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。     

白玉兰花粉生活力和贮藏性

以白玉兰新鲜花粉为试验材料,研究了α-萘酚-联苯胺、TTC、I_2-KI、次甲基蓝4种染色剂对白玉兰花粉活力的测定效果和在-20、4、25℃3种不同贮藏温度下花粉生活力的变化。结果表明:白玉兰花粉生活力的测定适合用次甲基蓝和α-萘酚-联苯胺染色法,不适合用TTC染色法;在-20、4、25℃3种不同温度下,白玉兰花粉生活力均呈下降趋势,但在-20℃环境中,生活力下降速度最慢,维持时间最长,更适宜花粉的保存。     

杜鹃红山茶花粉保存及其生活力测定

以5 a生盆栽杜鹃红山茶嫁接苗的花粉为试材,研究了不同培养基配方、不同培养时间对花粉发芽的作用,并探讨了不同保存条件和保存时间下花粉生活力的差异。结果表明：杜鹃红山茶花粉发芽率呈抛物线型,在2.5%琼脂＋10%蔗糖的培养基上发芽率最高,8 h的培养时间为杜鹃红山茶花粉发芽的最适观测时间,4℃和-20℃保存都是适合杜鹃红山茶花粉长期保存的条件,但4℃保存更具有实践意义。     

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%。     

贮存温度及形态对甜樱桃花粉耐贮性的影响研究

以吉美、艳阳、先锋、雷尼、斯坦拉等5个甜樱桃品种为材料,采用花粉离体培养法、烘干法、蔗糖悬浮液法和果胶酶酶解法等研究了温度条件和花药形态对樱桃花粉贮存时间的影响,以及中、晚熟优质樱桃品种花粉的生活力、出粉量和含水量等指标,为甜樱桃杂交育种提供理论依据和生产实践提供参考。结果为吉美、艳阳等5个甜樱桃品种的花粉总含水量在39.65%～68.62%,在25℃烘箱内烘干24h后含水率降至4.98%～6.1%,此时5个品种花粉生活力均在40%以上。吉美、艳阳、先锋三个品种甜樱桃单药出粉量分别为2 120,1 952,2 711粒;单花出粉量均在60.0×103以上,以先锋最高为103.0×103;吉美、先锋单克花粉量高于50.0×106。吉美、艳阳、先锋三种甜樱桃花粉在4℃条件下贮存2.5个月仍可以保持10%以上的花粉生活力;在-20℃低温和-80℃超低温条件下可实现周年保存,且贮存效果相差不大,365d花粉生活力均可保持贮存前14%以上,-80℃下先锋花粉活力最高可达36.22%。长期贮存中以花药形态贮存的甜樱桃花粉表现出了更好的耐贮存性,低温可实现其周年保存,低温贮存时选择-20℃最佳。吉美、艳阳、先锋三个品种均适合作为花粉生产品种,以先锋最适宜。     

贴梗海棠花粉生活力的测定

以贴梗海棠初开花朵为试验材料,研究了TTC、碘-碘化钾2种染色剂测定花粉生活力的效果,离体培养时葡萄糖对花粉萌发的影响和3种不同温度(15、20、25℃)条件下的花粉萌发的变化规律,3种贮藏条件(常温、4℃、-23℃)对花粉贮藏的影响。结果表明:不同染色剂测定的花粉生活力差异显著,TTC染色法(76.26%)显著优于碘-碘化钾染色法(42.46%)。在一定范围内,培养基葡萄糖浓度和萌发温度提高能促进花粉的萌发,超出范围后抑制萌发。试验证明:最佳的葡萄糖浓度为10%,最佳的萌发温度为20℃。贮藏温度对花粉生活力的影响显著,其中最佳的贮藏条件是冷冻干燥,但综合考虑成本、便捷性等因素,实际应用中一般选择4℃。     

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℃)。     

贮藏温度和时间对麻疯树花粉生活力的影响

为保证麻疯树杂交的正常开展,花粉贮藏和生活力测定是必需的.采用联苯胺染色法分析了麻疯树花粉在3种贮藏温度下,不同时间段的活力变化.结果表明:麻疯树盛开的花粉生活力可达93.4%;整体上花粉生活力随贮藏时间的增加呈逐渐下降的趋势;贮藏方法以冷冻(-24～-18℃)最佳,冷藏(0～4℃)次之,常温条件下花粉生活力下降最快,3种保存条件下花粉生活力存在明显差异.     

崇左金花茶花粉萌发及在不同贮藏条件下活力变化的研究

2015年7月,采集崇左金花茶Camellia chuangtsoensis S.Y.Liang et L.D.Huang花粉,分别置于室温25℃,4℃,-20℃和-80℃保存。采用离体液体培养基法筛选出最佳崇左金花茶花粉的萌发条件,在此基础上试验不同贮藏温度和不同贮藏时间对花粉萌发率的影响。结果表明,崇左金花茶花粉萌发的最适培养基为12%蔗糖+0.12%H3BO3。花粉-20℃条件下贮藏5个月时,花粉萌发率仍可达原来的(68.93%)25%;在-80℃条件下贮藏5个月时,花粉萌发率可达原来的32%,-80℃条件下保存的花粉其萌发率略高于-20℃。     

濒危植物大果青杄种子形态及萌发特性研究

对甘肃白龙江林区生长的濒危植物大果青杄种子的形态和萌发特性进行了研究,结果表明:不同海拔和不同年龄的大果青杄种子千粒质量、空壳率、含水量、生活力、长、宽及直径等差异显著。不同年龄树木种子形态和部分萌发指标之间存在多样性;而且树木年龄越大,空壳率随之减少,生活力减少的幅度更大。在常温(20℃)下,经蒸馏水浸种,浓硫酸催芽的种子的发芽率为0;而42年的大果青杄种子经200mg L-1赤霉素(GA 3)处理24h后,在14d内发芽率达到70%,且发芽整齐。大果青杄种子的休眠属综合休眠,且种皮透性并不是导致大果青杄种子休眠的主要原因。     

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.