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41.
对3年生杨柳无性系木材的纤维素含量和纤维形态的测定分析表明,各无性系之间无显著差异,而同一无性系木材纤维长度则随密度提高而变长,其中I—72杨的5个造林密度,I—69杨的1m×1.5m、1m×3m、2m×2m,J—172柳和J—194柳的1m×1.5m、1m×2m、1m×3m以及J—333柳的1m×1.5m、1m×2m等16个处理的木材均达到中级优质造纸纤维原料要求。  相似文献   
42.
Six Salix clones were inoculated with urediniospores of four isolates of Melampsora larici-epitea at five inoculum levels using a leaf-disc method. Disease reactions were recorded using a digital camera; the number and size of uredinia were examined using image analysis software; and spore yield per leaf disc was measured. In three Salix / Melampsora combinations, S.  ×  mollissima 'Q83'/Q1 (LET4); S. viminalis '78183'/V1 (LET1); and S.  ×  stipularis /V1, pustule numbers increased as inoculum density became higher. In the remainder, S. viminalis 'Mullatin'/V1; S.  ×  calodendron /DB (LET3); and S. burjatica 'Korso'/K (LR1), pustule numbers initially increased, then decreased as inoculum densities exceeded 140–360 spores per disc. Calculated infection efficiency ranged from 0·11 to 0·20 on the three willows inoculated with V1: 0·16–0·68 for S.  ×  calodendron /DB; 0·20–0·55 for 'Q83'/Q1; and 0·07–0·48 for Korso/K. In single-spore inoculations, up to 10% of spores produced single uredinia. Infection efficiency increased sharply between inoculum densities of 1–40 spores per leaf disc. Spore yield was more closely correlated to pustule area (accounting for 61·2% variance for the combined data) than to the number of pustules (42·7% variance). For spore yields in relation to pustule numbers, clone-specific individual lines having different intercepts and slopes fitted significantly better than either a single line for all the tested willows, or parallel lines fitted to each clone ( P  < 0·001). For spore yields in relation to pustule area, clone-specific individual parallel lines were significantly better than a single line ( P  < 0·001).  相似文献   
43.
针对我国柳树插条半自动扦插作业人工喂入劳动强度大和作业效率低的问题,提出一种实现有序出料、取料和送料功能的柳树插条自动喂入装置,并针对该装置进行取料机构的优化设计与相关试验研究。建立取料机构运动学模型和优化设计模型,应用自主开发的软件分析确定了取料机构参数的取值范围,进而利用Matlab软件的遗传算法工具箱实现取料机构的参数优化;完成取料机构结构设计,进行取料机构虚拟运动仿真验证;研制取料机构样机和柳树插条自动喂入装置试验台,开展取料机构高速摄像试验和柳树插条自动喂入试验,研究取料机构运动特性,检验自动喂入装置的工作性能。在自动喂入效率达到55株/min时,柳树插条喂入成功率约为83%,表明该装置具有应用于柳树插条自动扦插机的可行性。  相似文献   
44.
The effects of temperature on the growth characteristics of a Japanese willow (Salix gilgiana Seemen) were studied with respect to dry matter production, wood anatomy and the net photosynthetic rates of leaves. Clonal materials were grown in natural-light rooms (phytotrons) at 30°C/25°C, at 25°C/20°C or at 20°C/15°C (day/night: 12 h/12 h), respectively. The elongation rate of shoots from the beginning of June to the end of July was approximately 22 cm per week under the three different sets of conditions. The shoots reached approximately 3 m in height after 4 months of growth. Total dry matter production and dry weights of stems did not differ very much among the three sets of temperature conditions after 9 months of growth. The dry weight of leaves increased at high temperatures while that of roots decreased. The number of vessels increased significantly at 30°C/25°C and 25°C/20°C, whereas the diameters of vessels and fibers, and the double wall thickness of fibers did not vary markedly under all three temperature regimes. The net photosynthetic rate and the respiration rate in mature leaves were highest at 30°C/25°C, and both activities increased with increases in growth temperature. The increase in the photosynthetic rate was much smaller than that in the respiration rate. Individual plants had been completely adapted to the respective growth temperatures, as judged from the decrease in the photosynthetic rate after the transfer to different temperatures. Part of this work was reported at the 102nd Annual Meeting of the Japanese Forestry Society (Nagoya, Japan, 1991). This work was supported by Grants-in-Aid (Integrated Research Program for Effective Use of Biological Activities to Create New Demand) from the Ministry of Agriculture, forestry and Fisheries of Japan (BRP 97-IV-B-10).  相似文献   
45.
  • 1. A proposed trial reintroduction of the Eurasian beaver (Castor fiber L.) to Scotland has recently been approved (May 2008). A previous proposal was turned down by the licensing authority, partly over the perceived risks to woodland within a Special Area of Conservation.
  • 2. This paper presents data on two years of willow (Salix spp.) and aspen (Populus tremula L.) regrowth following tree felling by captive beavers within two large semi‐natural enclosures in eastern Scotland. Both willow and aspen are highly preferred by beavers.
  • 3. Regrowth of willow stems was quantified from cut stumps, felled logs and partially severed (‘incompletely felled’) trees, and compared with growth of stems in the canopies of untouched willows.
  • 4. Maximum annual regrowth was observed in incompletely felled trees, followed by cut stumps and then unfelled control trees. Mean regrowth rates were ca 18 m regrowth per metre of measured tree section per year in incompletely felled trees. This was approximately 12 times more annual regrowth than that observed in unfelled trees, despite apparently selective browsing of the regrowth of incompletely felled trees by roe deer.
  • 5. Although incompletely felled willows represent a relatively small component of felling activity (9% of all felled willow), they contribute disproportionately to the biomass of beaver‐engineered riparian woodlands, creating a more multi‐layered habitat structure.
  • 6. Willow regrowth in inundated areas was avoided by deer, and harvesting of regrowth by beavers was rare.
  • 7. Significant regrowth from 11 stumps of aspen in 2 years post‐felling occurred by suckering, with 85 suckers of mean height 2.1 m being recorded, all of which were subsequently avoided by browsing deer and beavers.
  • 8. These data suggest that rapid regeneration of willow and aspen will occur in riparian woodlands in the event of major felling activity by Eurasian beaver, even in the presence of low to moderate levels of roe deer browsing, and that the conservation status of both these trees or the wider habitats that they form would not be threatened by a well planned and managed reintroduction of beavers to Scotland.
Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
46.
为探讨盐胁迫对柳树叶PSⅡ的影响机理及其耐盐性,以两个耐盐性差异显著的灌木柳无性系为试验材料,水培法培养幼苗,盐胁迫(NaCl浓度分别为0、50、100、150、200 mmol· L-1)处理幼苗7 d,利用叶绿素荧光成像技术,研究盐胁迫对柳树叶片光合机构的影响。结果显示:NaCl抑制了灌木柳生长,且灌木柳无性系JW2345受抑制程度小于无性系JW2367;盐胁迫下灌木柳Fv/Fm 荧光图变化明显,荧光参数Fv/Fm、Fm、F′v/F′m 和ΦP,SⅡ值均显著下降,qP 则有所上升,但耐盐型JW2345的变化幅度均明显低于盐敏感型JW2367,叶片的损伤情况也符合此规律;经50 mmol· L-1 NaCl处理能显著提高耐盐型JW2345的NP,Q值,而100、150和200 mmol· L-1 NaCl处理对其NP,Q无明显影响,与此同时,盐胁迫下Fo 显著高于对照。  相似文献   
47.
以江苏省林业科学研究院新近杂交培育的6个灌木柳无性系1年生扦插苗为试材,采用水培试验方法,研究了0 ~ 3 g·L-1范围内不同质量浓度氯化钠胁迫对灌木柳无性系幼苗生长及光合作用的影响。结果表明,低质量浓度氯化钠胁迫(1 ~ 2 g·L-1)对根长、根生物量无显著影响,高质量浓度氯化钠胁迫(3 g·L-1)使根长、根生物量显著降低(P<0.05)。在氯化钠胁迫处理下,苗高、茎叶生物量、叶绿素质量分数、净光合速率和气孔导度均低于对照,并随着氯化钠质量浓度提高下降幅度加大(P<0.05)。供试灌木柳无性系中,JW2345和JW2372无性系生长和光合作用受氯化钠胁迫影响最小,耐盐性相对较强;JW1065和JW2334无性系受氯化钠胁迫影响最大,耐盐性相对较弱。图4表3参19  相似文献   
48.
The breeding performance of captive willow ptarmigan on different diets has been studied. The nutritional factors tested were protein concentration, natural feed supplement and grass meal and flavonoid admixture, and effects on egg numbers, fertility, hatchability, chick weights at hatching and 0–14 days mortality have been recorded.The breeding performance of ptarmigan hen in captivity showed great individual variations. Egg numbers were not statistically different in groups fed the different diets. Hens fed a 15 % crude protein died tended to produce smaller chicks with significantly lower viability than chicks from hens fed a 20 % crude protein diet. Supplement of natural feed tended to increase the number of chicks hatched through a combination of tendency to higher egg numbers and improved fertility. These tendencies were, however, statistically nonsignificant. Inclusion of 34 % grass meal to the diet also tended (non-significantly) to improve fertility and hatchability, while inclusion of flavonoids had no positive effect on reproduction.Eggs from captive hens showed significantly lower fertility, and a tendency to lower hatchability than eggs from wild hens. The former difference was probably caused by the close cage confinements for the captive ptarmigan, while the latter condition probably was due to different start of incubation, most of the eggs from wild hens being started naturally.  相似文献   
49.
Willow ptarmigan chicks were reared during 8 years on concentrates supplemented with blueberry plants. Mortality during the first 3 weeks after hatching ranged between 33 and 65 %, and was mainly caused by enteritis and digestive tract obstructions. The annual variations in chick survival seemed to be caused by the variations in plant phenology. The survival was highest when spring and blueberry plant development was late, and lowest when spring was early and warm, leading to early lignification of blueberry plant leaves.  相似文献   
50.
垂爆109柳、旱布329柳的选育及推广利用   总被引:5,自引:0,他引:5  
主要介绍 2个速生乔木柳树新品种垂爆 10 9柳 (Salix×′Chuibao10 9′)和旱布 32 9柳 (Salixmatsudana×S .bulkingensis)的选育过程、优良特性、推广应用情况及栽培技术 ,为新品种的进一步推广、育苗造林提供了可靠的理论依据  相似文献   
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