Bulk method of hardwood cutting propagation ofLarix olgensis

Larix olgensis is a major reforestation species in areas of the northeast part of China. Rooted cutting for vegetative propagation on this Larch has been carried out since 1990, and later the bulk method of hardwood cutting propagation also has been studied. The result is as follows: (1) Cuttings from physiologically juvenile trees are easy to root, and develop better roots. In addition, there are many methods to enhance the cuttings rooting. (2) The good time for seedling transplanting is in the middle of August. Treatments with plant hormones and rare-earth compounds can improve the seedling survival rate, and the survival rate of the seedlings soaked in chelate rare-earth molybdenum compound (300×10⁻⁶) for 3 hours reached 94.00%, 19.49% higher than that of the control. (3) Methods of maintaining juvenility such as hedging, is essential to further developments for operational planting of vegetative propagates. Hedges in 5 years old can produce 91.75 shoots per tree, exceeding the control to 152.2%. (Responsible Editor: Zhu Hong)     

Effect of low temperature on pollen vitality ofLarix olgensis

After the treatment of pollen oflarix olgensis at the different low temperature, the pollen vitality was observed by using fluorescent staining method. Several conclusions were obtained: 1) 0°C–3°C is the best temperature range for storing pollen ofLarix olgensis. 2) At the same temperature, humidity is the key factor influencing the pollen vitality. 3) Different clones shows different resistance to low temperature. Among the ten clones 2# clone shows the highest resistance.     

Geographic variation pattern ofLarix olgensis

On the basis of the data of provenance test for 10 years in the total natural range ofLarix olgensis from 10 seeds collection sites, the geographic variation patterns have been made by means of canonical correlation analysis: (1) The basic variation patterns of growth characters is in vertical gradual change along the elevation gradient as principal, and gradual change along the latitude as supplement. (2) The Xiaobehu provenance with low elevation and low equivalent latitude is the good gene resource center ofL. olgensis. It has the genetic characters of rapid growth, high stability and fine timber quality. (3) The synthetical interaction between water and heat factors is the major factor to produce the variation ofL. olgensis and the temperature is the principal one. (4) Among the genetic variations of geographic population characters, the variation of growth is the most obvious one, and it could be taken as the main character for provenance division. (5) By allocating the seeds from the low equivalent latitude region to the northern suitable afforestation areas, the greater genetic gain could be obtained. (Responsible Editor: Chai Ruihai)     

Study on prediction model of seed crop ofLarix olgensis seed orchard

By taking three forecasting methods (sample trees, sample branches and climate factors prediction) the forecasting equation of seed were established through correlation analysis and regression analysis on seed crop of Qingshan and QinheLarix olgensis seed orchard. The research results showed that it gave more accurate prediction with less working load by taking pistillate numbers of four sample branches at middle layer of crown to predicate seed crop. And the short-term prediction equation of this method was established. The correlation analysis between seed crop and climate factors showed that the relative humidity May and June, annual evaporative amount, and accumulated temperature above 10°C, possess the highest effect on bud differentiation and seed crop, then the middle-term predication equation of climate factors was established.     

A study on the geographic variation and selection of the best provenance ofLarix olgensis

On the basis of the results from the geographic provenance test of nine years oldlarix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best provenance ofLarix olgensis was carried out. The main results are as follows: I.The different provenances ofLarix olgensis have rich and wide genetic variation, and exist a linear correlation with latitude and longitude in collection area. General trends are enumerated below: Provenances at lower latitude and more west longitude have lighter thousand seed weight, short growth period, higher increment, wide branches, rich leaves and crown as well as worst adaptabillity. It is a dual-way variation along with two directions of latitude and longitude, and also embodies a change gradually in climate condition from south to north. The temperatures in seed production site, especially the mean temperature in January and ≥10 °C accumulated temperature, are important factors that produce geographic variation forlarix olgensis. 2. The variation of different provenances in periodic biological phenomena and growth rhythm trends are that: 1 both of the provenances from Changbai Mt. (III) and Dashitou(IV) at low latitude belong to the centralized growth type, and have shout growth period, the difference between these two provenances is that the provenance from Changbai Mt. grows well in all time, Dashitou provennce is well only in later period; 2 the provenance from Baidao Mt. (II) at middle latitude belongs to even growth type and has longer grpwth period, this provenance has higher increment in early and later periods relatively; 3 Xiaobeihu provenance at high latitude is a growth type among II. III and IV provenances and has a general growth period, the provenance grows better in middle time and worse in later time. 3. The best provenance in Liangshui Natural Reserve and its meighbourhood is Dashitou Procenance, which growth in height, diameter and volume has exceeded 16. 28%, 46. 27%, 30. 58%, 78. 20, 82. 00% as well as 392. 00% by comparison with the mean value of the contrast and the worst provenance respectively, The result from the height growth of three, five, seven and nine years oldLarix olgensis by using the method of order correlation analysis demonstrates that it is possible to make early selection of the provenance. Meanwhile, data from juvenile and mature oflarix olgensis plantation also prove the reliability of the early selection. 4. The provenance heritabilities of nine years oldlarix olgensis in Liangshui Natural Reserve are follows: The heritability of the height growth (h²) is 0.79; The heritability of the diameter breast height (h²) is 0.791; The geretic gain is 24.5% and 40.36% respectively.     

Study on photosynthetic characteristics ofLarix olgensis Henry at Erlongshan Forest Farm

Net photosynthetic rate (Pn) and respiration rate (R) of different directions and levels of crownof Larix olgensis Henry, growing at Erlongshan Forest Farm, were different. Pn of 14-year-oldL. olgensis was the biggest at the west of crown, and the lowest at the east of crown. Diurnal process of Pn of the south of crown showed monopeak curve pattern. Diurnal processes of Pn and R of 7-year-old and 16-year-oldL. olgensis showed bipeak curve pattern. Seasonal process of Pn ofL. ol-gensis showed monopeak curve pattern. Light compensation and saturation points ofL. olgensis were 18 and 1080 μ molm⁻² s⁻¹ respectively. Chlorophyll content of different directions and levels of crown ofL. olgensis were different. Chlorophyll content increased with the passage of time (May 22 – September 13), and reached its biggest content at August, then decreased. Seasonal process of chlorophyll content, like that of Pn, showed monopeak curve pattern. Chlorophyll content related to Pn positively.     

Study on physiological characteristics ofLarix olgensis andFraxinus manshurica under controlled conditions

The net photosythetical rate, respiration rate, light compensation point and light saturation point ofLarix olgensis andFraxinus manshurica were measured by Model-865 Co² Infrared Analyzer under controlled conditions (in coviron phytotron). For net photosythetical rate ofLarix ogensis andFraxinus manshurica, the optimum air temperature was 25, 28 °C respectively, the optimum soil water potantial was −20, −10 kPa repectively, the optimum soil water content was 20.31 %, 23.42% respectively, and the optimum air humidity was 90%. The optimum soil water potantial of respiration rate was −30 kPa. The light compensation point for the two species was 3.36, 4.8 μ mol / m²s respectively and light saturation was 804, 880 μ mol / m²s. The project supported by National Natural Science Foundation of China     

THE OCCURRENCE AND DEVELOPMENT OF THE ADVENTITIOUS ROOTS FORMING GREEN SHOOT CUTTING OF LARIX OLGENSIS

The experiment with the green shoot cutting propagation of Larix olgensis wasmade in the Maoer Mountain Forestry Farm on July 5,1990.After the callus formed ofthe cutting base before adventitious roots came out the materials were collected from thecutting base and fixed in FAA solution.By the paraffin sections and anatomical observatio-n.the results indicted that it needed 40 days from the cutting to the rooting.The inducedprimordium of the cutting was endogenous in origin,which came from:(1)vascularcambium of the callus,and became roots;(2)meristematic cell population in the intersectbetween the cambium and xylem ray of the cutting base.There were extruding,crushingprocess and enzymolysis when the adventitious roots broke through the outer layers in tworooting types.     

Comparative study on drought resistance ofLarix olgensis Henry andPinus sylvestris var.mongolica (I)

Water potential (ϕ w) and net photosynthetic rate (Pn) ofLarix olgensis andPinus. sylvestris var.mongolica decreased with the decrease of soil water content. ϕ w and Pn ofL. olgensis changed hardly during the first 9 days after stopping watering, then decreased sharply at the 10th day Pn ofP. sylvestris varmongolica decreased slightly during the first 8 days, then decreased sharply at the 9th day. Their respiration rate, chlorophyll content and their a/b ratio changed hardly. The following 3 conclusions were obtained and discussed exhaustively. (1) ϕ w can be used to direct watering as a sensitive index of judging whetherL. olgensis andP. sylvestris var.mongolica lacking water. (2) The decrease of Pn ofL. olgensis andP. sylvestris var.mongolica when drought had nothing to do with chlorophyll. (3)P. sylvestris var.mongolica had morphological drought resistance, while Lolgensis had physiological drought resistance, and their drought resistance was discussed comparatively first time.     

The effect of low temperature adversity on male flowers and pollen inLarix olgensis

The electric conductivity of pollen life-force and male flowers ofLarix olgemis on condition of low temperature adversity has been respectively measured by means of fluorescent dying method and conductivity method in 1992 and 1994. The results indicate that: (1) If the same clonal pollen is treated at equal time at different low temperatures, there are significant differences in pollen life-force, the pollen life-force is the largest between O°C and -3°C, in higher or lower temperature range, the pollen life-force will decrease. The measurement of electric conductivity of male flowers proves that the low temperature of below -3°C is the main reason that the cell membrane is damaged and the pollen life-force decreases. (2) The same clonal pollen life-force at the same low temperature will gradually decrease with the increasing of frozen time. Its main reason is that suffocation and losing body fluid result in the damage of cell membrane, the measurement of electric conductivity of male flowers can prove that. (3) If pollen is treated with the same low temperature, the humidity will be the main factor of affecting pollen life-force. (4) There are significant differences inLarix olgensis’s resistance against low temperature in its different growth stage, the male flower’s resistance of near pollen spreading period is low. (5) The resistance is different within clones. (6) The resistance against low temperature ofLarix can be increased by means of chemical treatment.     

Effect of cutting position on rooting and shoot growth of two poplar clones

One-year-old shoots from stooling beds of Populus × deltoides Walker and Populus jackii Northwest were collected in late fall to determine the effect of cutting position on rooting and growth of hardwood poplar cuttings. Cuttings with a minimum diameter of 9.0 mm were obtained from basal, middle and distal locations on the poplar shoot. Rooting and shoot growth were assessed in the greenhouse and under field conditions. Walker poplar cuttings collected from basal portions of the shoot and planted in the field had 87.6% rooting and 103.8 cm growth compared to 78.8% and 103.4 cm and 67.6% and 88.8 cm for middle and distal locations respectively. For Northwest rooting and growth under field conditions was 84.4% and 94.7 cm for basal, 78.4% and 90.5 cm for mid and 64.4% and 84.3 cm for distal locations. Rooting in the greenhouse was superior to the field. Walker cuttings had fewer roots and buds per cutting than Northwest, however, growth of Walker in the field was superior.     

抚育间伐对长白落叶松人工林生长及效益的影响

对九台市上河湾林场1997年营造的长白落叶松人工林进行抚育间伐试验,结果表明:间伐3 a后,间伐和未间伐的林分密度分别为2 150株·hm-2和3 150株·hm-2,平均胸径分别为11.0 cm和9.3 cm,总蓄积分别为119.6 m3·hm-2和89.0 m3·hm-2。对长白落叶松人工林进行合理抚育间伐,可显著提高林分质量和生长量及经济效益。     

Cultural factors influencing adventitious shoot and plantlet formation from slash pine cotyledons

Cultural factors affecting in vitro shoot and subsequent plantlet formation of slash pine (Pinus elliotti Engelm.) cotyledons were investigated. Basal media composition, N⁶-benzylaminopurine (BAP) concentration and exposure time significantly influenced bud induction in cotyledons cultured under a continuous photoperiod of 35–40 mol m^–2 s^–1 at 24 ± 1 °C. The largest number of adventitious shoots was obtained after 28 days exposure to 66 M BAP-supplemented modified Gresshoff and Doy 1 (GD1) medium. Relatively high frequencies of large shoots were obtained after a 14-day exposure to 22 M BAP-supplemented Brown and Lawrence (BL) or 66 M BAP-supplemented GD1. Adventitious shoots derived from 21- or 28-day exposures to BAP developed more slowly and were smaller in size than those derived from a 14-day exposure to the cytokinin. Shoot differentiation and subsequent growth were also influenced by basal media, media concentration, and presence of activated charcoal in the medium. The percentage of cotyledons forming shoots was highest on half-strength GD1 medium containing activated charcoal. Rooting was achieved in vitro under a continuous photoperiod of 60–70 mol M^–2 S^–1. Roots were formed when excised shoots were planted on GD 1/2 medium supplemented with 2.68 M 1^–1 a-napthaleneacetic acid (NAA) with or without BAP for 14 days. The proposed technique of slash pine propagation using cotyledon explants can produce up to 100 seedlings per embryo.     

Morphological variance and natural types' division of plus trees ofLarix principis-rupprechtii Mayr.

The phenotypic characteristics of the plus trees ofLarix principis-rupprechtii such as stem form, branch angle, branch/stem ratio, branch density, the crown width, crown length, number of short branch over 5-cm branch segment in length, and the leaf number of each short branch were investigated in seed orchard in the Changcheng Mountain, Shaanxi Province. According to the morphological characters, the plus tree clones ofLarix principis-rupprechtii were classified into 4 natural types: the narrow-dense-crown type, wide-dense-crown type, wide-sparse-crown type, and the narrow-sparse-crown type. The result of the cluster analysis showed there was a very significant difference in tree growth among the four natural types. While comparing the tree growth of four natural types for the last ten years, it was found that the performance order of various types from good to bad is as follows: the narrow-dense crown type > the wide-dense crown type > the wide-sparse crown type > the narrow-sparse crown type. The plus trees of narrow-dense-crown, as a fine type, should be paid great attention to production and prepared to popularize. Biography: ZHANG Xin-bo (1956-), male, Senior engineer of Shanxi Academy of Forestry Science and Northern Research Institute of Forestry of China, Taiyuan 030012, P. R. China Responsible editor: Chai Ruihai     

植物生长调节剂GGR7对冬枣扦插生根的影响

用冬枣当年生枣头嫩枝部分做插条,扦插前用植物生长调节剂GGR7处理,苗床基质由泥炭土、腐叶土和细沙混合而成,苗床上方使用塑膜拱棚和荫棚,膜棚内温度保持在20~28℃,湿度保持在75%以上;用50mg/L的GGR7浸泡插条1 h,插条生根率85%以上,根系长而多。     

Effect of cutting height and cutting interval on dry matter yield of Leucaena leucocephala (Lam) De Wit

The effect of cutting height and cutting interval on dry matter production of Leucaena leucocephala (Lam) De Wit was investigated at Njala, Sierra Leone using three year old Leucaena trees. Four cutting heights, (25, 50, 75 and 100 cm), and two cutting intervals (one and three months), were adopted.Dry matter yields were highest at the 75 and 100 cm cutting heights, especially at the longer, three-monthly, cutting interval. They were significantly reduced by more frequent cutting, probably due to the increased number of recovery phases.Leaf nitrogen yields per tree for trees cut at three-monthly intervals were over twice as high as the total yields obtained from monthly cutting over the same period.     

微红梢斑螟蛀害对马尾松幼林生长的影响及剪梢防治技术研究

通过标准地调查研究了微红梢斑螟蛀害对马尾松幼林生长的影响,并对剪梢防治微红梢斑螟的方法进行了简述.结果表明:微红梢斑螟蛀害对马尾松幼林生长产生了显著影响,受害后主梢当年生长量损失27.23%,树高下降13%,而地径增长7.23%.马尾松受害后除影响当年梢生长外还影响其次年梢生长.树高在141～180 cm左右的马尾松受...     

Parameters affecting shoot production and rooting of cuttings from lodgepole pine hedges

By propagating lodgepole pine (Pinus contorta) cuttings in vivo, we obtained after 7 growing cycles (ca 3.5 years) in a greenhouse, sufficient number of cuttings from most families to establish clonal progeny tests. Twenty-one full-sib families with approximately 20 clones per family were studied for five years. Years when cuttings were set, families within latitude and clones within families differed significantly in rooting percentages, with the variance components 4.2%, 8.2% and 9.5%, respectively. One way to get a frequent and uniform rooting is to take cuttings from non-leading shoots since they have higher rooting percentage than leading shoots. Neither total length of the cuttings nor length of the primary needles were significantly correlated to rooting percentage. With appropriate management of the ortets and the cuttings during rooting, most clones could be included in a cutting propagation program.     

金雀花扦插生根过程中内源激素动态变化

以2年生金雀花实生苗硬枝为试材,应用酶联免疫吸附测定法（ELISA）,研究金雀花硬枝在扦插生根过程中内源激素含量的变化,旨在揭示金雀花扦插生根机理。结果表明：900 mg/ L 吲哚乙酸（IAA）处理金雀花插穗较CK 显著缩短生根时间;不定根大量形成前,除脱落酸（ABA）外,其他均呈倒“V”形变化;内源激素变化曲线的峰值（或谷值）出现前,IAA 处理的 IAA 含量、IAA/ ZT（细胞分裂素）、IAA/ ABA、ZT/ ABA 均高于 CK,ABA 含量低于 CK;IAA 处理与 CK 内源激素的峰值（或谷值）分别出现在第10天和第15天,与其生根动态具有协同性。     

长白落叶松纸浆材优良家系多性状联合选择研究

采用胸径木芯与伐倒木取样方法,对24年生长白落叶松优树子代测定林14个处理的生长性状、木芯材质性状、解析木材质性状及其制浆造纸特性进行了研究,结果表明:生长性状、木芯基本密度、木芯管胞性状均存在丰富的变异;家系间生长性状差异极显著;木芯基本密度、木芯管胞性状差异显著,家系遗传力在0.56 0.80之间;解析木基本密度、早材微纤丝角、管胞长度、早材壁腔比、木质素、阿拉伯糖含量、抗张强度、撕裂度等差异极显著,家系遗传力在0.64 0.86之间;晚材率、管胞长宽比、综纤维素含量等差异显著,家系遗传力在0.51 0.61,家系水平的材性改良潜力较大。生长性状与木芯管胞长度呈极显著正相关,与木芯基本密度、管胞长宽比相关不显著;木芯基本密度、管胞长度、管胞宽度以及管胞长宽比与解析木相应性状呈极显著正相关关系,且回归模型较为理想,可以利用胸径木芯各性状值预测其单株值,间接选择和评价纸浆材优良家系。通过生长性状、木芯基本密度和木芯管胞长宽比综合分析选出166、169为优良家系,根据解析木生长、材质以及纸张物理性状选出的优良家系与其结果一致。优良家系材积、木芯基本密度和木芯管胞长宽比的遗传增益(超过对照)分别为48.34%(38.80%)、14.01%(3.63%)和19.89%(6.42%)。