城市森林土壤肥力质量指标筛选——以南京市为例

土壤质量指标的筛选是科学地进行土壤质量评价的前提.本文以城市森林土壤为研究对象,探讨了土壤肥力指标的筛选方法.采集南京市不同功能区森林土壤样品(0 ～ 20 cm),分析了24个土壤质量指标.根据指标间的相关性和聚类分析结果,筛选出体积质量(容重)、黏粒含量、分散系数、可蚀性因子K值、水稳性指数、pH值、有机质、速效钾和纤维素酶活性,共9个指标作为城市森林土壤肥力质量评价的因子.     

Fluctuations of diptera larvae in soil from a spruce forest in relation to climatic factors

Summary Diptera larvae were extracted by the wash and flotation method according to Healey and Russell-Smith (1970) as modified by Altmüller (1979). The larvae had been kept in alcohol for at least 2 months. After this time their specific gravity changed, and an additional flotation with MgSO₄-water solution of SG = 1.26 g/cm³ was very effective. This new method is described. The working procedure can be reduced to about 50%–70% of the time Altmüller (1979) and Hövemeyer (1984) needed. Many tests have shown that some small sciarid larvae settle out with the needle and humus particles in solution of SG = 1.26 and cannot be found, so that it is necessary to apply a correction factor. Samples taken each August from 1979 to 1984 were extracted and floated off by the methods described. Larvae from seven families of Diptera nematocera and from six families of Diptera brachycera were found. Numbers of sciarid larvae varied between 2500 (1979) and 100/m² (1981), of the cecidomyid larvae between 6700 (1983) and 400/m² (1980) and of the brachyceran larvae between 650 (1979) and 50/m² (1984). The correlation coefficient (= r) of larval population size with temperature and precipitation, respectively, was calculated and hence the coefficient of determination as a percentage (r ² x 100), which represents the proportion of the fluctuations in population size that is accounted for by weather factors. All families were influenced negatively by the temperature and positively by the precipitation in August, i.e., the higher the precipitation and the lower the temperature in August the higher the larval abundance in August. The development of the larvae begins in the previous year, and the influence of monthly climatic factors during the whole period of development was tested. It was shown that: Precipitation is correlated with the abundance of (1) sciarid larvae in June and August of the previous year (positively); (2) brachyceran larvae in June (August) of the previous year and in (February), March, April and August of the same year (positively); and (3) cecidomyid larvae in July of the same year (negatively). Temperature is correlated with the abundance of (1) sciarid larvae in August of the previous year (negatively); (2) brachyceran larvae in August of the previous year (negatively); and (3) cecidomyid larvae in September of the previous year, in January and July of the same year (positively). Monthly data for precipitation and temperature, taken together, showed maximum positive correlations with abundance as follows: (1) for sciarid larvae, with data for August of the previous year; (2) for brachyceran larvae, with data for August of the previous year; (3) for cecidomyid larvae, with data for July of the same year.     

干旱胁迫下白桦主要生理指标的变化及相互关系

以东北林业大学帽儿山实验林场的白桦全同胞子代幼树作为研究材料,通过测定干旱胁迫下样株叶片的生理指标,探讨了在不同施肥条件下白桦对干旱胁迫的反应。结果表明:在土壤干旱胁迫下,施肥处理和未施肥处理的白桦叶片相对含水量和叶片失水率下降,叶片相对电导率和丙二醛的量上升,可溶性糖和可溶性蛋白质量分数先上升后下降,叶片相对含水量与丙二醛的量和可溶性蛋白的质量分数呈显著负相关,非施肥处理可溶性糖质量分数与可溶性蛋白质量分数呈显著正相关。白桦叶片相对含水量、叶片失水率、相对电导率、丙二醛、可溶性蛋白的质量分数在施肥与不施肥2种处理间差异不显著,但进一步分析丙二醛的量和可溶性糖质量分数的变化发现,施肥处理的白桦幼树随着干旱时间的加长丙二醛的积累偏低,而可溶性糖的积累偏高,这意味着施肥处理的白桦相比之下可能对干旱胁迫有较强的耐受性。     

Path Analysis of Important Growth Functions of Indian Mustard (Brassica juncea L. Czern and Coss)

Field experiment conducted at the Viswavidyalaya Farm during the winter seasons of 1980—81 to 1983—84 to study the effects of major six productive functions viz. number of inflorescence bearing primary branches, number of inflorescence bearing secondary branches, leaf area indices at flowering, number of seeds/siliqua, number of siliqua/m² and test weight of grains on the grain yields of eight elite varieties of Indian mustard ( Brassica juncea L. Czern and Coss) when sown on three different times revealed that correlations between them were close and positive in all the varieties. Path analysis of the data, further, showed that except the inflorescence bearing primary branches and the seeds/siliqua all other attributes showed high direct influences on grain yield; the maximum direct influence was obtained from number of siliqua/m².     

Searching a spring wheat mutation resource for correlations between yield,grain size,and quality parameters

To broaden genetic variation, an irradiated wheat (Triticum aestivum L.) M₅ population was generated in the background of spring wheat cv. Almaken. This resource was used to measure components of productivity, including grain number and grain weight (GW) per main spike, GW per plant (GWP), 1000-grain weight (TGW), grain size and grain shape, and some quality parameters. Some mutant lines, mostly in the 200-Gy-dosed germplasm, had 2–4 times higher grain iron and zinc concentrations and 7–11% higher protein content relative to the parent line. Some irradiated lines had significantly larger TGW, and grain area (GA), length, and width than the parent, cv. Almaken. The largest GA and grain length (GL) were 30–40% greater than those of the parent. Correlations for Zn concentration versus GA = 0.191, p ? 0.01, grain protein content (GPC) versus GA = 0.128, p ? 0.05, GPC versus GL = 0.113, p ? 0.05, and GPC versus grain width = 0.191, p?0.001 were observed in 200 Gy-dosed mutants. In 100 Gy-dosed mutants, correlations for Fe concentration versus GWP = 0.302, p ? 0.001 and Fe concentration versus TGW = 0.153, p ? 0.01 were found. The mutant lines showed the capacity to biofortify wheat grain without negatively impacting on crop productivity and this population offers promising donors for improving grain parameters such as GA, length, and width and quality. The data presented showed how the genetic variation generated through radiation could be used to test the linkage between various important grain parameters.     

甘肃旱地冬小麦主栽品种的主要品质指标及其相关性分析

对目前甘肃省旱地冬小麦生产应用的53个品种的籽粒蛋白质、硬度、湿面筋、赖氨酸含量和沉降值等关键品质及其相关性进行了分析。结果表明,甘肃省冬小麦主要品种的营养品质较高,但加工品质相对较差,粗蛋白质含量大部分超过14．00％,低于13．00％含量的品种较少;赖氨酸含量水平主要分布于0．40％～0．50％;湿面筋和沉降值大多数品种处于中下水平。蛋白质含量与赖氨酸、湿面筋含量等指标具有显著相关性,赖氨酸含量与硬度、湿面筋含量也呈显著相关。     

文冠果种粒性状相关性

在文冠果主要分布区采集文冠果种子,并对种子性状数量指标包括种粒长度、种粒直径、种粒质量、种皮质量、种仁质量、种仁体积、种粒体积、种子出仁率等进行测试,对其各性状之间的相关性分析表明,文冠果种粒各性状指标均有较大的变幅,而这种变幅说明了文冠果种粒个体间存在着较大的变异.从种粒各性状的相关性来看,除了种粒长度与种粒直径的线...     

冬小麦品种（系）叶绿素荧光参数的因子分析

为了解小麦叶绿素荧光参数间的相互关系,在大田条件下应用PAM2100型叶绿素荧光仪对18个冬小麦品种（系）叶绿素荧光动力学参数进行了不同生育时期的观测,分析了冬小麦叶绿素荧光参数Fo等14个荧光参数间的相关性,并通过因子分析和聚类分析对其荧光特性进行了综合评价。结果表明,将14个叶绿素荧光参数压缩成可变荧光转换因子、实际量子效率因子、光合因子、稳态荧光产量因子和基础荧光因子5个相互独立的综合指标,分别决定总变异的49.06%、20.25%、15.96%、9.12%和4.30%,累计可表达总变异的98.69%。并通过聚类分析将18个小麦品种（系）划分为3类。     

施氮对海滨锦葵盐胁迫下生物量分配特征及其关联的影响

试验设置NaCl浓度梯度为50、150、250 mmol/L及50、150、250 mmol/L NaCl+15 mmol/L NH4NO3处理海滨锦葵小苗(具3～4枚真叶),每处理5个重复。处理35 d后,施氮显著增加了植株的高度,对主根长度没有影响。高盐下(250 mmol/L NaCl)施氮对主根直径的增粗比较明显。施氮后,显著增加了叶重比,降低了根比重和根冠比,对茎比重没有显著影响。结合主须根比,结果表明施氮抑制了须根的生长,促进了叶的生长。施氮后,增强了根生物量与叶生物量的关联性,有利于提高植株对资源的有效利用和分配。     

沪宁高速公路两侧植物重金属含量与分布特征分析

以沪宁高速公路两侧植物为研究对象,按不同的土地利用方式(有林带和无林带)采集植物样品,分析了尾气排放对植物重金属污染的影响及公路绿色通道建设对重金属污染的防护作用。研究结果表明:(1)杨树叶对Cu、Pb的富集能力较小,但对Zn的富集系数较大;(2)沪宁高速公路两侧杨树叶和黄豆叶中重金属Cu、Pb、Zn的含量均随距公路距离的增加而减少;(3)沪宁高速公路中黄豆叶和杨树叶中重金属含量与土壤中重金属含量没有明显的相关性。