杉木第二代种子园自由授粉子代测定效果分析   总被引：3，自引：0，他引：3  

余荣卓  施季森  梁元瑞  陈孝丑  谭建平  何祯祥 《福建林业科技》2001,(Z1)

对洋口林场杉木第二代种子园自由授粉子代试验林树高、胸径和材积等生长性状研究结果表明 :杉木第二代种子园子代生长在家系间存在着显著差异 ,家系内个体间的遗传分化剧烈。从群体中选出的优良家系及家系内优良的单株造林 ,增产效果显著 ;杉木在树高、胸径和材积等生长性状间有较高的表型和遗传相关性。  相似文献   

Inter-tree and intra-tree variations in ring width and wood density components in balsam fir (Abies balsamea)     

Koga  S.  Zhang  S. Y. 《Wood Science and Technology》2004,38(2):149-162

This study quantified and compared intra-tree and inter-tree variations in ring width and wood density components in balsam fir (Abies balsamea) grown in Quebec, Canada. In addition, the study examined correlations between ring width and wood density components at different stem positions from the stump level to the stem top. Ring width and wood density components of individual rings were measured by X-ray densitometry. Both the intra- and inter-tree variations in balsam fir are large, but the inter-tree variation is relatively smaller than the intra-tree variation. Much of the intra-tree variation is due to the radial variation, whereas the axial variation is much smaller. Compared to ring width and its components, wood density characteristics show a considerably smaller variation at both the inter- and intra-tree level. In almost all wood characteristics studied (except for latewood width), the intra- and inter-tree variations are more or less influenced by tree age. Cambial age explains more intra-tree variation in wood density components than ring width, whereas more intra-tree variation in ring width components is due to ring width. Cambial age and ring width explain a comparable percentage of variation in ring density. Only a few of the correlations between ring width and wood density components vary significantly with stem position from the stump to the stem top at the inter-tree level. In balsam fir, a negative correlation between ring density and ring width is significant in the butt log, but the correlation decreases to an insignificant level at and above a height of 3.0 m.  相似文献   

阳春市野生珍稀濒危植物和国家重点保护野生植物   总被引：1，自引：2，他引：1  

郑文经  邱祖械  肖志东 《广东林业科技》2003,19(3):38-40

阳春市植物资源丰富，东北部有百涌省级自然保护区，西南部有正在申报省级的鹅凰嶂自然保护区。据调查和现有资料统计，阳春市自然分布的珍稀濒危植物34种，国家重点保护野生植物19种。为保护好这批珍贵的植物资源，作者提出了具体的保护建议。  相似文献   

Salt distribution in response to optical stratification porosity and relative windspeed in a coastal forest in Niigata, Japan   总被引：3，自引：0，他引：3  

J.J. Zhu  Y. Gonda  T. Matsuzaki  M. Yamamoto 《Agroforestry Systems》2002,56(1):73-85

Wind velocity, vertical stand structure and seasalt distribution were measured at various heights inside a plantation of coastal pine forest, with thinning and unthinning, to assess whether any relationships exist between the wind profile, stand structure and seasalt distribution in the coastal pine forest. The vertical stand structure, i.e., optical stratification porosity (OSP), which is defined as vertical distribution of the proportion of sky hemisphere not obscured by tree elements inside a forest stand, was determined for each height by computer analysis of digital images taken with a hemispherical lens. The distribution of OSP in the coastal forest follows the Lambert-Beer's law with absorbency coefficient (). The relative windspeed within canopy can be described using the exponential form with the attenuation coefficient (). The sea-salt was collected using salt gauze (a surgical dressing of loosely woven cotton) both inside and outside the coastal forest, and the distribution of sea-salt within canopy was also in accordance with an exponential function. The relationships among windspeed, OSP and sea-salt indicate that the distributions of both sea-salt and windspeed within canopy were very closely correlated with the distribution of OSP. A linear relationship between OSP and sea-salt has been found. Additionally, linear regression between coefficients and has been obtained as well. Based on these relationships between OSP, wind and sea-salt in the coastal forest, the sea-salt distribution and wind profile within the canopy of the coastal forest can be predicted according to OSP. These results may therefore be useful in analyzing the effects of sea-salt on vegetation and evaluating the filter functions of coastal forests.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

Photosynthetic responses to needle water potentials in Scots pine after a four-year exposure to elevated CO(2) and temperature     

Kellomäki S  Wang KY 《Tree physiology》1996,16(9):765-772

Effects of needle water potential (Psi(l)) on gas exchange of Scots pine (Pinus sylvestris L.) grown for 4 years in open-top chambers with elevated temperature (ET), elevated CO(2) (EC) or a combination of elevated temperature and CO(2) (EC + ET) were examined at a high photon flux density (PPFD), saturated leaf to air water vapor pressure deficit (VPD) and optimal temperature (T). We used the Farquhar model of photosynthesis to estimate the separate effects of Psi(l) and the treatments on maximum carboxylation efficiency (V(c,max)), ribulose-1,5-bisphosphate regeneration capacity (J), rate of respiration in the light (R(d)), intercellular partial pressure of CO(2) (C(i)) and stomatal conductance (G(s)). Depression of CO(2) assimilation rate at low Psi(l) was the result of both stomatal and non-stomatal limitations on photosynthetic processes; however, stomatal limitations dominated during short-term water stress (Psi(l) < -1.2 MPa), whereas non-stomatal limitations dominated during severe water stress. Among the nonstomatal components, the decrease in J contributed more to the decline in photosynthesis than the decrease in V(c,max). Long-term elevation of CO(2) and temperature led to differences in the maximum values of the parameters, the threshold values of Psi(l) and the sensitivity of the parameters to decreasing Psi(l). The CO(2) treatment decreased the maximum values of V(c,max), J and R(d) but significantly increased the sensitivity of V(c,max), J and R(d) to decreasing Psi(l) (P < 0.05). The effects of the ET and EC + ET treatments on V(c,max), J and R(d) were opposite to the effects of the EC treatment on these parameters. The values of G(s), which were measured simultaneously with maximum net rate of assimilation (A(max)), declined in a curvilinear fashion as Psi(l) decreased. Both the EC + ET and ET treatments significantly decreased the sensitivity of G(s) to decreasing Psi(l). We conclude that, in the future, acclimation to increased atmospheric CO(2) and temperature could increase the tolerance of Scots pine to water stress.  相似文献   

西南桤木木塑复合材料的研究   总被引：6，自引：1，他引：6  

邱坚  肖绍琼  杜官本  木乔英 《林业科学》2003,39(3):98-105

采用乙烯基类系列单体——丙烯腈(AN)、甲基丙烯酸甲酯(MMA)、丙烯酸(AA)三元共聚单体注入西南桤木木材中，制成新型的高分子复合材料(AMA—WPC)。单体的注入用满细胞法，聚合用热引发法，并采用添加氯化锌对木材细胞壁进行活化等工艺对木塑复合材进行了研究和分析。实验样品按照国标GBl927—1943有关规定进行测试，并结合傅立叶红外光谱和扫描电镜探讨了各因素对AMA—WPC材料接枝率及性能的影响。结果表明：改性后西南桤木木塑复合材料具有优异的物理、力学性能。与素材相比较，AMA—WPC的密度提高了59．8％，顺纹抗压强度提高了76．7％，抗弯强度提高了90．4％，抗弯弹性模量提高22．2％，端面硬度提高102．3％，径面硬度提高153．6％，弦面硬度提高152．2％，吸水率降低56．7％，湿膨胀率降低19．0％。  相似文献   

油茶林土壤微生物生态分布及土壤酶活性的研究   总被引：24，自引：3，他引：24  

周国英  陈小艳  李倩茹  兰贵洪 《经济林研究》2001,19(1):9-12

为了了解油茶林土壤肥力状况，我们对株洲地区油茶林地土壤微生物数量和土壤酶活性进行了研究。研究结果表明：根际土壤中的细菌数量明显大于非根际土壤，根际土壤酶的活性高于非根际土壤；新造幼林地土壤微生物数量较萌芽更新林地多，土壤酶的活性也以新造幼林地较萌雅量更新林地土壤高；低改林地土壤微生物数量较未低改林地多，土壤酶的活性也以低改林地高。  相似文献   

华山松针叶中矿质元素含量的地理变异   总被引：1，自引：1，他引：1  

张云跃  李佩瑜 《林业科学》1996,32(3):206-212

以１２年生的种源林为取材对象，在１９９１年４月３０日、７月３０日、１０月３０日及１９９２年１月３０日同时采当年和１年生针叶，测定Ｎ、Ｐ、Ｋ、Ｃａ和Ｍｇ浓度。结果表明，除Ｋ外，其它矿质元素浓度种源间存在极显著差异。地理变异呈纬向渐变型。极端温度与元素地理差异有密切关系，并构成主导自然选择压。元素浓度的季节动态与针叶生长节律循环相伴。南、北华山松已分化成两个营养能力显著不同的地理种群，但动态模式基本相似。  相似文献   

Modified algorithm to determine localized modulus of elasticity of lumber     

F. Lam  Prof. Dr. R. O. Foschi  Prof. Dr. J. D. Barrett  Technician Q. Y. He 《Wood Science and Technology》1993,27(2):81-94

Summary A procedure has been developed to determine the cut-off frequency in an algorithm to evaluate the localized modulus of elasticity (MOE) in lumber. MOE profiles have been artificially generated to serve as input for evaluation of the procedure. A noise component has also been added to the input record to test the robustness and accuracy of the procedure. Good agreement between program predictions and the known localized MOE values has been obtained. The efficiency of the procedure has also been tested using MOE profiles collected from experiments. The program performed efficiently and program predictions seemed reasonable.  相似文献   

常山胡柚叶片DNA的抽提与分析     

仲山民  胡芳名  谭晓凤  郑勇平  何照斌  杜红亮 《江苏林业科技》2003,30(1):5-8

经反复实验，采用在抽提前加入一定量的抗氧化剂β－巯基乙醇，用冰冻的异丙醇来沉淀DNA，并增加氯仿／异戊醇抽提次数的所谓改良CTAB法，对常山胡柚叶片DNA抽提与分析，不仅成功提取到常山胡柚叶片DNA，而且所得的DNA浓度高、纯度好，20个试样的DNA苹均质量浓度为272.86μg/mL，平均每克鲜叶片可获DNA约82μg，纯度基本上都在1.4-1.8范围内，并经RAPD反应验证，完全能满足常规分子生物学分析的要求。  相似文献