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为给我国无籽梨品种培育提供重要的理论依据,初步探讨了无籽梨无籽果实形成的机制。对无籽梨雌蕊观察发现,其60.8%无籽梨花的雌蕊数量为2个,而‘幸水’雌蕊数量7个的小花占48.4%;无籽梨柱头发育不正常的比例较大,占64.2%,而‘幸水’正常雌蕊占94.1%。授粉试验结果表明,授粉刺激才能保证无籽梨正常坐果,授粉后坐果率达42.2%,无授粉无籽梨8周后坐果率几乎为零,说明了无籽梨在生产中配置授粉品种才能保证坐果率和产量。对花粉管伸长观察发现,无籽梨花柱授粉后,花柱顶部、中部和基部均能观察到花粉管顺利萌发和生长,但未观察到花粉管到达胚珠,而‘幸水’花柱顶部萌发后顺利通过中部、底部,并能观察到花粉管到达胚珠附近,且‘幸水’柱头和花柱中部花粉管伸长数量比无籽梨多。种子败育率统计发现,无籽梨发育不良比例高达91.3%,但正常种子大多数都能萌发。无籽梨果实心室2~4个,而幸水心室为5个。综上所述,雌蕊变异是无籽梨形成无籽果实的主要原因,而引起雌蕊败育的主要原因可能与无籽梨杂种后代不稳定性有关。 相似文献
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为了系统了解板栗雌雄花发育过程,以板栗优良品种‘遵玉’为试材,对大小孢子及雌雄配子体发生发育进行研究。结果表明:花药壁由外而内分别为表皮、药室内壁、中层及绒毡层(为腺质型),属于基本型。小孢子胞质分离为同时型,四分体为典型的四面体型,少数呈左右对称排列。雄配子体只经过1次有丝分裂,花粉成熟为2-细胞型。雌花胚囊发育为蓼型胚囊,只有1个胚囊母细胞发育成胚囊,四分体呈线性排列,整个发育过程与雌雄花外部特征密切相关。确定观察减数分裂最佳取样时期为:雄花花序长度为10~17 cm,总苞直径为0.9~1.6 cm。‘遵玉’小孢子及雄配子体发生发育不存在异常表现,表明‘遵玉’雄配子体发育正常,花粉可育,可以作为授粉树。 相似文献
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云南板栗花粉形态、萌发率和果实特性的研究 总被引：1，自引：0，他引：1
以4个云南板栗品种为试验材料,从其花粉形态特性,萌发率和通过相互授粉试验来研究果实直感效应.本次试验结果表明板栗花粉粒的形态大小在不同品种间具有一定的差异,云栗15号的花粉粒比云栗42号大,其在同一品种雌株上授粉所结果实亦比云栗42号的大;从板栗花粉萌发率上的结果上看.云栗42号的萌发率比云粟15号的要高,其球苞内坚果数亦比云栗15号多.板栗果实大小的直感效应受到授粉组合的亲和力、花粉粒大小和萌发率的影响. 相似文献
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为了揭示蔷薇原种金樱子与现代月季品种间远缘杂交常不能结实的原因,以现代月季品种‘芦王特’、‘歌林娇红’、‘同情’、‘白雪山’为母本,二倍体野生蔷薇原种金樱子为父本,开展远缘人工定向杂交,测定父本花粉活力,研究授粉后花粉在柱头萌发形态以及胚胎发育等生殖生物学特性。结果发现,与以上4个月季品种杂交时父本金樱子的花粉活力分别为8.0%、22.0%、63.7%、39.8%;‘同情’人工授粉后2 h平均每个柱头上萌发花粉数分别有8.1粒,其他品种均未在柱头上观察到花粉萌发;授粉后4h平均每个柱头上萌发花粉数分别为17.6、21.9、11.7、12.0粒;到授粉后12 h时数量达到最多,分别为23.4、60.4、40.3、34.4粒;随后萌发数量急剧下降,且大部分花粉管细短、弯曲并停留在柱头表面。另外,4个月季品种授粉后每个柱头上的花粉萌发率均先升后降;在授粉10天后观察到的子房中含有的球形胚异常降解,金樱子与‘同情’及‘白雪山’的杂交胚胎中可观察到鱼雷形及子叶形胚,但后期出现胚胎异常降解。杂交时使用的父本花粉活力并不低,但授粉24 h之后的花粉管出现异常以及受精后胚胎大量败育可能是导致金樱子远缘杂交不结实的重要因素。 相似文献
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《经济林研究》2014,(2)
为了探讨极晚熟杏品种‘冬杏’的杂交亲和性并为选育其晚熟品种奠定基础,以‘冬杏’为母本、15个不同成熟期的新疆杏品种为父本进行了杂交实验,通过观察坐果率及花粉管的生长状况,探讨了不同父本与‘冬杏’的亲和性。结果表明,15个父本杏品种的平均花粉量为1 413.24粒/花药,平均花粉活力为51.0%,与‘冬杏’杂交后的平均坐果率为22.5%,‘贾格达玛依桑’、‘木孜佳娜丽’、‘赛买提’、‘克孜朗’等品种与‘冬杏’的杂交坐果率较高,‘毛拉肖’、‘索格佳娜丽’、‘旦杏’等品种与‘冬杏’杂交的坐果率相对较低。‘冬杏’自交坐果率小于6%,为自交不亲和类型。授粉后2 h有部分品种花粉在柱头上开始萌发,所有品种的花粉管在96 h后均到达了‘冬杏’的花柱基部,但各品种花粉原位萌发及花粉管生长动态的差异较大,其中以‘赛买提’和‘贾格达玛依桑’的花粉管最早到达基部,‘木孜佳娜丽’和‘克孜朗’等较早。‘贾格达玛依桑’、‘木孜佳娜丽’、‘赛买提’、‘克孜朗’等品种与‘冬杏’的杂交亲和性较好。 相似文献
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为解决观赏桃杂交育种中花期不遇的问题,以‘粉花山碧’‘合欢二色’‘满天红’‘元春’4种观赏桃品种的花粉为材料,采用离体培养法,研究其在4、-20、-60、-80℃及室温环境下,随着贮藏时间的延长花粉生活力及培养2h花粉管长度的变化。结果表明:贮藏温度对花粉的生活力有显著影响,但对培养2h花粉管长度的影响不显著;5个贮藏温度中,4个品种均以-80℃为最佳贮藏温度,在其他温度下不同品种花粉的贮藏特性在不同贮藏阶段存在差异,差异主要表现在4和-20℃贮藏时,并不都符合温度越低,贮藏效果越好的规律。4个观赏桃品种间花粉耐贮性存在显著差异,按照耐贮性由强到弱排序,各品种依次为‘满天红’‘元春’‘合欢二色’‘粉花山碧’。 相似文献
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牡丹远缘杂种‘和谐’育性的初步研究 总被引：2，自引：0，他引：2
以我国选育出的首例牡丹与芍药远缘杂种‘和谐’为主要材料,对其雌雄蕊形态特征、花粉活力、授粉过程、杂交结实情况等影响其育性的关键因素和环节进行系列研究。结果表明:‘和谐’雄蕊量少,50～100枚,花丝长短不一,0.1～2.5cm;雌蕊4～5枚,花盘肉质,包裹心皮2/3左右。‘和谐’花粉多数败育,花粉活力为4.1%。牡丹和芍药混合花粉在‘和谐’柱头上萌发率很高,多数花粉管成团盘绕在柱头上,少数花粉管能进入柱头,但花粉管在花柱内因顶端膨大、胼胝质积累而停止生长,表明‘和谐’不结实是由受精前障碍造成的。‘和谐’作父本与‘艳紫’和‘粉蝴蝶’2个芍药品种杂交有一定的亲和性,并获得少量的种子和种苗,说明‘和谐’是珍贵的牡丹与芍药远缘杂交育种的亲本材料。 相似文献
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对19个板栗品种的花粉育性的两个方面(花粉萌发率、花粉管生长特性)进行了测定 分析,发现板栗花粉的萌发率一般高于65%,以70%～90%区域内分布为最多,高于90%和低 于70%的品种较少。花粉管生长在花粉萌动后的20min中伸长最快,而后逐渐趋于平稳。一 定浓度的蔗糖溶液有助于花粉管的生长,10%、20%蔗糖浓度均能显著提高花粉管伸长速度。 相似文献
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以5年生观赏海棠‘高原红’嫁接苗为试验材料,采用扫描电镜、花粉离体培养、荧光显微技术等研究了‘高原红’花粉的形态、生活力及贮藏特性,分析了花粉离体培养基成分、离体与活体萌发的区别及花粉贮藏过程中活力的变化。探讨了花粉萌发及贮藏特性,旨在为揭示花粉萌发特性、建立花粉贮藏体系提供理论依据。结果表明:硼酸与蔗糖溶液均对‘高原红’花粉萌发有显著的影响,单因素最佳培养基为10%蔗糖溶液;离体与活体花粉在萌发时间上有一定程度的差异,离体萌发较快于活体萌发,且活体萌发中花粉管在授粉后第8—12 h为快速伸长期;花粉贮藏过程中,室温(17—20℃)下贮藏的花粉活力急速下降,花粉管长度与4,-20℃及-70℃时差异显著,4℃下贮藏的花粉离体萌发率同样呈急速下降的趋势,与-20,-70℃时差异显著,而-20℃与-70℃下贮藏的花粉其离体萌发率之间与花粉管长度之间差异均不显著。 相似文献
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《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
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《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
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《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
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《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
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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
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《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
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《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
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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
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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