共查询到20条相似文献，搜索用时 250 毫秒
1.
Li Wen-bin Sun Ren-shan Liu Xu-hua Liu Yong 《中国林学(英文版)》2006,8(1):46-49
For the demands of automatic pruning, an effective discrimination rule of the forked and non-forked larch trees is established. First, information of trunk and branch diameters of a larch plantations was collected from the west mountain of Beijing. The growth characteristics of the forked and non-forked trees were studied. Given the statistical characteristics of the trunk and branch diameters, a discriminant function of the forked branch and non-forked larch trees was established statistically. Excellent discrimination results were obtained by the function and the rule. The study presents an effective discrimination rule to separate forked trees from straight trees for automatic pruning. 相似文献
2.
The mechanism underlying overwintering death in poplar:the cumulative effect of effective freeze-thaw damage 总被引：1，自引：0，他引：1
We analyzed the relationships linking overwintering death and frost cracking to temperature and sunlight as well as the effects of low temperatures and freeze–thaw cycles on bud-burst rates,relative electrical conductivity,and phloem and cambial ultrastructures of poplar.Overwintering death rates of poplar were not correlated with negative accumulated temperature or winter minimum temperature.Freeze–thaw cycles caused more bud damage than constant exposure to low temperatures.Resistance to freeze–thaw cycles differed among clones,and the budburst rate decreased with increasing exposure to freeze–thaw cycles.Cold-resistant clones had the lowest relative electrical conductivity.Chloroplasts exhibited the fastest and the most obvious reaction to freeze–thaw damage,whereas a single freeze–thaw cycle caused little damage to cambium ultrastructure.Several such cycles resulted in damage to plasma membranes,severe damage to organelles,dehydration of cells and cell death.We conclude that overwintering death of poplar is mainly attributed to the accumulation of effective freeze–thaw damage beyond the limits of freeze–thaw resistance. 相似文献
3.
Carbon partition in plants is one of the key points for carbon cycle research. In order to estimate the carbon storage of shelterbelts in plain areas of China accurately, the method of biomass inventory was used to study the individual biomass, organ carbon storage and partition in different organs of 8, 10, 13 and 16 year-old poplar shelterbelts in Yuncheng, Shandong Province. The results indicated that the biomass of different poplar organs followed the pattern of trunk>branch>root>leaf, and the biomass of trunk and branch accounted for about 80% of the total. The carbon concentration of the different organs followed leaf>branch >trunk >root. The carbon concentration of different organs ranged between 43.51% and 70.49%. The carbon concentration of the four age groups’ shelterbelts were higher than 50%, which was slightly higher than the average carbon concentration of poplar in Northern China(48.80%). The variation coefficient of carbon concentration was the smallest for leaf, and the largest for root. As for the difference of carbon concentration, it was significant among different organs for all the four age groups, and not significant among the whole trees for the four age groups. The carbon storage was closely related to its biomass for all tree organs, and its sequence was trunk>branch>root>leaf. The proportion of trunk carbon storage obviously increased with tree age. 相似文献
4.
Md. Salim AZAD 《中国林学(英文版)》2012,14(4):251-259
Bud flushing is very important for the survival and growth of trees, a phenomenon matched each year with the annual course of temperature and the timing of bud flushing in the spring. Essentially it represents a serious ecological and evolutionary tradeoff between survival and growth. The most suitable timing of bud burst permits trees to begin growth sufficiently early to take advantage of favorable spring conditions, but late enough to decrease the risks of tissue damage from late frost. In the present study bud burst spring phenology of poplar (Populus tremula and P. tremuloides) from eight different provenances, originating from Europe and the USA, was observed during March and April, 2009. The experimental plot was located at Solling, Germany (51°44′0″ N, 9°36′0″ E). A six stage subjective scoring system of bud burst phenology was used to identify the phenological stages of the seedlings, where each plant was observed twice a week. The aim of the study was to predict phenotypic variation in poplar, originating from regions between 42° and 60° N latitude, growing in similar environments. Timing of bud flushing of poplar was recorded. It was found that seedlings of provenance 3, which originated from 42.35° N latitude, started and completed flushing significantly earlier than those of other provenances, while seedlings of provenance 5, originating from 54.29° N latitude, started flushing very late and only a few plants reached top scoring at the end of the experimental period. Analysis of variance showed statistically highly significant differences (p < 0.05) in bud flushing among the provenances. The correlation between scoring and flushing periods was very strong within provenances although the flushing pattern differed among provenances (origin of the planted seedlings). Bud flushing showed a negative correlation with the origin of the planted seedlings. Given the field experience gained with this experiment, it is recommended that seedlings from provenances 5 and 8 could be used for future plantations where late frost may be a problem for the young shoots of seedlings. 相似文献
5.
DUAN Wenbiao CHEN LixinCollege of Forestry Northeast Forestry University Harbin P.R.China 《中国林业科技(英文版)》2004,3(4):17-29
Succession rules of soil acidity quality of larch plantations in first rotation at different development stages, succession rules of soil acidity quality of young stand of larch plantations in second rotation and the relationship between soil acidity and various forms of organic phosphorus and inorganic phosphorus were studied in mountainous area of eastern part of Northeastern China. The results showed that active acidity (pH value) inrhizosphere soil decreased continually with stand age increasing from young stand, half-mature stand, near mature stand to mature stand, but active acidity (pH value) in non-rhizosphere soil, exchange acidity, exchangeable aluminium, total hydrolytic acidity, and the ratio of exchange acidity and total hydrolytic acidity in rhizosphere soil and in non-rhizosphere soil increased apparently; total organic P, moderately resistant organic P, and highly resistant organic P in soil decreased at all age stages in larch plantations when soil acidity added. For rhizosphere soil of 相似文献
6.
Effects of substrates, type of auxin, treatment concentration and time on rooting ability of Acacia mangium were systematically studied, and the change trend of rooting ability over time were analyzed. The results obtained from the experiment indicated that the substrate of yellow subsoil could improve the rooting rate of the cuttings significantly. IBA was superior to other auxins in increase the number of mean roots and the longest root length. And general rooting effect for different treatments was evaluated based on subordinate function values analysis. The optimized combinations were the cutting treated by IBA 400 mg·L-1 soaked for 2 hours. Callus were occurred in 5 d after cutting, and higher rooting period occurred in 10—15 d and 25—30 d after cutting. 相似文献
7.
Pyemotes sp. and Scleroderma guani were used to control the larvae of Semanotus bifasciatus. The results as follows: (1) the suitable control time of Pyemotes sp.was from early April to early May. The reason was that in this time, the larvae of S. bifasciatus were young and not bored into xylem that was so easy to be parasitized by Pyemotes sp. With the parasitic rate 80% in average. Indoor experiment showed that the Pyemotes sp. had the same tropism selection to every instar for the host, but the parasitic rate was higher in low instar than other instars.(2)Using Scleroderma guani to control S. bjfasciatus, the suitable time was from mid May to mid June, the optimal ratio of host and parasite was 1∶ 1. Indoor experiment showed that Scleroderma guani had strong tropism toward middle-aged and elder larvae, the parasite linger around them and choose suitable position on hosts where they could lay eggs successfully. This behavior showed that Scleroderma guani had strict selectivity for their hosts. In experiment, the authors found a phenomenon that in one trap wood, both the Pyemotes sp. and Scleroderma guani could be found at the same time, they themselves did not affect each other and otherwise they could increase the parasitic rate for host. So, the authors suggested that in practice to control pests especially for boring pests, the Scleroderma guani and Pyemotes sp could be used at the same time. 相似文献
8.
Yezhou Xu Chaoqun Du Guowei Huang Zhenfang Li Xiangyang Xu Jingjin Zheng Chu Wu 《林业研究》2020,31(3):837-856
The structural characteristics of the tree crowns of Cunninghamia lanceolata var. Luotian(herein, Luotian), a natural variety of C. lanceolata(Chinese-fir, herein Lanceolata) in China, were analyzed using trunk and branch measurements and biomass determinations. Samples from two typical cultivated varietal populations were collected, including twenty-six 15–23-year-old trees of Luotian from a plantation, and nine 16–23-year-old trees of Lanceolata. Our results show that Luotian and Lanceolata samples differed significantly in crown structure, morphological indices, and biomass:(1) the oldest live branches on Luotian trees were 5–6 years old and 8–11 years old on Lanceolata. The ages of the live branches were not affected by the ages of the Luotian trees, while live branch ages increased with ages of Lanceolata trees;(2) the maximumbranching order of Luotian was level two. Compared to Lanceolata, the average number of first-order lateral branches(i.e., branches emerging from the trunk) and the number of first-order lateral branch whorls per sample tree were 12.9% and 32.2% lower, respectively, in Luotian.However, the average number of branches within a single whorl was 21.8% greater in Luotian;the average number of branch whorls at crown height was 51.1% greater. Thus,the Luotian variety has thicker branches;(3) the average lateral branch angles in Luotian and Lanceolata sample trees were 105.2° and 61.4°, respectively. The branch angles in 53.0% of lateral branches on Luotian ranged from105° to 135°, but 30° to 90° in 96% of the lateral branches on Lanceolata. Within the same crown layer, the average branch angle was 1.6–2.2 times greater in Luotian, and the angle was directly proportional to crown thickness;(4) the average base diameter and branch length on Luotian were1.3 cm and 75.8 cm, respectively, and 1.6 cm and112.2 cm for Lanceolata. For individual trees, branch growth differed significantly(p < 0.01) between Luotian and Lanceolata. However, the lateral branches grew at a similar rate among Luotian trees of different ages;(5) the average height to the lowest live branch on Luotian was128.3% greater than on Lanceolata, resulting in a significant difference(p < 0.01) in crown size. Compared to the crowns on Lanceolata, the Luotian crowns were 45.3%higher and 41.1% wider, and the surface area, volume, and growth of the crown were 27.0%, 11.4%, and 2.4 times greater than for Lanceolata, respectively;and,(6) the biomass of Luotian and Lanceolata sample trees also differed significantly. The mean crown, branch, and leaf biomass for Luotian was 40.0%, 25.2%, and 54.1% of those for Lanceolata, respectively. However, the leaf biomass in each layer of the Luotian crown was higher thanthat of Lanceolata, and leaf biomass increased with crown thickness. 相似文献
9.
LIU Zhen BI Huitao JIANG Jianping College of Forestry Horticulture Henan Agricultural University Zhengzhou P. R. China 《中国林业科技(英文版)》2005,4(4):24-32
Paulownia is a fast-growing tree species adaptable to intercrop with crops in Huang-huai-hai Plain of China. But the problem of large crown and low trunk of Paulownia not only directly affects the quality and the yield of Paulownia timber, but also indirectly affects crops production and ecological environment. In order to resolve this problem, since the 1960s, many scientists have explored the technique of cultivating high trunk of Paulownia by means of artificial trunk extension (Fan Guoq… 相似文献
10.
Xiang Cunti Sun Haifeng Li GuishengNortheast Forestry UniversityWu Xingyin Li Zhuo DangWenqiang Zhang Jinghua Zou XipinAcheng Forest Bureau of Heilongjiang Province 《林业研究》1991,2(1):48-55
The bacterial swollen stem canker of poplar is prevalent in planted poplars ofnortheast China.Serious damage occurs in the form of necrosis,putridity,cankers,swollen stemsand discolored wood of trunks and branches of young and mature trees.Tests of allergic reaction,pathogenicity,culture characteristic,Gram stain and anaerobic culture revealed that the pathogen isErwinia sp.Its occurrence depends mainly on the predisposing factors of the disease among whichthe susceptibility of poplars is the most important one.The disease becomes widespread in associa-tion with low-lying and high-humidity terrain,frost injury,node wounds,insect damage,and prun-ing and other mechanical wounds.Harmful factors promote the disease. 相似文献
11.
运用数量遗传学原理和方法，分析剖析了白花泡桐接干强度与树高、胸径和材积生长，接干后的分枝强度与整个树冠结构的遗传相关和表型相关，结果表明，泡桐接干能力对生长，和对树冠结构都有重要的影响。 相似文献
12.
为了改良白花泡桐的干形，对树冠结构、生长性状与干形的遗传相关进行了剖析和通径分析，计算出主要树冠性状、生长性状对干形的６３个选择指数方程。结果表明，胸径、小枝数、分枝总长、冠表面积和树高对形数、圆满度的决定系数在０．４０５～０．９４０和０．４２６～１．０６４之间。由以上５性状和形数或圆满度组成的综合选择指数方程效果最好。对形数选择的遗传进度、相对效率分别为０．１５５和１５９．０１５７％。对圆满度选择的遗传进度、相对效率分别为０．１７４和１２８．３６７９％。 相似文献
13.
14.
泡桐干形培育研究进展 总被引：31，自引：3，他引：28
在我国北方泡桐栽培区由于泡桐顶芽在冬季枯死,通过假二叉分枝的方式进行自然接干,造成出材率低,尖削度大,树干形数小,给泡桐的木材生产带来了巨大的损失。为此我国的泡桐科研工作者经过近４０年的努力,对泡桐干形进行了遗传改良,并在此基础上,围绕干形培育对泡桐的高干壮苗、人工接干、修枝、栽培密度与干形、混交与干形及其上述栽培管理措施与泡桐丛枝病的关系等问题进行了一系列研究。本文对我国泡桐干形培育的上述研究进行了综述,并对泡桐干形培育若干亟待解决的问题进行了讨论。 相似文献
15.
不同种泡桐叶片愈伤组织诱导及其植株再生(英文) 总被引：8，自引：0，他引：8
在确定5种泡桐叶片诱导愈伤组织基本培养基为MS的基础上,通过不同的NAA和BA的组合,筛选出了毛泡桐(Paulownia tomentosa)、南方泡桐(Pauiownia australis)、白花泡桐(Paulownia fortunei)、兰考泡桐(Paulownia elongata)和豫杂一号泡桐(P.tomentosa x P. fortunei)叶片愈伤组织诱导、芽分化和根分化的最适培养基。MS+0.5NAA+4BA、MS+0.3NAA+2BA、MS+0.5NAA+4BA、MS+0.3NAA+6BA和MS+0.3NAA+8BA分别为五种泡桐树种叶片愈伤组织诱导的最适培养基,上述树种的叶片愈伤组织诱导芽分化最适培养基分别为MS+0.3NAA+12 BA、MS+0.3NAA+12 BA、MS+0.5NAA+12 BA、MS+0.5NAA+12 BA和MS+0.7NAA+12 BA,最后找出了5种泡桐芽诱导根的最适培养基分别为1/2MS+0.1NAA、1/2MS+0.1NAA、1/2MS、1/2MS+0.3NAA和1/2MS+0.5NAA。这些结果为开展泡桐基因工程研究和利用不同种泡桐叶片原生质体融合培育泡桐新品种提供了参考。 相似文献
16.
泡桐叶片蛋白质多态性及其聚类分析(英文) 总被引：2，自引：0，他引：2
根据白花泡桐（Paulownia fargesii）、白花兰考泡桐（P.elongata f. alba）、毛泡 桐（P. tomentosa）、川泡桐（P. fargesii）、山明泡桐（P. lamprophylla）、成都泡桐 (P. albiphloea var chengtuensis)、鄂川泡桐（P. albiphloea）、南方泡桐（P. austra lis）、白花泡桐（P. fortunei）、兰考泡桐（P. elongata）叶片蛋白质单向电泳和双向 电泳结果，可将它们聚类分为白花泡桐组（白花泡桐和白花兰考泡桐）、南方泡桐组（南方 泡桐和成都泡桐）和毛泡桐组（毛泡桐、川泡桐、鄂川泡桐、山明泡桐和兰考泡桐）。该结 果为泡桐属植物的分类提供了参考依据，也为泡桐属植物种确立、杂种鉴定和新品种培育奠 定了基础。 相似文献
17.
通过对桐栗、桐竹、桐杉 3种不同泡桐混交模式中泡桐的生长量调查和经济效益分析 ,得出桐栗混交模式优于桐竹混交模式 ,桐竹混交模式又优于桐杉混交模式的结论 ,文中在分析其混交效果的基础上 ,总结了 3种混交模式的关键营造技术 相似文献
18.
广东泡桐造林技术研究 总被引：1，自引：1，他引：0
泡桐在我国北方已广为栽培，但在广东省推广种植起步较迟。1996年以来，在广东省从化市对泡桐的育苗、种植技术进行了试验，摸索出既简单易行、节约造林成本，又发挥泡桐速生丰产特性的种植方法，使广东省北部山区多了一个造林树种选择。 相似文献
19.
以2年生5种四倍体泡桐为材料，研究其光合作用、材积生长量、接干长度、比叶重（ SLW）等指标间的差异。结果表明，5种四倍体泡桐叶片的净光合速率（ Pn）、气孔导度（ Gs）、蒸腾速率（ Tr）、胞间CO2浓度（ Ci）光合因子的日变化规律相同。9月份叶片的Pn、 Gs、 Tr、 Ci日变化为单峰曲线，四倍体豫杂一号泡桐（ TF4）的最大净光合速率高于其余4个种。此外，四倍体毛泡桐（ T4）的树高生长量和接干高增长量、 TF4的胸径生长量和比叶重增长量、四倍体南方泡桐（ A4）的材积增长量最大。5种四倍体泡桐的树高、胸径、接干、材积的相关性表明，材积与胸径呈正相关关系，相关性显著；树高与比叶重呈正相关关系，但相关性不显著。 相似文献