田间条件下毛白杨无性系光合和蒸腾特性研究

测定了８个毛白杨无性系净光合速率、蒸腾速率、蒸腾效率和气孔阻力等生理指标，反映出它们抗旱性上的差异。毛白杨无性系净光合速率和蒸腾速率与其叶片形态特征和解剖特征有着密切关系。毛白杨各无性系单位面积日同化量之间的差异，来源于它们在１２：００ｐｍ─２：００ｐｍ时，对逆境忍受能力的差异和时至４：００ｐｍ时叶细胞膨压恢复能力的差异。短时间内测定的净光合速率不能作为预测树木生长量大小的直接指标。     

应用回归分析法测定白杨无性系生长的稳定性

本文报道了3个白杨杂种无性系在河北省5个县6a的造林试验结果。应用回归分析方法测定了无性系生长的稳定性,预测了它们的适生范围。结果表明,3个无性系平均树高和平均胸径均优于对照种易县毛白杨。741树高生长在有利环境条件下优势明显,胸径生长稳定性强,适合在各种生产水平下栽种。303树高生长在较差环境下表现出较大优势,胸径生长在各生产水平下栽种均表现较好。106稳定性较差,选用时应慎重。     

福州地区半常绿及落叶杨树无性系引种试验

杨树（Ｐｏｐｕｌｕｓｓｐｐ．）是重要的速生用材树种,在国内一般认为杨树是北方树种,不注意在南方发展杨树。实际上不少亚热带和热带国家（印度、南非、澳大利亚、巴基斯坦、伊朗、阿根廷和巴西等）都广泛栽培杨树［１,２］。为探讨南方营造杨树工业用材林的可能性,...     

新沂市农田林网杨树生物量的空间结构

本文采用分层切割法和壕沟全挖法对江苏省新沂市农田林网中，４年生主要的杨树无性系（Ｗ－４６杨，Ｉ－６９杨，ＮＬ－８０１０５杨和ＮＬ－８０２０５杨）的地上部分生物量以及根系生物量进行了测定和分析。结果表明，ＮＬ－８０２０５杨不仅平均单株的生物量最大，而且树干的形质优良。因此，在平原农田林网的经营中，选择ＮＬ－８０２０５杨，既可以提高营林的收益，又能够增强林网的防护效果。     

欧美杨无性系的对比试验

试验表明 ,38个 4年生欧美杨无性系间的树高、胸径、年生长量、造林成活率差异均呈极显著水平。用座标综合法评价了各无性系的优劣 ,从中初选出 6个优良无性系 ,其胸径和全高分别比对照高 2 1%和 2 0 %。     

木麻黄优良无性系在山地引种栽培试验

通过福建中部山地引种木麻黄造林试验,5 a的研究结果表明:木麻黄无性系与实生苗造林保存率都较高,分别达到98.15%和96.8%,差异不显著。试验还表明,采用木麻黄无性系造林,其树高、胸径、材积的生长明显优于木麻黄实生苗的生长速度。前者比后者三项主要指标的生长量增加25.0%、26.5%和94.2%,差异较为显著。采用木麻黄优良无性系造林,其林木干型通直、冠幅大、林相整齐;应用实生苗造林,个体分化较大、生长参差不齐。     

毛白杨无性系湿心材比例的遗传分析

对毛白杨无性系测定林分内25个无性系150棵单株木芯试样的湿心材比例进行测定和遗传分析。结果表明:无性系间湿心材比例差异达到5%显著水平,湿心材比例的无性系重复力高达0.749,受中度遗传控制,在无性系间进行可获得良好效果;湿心材比例与木质素含量及与木材基本密度之间无相关性,对这3个性状可以进行单独选择;湿心材比例与胸径之间在1%水平上呈极显著的负表型相关性和显著的负遗传相关性,可联合选择;在所研究的25个无性系中,可选择1232#无性系,它的湿心材比例较低、木质素含量较低、材色较白,且胸径较大。     

The use of isozyme genetic markers to estimate the rate of outcrossing in a Sitka spruce (Picea sitchensis (Bong.) Carr.) seed orchard in Scotland

Effects of genotype, collection date, auxin treatment, crown position and artificial chilling on rooting and subsequent vegetative growth of Cupressus sempervirens L. softwood cuttings taken from 13-year-old plants were evaluated. Three different clones (318, 296 and 22) previously selected for resistance to cypress cortical cancer caused by Seiridium cardinale were used. In all these clones, both the IBA treated and the untreated cuttings showed seasonal periodicity of rooting. Untreated cuttings rooted best when collected in April (up to 49% for the best clone, i.e. 296) and rooted very poorly in July and October. Auxin treatments appeared unable to overcome this periodicity, as the cuttings taken in July and October did not respond to IBA stimulation. However, in January and April, IBA treatments enhanced adventitious root formation of poorly rooting clones (318 and 22), as well as of clone 296, which performed best (89%) when cuttings were treated in April with 1.5% IBA. Cuttings of each clone collected in the lower third of the crown of the donor trees showed a significantly higher rooting percentage, when compared with those from the upper third. A 4-week post-severance chilling treatment (4°C) significantly enhanced the rooting capacity of cuttings taken in January, while a longer chilling treatment (8 weeks) had a negative effect. The subsequent growth of the rooted cuttings was not affected by either the crown position of the severed cuttings, or the genotype.     

Selection, propagation and cultivation of Pinus massoniana clones for pulp use

Based on the growth, wood property of the ortets, and rooting abilities of cuttings, 32 Pinus massoniana clones for pulp use were selected from forests of superior provenance, mixed families, and progeny test of seed orchard by two-step selection. The average height and DBH growth of three-year-old clones were 28.6% and 16.7%, respectively, higher than those from seedlings, and average gain of wood density reached 8.7%. Rooting rate of all these clones was over 80%, 28% higher than the clones selected by a single step. A cutting orchard of 0.33 hm² on the hillside was constructed to intensively produce cuttings according to the tests on construction methods, pruning, and fertilization. A total of 50,000 grade I, 37,500 grade II, and 62,500 grade III cuttings were collected per hectare of this cutting orchard each time, and were cut three times each year. With all the above techniques, 48 hm² of clonal forests for pulp use of those clones had been planted in five places in Fujian Province. Container stecklings are more likely to increase the planting survival rate. __________ Translated from Scientia Silvae Sinicae, 2004, 40(1): 64–69 [译自: 林业科学]