CO_2浓度倍增对宁夏枸杞叶绿素荧光参数的影响

为了了解气候变化对枸杞光合作用的影响,以宁夏枸杞苗木为试验材料,采用开顶式气室模拟控制CO2浓度,设置倍增CO2浓度(720±20μmol/mol)和自然环境大气CO2浓度(360±20μmol/mol,对照)处理,测定2种处理下枸杞叶片叶绿素荧光参数,分析其变化。结果表明:CO2浓度倍增处理对宁夏枸杞叶片的初始荧光(F0)无显著影响,而最大荧光(Fm)、PSII的潜在光化学活性(Fv/F0)、PSII的最大光化学效率(Fv/Fm)、表观光合电子传递速率(RET)、PSⅡ实际光化学量子产量(ΦPSII)均显著增加,说明CO2浓度倍增可以提高枸杞叶片的光能转化效率以及光能利用率,增强其光合能力。     

京东板栗低产树改接优良品种当年丰产技术研究

为解决遵化市部分实生老栗树产量极低、存在部分低产栗园等问题,于2012年在遵化市马兰峪镇魏进河板栗园进行了低产板栗树高接换优试验。结果表明,通过改接燕山早丰、遵化短刺和紫珀等优良品种,嫁接成活率达到了97．6％～98．2％,改接当年3个品种单株产量分别为1．77kg、1．83k和1．84kg,极显著高于对照;改接第2年3个品种单株产量分别为3．0kg、3．2kg、2．8kg,极显著高于对照,其中以改接遵化短刺产量最高,实现了改接当年丰产、第2年高产。     

红松人工林优树个体结实量与生长因子关系的研究

为探讨红松生长指标对结实量的影响,调查了草河口地区30～80年生5个林龄红松人工林优树个体结实量和胸径等生长指标,利用灰色关联度方法分析结实和生长因子之间的关系。结果表明,与个体结实量关联度较大的3个生长因子是树高、胸径和侧枝长。因此,除了个体结实量外,树高、胸径和侧枝长可作为红松结实型优树选择的重要依据。     

树高、胸径、树皮厚对厚朴产量的影响

为研究厚朴树高、胸径和树皮厚度对其产量的影响,从而为厚朴品种选优及丰产栽培提供理论指导。采用系统抽样方法抽取了10~14 a的90个厚朴单株样本,测量其单株树高、胸径、树皮厚和树皮产量,通过建立和分析厚朴产量回归方程可知,胸径、树高和树皮厚与产量均成正相关关系;胸径、树高、树皮厚对产量的直接影响从大到小依次为胸径、树高、树皮厚,其中胸径对产量的影响以直接影响为主,树高对产量的间接影响稍高于直接影响,其间接影响主要是通过胸径对产量产生影响,树皮厚主要通过胸径和树高对产量产生间接影响,直接影响较小。     

河口垦区橡胶树单产偏低的原因及对策

通过对比分析认为，河口垦区不利的气候因素、自然灾害和管理较差，是橡胶产量偏低的原因，据此提出相应的对策和措施。     

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of -cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.     

Modelling growth for two-storied stands: Incorporating an effect of shading on the tree growth into growth and yield models

The objective of this paper is to review research into growth and yield modelling for two-storied plantation forests. Difficulty with modelling growth for this kind of forest, compared with pure even-aged forests, is mentioned. Then research in this field is divided into three parts and described. First, growth models and equations which were driven theoretically from biological assumptions and may be available to develop growth models for two-storied stands are reviewed. Secondly, research into methods of controling light levels and the relationship between the growth of trees and light level beneath a canopy are reviewed. Thirdly, growth models developed for two-storied stands, especially two-storied plantation forests, are reviewed. In conclusion, some problems which are still left in this field are pointed out.     

SO2对菊花光合色素含量和叶绿素荧光特性的影响

对菊花在长期低浓度SO2情况下光合色素含量和叶绿素荧光特性进行了研究.结果表明:用0.3 mg.L-1的SO2处理1周,引起菊花叶片光合色素含量显著增加,叶绿素荧光动力学曲线明显下降,表观电子传递速率(E)、非环式电子传递的量子效率(Y)和光化学淬灭系数(qp)有所增加;熏气至6周,叶绿素荧光动力学曲线和非光化学淬灭系数(qN)显著升高,光合色素含量显著下降,PSII反应中心潜在活性(FV/F0)、E和Y明显降低,而对PSII原初光能转换效率(FV/Fm)和qp的影响较小.     

南缘油茶配方施肥对树体营养及产量的影响

施肥是促进林木生长、提高产量和质量的有效措施之一.2011-2013年在南缘油茶主产区广西三江县进行油茶配方施肥试验,试验共设置4个处理,研究了不同处理对油荼人工林土壤养分、叶片营养、鲜果产量及出油率等的影响.结果表明,处理1配方为相对最优配方,能有效提高树体叶片N、P、K、Ca元素的含量;鲜果产量最高为4 695 kg/hm2,出油率也最高,达到7.10％.     

Agroforestry for soil and water conservation in the western Himalayan Valley Region of India 2. Crop and tree production

A ten-year-study (1983 to 1992) conducted on nine 15 × 90 m runoff plots at 4% slope compared production efficiency of Leucaena leucocephala and Eucalyptus hybrid based agroforestry as well as monocropping landuse systems in the warm, subhumid climate of the western Himalayan region of India. Treatments for the first sequence were: monocropping systems of leucaena, eucalyptus, Chrysopogon fulvus grass and maize – wheat rotation, and alley cropping systems of grass and crops at 4.5 and 10.5 m alley widths with paired contour tree rows of leucaena and eucalyptus. In the second sequence, alley width increased to 22.5 m in 1989, grass was replaced by turmeric Curcuma longa and paired contour rows of leucaena hedges were introduced in monocropping systems of grain crops and turmeric. Integration of leucaena and eucalyptus trees with crops caused severe reduction of crop yields ranging from 21 to 92% for wheat grain, 59 to 69% for maize grain, 60 to 67% for dry grass and about 50% for turmeric rhizome depending upon the age of trees and alley width. The grain yield of crops stabilized at about 50% reduction with 22.5 m alley width. Total crop biomass (grain + straw) also revealed a similar trend; however, its magnitude of reduction was less severe than for grain. Production of biomass was much lower near the tree rows than in mid alleys. Managing leucaena as contour hedgerows eliminated crop yield reduction in alleys. Performance of grass and turmeric in alleys was not found to be satisfactory. Biomass produced from trees adequately compensated the crop yield reduction. Land equivalent ratios of agroforestry landuses were comparable or even better than monocropping systems indicating suitability of these systems for the western Himalayan valley region. This revised version was published online in June 2006 with corrections to the Cover Date.     

云南松与华山松人工混交林针叶光合速率对光及CO2浓度的响应特征

采用Licor-6400型便携式光合作用测定系统测定了人工混交林中云南松、华山松光合作用对光、CO2浓度的响应曲线,阐述了云南松、华山松光合作用对光和CO2浓度的响应特征.结果表明:云南松、华山松光合速率随光强或CO2浓度的提高而增大,均可用非直角双曲线拟合,并得出一些光合响应特征参数,两树种间差异显著(P＜0.05);云南松、华山松具有较高的光饱和点(LSP)和补偿点(LCP),表现为典型的喜阳性特点,具有较强的光能利用能力.在CO2饱和下,云南松、华山松最大净光合速率(Pmax)分别可达14.768、10.289 μmol·m-2·s-1,与光饱和下相比,最大净光合速率(Pmax)分别提高了56.9%和62.0%.与华山松及几个北方针叶树相比,云南松具有较高的光饱和点、最大净光合速率、RuBP羧化效率(CE)、光呼吸速率(却)、CO2饱和点(CSP),以及较低的暗呼吸速率(Rd)、光补偿点、CO2补偿点(CCP),云南松具有高光效和高CO2利用率等光合特性,属于高光能生产潜力的针叶树种.     

Using combined measurements for comparison of light induction of stomatal conductance, electron transport rate and CO2 fixation in woody and fern species adapted to different light regimes

We aimed to understand the relation of photosynthetic rate (A) with g(s) and electron transport rate (ETR) in species of great taxonomic range and light adaptation capability during photosynthetic light induction. We studied three woody species (Alnus formosana, Ardisia crenata and Ardisia cornudentata) and four fern species (Pyrrosia lingus, Asplenium antiquum, Diplazium donianum and Archangiopteris somai) with different light adaptation capabilities. Pot-grown materials received 100 and/or 10% sunlight according to their light adaptation capabilities. At least 4 months after light acclimation, CO(2) and H(2)O exchange and chlorophyll fluorescence were measured simultaneously by equipment in the laboratory. In plants adapted or acclimated to low light, dark-adapted leaves exposed to 500 or 2000 μmol m(-2) s(-1) photosynthetic photon flux (PPF) for 30 min showed low gross photosynthetic rate (P(g)) and short time required to reach 90% of maximum P(g) (). At the initiation of illumination, two broad-leaved understory shrubs and the four ferns, especially ferns adapted to heavy shade, showed higher stomatal conductance (g(s)) than pioneer tree species; materials with higher g(s) had short at both 500 and 2000 μmol m(-2) s(-1) PPF. With 500 or 2000 μmol m(-2) s(-1) PPF, the g(s) for the three woody species increased from 2 to 30 min after the start of illumination, but little change in the g(s) of the four ferns. Thus, P(g) and g(s) were not correlated for all material measured at the same PPF and induction time. However, P(g) was positively correlated with ETR, even though CO(2) assimilation may be influenced by stomatal, biochemical and photoinhibitory limitations. In addition, was closely related to time required to reach 90% maximal ETR for all materials and with two levels of PPF combined. Thus, ETR is a good indicator for estimating the light induction of photosynthetic rate of species, across a wide taxonomic range and light adaptation and acclimation capability.     

大气CO2浓度升高对莴苣生长和物质分配的影响

对CO2浓度(550×10-6)下莴苣的生长、物质积累及其分配和光合性状进行了比较研究.结果表明,高浓度CO2(550×10-6)下莴苣具有高光合速率、高生长速度,其根和茎的干物质积累速度较快,叶面积增长快而且不积累过多的光合作用产物,高光合速率能够产生足够能量将光合作用产物从源转运到库,用于生长发育.生长在CO2浓度550×10-6下,莴苣能提早7d达到市场要求.     

Increased atmospheric CO2 concentration enhances the development of photosynthetic capacity beyond the temperature effect for silver birch in simulated future climate

We conducted an experiment to find out how future climate conditions will impact the spring development of photosynthetic capacity of silver birch leaves. We had two greenhouse conditions. In the simulated future climate condition, we had both elevated temperatures and CO₂ concentration, while for reference we had trees growing under current climate conditions. We used two methods to measure the development of photosynthetic capacity: first, the maximum quantum efficiency of photosystem II with a fluorescence meter; and second, the CO₂ assimilation rate with gas exchange measurements. The development of full photosynthetic capacity took around two weeks following the bud burst. The maximum quantum efficiency developed slightly faster than the CO₂ assimilation rate. Both measurement methods showed that an elevated CO₂ concentration enhanced the development of photosynthetic capacity beyond the impact of temperature only. The enhancement under the conditions of our simulated climate change translates to achieving photosynthetic capacity up to five days earlier, which impact should be taken into account in simulations of photosynthetic productivity.     

Alley cropping of maize with calliandra and leucaena in the subhumid highlands of Kenya: Part 2. Soil-fertility changes and maize yield

Although N-rich leaf biomass of multipurpose trees is known to be a good source of N to crops, integrating such trees into crop production systems is a major challenge in the development of viable agroforestry systems. An approach to integrating calliandra (Calliandra calothyrsus Meissner) and leucaena (Leucaena leucocephala (Lam.) de Wit), two promising agroforestry tree species, into maize (Zea mays L.) production system was investigated in the subhumid highlands of central Kenya during four maize-growing seasons from 1994 to 1996. The experiment consisted of maize plots to which tree prunings obtained from hedgerows grown either in situ (alley cropping) or ex situ (biomass transfer from outside) were applied. When alley-cropped with leucaena, maize produced significantly higher yields compared to maize monoculture (both non-fertilized and fertilized) treatments, but when alley-cropped with calliandra, the yield of maize was less than that of the monocropped unfertilized control. Application of ex situ grown calliandra and leucaena prunings with or without fertilizer resulted in higher maize grain yield than in the nonfertilized and fertilized treatments. Yields of calliandra alley- cropped maize were 11% to 51% lower than those of nonalley-cropped treatments receiving calliandra prunings from ex situ grown trees; the decrease was 2% to 17% with leucaena, indicating that calliandra hedges were more competitive than leucaena hedges. The alley-cropped prunings-removed treatments produced the lowest maize yields. The study showed that, in the subhumid tropical highlands of Kenya, inclusion of calliandra hedges on cropland adversely affected maize yields. On the other hand, alley cropping with leucaena was advantageous. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evaluating the potential of sentinel-2, landsat-8, and irs satellite images in tree species classification of hyrcanian forest of iran using random forest

ABSTRACT

Spatially explicit information on tree species composition of any forest provides valuable information to forest managers as well as to nature conservationists. In this study, the potential of three spaceborne sensors: (1) Landsat-8, (2) Sentinel-2, and (3) IRS-Pansharpened were compared by applying Random Forest (RF) classification algorithms to classify the three most common tree species: Pinus taeda, Alnus spp., and Populus spp., in Hyrcanian forest of Iran. Three RF models with optimized parameters of mtry and ntree were used for the classification of trees species. Based on our Overall Accuracy (OA) and Kappa Coefficient (KC) analysis, IRS-Pansharpened data showed the highest accuracy (OA = 84.9% and KC = 79.7%), followed by Landsat-8 (OA = 78.2% and KC = 70.6%), and Sentinel-2 (OA = 77% and KC = 70%). According to the Mean Decrease in Accuracy (MDA) criterion delivered as an output of RF, the near-IR spectral band was found on the top rank (high variable importance) as compared to all other spectral bands for tree species classification. The findings of this study can be used by the researcher, forest managers, economists and policy and decision makers in the context of sustainable forest management of Hyrcanian forest resources.     

Comparing an individual tree growth model for <Emphasis Type="Italic">Pinus halepensis</Emphasis> Mill. in the Spanish region of Murcia with yield tables gained from the same area

To support forest management decisions on converting stands from even-aged to uneven-aged management, tree models are needed that can simulate both options. Therefore, an individual tree model for Pinus halepensis Mill. is compared with the respective yield table. The individual tree model is built from data of two Spanish forest inventories in this province and evaluated with published yield tables, which have been built from permanent observational plots. The individual tree model consists of a basal area increment model and a height increment model, both based on two measurements of about 4,000 trees from single species stands of Aleppo pine. The R2 values of 0.362 and 0.107 for the basal area increment model and the height increment model, respectively, are within the range of other published models of this type. Comparing the model with the yield tables for different site indices, we find that our model matches the yield table well. Only in higher ages where the database for the yield table was poor, our model indicates higher basal area growth rates than the yield table.     

Growth and yield prediction models for Acacia mangium grown in the plantations of the central region of Bangladesh

Acacia mangium is a very fast growing species belonging to the family Leguminosae that has been introduced in the plantations in Bangladesh for its faster growth and wide range of adaptability. The present study aimed at development of growth and yield prediction models for the species using simultaneous equation method. Models were selected for the species to estimate stand dominant height, stand diameter, stand basal area per hectare and total volume yield per hectare. Paired t-test, 45-degree line test, percent absolute deviation and biological principle of stand development were used for the validation of chosen models. The results suggest that the models derived were statistically and biologically acceptable and could be satisfactorily used for stands of Acacia mangium of ages 4–7 yrs based on a base age of 6 yr.     

Assessing the performance of woody plants in uptake and utilisation of carbon, water and nutrients: Implications for designing agricultural mimic systems

This article introduces a series of innovative experimental approaches for monitoring current and past performances of woody plant species in utilisation of key resources within ecosystems. We demonstrate how such information might be useful for monitoring the progress of any novel agricultural system which attempts to mimic such natural systems. The experimental data presented principally involve the use of stable isotope techniques coupled to collection and analysis of substances transported in the sap of xylem and phloem. Study species examined are sugar maple (Acer saccharum), tagasaste (Chamaecytisus proliferus), blue gum (Eucalyptus globulus), and acorn banksia (Banksia prionotes). Topics covered include investigations of (a) seasonal changes in water source utilisation using hydrogen stable isotope analyses, (b) water loss from tree roots to the surrounding soil (termed hydraulic lift) using hydrogen stable isotope analyses, (c) relationships between carbon isotope discrimination of plant dry matter and whole-plant water-use efficiency, (d) phloem sap analysis as a means for assessing aspects of a plant's water and nutrient status, (e) carbon isotope ratios of foliage and annual growth rings as they relate to seasonal changes in carbon isotope ratios of phloem translocate, and (f) the composition of simultaneously collected samples of xylem and phloem sap as a means of monitoring current plant performance in uptake and mobilisation of key mineral resources. The chapter concludes with discussion of prospective uses of the above- mentioned techniques in study of managed ecosystems in which woody species play pivotal roles in maintenance of functional stability. This revised version was published online in June 2006 with corrections to the Cover Date.