共查询到20条相似文献，搜索用时 62 毫秒
1.
银杏种子后熟生理与内源激素变化的研究 总被引：15，自引：1，他引：14
研究银杏种子后熟期间的生理变化以及内源激素对种子休眠与萌发过程的调控作用.结果表明:银杏种胚分化不完全、发育不充分是种子休眠的主要原因,银杏种子的后熟过程实质上是种胚不断分化生长的过程.在此过程中,物质代谢、酶活性的变化均有利于种胚发育和种子发芽,种子内部经历了一系列生理生化变化去调整内源激素平衡、完成种胚发育.研究发现,内源激素在银杏种子休眠与萌发过程中起着重要的作用:GA1 3是银杏种胚后熟的关键物质;ZRs对银杏种子生长起重要的促进作用;GA1 3/ABA及ZRs/ABA相对比例的变化对种子发育、胚的后熟及种子萌发均有重要的影响. 相似文献
2.
银杏种子后熟生理及贮藏方法的初步研究 总被引：5，自引：0，他引：5
<正>银杏种子属于种胚发育不完全而导致生理休眠的种子,也是属于标准含水量高的种子。但关于种胚在贮藏期间的后熟过程和贮藏方法对后熟的影响等问题还未曾查到较多资料。因此近年来对这方面的问题作了粗浅的研究现总结如下。 一、材料和方法 (一)材料 银杏种子采于易县大龙华,采种期9月30日,饱满度63%,其中饱满种子千粒重为3012克,含水量为48.3%。 相似文献
3.
银杏种子萌发生理的初步研究 总被引：3，自引：0，他引：3
研究银杏生理休眠对其播种繁殖具有重要意义，该项研究用常规方法测试了银杏种子萌发的五星生理指标及条件。结果表明：银杏种子的生理后熟，主要是促进胚继续生长，完成后熟的种子在萌芽前后，α－淀粉酶和过氧化氢酶的活性不断增强，用２５℃恒温和硝酸钾（０．１Ｍ）处理，促进银杏种子萌发的效果显著。还证明，应用细胞分裂素，赤霉酸等处理种子，显著促进胚根生长，断胚根则能明显促进侧根生长。 相似文献
4.
从生理学及解剖学角度研究了五味子种子的休眠原因及打破休眼的技术。结果表明，五味子种子胚发育不完全，未完成生理后熟，是休眠的主要原因；种子内源抑制物是另一个主要原因。将种子酸蚀２０ｍｉｎ，再低温（０～５℃）层积４个月，可取得较好的效果。 相似文献
5.
银杏自然种胚率和出苗率的调查研究王孝锋，师平均，王建灵，武同成（河南省嵩县林业局）银杏种子自然受粉受精程度和种胚发育与出苗，壮苗培育关系甚大。摸清种胚形态品质和播种出苗规律，将为银杏大面积播种育苗和降低苗木成本提供科学依据。１调查方法和材料来源银杏种... 相似文献
6.
层积催芽。即将种子和湿润物交互层积放置并经过冬天的低温,在通气条件下打破种子休眠和促进种子萌发。
作用：1软化种皮,增加种子透性,解除种子休眠。2消除导致种子休眠的抑制物质,同时增加了生长刺激物质,因而有利于发芽。3促进后熟,完成生理后熟的过程。如银杏、山茱萸等,在层积催芽过程中,胚明显增大。 相似文献
7.
不同品种银杏种子成分分析 总被引：1，自引：0，他引：1
1材料与方法实验材料为1995年10月采于洛阳的4个品种的银杏种子。将生理成熟调制后的银杏种子室温下风干，去掉外种皮后，进行各项测定。总糖测定用费林试剂热滴定法；淀粉和还原糖测定用索姆基法；总氮测定用克氏定氮法；脂肪测定用索氏抽提法；胡萝卜素和核黄素和总黄酮的测定用庄向平法；银杏内酯测定用Pitta法；矿质元素测定用毕守法法；白果酸和白果酚测定用游松法。2结果与分析2．卫平同品种银杏种子碳水化合物、脂肪和蛋白质的含量不同品种银杏种子的水分、脂肪、蛋白质、总糖、淀粉和还原糖的测定结果（表1）表明，品种不同，种子… 相似文献
8.
山茱萸种子在秋熟时,胚形态已发育完全,但不能萌发,表现出一个休眠生理后熟过程。这个过程受到新种皮的抑制物和它的透性不良及冬季低温的阻碍而在有氧和适温条件下得到促进。试验揭示种子在砂基介质中经过3个月的亚高温(21～16℃)与2个月亚低温(3～15℃)层积对休眠破除的有效性,并促进高萌发。 相似文献
9.
10.
日本三桠种子休眠及萌发特性的研究 总被引：2，自引：0，他引：2
日本三桠种子有胚生理后热现象，并具有顽拗性，必须湿藏贮存才能延长种子寿命，日本三桠种子在５℃条件下后熟速率最快，经９０天种子全部解除休眠，赤霉素有缩短种子后熟期，促进发芽的效果，种子最适宜发芽温度偏高，可适当推迟春季播期或采用地膜覆盖育苗。 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.
《Scandinavian Journal of Forest Research》2012,27(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 相似文献
17.
18.
《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
19.
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
20.
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