不同贮藏条件下锥栗花粉生活力研究

为了解决锥栗杂交育种中的花期不遇问题,以‘华栗4号’花粉为试材,研究了在室温和4、-20、-80℃这4个贮藏温度条件下干燥处理和非干燥处理对锥栗花粉生活力的影响情况。结果表明:在不同贮藏温度条件下‘华栗4号’的花粉生活力和耐贮藏能力不同;花粉适宜的贮藏条件为非干燥、低温环境。花粉生活力随贮藏时间的延长而下降,室温干燥条件下贮藏的花粉其生活力下降最快,贮藏27 d后花粉活力基本丧失;4℃的温度条件较利于花粉的短期贮藏,贮藏30 d后其萌发率仍为32.6%;而-20和-80℃的温度条件均较利于花粉的长期贮藏,且-80℃下贮藏的效果最佳,-80℃下贮藏270 d后花粉仍有一定的生活力,而在-20℃下贮藏210 d后花粉的生活力已基本丧失。     

金花茶花粉贮藏特性

采用花粉离体培养法,研究不同含水量、贮藏温度对金花茶花粉生活力的影响。结果表明:花粉生活力随贮藏时间的延长而降低,随贮藏温度的降低而延长。在室温条件下,花粉干燥处理萌发率高于非干燥处理,室温非干燥条件下,花粉生活力下降最快,10 d左右基本丧失生活力;在4℃和-20℃低温条件下,贮藏一定时间的花粉活力仍可达50%以上。花粉最佳的贮藏条件为冷冻干燥(-20℃)。     

榧树的花粉活力检测及短期贮藏条件

【目的】探究不同表型榧树（主要是散粉期和花蕾大小不同）花粉活力适宜的检测方式与不同贮藏环境下花粉活力的变化趋势,为榧树花粉活力检测和贮藏提供参考依据。【方法】以6个不同表型榧树花粉为试验材料,利用TTC染色法对比不同温度和pH值环境下的花粉活力染色情况,并通过隶属函数法得出适宜的检测方式组合;使用其中3个不同散粉期的试验材料,探究3种干燥方式干燥后对花粉活力的影响,以及不同干燥方式下不同贮藏温度、贮藏时间的变化趋势。【结果】1）不同表型的榧树花粉活力的检测方式不同,除晚期大花型外,TTC质量分数0.5%染色效果均较好,温度对早、晚期类型榧树花粉活力染色表现存在差异显著,pH值在微碱性环境下花粉染色效果均明显。2）早、中期类型采取烘箱28℃干燥后0℃或-18℃贮藏7～14 d,其花粉活力能保持在60%以上,超过30 d采取室内阴干干燥-18℃贮藏,能保持35%左右的花粉活力,晚期类型28 d后均低于30%。【结论】检测榧树花粉活力以在0.5%TTC、温度28℃、pH值8.0条件下培养6 h后进行镜检为宜;早、中期散粉榧树花粉在7～14 d内采用28℃干燥24 h后在0℃或-18℃进行短期...     

不同贮藏方法对华顶杜鹃花粉活力的影响

研究了华顶杜鹃Rhododendron huadingense花粉活力水平及不同贮藏方法对其活力的影响。结果表明,新鲜华顶杜鹃花粉的萌发率高达98.1%;室温存放的新鲜花粉在3 d内可保持较高的活力,3 d后其活力下降迅速;4℃贮藏7 d后的花粉萌发率仍保持在85.5%的较高水平,贮藏15 d时的萌发率仍高于50%,可作为华顶杜鹃花粉的短期(15 d内)保存方法;-20℃贮藏40 d后的花粉萌发率仍能达到87.4%,基本可满足实际需求;-80℃下贮藏60 d后萌发率依旧维持在95.2%,可用于华顶杜鹃花粉的长期保存。本研究结果说明花粉活力不是导致华顶杜鹃濒危的生物学原因。     

香水莲花花粉的采集、干燥和贮藏特性研究

【目的】研究香水莲花Nymphaea hybrid花粉活力和贮藏特性,以期为香水莲花有性繁殖和杂交育种的生产实践提供理论基础和技术指导。【方法】以黄、粉、紫3种不同花色的香水莲花品系为试材,采用花粉离体萌发培养基法测定不同开花天数(开花1、2、3、4、5 d)的香水莲花花粉活力、同一天不同时间段的香水莲花花粉活力、3个不同品系的香水莲花花粉活力、不同干燥方法(室内通风自然干燥、烘箱干燥和硅胶干燥)的香水莲花花粉活力及不同贮藏条件(室温、4、-20、-80℃)下贮藏不同时间(5、10、30、50、70、90、120、180 d)的香水莲花花粉活力。【结果】1)3种花色香水莲花的花粉活力均随开花时间呈现先升高后降低的变化规律,开花2 d的花粉活力最高;2)在一天7:30-17:30中,9:30-11:30的花粉活力较强;3)3个香水莲花品系间花粉活力存在差异,其中‘黄花型’香水莲花的花粉活力(60.61%)最高,‘紫花型’香水莲花的花粉活力(48.15%)最低;4)硅胶干燥法是香水莲花花粉干燥的最佳方式;5)4℃适于香水莲花花粉的短期贮藏,-20℃和-80℃适于香水莲花花粉的长期贮藏。【结论】在香水莲花开花2 d的9:30-11:30采集花粉,采用硅胶干燥法干燥后短期贮藏于4℃,长期贮藏于-20℃或-80℃条件下,可有效延长香水莲花花粉的寿命。     

紫薇花粉贮藏及花粉活力的分析

分析了3个紫薇品种花粉活力及不同贮藏温度对花粉活力的影响,结果表明:3个紫薇品种鲜花粉活力存在极显著差别.低温有效地延长了花粉活力的保持时间,在4℃条件下,花粉活力保持164.278 h;在-20℃条件下,花粉活力保持141.278 h;在室温条件下,紫薇花粉活力仅保持18.444 h.     

山茶花粉生活力及贮藏条件初探

以山茶两种开放程度花朵（初开和盛开）的花粉为试材,采用无机酸法和联苯胺染色法研究了花朵开放程度和贮藏条件对花粉生活力的影响.结果表明：无机酸法不适于山茶花粉生活力的测定,联苯胺染色法能快速地检测山茶花粉的生活力.实验结果表明,两种花粉生活力随着贮藏时间的增加呈逐渐下降的趋势.花朵的开放程度对花粉的生活力影响不大,而贮藏条件对其影响显著：室温（13℃～25℃）下,两种山茶花粉贮藏12 d后生活力完全丧失;冷藏（2℃）条件下,盛开花粉贮藏26 d后生活力完全丧失,而初开花粉生活力完全丧失需要30 d.     

猕猴桃花粉贮藏方法比较

为了提高猕猴桃花粉的贮藏水平，保障其贮藏后的生活力，以猕猴桃雄株品种‘海沃德’的花粉为试材，采用了花粉萌发测定法，比较分析猕猴桃花粉生活力在不同干燥方式及贮藏条件下的差异。结果表明：阴干干燥法所制备的猕猴桃花粉生活力最高，达到了45.85%;烘干干燥法所制备的猕猴桃花粉生活力最低，只有19.45%。-20℃低温贮藏条件能大大延长猕猴桃花粉的生活力，贮藏11月后花粉活力仍能保持在16.58%。贮藏环境有无光照、是否放置硅胶对猕猴桃花粉生活力均无显著性影响。该研究结果对于猕猴桃花粉贮藏技术的选择具有重要参考意义。     

两种槭属植物花粉生活力测定

以金沙槭(Acer paxii Franch.)和三角枫(Acer buergerianum Miq.)为试验材料,蕾期采粉,并且采用TTC染色法和液体培养基离体萌发法对它们的新鲜花粉,室温条件下(25℃)和4℃冷藏条件下保存的两种花粉进行了生活力测定。结果表明:液体培养基中蔗糖浓度对花粉萌发具有明显影响,三角枫花粉的最佳萌发浓度为10%,而金沙槭花粉的最佳萌发浓度为15%;TTC染色法测定的花粉生活力比液体培养基离体萌发法测定的花粉生活力高;室温条件下(25℃)保存的金沙槭花粉4天后便失去了生活力,三角枫花粉6天后完全失去生活力;4℃低温保存条件下,金沙槭花粉的可贮藏时间较短,约40d后花粉便失去了生活力,而三角枫的花粉贮藏40d后的萌发率为31.37%。     

贮藏条件对薄壳山核桃4个品系花粉活力影响

通过TTC染色法测定4个薄壳山核桃品系Mahan(‘马汉’)、Western(‘威斯登’)、Shoshoni(‘肖肖尼’)、‘钟山25’的花粉分别在室温、4℃和-20℃等不同贮藏条件下活力的变化。研究结果表明,-20℃条件下花粉活力贮藏时间最长,到140天时花粉活力仍在50%左右。以花粉活力保持在50%为标准,室温条件下Western和‘钟山25’贮藏时间最长(8天);4℃下Western花粉贮藏时间最长(21天);-20℃下,4个品系贮藏天数都在84天以上,其中Western、‘钟山25’贮藏时间最长,达140天。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

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.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

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.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

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.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

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.     

CAD与建筑设计的关系

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

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.     

Risk Perception Among Non-industrial Private Forest Owners

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.     

Interactions in decomposition and N mineralization between tropical legume residue components

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.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

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.