北固山湿地野生虉草生物量的研究

对北固山湿地野生虉草的株高、茎高、叶龄、生物量等进行了研究,结果表明,虉草的株高和茎高的变化呈现出近“S”型的生长曲线,叶龄与株高和茎高均呈一元线性显著的正相关关系,生物量的变化与生育期关系密切。     

生物质燃料常温变径成型锥头研究

针对生物质常温闭式成型机的不足,本文引入了开式成型的概念,并在原有闭式成型机液压驱动设备的基础上,改进了成型腔.通过对生物质原料的力学分析,设计了开式成型的变径成型锥头.并使用小刨花、锯末等材料进行验证,探讨了对生物质常温变径成型机成型效果的影响因素,同时确定了较高成型质量时成型腔的压缩比范围.     

竹酢液对杉木苗木生长的影响

以1年生Ⅰ级杉木裸根苗为研究对象,通过盆栽试验,比较喷施及土壤施入两种施用方法及7个不同浓度处理下,竹酢液对苗高、地径以及枝叶生物量、根系生物量和主干生物量影响,同时对不同处理下苗木净光合速率的变化特征进行了比较分析。结果表明：竹酢液合理使用可以明显促进苗高和地径的生长、提高枝叶生物量和根系生物量;竹酢液可以提高苗木的净光合速率,改善光合作用;P300和P800两种浓度和施入方法促进杉木苗木生长的作用最明显。     

DROUGHT STRESS: Soil Water Availability Alters the Inter‐ and Intra‐Cultivar Competition of Three Spring Wheat Cultivars Bred in Different Eras

Competition for water generates a classic aspect of the tragedy of the commons, the ‘race for fish’, where crops must allocate more resource to acquisition of the limiting resource than is optimal for crop yield allocation. A pot experiment using a simple additive (target–neighbour) design was conducted to examine the above‐ground and below‐ground growth of three spring wheat (Triticum aestivum L.) cultivars when grown alone and in mixtures at three levels of water availability. The effects of competition and water availability were compared by observing patterns of growth, biomass allocation and below‐ground outcomes. Competitive interactions were investigated among cultivars ‘HST’, ‘GY602’ and ‘LC8275’, target plant of each cultivar grown without neighbouring plants are referred to herein as control plant and one target plant of each cultivar sown surrounded either by same or another cultivar as intra‐ or inter‐cultivar competition. Competitive ability was assessed as the response ratio (lnRR) between the target plant surrounded by six other plants and the target plant in isolation. Our results showed that the cultivar ‘HST’, released over a century ago, produced a higher biomass and grain yield than the more recently released cultivars ‘LC8275’ and ‘GY602’ when grown as isolated plants with sufficient water supply. However, competition for resources from neighbours led to target plant biomass and grain yield being significantly reduced relative to controls in all three cultivars, particularly in ‘HST’. When subjected to intra‐cultivar competition, the two recently released cultivars ‘LC8275’ and ‘GY602’ had higher grain yields and water use efficiency for grain than ‘HST’ in all three water regimes. The landrace ‘HST’ had better and significantly linear relationships between biomass and biomass allocation, root length and specific root length, whereas the recent and modern cultivars had much more water‐related species‐specific changes in root morphology and allocation patterns. These results suggest that crop traits that influence competitive ability, such as biomass allocation to roots and root plasticity in response to drought have changed in modern wheat cultivars because of breeding and selection.     

优化施肥对大豆氮素积累及产量的影响

采用大田试验方法,在两种密度(28、33万株.hm-2)条件下,研究了优化施肥对大豆不同器官的含氮量、氮积累量及产量的影响。结果表明,优化施肥显著提高了大豆植株R6期的含氮量,在高密度条件下,叶片含氮量提高了10.6%,茎秆含氮量提高了11.3%(P<0.05)。优化施肥显著增加了R2~R6阶段的氮素积累,其中R4~R6阶段高密度条件下氮积累量提高了41.4%(P<0.01)。R2~R6阶段的氮素积累与产量呈显著正相关。高密度条件下,优化施肥的产量比常规施肥提高了10.5%(P<0.05)。     

腾冲过路黄的生长动态观察研究

对腾冲过路黄的物候期进行观察，并绘制出物候图谱。测定其各器官生长动态，结果显示：腾冲过路黄的根系集中分布层深度为10～26 cm，其茎含水量平均为82.02％，叶含水量平均为79.87％，根含水量平均为85.68％。采用相关分析及建立生物量一元线性回归方程，茎、叶、根的生物量（干重Y）可分别用Y=0.0213X4.3369、Y=0.0565X3.9657、Y=0.0382X3.517来推测。     

Comparison of nitrogen accumulation and nitrogen utilization efficiency between elite inbred lines and the landraces of maize

Abstract

Inadequate supply of nitrogen (N) fertilizers results in lower N use efficiency (NUE) and higher N losses which cause environmental deterioration, such as nitrate pollution of groundwater and emission of nitrous greenhouse gases. One way to increase NUE is to use N-efficient cultivars, which grow better under reduced N supplies. Both elite inbred lines and landraces are the basis for hybrid breeding in maize. While inbred lines are mostly selected from high N input conditions, landraces are historically distributed in poor soils with low N availability. Therefore, some potential NUE-related traits conserved in the landraces may have been lost during modern breeding processes. In the present study, the N accumulation and utilization efficiency of 15 elite inbred lines and four landraces of maize were compared at low (LN) and high N (HN) input conditions. In general, the grain yields of the inbred lines and the landraces were similar at both N rates. However, nitrogen accumulation ability in landraces was much higher than that of the inbred lines. The high N accumulation of landraces was closely related to their higher biomass, indicating that growth potential is the main driving force for N accumulation. Nevertheless, N utilization efficiency (grain produced per unit N absorbed) of the landraces was significantly lower than that in inbred lines. Correspondingly, assimilation allocation for grain formation, as indicated by the harvest index, was much lower in landraces than in inbred lines. The higher growth potential, and hence, the ability of N accumulation in landraces may be a valuable trait in breeding programs aiming to further improve N use efficiency.     

车筒竹地上生物量分配格局及秆形特征

为评价大型丛生竹种车筒竹Bambusa sinospinosa作为板材原料的适宜性，以毛竹Phyllostachys pubescens为参比竹种，研究了车筒竹地上生物量分配格局及秆形特征。结果表明：车筒竹地上各器官中，竹秆的生物量比例最大，占72.7%，其次为竹枝（15.9）和竹叶（11.4%）；秆形特征主要分析了胸径、秆高、秆质量、尖削度和竹壁厚等参数，其中，车筒竹全高（y/m）对胸径（x/cm）拟合的直线方程为y = 1.345 6x + 1.706 8（R² = 0.954 6，P = 0.000 0）。与毛竹相比，在胸径小于8 cm时，车筒竹全高比毛竹略小，而随着胸径的增大，全高逐渐大于毛竹；车筒竹秆鲜质量（y/kg）对胸径（x/cm）拟合的幂函数曲线为y = 0.138 2x^{2.481 2}（R² = 0.975 5，P = 0.002 2），大于相同胸径下的毛竹秆质量；从秆径和壁厚在竹秆纵向部位的变化看，车筒竹尖削度小于毛竹，而壁厚变化则相对较快。综合分析来看，车筒竹作为竹板材原料竹种具有较大的开发前景。图5表3参21     

毛竹人工林生物量结构变化研究

对会同县经营10年的毛竹人工林林分生物量结构变化进行研究,结果表明:人工竹林不同龄级、径级、枝下高级和不同密度的生物量分配,81.2%生物量分配于1~7年生幼龄、壮龄、中龄竹;83.4%生物量分配于胸径11~15 cm之内;90.7%的生物量分配于枝下高7~11 m之内;86.2%生物量分配于立竹4 500~9 000株/hm2的林分之内,其中立竹4 500~6 750株/hm2的中密度林分,群体和个体生物量都表现出较高的水平。试验竹林垂直总生物量和地上、地下生物量比对照竹林分别增多1.81倍和1.97倍、1.56倍,地上与地下生物量之比为1.774∶1,经济系数为0.501,生物量从大到小的排序,地上部分为秆﹥枝﹥叶﹥凋落物﹥竹箨﹥退笋,地下部分为鞕根﹥竹鞕﹥竹蔸﹥竹根﹥死鞕。     

两种林龄中山杉(Taxodium hybrid 'Zhongshanshan')林地土壤质量评价

以江苏省靖江市牧城公园和东湖公园两种种植年限分别为5 a和9 a的中山杉(Taxodium hybrid'Zhongshanshan')人工林土壤和无林地为研究对象,对0~15 cm、15~30 cm和30~45 cm深度土层土壤理化性质、养分含量和微生物生物量进行了分析。典型相关分析表明,土壤微生物生物量的变化是一个复杂的过程,是土壤各因子共同作用的结果,3种土壤U、V值均表现出层次性,随着土壤深度的增加逐渐降低;不同取样点相同深度土层U、V值为9 a林5 a林对照;单相关分析表明,土壤微生物生物量与速效磷、速效钾、有机质和全氮呈极显著正相关(P0.01),因此土壤微生物可以作为评价中山杉人工林在促进林地土壤质量改善过程中的重要生物指标;主成分分析表明,综合得分最高的9 a林为2.993,其次是5 a林为0.748,作为对照的无林地则为-3.742,说明9 a林地土壤质量最高。可见,中山杉对林下土壤质量有显著提高作用。