香花油茶不同无性系叶表型性状及叶绿素含量的差异

【目的】为香花油茶良种选育和生态经济型品种筛选提供参考。【方法】以生长良好的30个香花油茶无性系叶为材料,使用叶面积仪和Dualex植物多酚-叶绿素仪对叶表型性状和叶绿素含量进行测定。【结果】叶水分含量特征：叶含水量为52.07%～62.44%,含水量高于55%的无性系占比70%以上。叶表型性状：15号无性系的叶长最大,29号无性系的叶宽、叶面积、叶周长、形状系数均最小;各无性系叶表型性状的变异系数为9.18%～23.07%,叶周长的变异系数最小（为9.18%）,叶面积的变异系数最大（为23.07%）;叶宽、叶面积与其他叶表型性状间均存在极显著相关性;在主成分分析中,前2个主成分的累计贡献率达到92.708%,说明这2个主成分概括了6个性状的主要信息。其中,叶面积的特征向量值最大,其次是叶宽,叶面积和叶宽是区分香花油茶无性系最主要的叶性状。经聚类分析,香花油茶各无性系可被划分为3个类群。叶绿素含量：香花油茶不同无性系间叶绿素含量存在变异,变异系数为8.48%;25号无性系叶基、叶中的叶绿素含量与其他无性系有显著差异,叶尖叶绿素含量除与18号无性系无显著差异外,与其他无性系均有显著差异。...     

施肥和喷施芸苔素内酯对油茶春叶养分等指标影响试验

为了解不同肥料和不同浓度芸苔素内酯对油茶下一年春叶养分等指标的影响,选择长林4号、18号和166号优良无性系油茶品种,对其进行施肥（生物有机肥、油茶专用肥、复合肥）及叶面喷施芸苔素内酯的正交试验。结果表明：油茶春叶叶绿素SPAD值最高处理组合是长林4号、每株施生物有机肥1 kg和喷0.033 mg.kg-1芸苔素内酯;油茶春叶干物质含量最高的处理组合是长林18品系、每株施油茶专用肥0.5 kg和喷0.033 mg.kg-1芸苔素内酯;油茶春叶中氮和磷含量最高的处理组合是长林18品系、每株施油茶专用肥0.5 kg和喷0.033 mg.kg-1芸苔素内酯;叶片钾含量最高的处理组合是长林4品系、每株施生物有机肥1 g和喷0.067 mg.kg-1芸苔素内酯;钾对油茶春叶叶绿素SPAD值贡献率最高,氮对春叶干物质积累贡献率最高。     

南方4种木本植物相对叶绿素指标及其分布

利用SPAD-502叶绿素计测定我国南方九节、三叉苦、桃金娘和阴香4种植物的叶绿素相对含量.研究结果表明,成熟叶中的叶绿素相对含量均极显著大于嫩叶,而其在同一叶片不同部位的分布为:叶尖<叶中部<叶基,其中,叶尖与叶基有极显著差异(P<0.001),叶尖与叶中部仅在嫩叶中有极显著差异(P<0.0001).主脉左右两侧绿素相对含量分布为:左区>右区,在嫩叶中有显著差异(P<0.05),但在成熟叶与嫩叶的叶尖均无显著差异.叶绿素相对含量的最佳测定部位为全展开叶片的中部.本项研究可为不同目的叶片叶绿素含量测定与取样提供参考.     

竹节树无性系叶片生长特性与叶绿素荧光

对优选的6个竹节树(Carallia brachiata)无性系叶片性状(叶片干质量、叶面积、比叶重)、叶绿素相对含量和叶绿素荧光参数进行测定,并作单因素方差分析和聚类分析.结果表明:竹节树不同无性系叶片的干质量和叶面积差异不显著,叶绿素相对含量具有显著的差异性,不同无性系具有不同的光能吸收和利用能力;不同的无性系其叶绿素荧光的部分参数(Fo、Fv/Fm、Fv/Fo、ФPSⅡ、ETR)差异显著;竹节树无性系C-15植株与其他无性系相比具有较高水平的实际光化学效率(ΦPSⅡ)值,而非化学猝灭系数(qN)较低,同时具有较高的表观电子传递速率(ETR),表明竹节树无性系C-15有较高的光呼吸;相关分析表明,叶片生长较好的无性系其叶绿素相对含量较高,同时也具有较高的PSⅡ光化学效率;无性系C-15号具有较高的叶绿素相对含量及较强的光化学特性,可进行大力推广研发.     

油茶不同无性系叶片营养元素吸收情况评价

对油茶不同无性系叶片营养元素含量的测定,研究结果表明:油茶叶片营养元素N含量最高,其次是Ca和K,Cu含量最低;油茶不同无性系叶片营养元素差异均达到极显著水平;通过主成分分析结果,综合评价油茶不同无性系营养元素吸收情况,按综合得分排序依次是桂软3号、桂软2号、湘林A5、湘林70号、桂软1号、桂软11号、桂软22号、桂软24号、桂软23号。     

玉兰叶片叶绿素荧光特性的研究

用叶绿素荧光技术测定玉兰不同无性系叶片的叶绿素荧光参数,结果表明:玉兰同一叶片不同部位叶绿素荧光参数(Fv/Fm)存在着差异,叶片基部、叶片中左、右部高于叶片尖部.南北两侧Fv/Fm差异不显著.叶绿素荧光测定的功能叶片区域很大,从整株来看,从树冠顶层第2轮开始到树冠底层第2轮结束,中间的叶片都可以看成是功能叶片.叶绿素荧光参数日变化表现为降-升-降-升的动态曲线.8:00～10:00时为最高.18:00时逐渐上升,到20:00～22:00时上升到原来状态.     

遮光对油茶苗期生长及光合特性的影响

为了探讨不同遮光环境对油茶苗期生长及光合特性的影响,以国家审定的4个长林系列油茶优良无性系2年生苗木为试验材料,研究了苗期遮光对不同无性系油茶苗木生长、光合以及叶绿素含量的影响。结果表明:适当的遮光处理能够促进油茶苗木的苗高、叶长、叶宽、单叶面积和全株叶面积的生长以及叶绿素的合成;经过2个月的遮光处理,50%全光、25%全光和12.5%全光处理植株的苗高、叶长、叶宽、单叶面积、全株叶面积和叶绿素相对含量均显著高于全光CK植株;50%全光、25%全光和12.5%全光处理植株的基径生长量均低于CK植株;在一定的检测光照强度下,4个无性系油茶的净光合速率均随着遮光强度的增强而增加,50%全光、25%全光和12.5%全光处理植株的叶片净光合速率均均显著高于全光CK植株。研究结果可为培育具有相对竞争优势的油茶上山造林壮苗提供技术支撑。     

油茶叶绿素含量动态变化和耐阴性的探讨

通过测定不同样地油茶树上不同叶龄叶绿素含量的年变化,明确了油茶叶绿素含量的变化规律。同时分析了这一规律与油茶果实生长的关系,说明了环境条件对油茶叶绿素含量和叶片寿命的影响,为油茶林的经营管理提供了依据。     

配方施肥对油茶幼树生长的影响

采用随机区组田间试验设计,以油茶优良无性系幼林为试材,研究了不同氮磷钾配方施肥对油茶幼树营养生长及叶绿素含量的影响。结果表明配方施肥对油茶优良无性系幼树树高、冠幅、梢长生长均有不同程度的促进作用,但不同的配方施肥和施肥量对油茶幼林的营养生长及叶绿素含量有很大的差异性,其中处理7油茶幼树各指标增量极显著大于其它处理。本试验氮、磷、钾(N∶P2O5∶K2O)最适配方为10∶5∶2。     

不同光强对6个欧美杨无性系苗期生长及光合特性的影响

[目的]研究6个欧美杨无性系生长及光合特性对不同光强的响应差异,为欧美杨苗期快速选育高光效优良品种提供一定的理论依据。[方法]在大田用遮阴网设置CK(100%自然光强)、L1(55%自然光强)和L2(20%自然光强),测定欧美杨的苗高增长量、叶片形态、光合速率、叶绿素荧光特性、叶绿素含量及矿质元素含量。[结果]除11-26-9外,无性系的苗高总生长量随着光强的降低呈下降趋势;随着光强的降低,不同无性系的叶片形态变化趋势不一致,3个光强下无性系间的单叶面积、叶形指数和比叶面积存在差异;无性系在L2处理下的净光合速率(Pn)最低,胞间CO2浓度(Ci)最高;3个处理下,11-26-8的气孔导度均最大;在L1与L2下,11-26-9的F1/F0值均最大;无性系的叶绿素b含量与叶绿素总含量呈现相同的变化趋势;11-26-4、11-26-8和11-36-26的钾、钙、镁元素含量随着光强的降低而增加。[结论]不同无性系对光强变化的适应策略不同,部分无性系的高生长和净光合速率随着光强的降低而减小,降低光强没有破坏无性系的PSⅡ结构。多数无性系的总叶绿素含量、矿质元素含量随着光强的降低而升高。11-36-26无性系的生长势及抗弱光能力较弱。     

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.