more energy to defence than P. menziesii.     

河北省华北落叶松河北群体遗传多样性分析

以来自河北8个群体共312个华北落叶松天然个体为材料,利用10对SSR引物对群体进行扩增,所得数据用于其遗传多样性和遗传结构的研究。结果表明:10对SSR位点共检测到42个位点,平均每个位点有4.2个等位基因,位点的等位基因数(Na)为2~6个。群体平均等位基因数为3.36,Shannon指数(I)平均为0.749,观察杂合度Ho为0.405、期望杂合度He为0.423,来自河北北部的围场台子水和吉字以及兴隆雾灵山的多样性水平最高,南部的阜平群体多样性水平最低。AMOVA分子差异分析显示3%的遗传变异存在于群体间,97%的遗传变异则存在于群体内,基因分化系数Gst仅为0.028,表明华北落叶松在河北的群体分化很低。聚类结果表明河北围场两个群体为一类,蔚县、隆化和涿鹿为一类,阜平和赤城为一类,兴隆雾灵山群体距离其他较远。多样性北部群体较高,南部较低,表明华北落叶松可能的衍化方向是从北向南,印证了北部可能是起源中心的结论。