SO2气体对树木叶片叶绿素含量的影响

应用分光光度法研究乌鲁木齐市常见行道树种新疆扬、大叶白腊和新疆大叶榆受ＳＯ２气体危害后,树木叶片叶绿素（ＣＡ、ＣＢ、Ｃｒ）含量的动态变化,以了解其抗性特点。表明,名树种在受危害全进程中其表现不同,树木一身亦具有一定的自调节能力。同时叶绿素在各阶段相对含量的动态变化特点是衡量树种抗性大小的可供参考的有价值指标之一。     

Faecal shield chemical defence is not important in larvae of the tortoise beetle Chelymorpha reimoseri (Chrysomelidae: Cassidinae: Stolaini)

The most frequently investigated defence mechanism among larvae of tortoise beetles is protection by faecal shields, which generally present chemicals that are directly sequestered and/or modified from larval host-plants. In the present work we investigate the tortoise beetle Chelymorpha reimoseri that feeds on the leaves of Ipomoea carnea fistulosa (Convolvulaceae), seeking for the importance of this mechanism to their larvae. We show that 4th instar larvae suffer low predation regardless of the presence of shields in field and laboratory bioassays with ants and chicks. Chloroform extract from larvae without shields provided high protection against predation as shown in bioassays in the field, as well as against chicks, suggesting that C. reimoseri does not rely on the shield for protection. The aqueous extract of the shields did not show activity in such bioassays. The compounds responsible for this protection have yet to be identified, and it remains an open question as to whether they are sequestered from the host plant or de novo biosynthesized. This is the first record of chemical defence in cassidine beetles without the need for faecal shields. These findings indicate that more attention should be paid to chemicals present in the tissues of larvae and/or adults of tortoise beetles; the protective compounds sequestered from host plants or de novo biosynthesized can provide an alternative or complementary strategy against predation in these insects.     

Mathematical analysis of change in forest carbon use efficiency with stand development: A case study on Abies veitchii Lindl.

Changes in carbon use efficiency (CUE), which is defined as the ratio of net primary production (NPP) to gross primary production (GPP), were analyzed for Abies veitchii Lindl. forests with respect to stand development by developing a simple mathematical model incorporating data on physiological variables and leaf mass ratio. A decrease in CUE with stand development was successfully expressed as a function of stand biomass (y) based on the following three assumptions: (1) a power-law relationship between mean respiration and mean individual tree mass, (2) a power-functional relationship between mean gross primary production and mean individual tree mass, and (3) self-thinning relationship between stand biomass and density. Based on this model, a parameter of CUE–y relationship was defined, and it was clarified that CUE decrease with stand development is caused not by the ratio of specific respiration rate to specific gross photosynthetic rate, but by leaf mass ratio. Since CUE is high in young forests, helpful information on selecting woody species when planting seedlings was provided from the viewpoints of reducing CO₂ in the atmosphere and global warming.     

磷矿矿山顶板稳定性分级方法

冒顶片帮事故是地下矿山危害最为严重的事故,矿山地压管理是地下开采矿山安全管理的重要任务.顶板稳定性分析是地压管理的重要方法.提出了顶板稳定性分级的指标和分级方法.首次指出风化作用对顶板稳定性的影响,并就地下水对顶板稳定性的影响进行了分析.     

Effects of chronic elevated ozone exposure on gas exchange responses of adult beech trees (Fagus sylvatica) as related to the within-canopy light gradient

The effects of elevated O₃ on photosynthetic properties in adult beech trees (Fagus sylvatica) were investigated in relation to leaf mass per area as a measure of the gradually changing, within-canopy light availability. Leaves under elevated O₃ showed decreased stomatal conductance at unchanged carboxylation capacity of Rubisco, which was consistent with enhanced δ¹³C of leaf organic matter, regardless of the light environment during growth. In parallel, increased energy demand for O₃ detoxification and repair was suggested under elevated O₃ owing to enhanced dark respiration. Only in shade-grown leaves, light-limited photosynthesis was reduced under elevated O₃, this effect being accompanied by lowered F_v/F_m. These results suggest that chronic O₃ exposure primarily caused stomatal closure to adult beech trees in the field regardless of the within-canopy light gradient. However, light limitation apparently raised the O₃ sensitivity of photosynthesis and accelerated senescence in shade leaves.     

Anthocyanins and tannins in ozone-fumigated guava trees

Psidium guajava “Paluma”, a tropical tree species, is known to be an efficient ozone indicator in tropical countries. When exposed to ozone, this species displays a characteristic leaf injury identified by inter-veinal red stippling on adaxial leaf surfaces. Following 30 days of three ozone treatments consisting of carbon filtered air (CF – AOT40 = 17 ppb h), ambient non-filtered air (NF – AOT40 = 542 ppb h) and ambient non-filtered air + 40 ppb ozone (NF + O₃ – AOT40 = 7802 ppb h), the amounts of residual anthocyanins and tannins present in 10 P. guajava (“Paluma”) saplings were quantified. Higher amounts of anthocyanins were found in the NF + O₃ treatment (1.6%) when compared to the CF (0.97%) and NF (1.30%) (p < 0.05), and of total tannins in the NF + O₃ treatment (0.16%) compared to the CF (0.14%). Condensed tannins showed the same tendency as enhanced amounts. Regression analyses using amounts of tannins and anthocyanins, AOT40 and the leaf injury index (LII), showed a correlation between the leaf injury index and quantities of anthocyanins and total tannins. These results are in accordance with the association between the incidence of red-stippled leaves and ozone polluted environments.     

北京道路降尘排放特征研究

道路扬尘是城市大气颗粒物主要来源之一,本研究采用降尘法监测北京道路扬尘并分析降尘排放特征。对北京不同类型道路共40条,每条道路布置2个降尘监测点,并对背景降尘值进行了监测,道路降尘(DFr)与背景降尘(DFb)的差值作为道路自身降尘(ΔDF)。结果显示,快速路、主干道、次干道和支路的ΔDF分别为18.9、13.9、9.9和9.7 t/(km2.30 d),降尘值比例为100∶74∶52∶51,单辆车引起的降尘比例为1.00∶2.55∶5.20∶5.67;夏季道路降尘量最大,其次为冬季。以一年为周期,道路月均降尘为ΔDF,则1~4月份交通降尘量为0.72~0.94ΔDF,5~8月份降尘量为1.10~1.30ΔDF,9~12月份月降尘量为0.96~0.99ΔDF;不同类型道路ΔDF数据均呈偏态分布,道路降尘不同季节也均为偏态分布。道路降尘量与车流量呈正线性相关。     

Effects of ozone on growth, yield and leaf gas exchange rates of four Bangladeshi cultivars of rice (Oryza sativa L.)

To assess the effects of tropospheric O₃ on rice cultivated in Bangladesh, four Bangladeshi cultivars (BR11, BR14, BR28 and BR29) of rice (Oryza sativa L.) were exposed daily to charcoal-filtered air or O₃ at 60 and 100 nl l⁻¹ (10:00-17:00) from 1 July to 28 November 2008. The whole-plant dry mass and grain yield per plant of the four cultivars were significantly reduced by the exposure to O₃. The exposure to O₃ significantly reduced net photosynthetic rate of the 12th and flag leaves of the four cultivars. The sensitivity to O₃ of growth, yield and leaf gas exchange rates was not significantly different among the four cultivars. The present study suggests that the sensitivity to O₃ of yield of the four Bangladeshi rice cultivars is greater than that of American rice cultivars and is similar to that of Japanese rice cultivars and that O₃ may detrimentally affect rice production in Bangladesh.     

Dust deposition in a sub-tropical opencast coalmine area, India

This paper provides baseline information about the total annual dust fall, and its constituents and seasonal variation, from a sub-tropical opencast coalmine area in Bina, India. Dust samples were collected monthly for 2 years (June 2002-May 2004) from five sampling sites in the region and analyzed in the laboratory for water-soluble and -insoluble matter. Water-insoluble components constituted the major fraction of the total annual dust fall. Two-way ANOVA indicated significant variations in dust fall at different sites, over the months and in their interactions. The dust deposition rate was highest during summer (March-June), followed by winter (November-February) and lowest in the rainy season (July-October). Maximum dust fall was observed near the coal handling plant (at site 2) followed by the receiving pit of the coal handling plant (site 3), near the main sub-station (site 4), Jawahar colony (site 1) and Gharasari village (site 5). An inverse and significant relation was observed between dust fall and precipitation. Our studies have shown that the main residential areas are experiencing higher levels of dust fall which makes them unsuitable for living. We suggest that residential areas should be moved farther away from the mining area in the opposite direction of prevalent winds.     

道路降尘与扬尘PM_(10)排放的关系研究

道路扬尘是城市大气颗粒物主要来源之一,文章主要分析呼和浩特城区道路降尘排放、扬尘PM10排放强度并研究二者之间的关系。对呼和浩特30条典型道路进行了降尘监测,并在降尘监测期间对道路尘负荷进行了采样分析,同时记录车流量和车辆构成数据,应用AP-42排放因子模型计算PM10排放强度,分析道路降尘与PM10排放强度之间的关系。结果发现,道路降尘值为外环路>主干路>次干路>支路>胡同,分别为76.3、36.1、31.7、25.8和19.0 t(/km.230d),背景值为9.4 t(/km.230d);外环路、主干道、次干道、支路和胡同的PM10排放强度平均值分别为178、169、130、100和11 kg(/km.d);降尘值DF与道路扬尘PM10排放强度呈现较好的正相关关系,道路扬尘PM10排放强度可以用降尘表示为Q=2.6×(DFr-DFb)。