15个国外李子品种花粉生活力的观察

采用形态法、沙尔达考夫染色法和悬滴液发芽法测定15个国外李子品种的花粉量、花粉粒的正常形态和花粉生活力。结果表明，10个品种的花粉量较多，5个品种较少；12个品种的花粉粒正常形态为长椭圆表，3个品种为长桶形，花粉适宜的发芽温度为15℃～20℃，低温对发芽有抑制作用，9℃条件下，2个品种的发芽率为40.6%和46.8%，其余品种在12.6%～24.8%之间。3℃条件下，4个品种的发芽率在11.8%～16.2%之间，其余品种在1.4%～7.8%之间，形态法、染色法的精确度低于发芽法，有77％的可靠性。     

柿花粉生活力及雌花可授期

柿不同物种品种的花粉粒大小、发芽率有极显著差异,花粉发芽率一般在４０％以上,但完全甜柿、涩柿品种的发芽率较低。花粉在常温下不仅贮藏５ｄ～１０ｄ,而常温干燥,低温干燥可分别贮藏１５ｄ～２０ｄ、３０ｄ以上。温度、庶糖浓度高低影响花粉发芽率,适宜硼浓度明显促进花粉萌发,柿花粉发芽适宜条件为温度２５℃、２％琼脂＋２５％庶糖＋５～５０ｍｇ．Ｌ＾－１硼砂。雌花开放后在１天～２天内授粉坐果率最高。     

不同处理对阿月浑子种子发芽率的影响

采用不同的方法对阿月浑子2个品种——美国品种Kerman与新疆地方品种长果阿月浑子的种子进行处理，在不同的发芽基质中进行发芽率的测定。结果表明：用60℃水浸种，可以明显提高Kerman和长果阿月浑子种子的发芽率，其中．Kerman提高了8％，长果阿月浑子提高了7％；使用GA3对阿月浑予种于进行处理，不同浓度对不同品种的发芽率有不同的影响．用0.10g／L GA；处理Kerman品种效果最好，其种子发芽率为61％，较对照提高了31％，用0．30gjLGA。处理长果阿月浑子效果最好，其种子发芽率为53％，与对照相比提高了43％；此外，试验结果表明珍珠岩是较理想的发芽基质；     

冷季型草坪草种发芽试验

对长春市8种（品种）主要冷季型草坪草种种子发芽率进行了测定,结果表明,8个草种（品种）发芽率为14％～94．0％,发芽势为4．0％～89．0％,其中“匍匐”紫羊茅、草地雀麦、剪股颖和冰草4个草种（品种）发芽早,发芽率和发芽势高,可优先选用,其余种（品种）发芽晚,发芽率和发芽势都较低,利用时应注意播量、种子处理和播种与播后管理。     

不同温度、时间层积处理对北美鹅掌楸种子发芽影响

通过7种不同温度、不同时间的层积处理研究其对北美鹅掌楸种子发芽的影响。结果表明：低温层积处理能显著促进北关鹅掌楸的种子萌发。在2℃、层积处理时间为60d的条件下种子发芽效果最好，种子绝对发芽率为86．84％，发芽速度最快；在2～12℃变温层积处理56d的条件下，种子绝对发芽率为80.71％，种子发芽较快。在7℃，层积处理时间为30d的条件下种子发芽效果最差，种子绝对发芽率为62．29％。     

不同倍性广东桑的花粉形态

【目的】针对桑树形态倍性鉴定及品种间鉴别问题,研究广东桑不同倍性及品种之间孢粉学上的异同,为桑树多倍体育种提供科学依据。【方法】利用扫描电镜对广东桑10个不同倍性品种花粉的形态、大小、萌发孔、外壁纹饰等孢粉学特性进行观察,并运用图片分析结合数理统计的方法对其花粉形态进行研究。【结果】供试广东桑不同品种的花粉微观形态相近,均为小型花粉,近球形,花粉粒极轴长16.98～24.46μm,赤道轴长15.37～23.86μm,极轴长与赤道轴长的比值为1.01～1.12;供试不同品种花粉粒萌发孔1～3个,圆形,直径为2.11～3.51μm,部分花粉粒萌发孔外壁内陷形成漏斗形,按照额尔特曼 G 的 NPC(萌发器官的数目、位置及特征)分类系统属N3P3C4类型;不同倍性间广东桑花粉的赤道轴长、极轴长和萌发孔大小存在显著性差异(P ＜0.05),均表现为四倍体＞二倍体,但花粉粒的极轴/赤轴比值差异不显著(P＞0.05);广东桑花粉外壁为分布不均的刺状突起－脑条纹复合纹饰,不同品种间花粉的表面纹饰有明显差别,根据外壁纹饰可将供试10个品种花粉分为细刺颗粒状突起－细条纹纹饰、细刺颗粒状突起－粗条纹纹饰、粗刺颗粒状突起－细条纹纹饰和粗刺颗粒状突起－粗条纹纹饰4种类型,花粉外壁纹饰体现了不同品种的遗传多样性和遗传分化;不同倍性间广东桑花粉表面的刺状突起密度及大小差异不显著(P＞0.05);供试四倍体广东桑品种花粉存在少数败育花粉粒,表现为干瘪而不充实,外形异常。【结论】供试广东桑不同倍性及品种间花粉形态特征具有差异,不同倍性间花粉粒和萌发孔大小存在差异,不同品种间花粉的表面纹饰存在明显差别,初步认为花粉的亚显微结构特征可作为广东桑倍性鉴定及品种间鉴别的重要标准之一。     

不同李品种花粉生活力观察

采集玉黄李、早黄李、crimson－2、红心李、李、金塘李、芙蓉李和盖县大李等8个李品种花粉,用蔗糖培养基在不同温度条件下经过不同时间的培养,测定出花粉的生活力。结果表明:玉黄李的花粉生活力很差;早黄李的花粉生活力较低;其余6个品种在不同温度条件下生活力均较强,在22℃、9℃、6℃、3℃花粉生活力分别为47．90％～66．07％、46．95％～51．94％、41．61％.     

肉花卫矛种子休眠及其解除的研究

＞Ｆ０．０１＝５．９９）。经ＬＳＲ检验，变温层积（２０～２５℃４５ｄ＋２～５℃　４５ｄ）的发芽率最高，可达５６．７％，且与其它各层积处理的发芽率之间存在极显著的差异；２～５℃层积９０ｄ、７０ｄ及对照（２～１５℃层积９０ｄ）的种子发芽率之间差异不显著；２～５℃层积３０ｄ的发芽率最低，仅为２２％（表２）。以上试验小结为：（１）成熟且发育完善的肉花卫矛种子在适宜的温度、水分等条件下不能发芽，种皮透气性差是肉花卫矛种子休眠的原因。（２）层积处理可以提高种子的发芽率，其中以２０～２５℃４５ｄ＋２～５℃４５ｄ变温层积处理的发芽率最高，可达５６．７％，解除了种子休眠。     

保存温度对红山茶组物种及品种花粉生活力的影响

采用固体培养基测定不同温度条件下贮藏的红山茶组3个物种及山茶6个品种的花粉发芽力.结果表明,3个物种冷冻温度下贮藏效果比冷藏温度效果好,室温密封条件下花粉的发芽率讯速下降;6个山茶品种在室温条件下,花粉发芽力下降较快,冷藏温度贮藏花粉效果也不理想,冷冻温度(-18℃)密封贮藏1a后发芽率保持在34.83%;鲜花枝水培3 ～ 4d内发芽率较高.     

莱州F1代仙客来栽培技术

总结出了仙客来F1代种籽品种特性、育苗技术、生产技术及病虫害防治等。一代仙客来发芽温度18℃～20℃，相对湿度90％～95％；培育小苗最佳温度18℃～20℃，相对湿度65％～70％；幼苗期温度18℃～20℃；生长发育期白天温度17℃～18℃．夜间15℃左右；浇水做到适时、适温、适量；pH值控制在6．5～6．8；换盆最佳EC值为0.8；合理施肥；对场地、基质及器具进行严格消毒。     

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.