共查询到20条相似文献，搜索用时 156 毫秒
1.
2.
通过对钟萼木（BretschneiderasinensisHemsl）种子进行各种处理，然后进行发芽试验．以及直接将新采集的种子和离体胚进行发芽试验，并进行生物鉴定（白菜籽发芽试验），研究了钟萼木种子生理休眠特性及打破休眠的方法．结果表明，种胚、内种皮及胚乳内的抑制物质虽可引起种子休眠，但引起种子休眠的主要原因是种子内缺乏萌发促进物质和酶活性低；用30kg／100mL的赤霉素溶液浸种24h或低温（5℃）层积60d，可解除种子休眠，萌发率由8．00％可提高到87．00％～96．00％，低温层积后适宜的萌发温度为30℃，25℃，20℃，其次是变温条件（昼30℃，夜20℃）；将种子置于聚乙烯薄膜袋内低温（5℃）干藏120d，也可解除休眠．低温干藏120d后再层积20d，解决休眠的效果最佳，如此处理置床后第三天即开始发芽，9d完成萌发过程，萌发率达94．00％． 相似文献
3.
4.
四唑法是快速测定种子生活力的一种有效方法。它是根据种子胚部是否染成红色及染色的部位、形状和大小，来判断种子生活力的。此法简单快速，准确可靠，不受种子休眠期的限制，可在林木种子收购、贮藏、调运及休眠种子的检验中推广应用。１ 测定方法１．１取样从纯净种子中随机抽取２５或５０粒为１组，共取４组，即４次重复。１．２种子预处理为了软化种皮，便于剥取种仁，要对种子进行预处理。一般种壳较薄，易吸水、剥胚的种子（如油松等），用始温４０℃水浸种２４ｈ即可。而种壳较厚且深休眠的种子（如核桃、山杏等），要浸种３～６ｄ… 相似文献
5.
杜梨属于深休眠的种子，测定发芽率一般需要３℃～５℃下预冷处理（层积）３～４个月。目前使用的国家《林木种子检验方法》（ＧＢ２７７２－８１）、《国际种子检验规程》（１９９６），对杜梨种子检验也未规定具体方法。笔者在林木种子经营管理过程中，经过反复测试，总结出几种操作简单，结果可靠的检验方法，以期为杜梨种子收购、调运期间及时准确检测种子质量提供参考。１ 解剖法从种批抽样检得纯净种子中，随机抽取１００×４粒（即４个重复），在室温下浸种４８～７２ｈ，每天换水１次，使外种皮变软，用解剖刀、手指甲轻轻撬开或剥… 相似文献
6.
阔瓣含笑种子休眠生理的初步研究 总被引：1，自引：0，他引：1
阔瓣含笑种子胚形态发育完善,具生理休眠特性。研究表明,内源促进物质缺乏可能是引起种子休眠的主要原因,种皮透气性差也有一定影响。该种子含水量高,忌干藏。种子在室温下层积80天或用低温(5℃)层积120天可解除休眠。层积期间种子含水量在40—50%可保持种子生活力和解除休眠。另外,种子用300ppm GA_3处理48小时可代替层积。种子适宜的发芽条件是黑暗30℃恒温。 相似文献
7.
檫树(Sassafrs tzumn Hemsl)种子具有休眠特性,对其休眠生理进行研究表明,该种子属于双重休眠,种子中存在高浓度的发芽抑制物,是其休眠的主要原因。经过冷(0～5℃)或暖层积处理,可导致90%以上的种胚解除休眠,但种子萌发率仍只有60%左右,改善种皮的透气性和消除种皮中的发芽抑制物,是提高檫树种子育苗成功率的关键。 相似文献
8.
为了打破种子休眠 ,使种子提前萌动、幼芽适时出土、发芽迅速整齐 ,播种前 ,常常要对种子进行催芽处理。其方法主要有以下几种 :1 水浸法其目的是软化种皮 ,使种子吸水膨胀 ,促使储藏物质水解 ,以供种子发芽需要 ,同时 ,也利于抑制剂溶解浸出 ,从而打破休眠。浸种的水温和浸种时间 ,需根据种粒大小和种皮厚薄而异。比如 :刺槐、合欢、紫穗槐、皂角种子浸种水温为 80～ 90℃ ,浸种时间为一昼夜 ;紫荆、国槐、君迁子种子为 6 0～ 70℃ ,浸种时间为 1～ 3d;海棠 ,白蜡、杜梨浸种水温为 4 0～ 50℃ ,浸种时间 1～ 2 d;杨、柳、榆、泡桐种子需用… 相似文献
9.
4种槭树种子的休眠原因及催芽方法试验 总被引：1，自引：0，他引：1
乡土树种鸡爪槭、色木槭、元宝枫和美国红枫等4个树种的种子都具有显著的休眠特性。采用人工介入手段进行休眠原因和催芽技术试验研究,结果表明:这4种槭树种子的种皮含有的化学物质和机械性阻碍导致了槭树种子的休眠;采用层积处理和GA3赤霉素浸种,能明显缩短种子的休眠期;彻底解除供试种子的休眠方法就是延长浸种沙藏层积的时间。措施,对保证育苗生产,提高出苗率和出苗整齐度有一定的研究价值。文章从层积处理和赤霉素处理入手,研究不同条件下催芽处理的效果,以此解释休眠的原因。 相似文献
10.
树木种子休眠是植物为了种的生存，适应环境，在长期生长发育过程中形成的特性。树木种子的休眠从休眠程度上分为：强迫休眠和长期休眠。引起长期休眠的因素很多，如种皮的机械障碍、含有抑制物质、生理后熟、综合因素的影响。无论哪种休眠都极大影响种子的发芽。在播种育苗或在室内检验种子的品质都需采取措施，克服种子的休眠，促进种子的发芽，不同树种采取的措施也不尽相同。克服种子休眠的方法称为催芽。在实验和实践中总结出以下几种催芽方法：一、浸入催芽法此方法主要是通过不同温度的水在一定时间内浸种，使种子的种皮软化、通气、… 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
13.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
14.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
15.
本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献
16.
17.
《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
18.
Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
19.
A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(2):166-178
This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes. 相似文献