Seed dispersal by small rodents favors oak over pine regeneration in the pine-oak forests of the Qinling mountains,China

Abstract

Natural regeneration differences between oak and pine are common in the Qinling Mountains of central China. Thus, we examined whether this difference could be explained by seed dispersal. We investigated the seed dispersal of Quercus aliena var. acuteserrata Maxim. and Pinus tabulaeformis Carr. and the regeneration characteristics of both species were investigated in the pine-oak forest belt (oak stands, pine-oak stands, and pine stands) of Huoditang Forest in the Qinling Mountains in central China. We found that Q. aliena var. acuteserrata acorns were usually scatterhoarded, while seeds of P. tabulaeformis were generally consumed immediately. We found that 55% of the released acorns were transferred to the P. tabulaeformis stands. Moreover, Q. aliena var. acuteserrata regenerated successfully and was recruited in the three forest stands. However, the natural regeneration of P. tabulaeformis was very low in all stands because of high predation by small rodents. We propose, therefore, that the seed dispersal advantage of Q. aliena var. acuteserrata compared with P. tabulaeformis contributed greatly to the regeneration difference between these two species in the pine-oak forest belt of the Qinling Mountains in China.     

种植深度对栓皮栎种子萌发及幼苗生长发育的影响

为了了解林木种子直播过程中,播种深度对林木种子出苗率及幼苗生长发育的影响,在济源王屋山地区次生栓皮栎林内,设置4 cm和12 cm两种播种深度,种植100枚健康栓皮栎种子,定期观察记录其发芽和成长状况。结果显示:①4 cm条件下,栓皮栎的发芽率为92%,而12 cm条件下,发芽率仅为62%,二者差异显著;②在2种种植深度下,栓皮栎幼苗的地上茎长度分别为11.79±0.55 cm和11.41±0.65 cm,差异不显著,而叶片数分别为10.33±0.68和9.54±1.13,亦无显著差异。由此可见,在一定范围内,种植深度对林木种子的发芽和出苗率有直接影响,但对出苗后幼苗的生长发育并无明显影响。     

长阳栓皮栎天然群体遗传多样性的等位酶分析

采用5种等位酶对长阳栓皮栎天然群体的遗传多样性和遗传变异进行了研究。共检测到7个基因位点,15个等位基因,其中5个位点为多态位点;群体多态位点比例P=71.4%,平均等位基因数A=3.2000,平均有效等位基因数AE=1.6090,平均期望杂合度HE=0.3563,观测杂合度HO=0.3625。长阳栓皮栎群体的遗传多样性较高,遗传变异水平较高。     

野生槭树大苗归圃装箱培育试验

经过近2年对野生槭树大苗装箱培育试验,结果表明,装箱培育方式育出的野生槭树绿化大苗从叶色、形态、生长状况、苗木质量上看,明显高于对照平地育苗,利润是平地育苗的8.5倍,同时装箱育苗中的起苗、运输、栽植等环节不受季节限制,绿化栽植成活率100%,市场前景广阔,有较高的推广利用价值。     

栓皮栎热值与苯—乙醇抽出物及半纤维素关系

对6个不同年龄(16、24、32、39、48、55 a)栓皮栎4个器官(干、皮、枝、叶)的苯—乙醇抽出物质量分数及半纤维素质量分数与热值的关系进行研究,利用SPSS18.0进行偏相关分析。结果表明:不同器官栓皮栎热值、苯—乙醇抽出物、半纤维素均具有极显著差异。对不同器官苯—乙醇抽出物、半纤维素与热值的相关性分析,得到苯—乙醇抽出物与干质量热值、去灰分热值均呈正相关,未达到显著水平;总体上半纤维素与干质量热值和去灰分热值相关性也不显著,而枝的半纤维素质量分数与去灰分热值呈显著正相关。栓皮栎不同器官干质量热值和去灰分热值总体趋势均为:皮>叶>枝>干;不同器官苯—乙醇抽出物和半纤维质量分数分别表现为:叶>皮>枝>干,干>枝>叶>皮。24 a栓皮栎苯乙醇抽出物质量分数最高,利于能源林生产。     

枳水浸提液对嗜酒大白鼠机能的影响

设计正常饲养、低剂量饲养、高剂量饲养和模型对照4个实验组,研究枳椇水浸提液对嗜酒30 d大白鼠的体质量增加,以及血液中乙醇含量、丙二醛(MDA)含量及乙醇脱氢酶(ADH)活性的影响。试验结果表明,在体质量增加方面,高剂量和低剂量实验组比模型对照组非常显著性升高(p<0.01);在血液中丙二醛(MDA)含量和乙醇脱氢酶(ADH)活性方面,高剂量实验组大白鼠血液中的丙二醛(MDA)含量比对照组非常显著差性降低(p<0.01),而乙醇脱氢酶(ADH)活性比对照组非常显著性升高(p<0.01);在血液中乙醇浓度方面,2个枳椇提取液实验组中大白鼠血液的乙醇含量均低于模型对照组。枳椇水浸提液对大白鼠的长期嗜酒产生的功能损伤具有一定的保护作用。     

Flower bud abscission triggered by the anther in the Asiatic hybrid lily

It is not well documented which floral parts may trigger the onset of tepal or petal senescence and or flower bud abscission. Asiatic hybrid (Lilium × elegans Thunb.) ‘Red Carpet’ lily flowers were selected as a model to study this relationship because the various floral organs of a lily flower can be easily dissected and collected for physiological studies. We hypothesized that anther is the organ that triggers flower bud abscission. Ethanol-soluble sucrose, fructose, and glucose were analyzed in the tepal, anther, filament, and pistil. The analysis was conducted on flower buds weighing 1.5 g (small buds) and 3.9 g (large buds). The sucrose content in the anthers of small buds remained high when cut flowers were held at 21 °C for 5 d, suggesting that sucrose is not hydrolyzed into fructose and glucose. However, in large buds, sucrose was not detected when flowers were held at 21 °C for 5 d. The respiration rate of small buds (2.06 g) was high (2000-3000 mg/kg fw) when the tepals were removed and the anther remained attached to the filament, but was low (less than 400 mg/kg fw) in large buds approaching anthesis. Ethylene was produced only in small buds (1.42 g) when the anthers were present. Radioactive ¹⁴C sucrose applied to the cut end of the pedicel was translocated rapidly to the anther at harvest, but was not translocated to the anther when abscission was induced by keeping flower buds at 21 °C. Ethylene detected in small flower buds possibly was stimulated by physiological changes resulting from the lack of assimilates available to the anther and the lack of sucrose hydrolysis occurring in the anther. The absence of sucrose hydrolysis in the anther and lack of translocation of sucrose from the filaments to the anther in small buds may be factors that contribute to flower bud abscission in ‘Red Carpet’ lily.     

中药萝藦中C21甾苷的含量测定

[目的]测定萝藦中C21甾苷的含量。[方法]以孕甾烯醇酮为标准物,采用磺基醋酸汞试剂法于510 nm波长处测定C21甾苷的吸光度值,并计算其含量。[结果]萝藦中C21甾苷含量为0.003 3 mg/ml,与相关文献中萝藦科植物中甾苷的含量接近。[结论]该方法准确率、重现性、线性关系等都满足科研和生产要求,可以用于萝藦中C21甾苷的含量测定。     

气候变化情景下河北省3个优势树种适宜分布区预测

【目的】探究河北省3个优势树种分布与气候因子的关系,并进行适宜分布区预测,以期为评估气候变化的影响及制定适宜未来气候变化的森林经营策略提供理论依据。【方法】依据河北省森林资源调查数据,选取华北落叶松、蒙古栎和油松这3个主要树种,采用ClimateAP气候模型生成当前及未来(2040—2069年和2070—2099年)与降水和温度相关的10个气候因子,利用MaxEnt生态位模型和基于3个气候变化情景(温室气体最低排放,RCP2.6;中度稳定排放,RCP4.5;高度排放,RCP8.5)的一致性预测,模拟3个树种当前和未来的潜在适宜分布区,并采取响应曲线分析主要气候因子对3个树种适宜分布区的影响。【结果】3个树种MaxEnt模型的受试者工作特征曲线下面积(AUC值)都大于0.85,具有较好的预测能力;当前3个树种主要适宜分布在燕山和太行山地区;影响3个树种分布的主导气候因子存在差异,华北落叶松主要受小于0℃年积温和湿季降水量的影响,蒙古栎则主要受最热月平均气温、Hargreaves水分亏缺和湿季降水量的影响,而最热月平均气温、湿季降水量、大于5℃年积温和年均气温是影响油松分布的主要气候因子;一致性预测表明,在2040—2069年,河北省华北落叶松分布面积明显扩大,蒙古栎分布面积变化较小,而油松分布面积显著缩小;在2070—2099年,3个树种的适宜分布面积都显著缩小,幅度均超过3%。【结论】随着气候变化,3个树种均有向高海拔地区迁移的趋势,但在经纬度方向上的分布变化不大。在未来3个树种的适宜分布区,采取人工手段(如造林)辅助树种扩散以适应气候变化,有利于提高森林生产力,构建健康稳定的森林生态系统。     

有效微生物群对舒玛栎容器苗生长的影响

以舒玛栎( Quercus shumardii.)容器苗为试验材料,研究施用不同体积分数有效微生物群(EM)对其生长的影响。结果表明:T 1(50倍稀释液)、T 2(100倍稀释液)和T 3(150倍稀释液)对苗高和地径生长均有一定提升效果,T 1和T 2处理后苗木的高径比显著低于清水对照(CK);不同体积分数EM处理后,苗木地下(根系)和地上部分(茎和叶)的鲜质量、干质量均显著大于CK;T 1和T 2显著提高了苗木叶片全氮、全磷和全钾的质量分数,对全钾质量分数的增加效果尤其显著;EM处理后显著提高了苗木叶片叶绿素质量分数、净光合速率( P n)、气孔导度( G s)和蒸腾速率( T r),而胞间CO 2摩尔分数( C i)低于CK。因此,施用EM后对舒玛栎苗木生长有一定的提升效果,特别是高浓度的T 1显著提高了苗木的各项指标。