气温和根区温度对葡萄叶片光合荧光特性的影响

为探究气温和根区温度对葡萄(Vitis vinifera)叶片光合荧光特性的影响, 以一年生巨峰葡萄为试材, 设置对照、高气温、高根区温度和两者交叉作用共4组处理。结果表明, 相较于对照和高气温, 高根区温度以及交叉处理叶片最大光化学效率(F_v/F_m)降低更明显; 与对照相比, 高根区温度以及高气温与高根区温度交叉处理下光系统II (PSII)实际光化学效率Y(II)显著降低, 非调节能量耗散的量子产量Y(NPQ)及Q_A氧化还原状态(1-q_P)值显著上升。同时, 高根区温度以及高气温与高根区温度交叉处理显著增加了J点的可变荧光(V_j), 而用于电子传递的量子产额(φ_Eo)及性能指数(PI_ABS)显著降低。此外, 高根区温度以及高气温与高根区温度交叉处理下单位面积有活性的反应中心数目(RC/CS_m)也显著下降, K点相对可变荧光(W_k)明显上升。综上所述, 高根区温度是高气温与根区高温交叉胁迫的主导因子, PSII受体侧是主要的伤害位点, 高气温加剧了高根区温度对PSII造成的伤害。     

Testing the association between residential fungus and health using ergosterol measures and cough recordings

Questionnaire surveys in several countries have consistently detected an association between symptoms and residential mould growth. Confirmation by objective measures would strengthen the argument for causality. To address this issue, quantitative and qualitative fungal measures (airborne ergosterol and viable fungi in dust) were compared to respiratory symptoms (n = 403) and nocturnal cough recordings (n = 145) in Canadian elementary schoolchildren during the winter of 1993–1994. There was a 25 percent to 50 percent relative increase in symptom prevalence when mould was reported to be present (p < 0.05). However, neither symptoms nor recorded cough was related to objective measures of mould. In conclusion, the inability to find an association between objective measures of fungus and health suggest that either these objective measures, or the traditionally used questionnaire data are inaccurate. This discrepancy limits the acceptance of a causal relation between indoor fungal growth and illness.This revised version was published online in October 2005 with corrections to the Cover Date.     

A report on <Emphasis Type="Italic">Penicillium</Emphasis> in the intramural and extramural air of residential areas of Nagpur city (India)

Prevalence of different species of Penicillium and their concentrations per cubic meter of air were evaluated with the use of Hi-Air sampler system Mark II (Hi-Media Laboratories Ltd., India) in the air of homes (bed-rooms) at four different sites in Nagpur. At each of these sites, air sampling was done fortnightly in triplicate for 2 years duration from June 2000 to May 2002. The sampling was also done in triplicate for the outdoor air in the vicinity of each home on the same day immediately after the indoor sampling was over. The mean concentration of Penicillium colony forming units at four different sites in the indoor air was 32, 46.9, 35 and 35.4 CFU/m³, respectively, whereas in the outdoor air at these same four sites, the mean concentration was 24, 28, 25 and 25.8 CFU/m³ respectively. The Penicillium concentration in the indoor air was found to be higher in winter than in other seasons (ANOVA, p < 0.05). Concentration of Penicillium spp. in intramural environment was always higher than that in extramural environment. Statistically significant difference existed between intramural and extramural environments at all the sites, with maximum difference at a site, which is old crowded area of the city. During the 2-years investigations, 11 species of Penicillium were isolated from the indoor air while nine species were isolated from the air outside the homes. The dominant species of Penicillium in indoor as well as outdoor air were P. citrinum (33.78 and 32.81), P. oxalicum (19.70 and 22.60), and P. chrysogenum (17.64 and 14.50). The percentage of the Penicillium in the indoor air was 10.70 while it was 8.36 in outdoor air. Indoor air showed the presence of P. glaber and P. sclerotiorum, which were absent in the outdoor air.     

Morphology of the air-breathing stomach of the catfish Hypostomus plecostomus

Histological and ultrastructural investigations of the stomach of the catfish Hypostomus plecostomus show that its structure is different from that typical of the stomachs of other teleostean fishes: the wall is thin and transparent, while the mucosal layer is smooth and devoid of folds. The epithelium lining the whole internal surface of the stomach consists of several types of cells, the most prominent being flattened respiratory epithelial cells. There are also two types of gastric gland cells, three types of endocrine cells (EC), and basal cells. The epithelial layer is underlain by capillaries of a diameter ranging from 6.1-13.1 microm. Capillaries are more numerous in the anterior part of the stomach, where the mean number of capillary sections per 100 microm of epithelium length is 4, compared with 3 in the posterior part. The cytoplasm of the epithelial cells, apart from its typical organelles, contains electron-dense and lamellar bodies at different stages of maturation, which form the sites of accumulation of surfactant. Small, electron-dense vesicles containing acidic mucopolysaccharides are found in the apical parts of some respiratory epithelial cells. Numerous gastric glands (2 glands per 100 microm of epithelium length), composed of two types of pyramidal cells, extend from the surface epithelium into the subjacent lamina propria. The gland outlets, as well as the apical cytoplasm of the cells are Alcian blue-positive, indicating the presence of acidic mucopolysaccharides. Zymogen granules have not been found, but the apical parts of cells contain vesicles of variable electron density. The cytoplasm of the gastric gland cells also contains numerous electron-dense and lamellar bodies. Gastric gland cells with electron-dense cytoplasm and tubulovesicular system are probably involved in the production of hydrochloric acid. Fixation with tannic acid as well as with ruthenium red revealed a thin layer of phospholipids and glycosaminoglycans covering the entire inner surface of the stomach. In regions of the epithelium where the capillaries are covered by the thin cytoplasmic sheets of the respiratory epithelial cells, a thin air-blood barrier (0.25-2.02 microm) is formed, thus enabling gaseous exchange. Relatively numerous pores closed by diaphragms are seen in the endothelium lining the apical and lateral parts of the capillaries. Between gastric gland cells, solitary, noninnervated endocrine cells (EC) of three types were found. EC are characterized by lighter cytoplasm than the surrounding cells and they contain dense core vesicles (DCV) with a halo between the electron-dense core and the limiting membrane. EC of type I are the most abundant. They are of an open type, reaching the stomach lumen. The round DCV of this type, with a diameter from 92-194 nm, have a centrally located core surrounded by a narrow halo. EC of type II are rarely observed and are of a closed type. They possess two kinds of DCV with a very narrow halo. The majority of them are round, with a diameter ranging from 88-177 nm, while elongated ones, 159-389 nm long, are rare. EC of type III are numerous and also closed. The whole cytoplasm is filled with large DCV: round, with a diameter from 123-283 nm, and oval, 230-371 nm long, both with a core of irregular shape and a wide, irregular halo. EC are involved in the regulation of digestion and probably local gas exchange. In conclusion, the thin-walled stomach of Hypostomus plecostomus, with its rich network of capillaries, has a morphology suggesting it is an efficient organ for air breathing.     

Influence of different combinations of bacteria and yeasts in voice prosthesis biofilms on air flow resistance

Laryngectomized patients use silicone rubber voice prostheses to rehabilitate their voice. However, biofilm formation limits the lifetime of voice prostheses. The presence of particular combinations of bacterial and yeast strains in voice prosthesis biofilms has been suggested to be crucial for causing valve failure. In order to identify combinations of bacterial and yeast strains causative to failure of voice prostheses, the effects of various combinations of bacterial and yeast strains on air flow resistances of Groningen button voice prostheses were determined. Biofilms were grown on Groningen button voice prostheses by inoculating so-called artificial throats with various combinations of clinically relevant bacterial and yeast strains. After 3 days, all throats were perfused three times daily with 250 ml phosphate buffered saline and at the end of each day the artificial throats were filled with growth medium for half an hour. After 7 days, the air flow resistances of the prostheses were measured. These air flow resistances were expressed relative to the air flow resistances of the same prostheses prior to biofilm formation. This study shows that biofilms causing strong increases in air flow resistance (26 to 28 cm water.s/l) comprised combinations of microorganisms, involving Candida tropicalis, Staphylococcus aureus and Rothia dentocariosa. This revised version was published online in June 2006 with corrections to the Cover Date.     

A two-phase partitioning bioreactor system for treating benzene-contaminated soil

Benzene-contaminated topsoil, with an organic content of 42%, was treated by an air volatilization process, followed by a two-phase partitioning bioreactor to allow benzene mineralization. The effects of moisture content and temperature on the adsorption and desorption of benzene on to soil were investigated, and 95% of the benzene (at a concentration equivalent to 3.7 kg benzene m^–3 soil^–1) was removed at 50°C by air volatilization. When 30 g soil was contaminated with 1000 mg benzene (a concentration 3 times higher), 93% of the benzene was removed by the air volatilization technique, of which 91% was consumed in a two-phase partitioning bioreactor within 2 h.     

Development of an automation system for a tablet coater

An instrumentation and automation system for a side-vented pan coater with a novel air-flow rate measurement system for monitoring the film-coating process of tablets was designed and tested. The instrumented coating system was tested and validated by film-coating over 20 pilot-scale batches of tablets with aqueous-based hydroxypropyl methylcellulose (HPMC). Thirteen different process parameters were continuously measured and monitored, and the most significant ones were logged for analysis. Laser profilometry was used to measure the surface roughness of the coated tablets. The instrumentation system provided comprehensive and quantitative information on the process parameters monitored. The measured process parameters and the responses of the film-coated tablet batches showed that the coating process is reproducible. The inlet air-flow rate influenced the coating process and the subsequent quality of the coated tablets. Increasing the inlet flow rate accelerated the drying of the tablet surface. At high inlet flow rate, obvious film-coating defects (ie, unacceptable surface roughness of the coated tablets) were observed and the loss of coating material increased. The instrumented and automated pancoating system described, including historical data storage capability and a novel air-flow measurement system, is a useful tool for controlling and characterizing the tablet film-coating process. Monitoring of critical process parameters increases the overall coating process efficiency and predictability.     

Combined effects of air and soil pollution by fluoride emissions on Tibouchina pulchra Cogn., at Cubatão,SE Brazil,and their relations with aluminium

High deposition of gaseous/particulate fluorides and other air pollutants has resulted in an acidification and probable formation of soluble AlF_x complexes in the soil in the vicinity of the industrial complex of Cubatão, SE Brazil. With the present field study we aimed at determining the contribution of F and Al uptake from fluoride-contaminated soil, supposedly as AlF_x complexes, to the increase of foliar F and Al contents in saplings of an Al-accumulator tree species (Tibouchina pulchra) which were concomitantly exposed to fluoride-contaminated air and also the proportional contribution of both air and soil contamination to the mentioned foliar accumulation of these elements. The seasonal variations in F and Al accumulation and possible metabolic changes in the plants due to F and Al accumulation were also investigated. The saplings were exposed during three consecutive periods of 16 weeks to: (a) air and soil from a reference site (PV_noF); (b) air or soil from two polluted sites (CM-high air pollution, low F and MV-high air pollution, high F); and (c) both air and soil from these polluted sites. After exposure, the changes in the foliar concentrations of F and Al, the relations between both element contents and their relationships with oxidative stress indicators were determined. The data were grouped in three matrices: PV_noF–CM_lwF and PV_noF–MV_hgF, taking in account the possible air/soil exposure combinations in each, and soil/air from all sites. The slight F accumulation in plants of PV_noF–CM_lwF matrix was a result of higher uptake from soil than from air (54 and 46%, respectively). At PV_noF–MV_hgF matrix, the extremely high F accumulation in leaves of T. pulchra could be attributed to the combination of both air and soil contamination (83 and 17%, respectively). T. pulchra always showed higher foliar Al concentrations than 1000 g g^–1 dry mass, mainly after exposure to air and soil of both polluted sites (CM_lwF and MV_hgF). A highly significant linear regression was estimated between molar Al and F contents, taking in account the data obtained for saplings of T. pulchra cultivated in the different soils and exposed to ambient air of PV_noF, suggesting that both elements were taken as Al–F complexes from soil. The uptake of fluorides from air and/or soil of MV_hgF caused significant metabolic changes in T. pulchra, but visible injury supposedly induced by fluorides were observed only when the foliar F contents surpassed 700 g g^–1 dry mass. On the contrary, Al did not cause any metabolic stress to the plants.     

More than a 600-fold variation in nitrogen dioxide assimilation among 217 plant taxa

Assimilation of nitrogen dioxide in response to fumigation with ¹⁵N-labelled nitrogen dioxide was studied in 217 plant taxa. The taxa included 50 wild herbaceous plants collected from roadsides (42 genera, 15 families), 60 cultivated herbaceous plants (55 genera, 30 families) and 107 cultivated woody plants (74 genera, 45 families). Two parameters, the 'NO₂-N content', or NO₂-derived reduced nitrogen content in fumigated plant leaves (mg N g^–1 dry weight), and the 'NO₂-utilization index', or percentage of the NO₂-derived reduced nitrogen in the total reduced nitrogen, were determined. The NO₂-N content differed 657-fold between the highest ( Eucalyptus viminalis ; 6·57) and lowest ( Tillandsia ionantha and T. caput-medusae ; 0·01) values in the 217 taxa; 62-fold in a family (Theaceae) and 26-fold in a species ( Solidago altissima ). Nine species had NO₂-utilization indices greater than 10%, of which Magnolia kobus , Eucalyptus viminalis , Populus nigra , Nicotiana tabacum and Erechtites hieracifolia had NO₂-N contents > 4·9. These plants can be considered 'NO₂-philic' because in them NO₂-nitrogen has an important function(s). The Compositae and Myrtaceae had high values for both parameters, whereas the monocots and gymnosperms had low ones. These findings suggest that the metabolic pathway of NO₂-nitrogen differs among plant species. The information presented here will be useful for creating a novel vegetation technology to reduce the atmospheric concentration of nitrogen dioxide.