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林木遗传改良发展中的新见解 总被引：3，自引：0，他引：3
本文针对我国林木育种界中存在的问题,重点介绍了国际上已通过试验验证了的一些新见解。这些新学术见解正推动着世界林木遗传改良沿高效、低成本和快速的方向发展,对正处在发展中的我国林木育种事业有重要借鉴意义。合理吸收和利用它们将有助于使我国林木遗传改良向低成本和高速方向发展,以缩小与世界水平的差距。 相似文献
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Seed deterioration is an irresistible physiological phenomenon.The aim to studyseed deterioration is to see if seed deterioration can be retarded artificially and the higher seedvigor of fine varieties be maintained.The change of seed deterioration occurs in almost every sys-tem,and affects many kinds of enzyme and almost all organelle,as a result,the seed loses its vig-or.The reason of seed deterioration and the lost of seed vigor are mainly studied and discussed inthis paper.According to the external and internal two kinds of theory advanced by E.H.Roberts,Much deep discussions are made from the view of biochemistry. 相似文献
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马挂木种子发芽试验简报 总被引：2，自引：0，他引：2
对马挂木鲜种子和砂藏咱子进行变温或恒温、浸种呈不浸种等不同处理的室发芽试验，以及砂藏、干藏和不经贮藏而采用早播等马挂木种子的场圃发芽试验表明：测定调制好的鲜种子发芽率必需进行变温浸种处理，有胚种子的萌发效率达８０％左右，良芽率基本一致，测定砂茂个种子发芽率，不为温或中与否，萌发效率基本相同，为８５％左右，因此可按常规方法测定即可，马挂木种子在播种前腚经２个月砂藏处理，方法简便，效果明显，不仅有胚种 相似文献
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A. A. Mackenzie 《Southern Forests》2013,75(1):1-7
Experiments to test direct sowing as an establishment technique for Pinus radiata are described and discussed. It is concluded that sowing should be restricted to sites which can be established by planting without difficulty; that seed should be treated for dormancy; and that only repellent-coated seed should be used. Spot sowing proved an economically attractive method which deserves much wider attention. Costs of spot sowing operations are given and compared with planting costs. Sowing to establish dense stands is shown to be feasible but wasteful of seed. Burning is recommended before sowing to establish dense stands. 相似文献
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A juvenile radiata pine clonal seed orchard (Pinus radiata D. Don) in Sergude (northwestern Spain), comprising 57 clones, was evaluated for fertility, offspring diversity and genetic drift during 4 years. Flower and fruit production was used to asses clone fertility in the orchard. Fertility variation measured as “sibling coefficient” was found to be an average of 1.5, having high genetic diversity (0.99) and low coancestry (0.013). The clones varied in fertility from year to year. Effective population size in the orchard was between 35 and 40, indicating that between 60.30 and 69 %, the clones contributed effectively to seed yield. One way to improve seed yield in the orchard is by increasing the effective population size. Thinning and pruning highly reproductive clones of gibberellin application might be useful in increasing effective population size. The orchard’s parental balance showed consistent improvement over time. Cone and seed characteristics were also investigated. The results showed that significant genetic variation exists among clones for cone width and length; total, sound and empty seed number; as well as 100 seed weight. The seed orchard is still in a juvenile phase; moreover, the broad-sense heritability and variation data obtained in this study could be very valuable in the management practices of the existing radiata pine clonal seed orchard and can be also used for better planning of advanced generation of clonal seed orchards in Spain. 相似文献
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The expansion of tree species within a grassland-woodland matrix relies heavily on an abundant seed crop, which may be affected by many factors; among these, browsing by livestock has gone largely ignored. Here we explore how seed production is affected by tree size, grazing by large domestic herbivores and interannual climate fluctuations in a small-sized tree (Polylepis australis, Rosaceae), which dominates the remnant forests in the high mountains of central Argentina. Seed number and seed mass per tree were quantified in 100 different-sized trees located in areas with and without livestock. Using seed traps we also determined seed rain variation in 15 plots between 2005 and 2008. The estimated number of seeds per tree ranged from 0 to 224,000 and increased with tree height (power relation); for trees smaller than 354 cm in height, seed production was lower in areas with livestock and higher in areas without livestock. Mass per seed increased with tree height, with no significant livestock effect. The largest seed rain was recorded in 2008, probably due to growth of seed trees and not in response to climate. To promote seed production and forest expansion, livestock should be excluded from areas with small trees, such as forest edges. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
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Temperature during seed maturation can induce an epigenetic memory effect in growth phenology of Norway spruce (Picea abies (L.) Karst.) that lasts for several years. To quantify the epigenetic modifications induced by natural climatic variation, common garden experiments with plants originating from different provenances and seed years were performed. Plants from warmer seed years showed delayed phenology with later bud flush, bud set and growth cessation. This effect was quantified by linear models of phenology traits as a function of climate indices for the origin and seed year of the plants. Significant effects of the temperature during seed production (seed year) was found for the bud set in seedlings in their first growing season and for bud flush and growth cessation in the 7th-8th growing season from seed. The models suggest that growth start and growth cessation are delayed 0.7–1.8 days per 100 additional degree days experienced by the seed during embryo development and seed maturation. Models that include factors that are known to induce epigenetic effects could be used to better predict future performance of forest reproductive material. 相似文献
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Salvage logging is a common practice carried out in burned forests worldwide, and intended to mitigate the economic losses caused by wildfires. Logging implies an additional disturbance occurring shortly after fire, although its ecological effects can be somewhat mitigated by leaving wood debris on site. The composition of the bird community and its capacity to provide ecosystem services such as seed dispersal of fleshy-fruited plants have been shown to be affected by postfire logging. We assessed the effects of the habitat structure resulting from different postfire management practices on the bird community, in three burned pine forests in Catalonia (western Mediterranean). For this purpose, we focused on the group of species that is responsible for seed dispersal, a process which takes place primarily during the winter in the Mediterranean basin. In addition, we assessed microhabitat selection by seed disperser birds in such environments in relation to management practices. Our results showed a significant, positive relationship between the density of wood debris piles and the abundance of seed disperser birds. Furthermore, such piles were the preferred microhabitat of these species. This reveals an important effect of forest management on seed disperser birds, which is likely to affect the dynamics of bird-dependent seed dispersal. Thus, building wood debris piles can be a useful practice for the conservation of both the species and their ecosystem services, while also being compatible with timber harvesting. 相似文献
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共设＜5℃、5～10℃、10～15℃、15～20℃、20～25℃5个区段温度,研究不同温度对色季拉山不同海拔（3800～4400 m）急尖长苞冷杉种子发芽能力的影响,结果表明：色季拉山急尖长苞冷杉种子的平均千粒重为7.78 g,与其它冷杉属的种子比较,其种子千粒重较小,但有较低海拔（4000 m以下）种子千粒重较大而较高海拔（4000 m以上）种子千粒重较小的趋势;急尖长苞冷杉种子的适宜发芽温度为15～20℃,低于5℃无法发芽;不同海拔急尖长苞冷杉的种子发芽能力不同,以海拔3900 m的急尖长苞冷杉种子发芽率最高,为50％,从海拔3900 m开始,其种子发芽能力随着海拔的升高而逐渐降低。 相似文献
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《Forest Ecology and Management》2002,159(3):241-248
Comparison of branch-level foliage and branch (wood+bark) biomass relationships for North Carolina Coastal (NCC) and Oklahoma/Arkansas (O/A) loblolly pine (Pinus taeda L.) seed sources provided an indication of biomass partitioning differences between these two seed sources. The objective of this study was to quantify and compare the branch-level foliage and branch biomass of NCC and O/A provenances on an excessively drained site in southeastern Oklahoma to assess their branch-level biomass partitioning patterns; a modeling process was developed to accomplish this objective. It was found that seed source significantly influenced the amount of foliage per branch. If tree and branch dimensions were held constant, NCC branches would carry approximately 30% more foliage per branch than O/A branches. The relationship between tree and branch dimensions and branch production did not differ for the two seed sources. Vertical distributions of branch and foliage biomass were found to be similar for the two seed sources as well. Thus, on the droughty site observed in this study: (1) the NCC seed source tended to partition more biomass into the foliage component at the individual branch level than did the O/A seed source; (2) the two seed sources were similar in their propensity to partition biomass into the branch component at the branch level, and (3) the two seed sources were similar in the vertical distribution of branch and foliage biomass within the crown. 相似文献
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不同采收期对黄山松种子品质的影响 总被引：3，自引：0，他引：3
对在霜降日及提早半个月和1个月采收的黄山松种子的播种品质作了比较分析,结果表明霜降日采收的种子其千粒重、发芽率、发芽势和种子活力指数都要比提前采种的高11.4％～175．3％,采种时间越提前,品质越差。因此,分布在高海拔地区的黄山松采种时间应严格掌握在霜降前后,不能提前半月以上,否则将严重影响种子品质。 相似文献
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Seedling emergence, growth, and allocation of Oriental bittersweet: effects of seed input, seed bank, and forest floor litter 总被引：3，自引：0，他引：3
Joshua W. Ellsworth Robin A. Harrington James H. Fownes 《Forest Ecology and Management》2004,190(2-3):255-264
The establishment of invasive plant populations is controlled by seed input, survival in the soil seed bank, and effects of soil surface disturbance on emergence, growth, and survival. We studied the invasive vine Celastrus orbiculatus Thunb. (Oriental bittersweet) to determine if seedlings in forest understory germinate from the seed bank or from seed rain. We also conducted a greenhouse experiment to investigate the role of leaf litter mass and physical texture on seedling survival, growth, and allocation. In the understory of an invaded mixed hardwood forest, we measured seed input, seedling emergence with seed rain, and seedling emergence without seed rain. Mean seed rain was 168 seeds m−2: mean seedling emergence was 107 m−2, and there was a strong correlation between seed rain and seedling emergence. The ratio of seedlings to seed input (0.61) was close to the seed viability (0.66) leaving very few seeds to enter the seed bank. Seed bank germination under field conditions was low (1 seedling m−2). Soil cores were incubated in a greenhouse to determine seed bank viability, and germination from these soil cores did not occur. To determine how litter affects seedling establishment and growth, we measured seedling emergence and biomass allocation in a greenhouse experiment. Seeds were placed below intact and fragmented deciduous leaf litter in amounts ranging from zero to the equivalent of 16 Mg ha−1. Seedling emergence was not affected by fragmented litter, but decreased to <20% as intact litter increased to 16 Mg ha−1. Increasing litter resulted in greater allocation to hypocotyl and less to cotyledon and radicle, and this effect was greater in intact litter. C. orbiculatus seedlings achieve emergence through forest floor litter through plasticity in allocation to hypocotyl growth. The low survival of C. orbiculatus in the seed bank suggests that eradication of seedling advance regeneration and adult plants prior to seed rain may be an effective control strategy. However, the intact forest floor litter of an undisturbed forest will not prevent seedling establishment. 相似文献
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浙江12种杜鹃花属植物的果实形态、种子数及其相关性研究 总被引：4，自引：0，他引：4
杜鹃花属(ＲｈｏｄｏｄｅｎｄｒｏｎＬ.)的系统学研究尚有许多值得探索的问题(余树勋,1986;闵天禄等,1990;Ｐｈｉｌｉｐｓｏｎｅｔａｌ.,1973)。近年来,本课题组陆续对浙江杜鹃花属植物开展了分类学和形态学的研究(丁炳扬等,1987;1989;1990;1995)。本文就浙江12种野生杜鹃花属植物的果实形态、种子数及其相关性进行研究,为该属的系统学研究及引种驯化提供理论依据。1 材料与方法11 常绿杜鹃亚属(ＳｕｂｇｅｎＨｙｍｅｎａｎｔｈｅｓ) 云锦杜鹃(Ｒ.ｆｏｒｔｕｎｅｉＬｉｎｄ1.)、猴头杜鹃(Ｒ.ｓｉｍｉａｒｕｍＨａｎｃｅ)、安徽杜鹃(Ｒ.… 相似文献
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10余年来对滇西和滇中的云南松天然优良林分疏伐营建母树林及遗传增益的研究结果表明疏伐是优良林分营建母树林的重要技术措施。改建16年生左右的云南松天然优良林分为母树林,以选择0．3(郁闭度)疏伐强度为好,母树林经2次疏伐后即可定型,其疏伐间隔期不超过4年。1993～1995年,母树林平均单株结球果达60个,每公顷结10329个,结实株率达95．65％,分别是对照的5．08倍、1．26倍和1．15倍。母树的结实性状较为稳定,单株结实量的频率分布呈对数正态分布,一般以4年为1个结实周期。云南松天然优良林分和母树林子代均具有干型通直、木纹理扭转度小、生长量大的特点。云南松诸性状间较多地受基因连锁或共效基因的作用,而受环境的影响相对较小,大多数性状具有较高的遗传稳定性。在云南松种子的调拨中应注意不同种源的适生区域。云南松优良林分和母树林子代林6～10年生的树高、胸(地)径、材积和木纹理扭转度的遗传增益分别为5．74％～20．14％、8．61％～40．46％、27．88％～107．11％和17．42％～59．79％。 相似文献