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对四川省木里县天然云南红豆杉复壮可行性进行了研究,结果表明:木里天然生长的云南红豆杉以成过熟林分为主,主梢枯死率平均在78.5%左右,且天然更新不良,但该树种在主干或主枝受损后具有较强的萌蘖更新能力;对云南红豆杉进行适度采枝,不仅可刺激母树主干萌蘖更新芽的形成和生长,而且能有效增加2级以上各级侧枝的数量和提高枝条生长量,使母树焕发生机,故采用人工辅助方式对成、过熟红豆杉复壮具有较好效果。 相似文献
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《林业实用技术》2017,(1)
为了降低退耕还林地多年生沙棘(Hippophea rhamnoides L.)的干枯死亡率和提高结果能力,研究了不同修剪措施对沙棘树体更新复壮和结果能力的影响。结果表明:冬季落叶后剪除直径0~1.5cm枝条后,沙棘树体萌发新枝的能力、结果量和果实品质相对最高,发枝量、单株产果量、果实可溶性糖含量和Vc含量分别为32.16个/株、2.54kg、3.03%和3 652.62mg/kg,较对照CK分别提高了270.93%、61.78%、35.87%和37.98%;果实有机酸含量为2.67%,较对照CK降低了9.49%。冬季落叶后剪除直径0~1.5cm枝条处理的所有测定指标与对照CK相比,均达到了显著水平(P0.05)。鉴于冬季落叶后剪除直径0~1.5cm枝条处理对沙棘树体更新复壮和提高结果能力的相对最佳效果,建议采用这一措施来复壮树体和提高结果能力。 相似文献
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云南红豆杉种子休眠原因的初步研究 总被引:2,自引:0,他引:2
本文是作者对三年来试验研究情况的总结分析。结果表明:云南红豆杉种子休眠的主要原因,是由于种子内含有抑制物、果胶及皂碱等。混沙搓洗后再行层积处理是消除种子抑制物,打破(解除)休眠,提高种子发芽率的有效方法之一。 相似文献
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更新复壮技术对冷箭竹种群密度影响的初步研究 总被引:1,自引:0,他引:1
更新复壮技术对冷箭竹种群密度影响的初步研究周世强(中国保护大熊猫研究中心)大熊猫主要取食冷箭竹(Bashaniafangiana)的竹笋、竹茎、竹叶和少量竹枝[1],因为笔者认为,评价老林复壮技术对冷箭竹繁殖生长的影响效果,应该采用试验区内冷箭竹的发... 相似文献
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云南红豆杉天然群体的遗传多样性和群体分化 总被引:1,自引:0,他引:1
利用云南红豆杉Taxusyunnanensis种子的单倍体胚乳,采用水平淀粉凝胶电泳技术,对分布于金沙江流域的云南红豆杉天然群体的遗传多样性和群体分化进行了研究.对8个酶系统15个酶位点的分析结果表明该地区的云南红豆杉天然群体遗传变异水平较高,多态位点比率P=0.933,等位基因平均数A=2.90.平均期望杂合度He=0.290;4个小群体间遗传分化很小.基因分化系数GST=0.071.云南红豆杉天然群体具有明显丰富的遗传变异和较小的群体间分化,其原因是云南红豆杉寿命长、风媒异花授粉、种子传播、基因交流频繁. 相似文献
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更新复壮技术对大熊猫主食竹竹笋密度及生长发育影响的初步研究 总被引:4,自引:0,他引:4
更新复壮技术有利于大熊猫主食竹(拐棍竹、冷箭竹)竹笋的地径和株高生长,提高竹子发笋率,增加竹笋生物量。并且随着离实验年限的递增,影响效果呈递降趋势。 相似文献
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In Japan, selective thinning is a common thinning method, though line thinning receives much attention because of its economic merits. In this study, we examined effects of the two thinning methods on bird communities in Todo fir (Abies sachalinensis) plantations in Hokkaido, Japan. We surveyed bird species in forests under four different management types — unthinned, selectively thinned, line-thinned plantation, and naturally regenerated forest (here after referred to as natural forest) stands — using a line-transect method. We also investigated vegetation structure (canopy tree and understory) of these stands. Bird species richness did not differ between natural forests and plantations, while bird total abundance was greater in plantations than in natural forests. Bird species richness and total abundance were comparable among the three management types for plantations. Abundances of 10 bird species were different among the four management types, and five species were more abundant in line-thinned plantations. However, two species were more abundant in selectively thinned stands than in line-thinned stands, and they frequently appeared in natural forests. There were no distinct differences in vegetation structure among the management types for plantations. Our results suggest that line thinning could be beneficial for some bird species in plantations. 相似文献
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Rainfall, throughfall and stemflow were measured and canopy interception loss was derived for 14 rainfall events from June 22 to August 30, 2008 within a mature declining hybrid white spruce(Picea glauca(Moench) Voss × P. engelmannii Parry ex Engelm.)- subalpine fir(Abies lasiocarpa(Hook.) Nutt.)- lodgepole pine(Pinus contorta var.latifolia Dougl. ex Loud.) stand in south-central British Columbia, Canada. Stemflow was negligible during the study period, while, respectively throughfall and canopy interception loss accounted for approximately59.4% and 40.6% of the 50.1 mm of cumulative rainfall. Throughfall variability was assessed with three approaches involving roving and stationary wedge-type gauges, and stationary trough gauges. Throughfall exhibited large spatial variability with the coefficient of variability of study period throughfall sampled using 16 stationary trough gauges being30.3%, while it was 38.0% and 28.7% for 32 stationary and 32 roving wedge gauges, respectively. Our analysis suggests that a roving gauge method is better than a stationary approach since the errors associated with event mean throughfalls are summed quadratically and a greater portion of the canopy area is sampled. Trough gauges were more efficient than wedge gauges; however, this efficiency was less than expected given their much larger sampling areas, suggesting that spatial autocor-relation lengths of throughfall may be longer than the trough systems. The spatial distribution of throughfall showed a high degree of temporal persistence throughout the study suggesting the existence of stable "wet" and "dry" inputs to the floors of these coniferous forests. 相似文献
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中国沙棘果实化学成分初步研究 总被引:6,自引:0,他引:6
采用系统预试法,对中国沙棘果皮渣所含化学成分进行了定性检验,并测定了油脂和黄酮含量。结果表明,中国沙棘果实含有鞣质,有机酸,酚类,黄酮类、挥发油及油脂,并且油脂和黄酮含量较高。 相似文献
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为了确立早实核桃成龄树的适宜修剪方法,以10年生早实核桃‘绿岭’为试材,研究了重回缩、拉枝、既重回缩又拉枝和放任生长4种不同修剪方式的部分水分生理效应.结果表明:重回缩、拉枝、既重回缩又拉枝和放任生长4种修剪方式的液流速率峰值分别为7.58、13.19、5.47和10.55 cm/h,拉枝处理的最大.随着修剪程度的加大,核桃叶片的水势变化幅度增大,但全天平均水势随着修剪程度的加大而提高.4个处理的全天平均叶水势从高到低依次为既重回缩又拉枝(-0.786 MPa)、重回缩(-0.780 MPa)、拉枝(-0.797 MPa)和放任生长(-0.798MPa);4个处理的核桃叶片水势变化幅度从高到低依次为既重回缩又拉枝(0.467 MPa)、重回缩(0.452 MPa)、拉枝(0.447 MPa)和放任生长(0.327 MPa).4种不同修剪方式处理上午10时的水分利用效率分别为1.50、1.69、1.93和1.30 μmol/mmol,既重回缩又拉枝处理的水分利用效率显著高于放任生长. 相似文献
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