共查询到20条相似文献，搜索用时 250 毫秒
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通过采用不同促成定植法栽植1年生葡萄苗木，结果表明：促成定植能明显提高苗木成活率、促进新报发生和生长，从而明显促进新梢生长。其中以50～100PPm萘乙酸浸根24h十大炕催粮十拱棚催芽或地膜覆盖法效果好，其新消长度和新粮鲜重都极显著地高于对照，适用于少量栽植和发展庭院葡萄；萘乙酸没粮十地膜覆盖显著地促进新粮生长，机显著地促进新消生长，适用于大量栽植葡萄。 相似文献
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采用生物数学方法，研究了柚木育苗密度与小棒槌苗的生长、棒槌状主根段的形成、单位面积苗木产量与质量等关系。用指数函数、幂函数、对数函数等１０种曲线方程，建立了３５个数学模型以描述其复杂的关系。经分析揭示出：（１）在一定的育苗密度下，土壤肥力较高的尖峰点，苗木地上、地下部分生长与产苗量远不如土壤肥力低的广州点，其差距随密度的增大而增大，主因是点间水热协调性质与日照长短的差异所致；（２）依不同地点生态因素的差异来调控育苗密度，以提高苗木产量和质量远比在同一地点延长育苗时间更为有效；（３）调控好育苗的最适密度，就可取得最好的苗木产量与质量。尖峰点和广州点适宜的育苗密度分别为１００～２００株／ｍ２与３００～４００株／ｍ２。两地相差约３～４个密度级（５０株／ｍ２为Ⅰ级）。 相似文献
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3树种苗木水分状况与造林成活效果的研究 总被引：2，自引：0，他引：2
对山杏，侧柏，大叶黄杨苗木进行浸根和晾晒处理后，用常规方法测定了苗木的主要水分指标，分析探讨了３树种苗木水分状况与造林成活效果的关系，并运用压力室技术，测定分析了３树种苗木的Ｐ－Ｖ曲线及其耐旱性性能指标。 相似文献
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研究了不同扦插密度下苗木的生长性状，质量，产量和生产成本。结果表明：不同扦插密度下，苗木的基径，高径比差异达显著或极显著水平。随着扦插密度的增加，苗木基径下降，高径比增大，质量下降，整齐度更差，Ⅰ级苗比率和成苗率均下降，苗高和分枝数也呈下降趋势。 相似文献
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马尾松大田育苗的调控技术，是指在传统的苗圃耕作培管的基础上，一方面对种子实行分级播种、控制播种量、控制苗木密度，另一方面对苗木实行切根与剪顶，调节苗木生长，使根系发达、茎干粗壮。多年实践表明，对种子与苗木实施调控技术，简便易行，效果很好；培育的大田苗根富苗壮，有效地提高了造林质量。 相似文献
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应用室内试验和室外栽培相结合的方法，对水分胁迫下２年生樟子松苗木的几项生理指标进行了测定，结果表明：樟子松苗木在水逆境条件下，根和针叶质膜透性增加，同时伴有脯氨酸和可溶性糖在叶片叶积累。在苗木失水程度不同的情况下，根浸出物质的成分和量值不同；可溶性糖的大量浸出与根ＴＴＣ还原力的急剧下降具有同步性。若用湿砂在低温下使苗木缓慢复水可以避免根系无机离子和可溶性有机物的大量浸出与根ＴＴＣ还原力的急剧下降具 相似文献
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张德兰 《北京林业学院学报》1981,(1):43-55
本文研究的问题为小叶杨的年生长规律和矿质肥料的三要素，追肥时期，追肥方法对小叶杨二年生播种苗的质量与产量的影响，研究方法是采用田间定位试验与土培试验结合进行的，并进行了土壤理化性质的分析及植物生物指标的测定。本文主要内容：（1）小叶杨苗木的年生长，根据苗木高生长的形态表现分为：出苗期，幼苗期，速生期和硬化期等四个时期，苗木的高生长与地际直径生长，根系生长是交替进行的；高生长停止期在先，直径与根系生长停止期在后；（2）肥料三要素（氮，磷，钾）加速了苗木的生长，促进苗木体内的氮，磷和糖含量的积累，加强了光合作用与叶绿素的合成能力，使Ⅰ，Ⅱ级苗木的产量比不施肥的提高15－37％，也提高了苗木移植后的成活率和第二年的生长量，在氮、磷、钾中以氮促进生长的作用最大，缺氮的苗木生长不佳，I，Ⅱ级苗的产量比施N，P，K的苗木低22％，磷肥效果次之，钾对生长的作用最小；（3）追肥时期对苗木质量有影响，氮，磷，钾分为早，中，晚三个时期施入的效果以幼苗期的早期追肥的苗木质量好，I，Ⅱ级苗木的产量比不追肥的高37％，比中期追肥的高15％，（4）相同的肥料和用量，以土壤追肥及土壤加根外追肥的效果最好，I，Ⅱ级苗的产量比不追肥的增产36－38％，而只用根外追肥的效果比不追肥的增产29％。 相似文献
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M. S. Lamhamedi P. Y. Bernier C. Hbert R. Jobidon 《Forest Ecology and Management》1998,110(1-3):13-23
Three different stock sizes of containerized black spruce (Picea mariana [Mill.] B.S.P.) seedlings were planted in an abandoned agricultural field. The small planting stock was of a conventional type produced in 110 cm3 containers. The experimental medium and large stock types were produced in 340 and 700 cm3 containers, respectively. Gas exchange, xylem water potential and dry masses were measured six times during each of the first two growing seasons in field plots with and without vegetation control. During the first growing season, the effect of planting shock masked most physiological and growth differences among seedling types. During the second growing season, in plots with vegetation control, small and medium seedlings had similar values of physiological variables and of growth as measured by relative growth rates (RGR), but the large seedlings showed lower values of both net photosynthesis and of RGR, a difference attributed to low initial quality of the root system in the larger seedlings. In plots without vegetation control, the trend was identical, but differences were not significant; the greater height of the larger seedlings, and the resulting greater access to light, compensated for their lower initial quality. The similarity in response between the medium and the small seedlings shows that a fourfold increase in shoot size (1.68–6.82 g) in the initial size and a doubling of the shoot : root ratio (2.17–4.54) of the planting stock did not result in increased planting shock or reduced growth in these containerized conifer stock types. The results also show the importance of the interaction between stock height and the vertical light profile created by the competing vegetation in the final assessment of stock performance. 相似文献
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Effects of artificial frosts on light-saturated photosynthesis (A(max)) and ground, maximal and variable fluorescence variables (F(o), F(m), and F(v) and F(v)/F(m)) were monitored on 1-year-old foliage of black spruce seedlings (Picea mariana (Mill.) BSP) grown at high (25 degrees C), moderate (15 degrees C) and low (5 degrees C) temperatures and moderate (240 &mgr;mol m(-2) s(-1)) and low (80 &mgr;mol m(-2) s(-1)) irradiances. Photoinhibition of 1-year-old foliage was greater in seedlings grown in moderate light than in seedlings grown in low light. Photoinhibition increased with decreasing growth chamber temperature at both irradiances. Most changes in F(v)/F(m) were caused by changes in F(v). Exposure to -4 degrees C decreased both F(v)/F(m) and A(max) compared with control values. The effect of the -4 degrees C frost treatment was greater in seedlings grown in low light than in seedlings grown in moderate light, probably because seedlings grown in moderate light were already partially photoinhibited before the frost treatment. Following -4 degrees C treatment, neither F(v)/F(m) nor A(max) recovered in seedlings grown in low light. Light-saturated photosynthesis decreased with decreasing growth chamber temperature. Light-saturated photosynthesis was more sensitive to the -3 and -4 degrees C frost treatments in seedlings grown at 25 degrees C than in seedlings grown at 15 and 5 degrees C. The A(max) of seedlings grown at 15 degrees C was sensitive only to the -4 degrees C frost treatment, whereas A(max) of seedlings grown at 5 degrees C was not sensitive to any of the frost treatments. Recovery of A(max) following frost took longer in seedlings grown at high temperatures than in seedlings grown at low temperatures. For seedlings grown at the same temperature but under different irradiances, both A(max) and F(v)/F(m) reflected damage to the photosynthetic system following a moderate frost. However, for seedlings grown at the same irradiance but different temperatures, A(max) provided a more sensitive indicator of frost damage to the photosynthetic system than F(v)/F(m) ratio. 相似文献
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通过对3年生樟子松容器苗与裸根苗定植后的成活率、保存率、生长量、生产管理和投资费用对比分析,提出了定植容器苗大大优于裸根苗,定植成活率和保存率分别达到96.3%和99%。与裸根苗相比,容器苗造林每667 m2可节约投资764元。特别是在风沙、干旱、瘠薄的榆林沙区,由于风沙侵蚀严重,立地条件低劣,更应提倡并推广使用容器苗... 相似文献
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云南红豆杉人工药用原料林的经营技术 总被引：11，自引：7，他引：11
对云南红豆杉人工药用原料林的种植技术及经营方式的研究试验进行了阶段性综合总结,认为云南红豆杉具有喜荫喜湿喜肥,对温度的适应范围广的特性,提出了可以扩大栽培区域的观点。分析了云南红豆杉最适宜种植的气候土壤条件是:年降雨量在1500mm以上,年干燥度<0 8,黑土层>20cm的肥沃砂壤至轻壤土,作为药用原料林种植地应选择海拔高度为1300～2200mm的温暖及温热气候。研究了"扦插繁殖、密集种植、苗期利用"的原料林种植经营方式,大棚扦插成苗达89 56%,4年生林木生物量产量达到15000～32250kg/hm2(风干含水率11%)。并对采穗圃与苗木更新、人工复合群落等营造技术进行总结和论述,报导了云南红豆杉人工药用原料林的生物量及紫杉醇含量的测定结果。 相似文献
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To determine the extent to which loblolly pine seedlings (Pinus taeda L.) acclimate to high temperatures, seedlings from three provenances-southeastern Texas (mean annual temperature 20.3 degrees C), southwestern Arkansas (mean annual temperature 16.2 degrees C) and Chesapeake, Maryland (mean annual temperature 12.8 degrees C)-were grown at constant temperatures of 25, 30, 35 or 40 degrees C in growth chambers. After two months, only 14% of the seedlings in the 40 degrees C treatment survived, so the treatment was dropped from the experiment. Provenance and family differences were not significant for most measured variables. Total biomass was similar in the 25 and 30 degrees C treatments, and less in the 35 degrees C treatment. Foliage biomass was higher, and root biomass lower, in the 30 degrees C treatment compared with the 25 degrees C treatment. Net photosynthesis and dark respiration of all seedlings were measured at 25, 30 and 35 degrees C. Both net photosynthesis and dark respiration exhibited acclimation to the temperature at which the seedlings were grown. For each temperature treatment, the highest rate of net photosynthesis was measured at the growth temperature. Dark respiration rates increased with increasing measurement temperature, but the basal rate of respiration, measured at 25 degrees C, decreased from 0.617 &mgr;mol m(-2) s(-1) in the 25 degrees C treatment to 0.348 &mgr;mol m(-2) s(-1) in the 35 degrees C treatment, resulting in less carbon loss in the higher temperature treatments than if the seedlings had not acclimated to the growth conditions. Temperature acclimation, particularly of dark respiration, may explain why total biomass of seedlings grown at 30 degrees C was similar to that of seedlings grown at 25 degrees C. 相似文献
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Norway spruce (Picea abies (L.) Karst.) is shade-tolerant and sensitive to high irradiance, summer frosts and winter desiccation, which can impair its reforestation success. In this study, artificial pre- and post-planting shading was examined to determine their effects on post-planting shoot and root growth as well as the vigor of one- and two-year-old Norway spruce seedlings. Three planting experiments were carried out on open nursery fields (Exp. 1, 2) and on a mounded forest clearcut in central Finland (Exp. 3). Before planting, the seedlings were stored over winter either in a freezer or on open fields under snow cover. For two weeks prior to planting, half of the seedlings were placed in the open and the other half under a horizontal shade netting (light transmittance 56 %) (Exp. 1, 2). All seedlings were planted with or without a vertical post-planting shade, which was located on the southern side. Post-planting shading enhanced shoot growth and reduced damage (better visual vigor and needle color and less pine-weevil damage) on Norway spruce seedlings for at least two years after planting (Exp. 2, 3). Those seedlings, that had been stored over winter in the open and kept in shade prior to planting seemed to benefit most from post-planting shading (Exp. 2). However, post-planting shading may give variable results, depending on the seedling quality and weather conditions after planting, and may even reduce shoot growth if no pre-planting shading is used (Exp. 1). Shoot growth may also be improved at the expense of root growth (Exp. 3). The costs of manufacturing and installing post-planting shades may limit their use in practice, for example, to selected regeneration sites where there is high risk of frost damage but where no alternative silvicultural procedure (shelterwood or nurse crop) has been used. 相似文献
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Warren CR 《Tree physiology》2008,28(1):11-19
Internal conductance to CO(2) transfer from intercellular spaces to chloroplasts (g(i)) poses a major limitation to photosynthesis, but only three studies have investigated the temperature dependance of g(i). The aim of this study was to determine whether acclimation to 15 versus 30 degrees C affects the temperature response of photosynthesis and g(i) in seedlings of the evergreen tree species Eucalyptus regnans F. Muell. Six-month-old seedlings were acclimated to 15 or 30 degrees C for 6 weeks before g(i) was estimated by simultaneous measurements of gas exchange and chlorophyll fluorescence (variable J method). There was little evidence for acclimation of photosynthesis to growth temperature. In seedlings acclimated to either 15 or 30 degrees C, the maximum rate of net photosynthesis peaked at around 30 or 35 degrees C. Such lack of temperature acclimation may be related to the constant day and night temperature acclimation regime, which differed from most other studies in which night temperatures were lower than day temperatures. Internal conductance averaged 0.25 mol m(-2) s(-1) at 25 degrees C and increased threefold from 10 to 35 degrees C. There was some evidence that g(i) was greater in seedlings acclimated to 15 than to 30 degrees C, which resulted in seedlings acclimated to 15 degrees C having, if anything, a smaller relative limitation due to g(i) than seedlings acclimated to 30 degrees C. Stomatal limitations were also smaller in seedlings acclimated to 15 degrees C than in seedlings acclimated to 30 degrees C. Based on chloroplast CO(2) concentration, neither maximum rates of carboxylation nor RuBP-limited rate of electron transport peaked between 10 and 35 degrees C. Both were described well by an Arrhenius function and had similar activation energies (57-70 kJ mol(-1)). These findings confirm previous studies showing g(i) to be positively related to measurement temperature. 相似文献
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The objective of this research was to evaluate the influence of vegetation control on the microclimate (light, air temperature, vapor-pressure deficit (VPD)) and on the growth of young planted, sessile oak seedlings. Three types of vegetation control, creating a range of above-ground interaction intensity, were compared. In the open treatment, vegetation was chemically controlled and was maintained at a low height; in the closed treatment, vegetation was manually controlled and a few dominant individuals that overtopped the oak seedlings were cut; and in the sheath treatment, the vegetation in a 0.5-m diameter circle around each seedling was manually cut to a height equal to three quarters of the total seedling height. In all treatments, a strong reduction of incoming radiation was observed, as well as an increase in air temperature and VPD during the day, and a decrease in daily PET, compared to the reference located 4 m above the vegetation. However, the neighboring vegetation did not modify the microclimate around the seedling to a level that could have induced a significant reduction in seedling photosynthesis and, thus, in seedling growth. Seven years after planting, seedlings were shortest in the open treatment and tallest in the closed treatment (334, 372, 378 cm in the open, sheath and closed treatments, respectively). Seedlings in the open treatment allocated proportionally more biomass to diameter increment than to height growth, compared to seedlings in the sheath and closed treatments. The seedlings averaged 1.77, 1.10 and 1.00 forks in the open, sheath and closed treatments, respectively, and the average height of the lowest fork was 171, 206 and 226 cm in the same treatments. The reduction of the number of forks per seedling was not related to a reduction of the appearance of new forks, but rather to a reduction in the persistence of the existing forks. These changes in stem allometry and in fork development seemed to be related to the lateral shade afforded by the vegetation. 相似文献
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采用日本落叶松35个无性系苗木,另加2a混系扦插苗、2a实生苗、2a实生换床苗及长岭岗林场种子园2a实生苗进行造林试验,以早期选择出适应性强的无性系进行无性系造林并加以推广。试验方法采用完全随机区组排列,5次重复,每重复2排40个小区;小区设置为4株,造林规格2m×2m。7a生长调查结果表明：在胸径、树高生长方面有极显... 相似文献