7年生平欧杂种榛果实生长发育规律的研究

以‘82-11’、‘84-237’和‘84-402’等3个杂种榛优良品系为试材,采用动态监测的方法,研究7年生平欧杂种榛果实生长发育规律。结果表明,3个榛子品系果实重量生长曲线为“慢-快-慢”的“单S”型曲线,其生长过程可分为初始缓慢生长期、快速生长期、第二次缓慢生长期3个阶段。3个榛子品系果仁重量生长曲线为“单S”型曲线,随着果仁的发育,果仁鲜重逐渐增加,果仁重量的增加在果仁发育前期较快,后期较慢。果实发育前期,果实重量的增长主要来自细胞的分裂与膨大,果实发育后期,果实重量的增长主要由果仁的生长引起。     

木瓜杏果实生长发育的初步研究

在果实生长发育期,通过测定果实纵径、横径、侧径、体积、鲜重及干重,研究了木瓜杏果实发育规律。结果表明,木瓜杏果实的生长发育动态呈"慢—快—慢—快—慢"的"双S"形曲线,整个发育过程可分为5个时期:幼果缓慢生长期、果实第1次迅速生长期、果实第2次缓慢生长期、果实第2次迅速生长期和果实熟前缓慢生长期。果实第2次缓慢生长期与果实硬核期相吻合,果实第一,二次迅速生长期是果实增长的两个关键时期。果实纵、横、侧径与果实鲜重、体积变化曲线极为相似,并具有同步增长的趋势。     

光皮树果实生长发育规律研究

对光皮树果实纵径、横径进行定期田间测定,同时对果实鲜重和干重进行定期测定,绘制生长曲线,结果表明光皮树果实生长发育过程可分为3个时期：幼果缓慢生长期,果实缓慢生长期,果实熟前迅速生长期。果实含水率一直在下降,而含油率则一直在增长,达到最大合油率34．23％后趋于稳定。     

美国薄壳山核桃果实发育研究

1995～ 1998年 ,在云南省林业科学院漾濞研究站从浙江引种的美国山核桃林内 ,对金华 1号、绍兴 1号、山站 2号、长林 13号 4个品种的果实发育进行了观测和解剖研究。结果表明 ,这 4个品种都具有明显的缓慢生长期、迅速膨大期、硬核期、果仁生长期 4个发育期 ;果实的体积和重量生长速率有 3～ 4次高峰 ,并与各发育期吻合 ;胚在硬核期出现 ,经历 18～ 19天基本定型 ,胚出现果实到采收需经历 5 2～ 5 9天 ,研究为正确制定丰产栽培措施提供了理论依据。通过对气温和降雨量的分析认为 ,美国山核桃为喜热树种 ,漾濞引种的美国山核桃发叶开花时间比浙江早 10天左右 ,果实进入迅速膨大期反而迟 10～ 15天。     

黑老虎果实发育及种子油脂积累规律

【目的】研究黑老虎果实发育及种子油脂积累规律,可为其果实发育期的栽培管理和种子油脂的开发利用提供理论基础。【方法】观测黑老虎果实发育的8个不同时期果实和种子表型、横纵径、形状指数;并利用索氏抽提法、激光共聚焦显微镜观察法和气相色谱法,观测种子含油量、油体形状和分布、脂肪酸组分。【结果】黑老虎果实发育期为110天左右,发育期分为青果期(14～56 DAF)、转色期(56～84 DAF)、红果期(84～112 DAF)3个阶段(DAF：花后天数)。果实和种子的横纵径、质量生长曲线均呈单“S”型变化规律,符合Logistic回归模型,决定系数高达0.967 2～0.998 6。14～98 DAF为果实生长期,横纵径和质量快速增加,成熟时果实横径为115.99 mm、纵径为105.65 mm、单果质量为526.08 g;14～84 DAF为种子生长期,成熟时黑老虎种子横径为12.38 mm、纵径为14.26 mm、种子百粒质量为47.85 g。种子油脂积累规律呈“慢—快—慢”变化,青果期积累缓慢、转色期快速积累、红果期积累减缓,油脂积累方程为y=56.261 2·(1+e^{6.582 ...}     

美国薄壳山核桃果实发育研究

1995－1998年，在处林业科学院漾鼻研究站从浙江引种的美国山核桃林内，对金华1号，绍兴1号，山站2号，长林13号4个品种的果实发育进行了观测和解剖研究。结果表明，这4个品种都具有明显的缓慢生长期，迅速膨大期，硬核期，果仁生长期4个发育期；果实的体积和重量生长速率有3－4次高峰，并与各发育期吻合；胚在硬核期出现，经历18－19天基本定型，胚出现果实到采收需经历52－59天，研究为正确制定丰产栽培措施提供了理论依据。通过对气温和降雨量的分析认为，美国山核桃为喜热树种，漾鼻引种的美国山核桃发叶开花时间比浙江早10天左右，果实进入迅速膨大期反而迟10－15天。     

黑龙江野生毛榛果实表型性状的多样性研究

旨在揭示黑龙江野生毛榛果实表型性状的变异特点和多样性,为野生毛榛种质资源评价和优良种质挖掘提供依据,采用变异分析、相关性分析、主成分分析和聚类分析方法对黑龙江省9个地理种源的58份毛榛种质资源的7个质量性状、17个数量性状,共计24个果实表型性状进行多样性研究。结果显示：(1)毛榛果实表型性状多样性丰富,7个质量性状的遗传多样性指数变化范围为0.086～1.087,坚果颜色和果基形状的H′值均高于0.8;有14个数量性状的变异系数大于10%,果仁质量的变异系数最大为39.98%。(2)17个数量性状之间有较高程度的相关性,果仁质量与坚果三径等11个性状呈极显著正相关,可通过果仁性状来筛选毛榛优良单株。(3)主成分分析表明第1主成分的贡献率最高为48.301%,主要反映坚果质量和果仁大小指标;第2主成分的贡献率为18.394%,主要反映果仁饱满度指标;前4个主成分的累计贡献率为84.045%。(4)聚类分析将58份毛榛资源分为3类,第1类坚果和果仁质量大,出仁率高、果壳薄,果仁饱满,适合选育大果品种;第2、3类坚果和果仁质量居中,出仁率较高,壳仁间隙较小,果仁饱满,可作为遗传改良的优良资...     

杂交榛果实发育过程中糖类与脂肪酸相关性研究

笔者对榛子不同时期不同种类糖类和脂肪酸的相关性进行了分析,并对其代谢过程中的关键酶进行定量测定。结果表明,杂交榛84-545果仁中,葡萄糖和亚油酸、硬脂酸呈显著负相关,相关系数分别为-0.72和-0.70;蔗糖与各种脂肪酸均呈显著正相关,相关系数均大于0.75.杂交榛81-19具有相似特性。不同品系中ACCase酶的含量变化规律相似,但也有一定的区别。ACCase酶在榛子果实的果仁充实期和果实成熟期含量最高;果实成熟期的不饱和脂肪酸主要是通过消耗果仁中的饱和脂肪酸而得到,果实成熟期也是不饱和脂肪酸积累的一个重要时期。     

甜樱桃果实发育中糖酸组分及组织结构的变化规律

【目的】探明甜樱桃果实发育过程中果实质量增加特点、糖酸含量变化规律及果实发育过程中果实组织结构差异特点,为甜樱桃的田间肥水管理、适时采收、产量和果实品质的提高提供参考依据。【方法】以甜樱桃品种‘拉宾斯’为供试品种,选取其不同发育时期的果实,用天平测定果实质量,用高效液相色谱仪测定其糖酸组分和含量,用光学显微镜观察果实石蜡切片并分析其组织结构。【结果】在甜樱桃果实发育过程中其果实质量的变化曲线呈双S型曲线,其果实质量出现了2个显著增加的时期:第1个时期是盛花期(50%已开花)后的第2周,此期果实质量明显增加,果肉细胞显著膨大,果实处于快速生长期;第2个时期是盛花期后的第5—6周,此期果实质量显著增加,果实亦处于快速生长期。盛花期后的第6周以后,从转色期进入成熟期,果实质量持续增加,此期果肉细胞无明显变化。在甜樱桃果实发育过程中,果实中主要有机酸的苹果酸含量不断增加,转色期后苹果酸持续积累;果实中主要糖分的葡萄糖和果糖,在果实发育前期有一个平稳积累期,转色期后其含量均迅速增加,至果实成熟期其积累均减慢,但其含量仍均持续稳定地增加。【结论】甜樱桃果实虽有2个快速发育时期,但果实中的糖酸变化时期主要集中在第2个快速生长发育时期,即盛花期后的第5—6周是果实生长发育的关键时期,此期果实的质量、体积及品质等都发生了重要变化。因此,这个阶段是加强肥水管理的关键时期,果实成熟期即果实质量增加不显著时,也即果实中糖和酸的积累均减慢之时,就可以采收果实了,即花后第8周以后是甜樱桃品种‘拉宾斯’的适宜采收期。     

宝鸡市鲜食核桃良种“西林3号”幼果生长观测

为指导宝鸡市鲜食核桃良种“西林3号”青果生长期管理,在主产区千阳县进行了幼果生长定期观察测定,结果为“西林3号”幼果生长期可分为二个阶段,即5月上旬到6月上旬的快速增长期,和6月上旬到8月中旬果实成熟期的缓慢生长期;建议在6月上旬之前应加强快速膨大期田间水肥和病虫害等管理,在整形修剪方面,可适当摘除(剪除)长侧枝(1.5～2.0 m)的顶芽,促进侧枝的侧果生长发育。     

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.