共查询到18条相似文献，搜索用时 250 毫秒
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在2009年森林防火紧要期,依据对华山松林木针叶进行的耐火性试验结果,建立了华山松针叶死亡率y与枝的直径x1、针叶长度x2、受热时间x3、受热温度x4的关系模型,即y＝4.085-6.757x1-3.537x2+0.302x3+ 0.930x4.分析表明,影响华山松针叶耐火性的因子依次为x4>x3>x1>x2. 相似文献
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<正> 为提高选优效果,我们试图通过多种性状的综合鉴定,用相关选择来辅助现行的选优方法。以下准备结合我们的生产实践和鉴定工作,论述一下兴安落叶松的性状与材积生长的相关关系。一、叶长及叶重的测定兴安落叶松幼龄嫁接苗的针叶比优树上的针叶长,当年生枝条比老龄枝条的针叶长,所以在重复取样中采用了相同部位的针叶。测量结果,叶长、叶重在不同无性系间虽有差异,但与无性系鉴定结果并无明显相关。分析原因,认为这是由于针叶总数、有效叶面积以及针叶的功能不同造成的.所以,鉴定叶长、叶重指标时,尚需考虑枝条密度及长度,针叶密度以及冠型等性状。在生产实践中目前还无法测定。 相似文献
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本项研究选取云南切梢小蠹寄主植物云南松的针叶和藏柏、樟树、滇青冈等20种非寄主树种的叶与云南松针叶混合物(质量比为1∶4),利用Y型嗅觉仪测定其趋向行为,测试云南切梢小蠹对纯云南松针叶、混合样及空气间的趋向行为选择的差异性.结果表明,以云南松针叶作参照,云南切梢小蠹对云南松+藏柏、云南松+缅桂、云南松+滇朴、云南松+旱冬瓜的趋向率较低,分别为32.3％、33.4％、32.3％、31.5％;以空气作参照,混合样趋向率由小到大依次为云南松+藏柏、云南松+缅桂、云南松+滇朴、云南松+旱冬瓜,分别为38％、39％、40％、42％,均小于50％;藏柏、缅桂、滇朴、旱冬瓜4个树种对云南切梢小蠹表现较强的趋避作用,可作为营建抗云南切梢小蠹虫危害的混交树种. 相似文献
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依据森林资源连续清查获得的云南松天然林样地调查数据及气象数据,研究了年均温、年均降水量与云南松天然林平均胸径生长率的关系。结果表明,不同年均温区域云南松天然林样木平均胸径生长率总体上呈现出温度越高生长率越大的趋势,但趋势在年均温为16℃时出现了拐点,当年均温>16℃时,随着年均温的升高,云南松天然林生长率反而开始降低。在不同降水量区域的云南松天然林平均胸径生长率总体上与年均降水量呈正相关,降水量越大,生长越快。但在降水量为900~1099mm区域,6~16径阶云南松天然林的生长率却超过了降水量≥1100mm区域。文中对上述现象进行了讨论,认为其原因涉及云南松的适生区、生态稳定性以及林木的生物学与生态学机制等。 相似文献
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火是自然界广泛存在的干扰因素,过火对生境中的植物个体生存发展以及种群的动态均会产生深刻的影响。以云南省澄江县梁王山自然保护区鲁溪冲林区火烧迹地中的云南松作为研究对象,对发生地表火林冠针叶呈绿色、针叶变黄脱落和发生林冠火地段的云南松受损程度和火后自然更新,以及未过火地段林内更新进行调查。结果显示,2种过火类型地段中云南松受损呈现两极分化,林冠火地段的云南松死亡率为100%,地表火过火地段则没有全株死亡的现象。3个过火样地云南松植冠种子库种子活力均显著下降,其中林冠火样地种子萌发率最低,仅为(40±21.21)%。不同过火强度林区自然更新的幼苗数量存在显著差异(P0.05),数量排序为地表火针叶绿地表火针叶变黄脱落林冠火。跟踪调查发现,过火地段云南松幼苗的地上部分高生长和地径生长明显地高于其它地段。林火后3年,林冠火区幼苗高生长达到(22.13±5.75)cm,而未过火林区幼苗高生长仅为(8.33±4.16)cm。林冠火地段云南松自然更新后幼苗生长没有出现蹲苗现象。 相似文献
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分析了15年生云南松在横坑切梢小蠹、云南纵坑切梢小蠹在蛀梢和蛀干为害期的针叶光合生理反应.Dun-can多重比较结果表明:云南松在小蠹虫蛀梢和蛀干期显著影响了针叶同化CO<,2>的能力,针叶净光合速率分别下降了31%和65%,气孔导度、蒸腾速率等光合指标也出现极显著下降(P<0.01).相关性分析表明:针叶净光合速率与各生理生态因子的相关关系以及主要生理生态因子之间的相关关系在小蠹虫不同的蛀害期而不同.小蠹虫蛀梢和蛀干为害显著降低了针叶叶绿素含量(P<0.05),但受蛀梢为害的云南松针叶叶绿素a/b值显著高于健康或受蛀干为害的云南松.针叶最大荧光(Fm)、最大光量子效率(Fv/Fm)以及Fv/Fo均因小蠹虫蛀梢和蛀干为害而显著下降,尤以在被蛀干时的针叶Fm、Fv/Fm、Fv/Fo下降幅度更大.综合分析表明:受小蠹虫"胁迫"(蛀梢、蛀干)后针叶叶绿素合成受到显著影响,引起了寄主云南松光合机构的破坏,导致寄主云南松树势下降,这必为喜欢攻击亚健康或衰弱林木的次期性昆虫创造合适的寄主. 相似文献
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以云南玉溪森林生态系统定位研究站内不同林龄(15、30和45 a)云南松为对象,通过1 a的定位观测,对不同林龄云南松的养分回流及利用效率特征进行了分析,以期为深入揭示云南松养分自我保持机制及云南松林地的养分管理提供科学依据。结果表明:(1)云南松针叶中养分元素含量夏秋季相对较高,而冬季相对较低,N元素含量随林龄增加而减少,其它元素则以45 a含量相对较高,30 a含量相对较低,总体上,各林龄养分元素平均含量从高到低为Ca、N、K、Mg、P。(2)各林龄云南松针叶中N、P、K在不同季节中均有明显的回流,回流率随林龄及季节的变化而差异明显,大多在冬季的回流率相对较高;Ca元素则在各林龄各季中出现富集,富集率随林龄增加而增大;Mg元素除45 a在春秋冬季中有少量回流外,其它林龄及季节则均出现富集。(3)各林龄N、P、K的利用效率在冬季较高,而Ca、Mg的利用效率则在秋季较高,利用效率随林龄及季节的变化而变化明显。结果显示,各林龄对养分元素的平均回流率从大到小为K、P、N、Mg、Ca,平均利用效率从高到低为P、K、Mg、N、Ca,养分元素的回流率及利用效率与养分元素含量呈显著负相关关系。云南松针叶对N、P、K保持较高的回流率和利用效率,表明云南松对贫瘠低磷环境具有较强的适应能力,是贫瘠低磷环境下造林的优良树种。 相似文献
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TIAN Xiaorui ZHANG Youhui YANG Sidao ZHONG Youhong .Institute of Forest Protection Chinese Academy of Forestry Beijing P.R.China Tel: --- Fax: --- .Nursery of Guan County Shandong Guan County P.R.China . Forest Public Security Bureau of Guangdong Province Guangzhou P.R.China 《中国林业科技(英文版)》2005,4(2):15-23
Schima superba is a pioneer species for forestation inwildland in tropical and subtropical zones. It can growwell in arid and barren sites and has a strong power ofsprouting from stools. The species has been widelyused for fuelbreak in southern China. In China thefuelbreak is often created by planting broadleaf treesalong the ridge, which is different from the conceptdiscussed in some papers (Agee, et al, 2000; Green,1977; Omi, 1996). In these studies, the shaded fuelbreakwas created by alte… 相似文献
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失叶对油松抗赤松毛虫的影响及其防治策略 总被引：6，自引：0，他引：6
本文研究了不同失叶量、不同季节失叶、不同叶龄对油松(Pinus tabulaefo-rmis)叶的光合、蒸腾、叶绿素、淀粉、可溶性糖及油松生长与抗性的影响,还研究了油松的贮藏营养物质。结果表明:30％失叶量能提高树势与对赤松毛虫的抗性;油松的贮藏营养是脂肪,主要贮存于叶内,新叶的营养制造与贮存大于老叶;油松失新叶后所抽的梢比失老叶后的短,光合、蒸腾及树势与抗性更弱;为增强树势与抗性,新叶是应重点保护的对象;赤松毛虫(Dendrolimus spectabilis)幼龄幼虫主要危害新叶,取食新叶死亡率低,体重增长率大,为保护新叶与树势,应抓紧对幼龄幼虫的防治。 相似文献
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Paulo M. Fernandes Jos A. Vega Enrique Jimnez Eric Rigolot 《Forest Ecology and Management》2008,256(3):246
Pine resistance to low- to moderate-intensity fire arises from traits (namely related to tissue insulation from heat) that enable tree survival. Predictive models of the likelihood of tree mortality after fire are quite valuable to assist decision-making after wildfire and to plan prescribed burning. Data and models pertaining to the survival of European pines following fire are reviewed. The type and quality of the current information on fire resistance of the various European species is quite variable. Data from low-intensity fire experiments or regimes is comparatively abundant for Pinus pinaster and Pinus sylvestris, while tree survival after wildfire has been modelled for Pinus pinea and Pinus halepensis. P. pinaster and P. pinea, and Pinus canariensis in special, are better equipped to survive fire, but low-intensity fire is tolerated even by species often referred to as fire-sensitive (P. halepensis and Pinus radiata). The relative fire resistance of European pine species is assessed on the basis of (i) morphological and experimental data, and (ii) mortality modelling that considers fire behaviour. Limitations of these approaches to rate fire resistance are discussed, and the current knowledge gaps are indicated. 相似文献
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我国松树诱导抗虫性研究进展 总被引：18，自引：3，他引：18
从4个方面综述了我国松树诱导抗虫性研究进展，重点阐述了受害松针体内化学物质的变化，受害松针对松毛虫种群特征的影响以及松树诱导抗虫性的特性和影响因子等。已有的研究结果表明，受害后松针内化学物质有较大变化：一些营养物质(糖、氨基酸、蛋白质、脂肪酸等)的含量出现不同程度的降低，而体内的某些次生代谢物质(挥发性的和非挥发性的次生代谢物质)的含量呈上升趋势。这一抗性机制将使松毛虫的发育期延长、死亡率增加、生殖力减弱，从而进一步导致整个种群数量的下降。由此进一步分析了松毛虫周期性暴发的机理，旨在为松毛虫的综合治理提供理论参考。 相似文献
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Detached needles from 20-week-old black spruce (Picea mariana (Mill.) B.S.P.) seedlings root-drenched with 60 mg of paclobutrazol were exposed to two temperatures (22 and 50 degrees C) and two light treatments (100 and 1900 &mgr;mol m(-2) s(-1) PAR) in a factorial combination for 4 h in vitro. Mean dry weights of individual needles from paclobutrazol-treated plants were approximately 1.9 times heavier than that of needles from untreated controls at 22 degrees C, but no differences were observed following incubation at 50 degrees C. Numbers of cells per needle remained constant in all treatments. Chlorophyll and carotenoid contents per needle were higher in seedlings treated with paclobutrazol than in untreated control seedlings, and the differences were most pronounced in the high temperature plus high light treatment. In low light at 50 degrees C, quantum efficiency of photosystem II was 45% higher in needles of paclobutrazol-treated seedlings than in needles of untreated control seedlings, but quantum efficiency of needles from treated seedlings declined when needles were exposed to high light at either temperature. Peroxidase and superoxide dismutase activities were up-regulated by paclobutrazol, whereas catalase activities were depressed and no significant differences were observed between treated and control needles at 50 degrees C in either light treatment. Paclobutrazol treatment did not moderate the depressive effects of high temperature on total soluble protein or on the activity of ribulose-1,5-bisphosphate carboxylase. In contrast, high activities of phosphoenolpyruvate carboxylase were maintained in paclobutrazol-treated needles under all stress conditions, whereas large losses in activity were recorded in untreated needles at 50 degrees C. Collectively, these observations suggest that paclobutrazol treatment may convey resistance to excessive light and high temperatures by increasing the potential of conifers to limit damage caused by oxidative stress. 相似文献
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Naturally regenerated 20-25-year-old Scots pine (Pinus sylvestris L.) trees were grown in open-top chambers in the presence of an elevated temperature or CO(2) concentration, or both. The elevated temperature treatment was administered year-round for 3 years. The CO(2) treatment was applied between April 15 and September 15 for 2 years. The photosynthetic responses of 1- and 2-year-old needles to varying photon flux densities (0-1500 micro mol m(-2) s(-1)) and CO(2) concentrations (350, 700 and 1400 micro mol mol(-1)) during measurement were determined. The CO(2) treatment alone increased maximum photosynthetic rate and light-use efficiency, but decreased dark respiration rate, light compensation and light saturation regardless of needle age. In contrast, the temperature treatment decreased maximum photosynthetic rate and photosynthetic efficiency, but increased dark respiration rate, light compensation and light saturation. The aging of needles affected the photosynthetic performance of the shoots; values of all parameters except photosynthetic efficiency were less in 2- than in 1-year-old needles. The CO(2) treatment decreased and the temperature treatment enhanced the reduction in maximum photosynthesis due to needle aging. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):433-440
No differences were found in the frost resistance of the different‐aged (2–7 weeks) germlings of Scots pine. The critical temperature was ‐6°C to —3°C. A temperature of ‐4°C killed half of the germlings and produced damage in one fifth of the surviving seedlings; the needles turned brown and growth ceased. The frost resistance of the previous year's shoots of two‐year‐old seedlings, measured by the impedance method, decreased during the shoot elongation period from — 10°C to — 4°C. Damage to the current shoots during shoot elongation appeared as deformation and discolouration of the needles and abnormal development or death of the apical bud. The results indicate that frost is not the cause of growth disturbances observed in Finnish nurseries. 相似文献