Association between ambient air pollution and thyroid hormones levels: A systematic review and meta-analysis.

BACKGROUND: Growing studies have focused on the effects of ambient air pollution on thyroid hormones (THs), but the results were controversial. Therefore, a systematic review and meta-analysis was conducted by pooling current evidence on this association. METHODS: Four databases were searched for studies examining the associations of particulate matter [diameter ≤10 µm (PM10) or ≤2.5 µm (PM2.5)] and gaseous [sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), carbon monoxide (CO)] pollutants with THs levels. Random effects models were used to pool the changes in THs levels with increasing air pollutant concentrations. Subgroup analyses were constructed by region, design, sample size, pollutant concentrations, evaluated methods, and potential risk exposure windows. RESULTS: A total of 14 studies covering 357,226 participants were included in this meta-analysis. The pooled results showed significant associations of exposure to PM2.5, PM10, NO2, SO2, and CO with decreases in free thyroxine (FT4) with percent changes (PC) ranging from -0.593 % to -3.925 %. PM2.5, NO2, and CO were negatively associated with levels of FT4/FT3 (PC: from -0.604 % to -2.975 %). In addition, results showed significant associations of PM2.5 with hypothyroxinemia and high thyroid-stimulating hormone (TSH). Subgroup analyses indicated that PM2.5 and NO2 were significantly associated with FT4 in studies of Chinese, and similar significant findings were found in studies of PM2.5 and FT4/FT3 in areas with higher concentrations of air pollutants and larger samples. PM2.5 exposure in the first trimester was found to be associated with lower FT4 levels in pregnant women. CONCLUSION: Our findings suggest that exposure to air pollution is associated with changes in THs levels. Enhanced management of highly polluted areas, identification of harmful components and sources of PM, and protection from harmful exposures in early pregnancy may be of great public health importance for the population's thyroid function.

Highly Prevalent SARS-CoV-2 Antigenemia in COVID-19 Patients.

Background: Many issues, such as severity assessment and antibody responses, remain to be answered eagerly for evaluation and understanding of COVID-19. Immune lesion is one of key pathogenesis of the disease. It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection. Methods: A total of 156 patients admitted to the First People's Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study. SARS-CoV-2 nucleocapsid (NP) antigen, specific IgM/IgG antibodies, and RNA were detected in sequential sera from three COVID-19 patients, and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay, colloidal gold quick diagnosis, and real-time RT-PCR, respectively. The clinical types of COVID-19 patients were classified into asymptomatic, mild, moderate, severe, and critical, following on the Chinese guideline of COVID-19 diagnosis and treatment. The demographic and clinical data of patients were obtained for comparable analysis. Results: NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms, and 60.13% (92/153) expanded samples collected within 17 days after illness onset. No SARS-CoV-2 RNA segment was detected in these sera. The NP positive proportion reached a peak (84.85%, 28/33) on 6 to 8 days after illness onset. Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19. Compared to NP negative patients, NP positive patients had older age [years, medians (interquartile ranges (IQR)), 49 (6) vs. 31 (11)], lower positive proportion of NP specific IgM [27.17% (25/92) vs. 59.02% (36/61)], and IgG [21.74% (20/92) vs. 59.02% (36/61)] antibodies, and longer duration [days, medians (IQR), 24 (10) vs. 21 (13)] from illness to recovery. Conclusions: SARS-CoV-2 NP antigenemia occurred in COVID-19, and presented highly prevalent at early stage of the disease. The antigenemia was related to clinical severity of the disease, and may be responsible for the delay of detectable SARS-Cov-2 IgM.

The contrasting relationships of relative humidity with influenza A and B in a humid subtropical region.

Influenza is an acute respiratory disease that seriously threatens public health. The occurrence of influenza has been proved to be related to a variety of meteorological factors. However, less attention has been paid to the effect of relative humidity (RH) on different types of influenza, especially in subtropical regions. Daily data on laboratory-confirmed influenza cases, weather variables, and air pollutants in Hefei covering the 2014-2019 period were collected. The seasonality and trend of daily influenza cases were explored by the time series seasonal decomposition method. Generalized linear model was fitted in conjunction with distributed lag nonlinear model to quantify the associations of RH with influenza A and influenza B. Subgroup analyses were conducted by sex, age (0-4, 5-17, and ≥18 years), and season (cold and warm seasons). A total of 5238 influenza cases including 2847 influenza A cases and 2391 influenza B cases were recorded. The epidemic of influenza presented a distinct seasonal pattern, and the number of daily influenza cases increased steadily since 2016. High RH was related to an increased risk of influenza A (maximum RR = 1.683, 95%CI: 1.365-2.076), especially among males, females, and school-age children. Low RH was associated with an increased risk of influenza B (maximum RR = 1.252, 95%CI: 1.169-1.340). The contrasting relationships of RH with influenza A and B remained significant in cold seasons. High RH and low RH were significantly associated with the increased risk of influenza A and B, respectively. The findings of our study may provide clues for proposing new effective interventions.

Deep Learning to Predict EGFR Mutation and PD-L1 Expression Status in Non-Small-Cell Lung Cancer on Computed Tomography Images.

OBJECTIVE: The detection of epidermal growth factor receptor (EGFR) mutation and programmed death ligand-1 (PD-L1) expression status is crucial to determine the treatment strategies for patients with non-small-cell lung cancer (NSCLC). Recently, the rapid development of radiomics including but not limited to deep learning techniques has indicated the potential role of medical images in the diagnosis and treatment of diseases. METHODS: Eligible patients diagnosed/treated at the West China Hospital of Sichuan University from January 2013 to April 2019 were identified retrospectively. The preoperative CT images were obtained, as well as the gene status regarding EGFR mutation and PD-L1 expression. Tumor region of interest (ROI) was delineated manually by experienced respiratory specialists. We used 3D convolutional neural network (CNN) with ROI information as input to construct a classification model and established a prognostic model combining deep learning features and clinical features to stratify survival risk of lung cancer patients. RESULTS: The whole cohort (N = 1262) was divided into a training set (N = 882, 70%), validation set (N = 125, 10%), and test set (N = 255, 20%). We used a 3D convolutional neural network (CNN) to construct a prediction model, with AUCs of 0.96 (95% CI: 0.94-0.98), 0.80 (95% CI: 0.72-0.88), and 0.73 (95% CI: 0.63-0.83) in the training, validation, and test cohorts, respectively. The combined prognostic model showed a good performance on survival prediction in NSCLC patients (C-index: 0.71). CONCLUSION: In this study, a noninvasive and effective model was proposed to predict EGFR mutation and PD-L1 expression status as a clinical decision support tool. Additionally, the combination of deep learning features with clinical features demonstrated great stratification capabilities in the prognostic model. Our team would continue to explore the application of imaging markers for treatment selection of lung cancer patients.

Epidemiological characteristics of severe fever with thrombocytopenia syndrome in Hefei of Anhui Province: a population-based surveillance study from 2011 to 2018.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease caused by the SFTS virus (SFTSV) of family Phenuiviridae. Since the virus was first identified in 2009, it has been rapidly spread in many Asian countries including Myanmar, Korea, Japan, and central China. In this study, we investigated the epidemiological characteristics of SFTS patients in Hefei from 2011 to 2018. In addition, we conducted a serological survey of SFTSV-specific antibody among healthy residents of five counties. We performed a retrospective observational study of SFTS cases reported to Hefei Center for Disease Control and Prevention (CDC) during Jan 2011 to Dec 2018. Almost every patient completed a structure questionnaire including clinical examination, course of disease, and history of epidemiology. A total of 754 serum specimens were collected and tested for IgG antibody with double-antigen sandwich ELISA method. Of 257 cases reported during that period, 33 died, with a case fatality rate of 13.0%. We found no significant difference between 30 non-survivors and 198 survivors except for age. The overall rate of seropositivity for SFTSV antibodies among healthy residents were 20.16%. We demonstrated that living in hilly areas, direct contact with domestic livestock and knowledge of tick-borne disease were significantly associated with positive serology result. SFTSV infection was prevalent among farming-related populations. Our study identified a relatively high seroprevalence of SFTSV-specific antibody in healthy residents, which provided the basis for asymptomatic SFTSV infections. More attention should be given to susceptible population and prevent SFTSV outbreak in high-endemic areas.

A hospital cluster combined with a family cluster of avian influenza H7N9 infection in Anhui Province, China.

OBJECTIVES: To identify human-to-human transmission of H7N9 avian influenza virus, we investigated a hospital cluster combined with family cluster in this study. METHODS: We obtained and analyzed clinical, epidemiological and virological data from the three patients. RT-PCR, viral culture and sequencing were conducted for determination of causative pathogen. RESULTS: The index case presented developed pneumonia with fever after exposure to chicken in a poultry farm. Case A presented pneumonia with high fever on day 3 after she shared a hospital room with the index case. Case B, the father of the index case, presented pneumonia with high fever on day 15 after he took care of the index case. H7N9 virus circulated in the local farm to which the index case was exposed. Full genomic sequence of virus showed 99.8-100% identity shared between the index case and case A or case B. Compared to the earliest virus of Anhui, a total of 29 amino acid variation sites were observed in the 8 segments. CONCLUSIONS: A hospital cluster combined with family cluster of H7N9 avian influenza infection was identified. Air transmission resulted in the hospital cluster possibly. A poultry farm was the initially infectious source of the cluster.

Effects of air pollutants on occurrences of influenza-like illness and laboratory-confirmed influenza in Hefei, China.

Accumulating evidence suggests that air pollution is a risk factor for adverse respiratory and cardiovascular health outcomes. However, the different impacts of exposure to air pollutants on influenza virus activity and influenza-like illness (ILI) have not been well documented in epidemiological studies. We examined the association between air pollutants of particular matters < 2.5 µm (PM2.5), particular matters < 10 µm (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), and influenza occurrences in Hefei, China, from December 2013 to December 2015 by generalized Poisson additive regression models. The result suggested that PM2.5 and PM10 had similar effects on clinical ILI and influenza incidence. PM10 was negatively associated with clinical ILI (relative risk (RR) 0.980, 95% confidence interval (CI) 0.974-0.987), while PM2.5 were positively associated with clinical ILI (RR 1.040; 95% CI 1.032-1.049). RRs for the laboratory-confirmed cases of influenza were 0.813 (95% CI, 0.755-0.875) for PM10 and 1.216 (95% CI, 1.134-1.304) for PM2.5. Nevertheless, the impacts of SO2 and NO2 on ILI and influenza were distinct. SO2 had significant influence on laboratory-confirmed influenza and had no significant linear relationship with ILI. NO2 was negatively correlated with influenza but had no obvious effect on clinical ILI cases. The present study contributes novel evidence on understanding of the effects of various air pollutants on influenza activities, and these findings can be useful and important for the development of influenza surveillance and early warning systems.

Seasonal pattern of influenza activity in a subtropical city, China, 2010-2015.

Influenza seasonality study is critical for policy-makers to choose an optimal time for influenza vaccination campaign, especially for subtropical regions where influenza seasonality and periodicity are unclear. In this study, we explored the seasonality and periodicity of influenza in Hefei, China during 2010 to 2015 using five proxies originated from three data sources of clinical surveillance of influenza-like illness (ILI), laboratory surveillance of influenza and death registration of pneumonia and influenza. We combined both wavelets analysis and de-linear-trend regression with Fourier harmonic terms to estimate seasonal characteristics of epidemic phase, peak time, amplitude, ratio of dominant seasonality. We found both annual cycle of influenza epidemics peaking in December-February and semi-annual cycle peaking in December-February and June-July in subtropical city Hefei, China. Compared to proxies developed by ILI and death registration data separately, influenza proxies incorporated laboratory surveillance data performed better seasonality and periodicity, especially in semi-annual periodicity in Hefei. Proxy of ILI consultation rate showed more timeliness peak than other proxies, and could be useful in developing the early warning model for influenza epidemics. Our study suggests to integrate clinical and laboratory surveillance of influenza for future influenza seasonality studies in subtropical regions.

Excess mortality associated with influenza after the 2009 H1N1 pandemic in a subtropical city in China, 2010-2015.

OBJECTIVES: The aim of this study was to use a quasi-Poisson regression model to estimate the mortality burden associated with influenza type/subtypes in a subtropical city in China, for the years 2010-2015. METHODS: Quasi-Poisson models were fitted separately to weekly numbers of deaths from various causes. The exploratory variables were products of weekly proportions of specimens positive for influenza type/subtypes and weekly influenza-like illness consultation rates to represent influenza activity. Adjustments were made for long-term and seasonal trends, absolute humidity, and population size as confounding factors in the models. Excess deaths associated with influenza were regarded as the measurement for disease burden of influenza. RESULTS: The excess mortality for all-cause death associated with influenza was 9.9 per 100000 population in Hefei, with influenza A(H3N2) virus having the highest excess mortality rate, followed by influenza A(H1N1) virus and influenza B virus. Following the 2009 H1N1 pandemic, the highest excess mortality rate associated with influenza for different causes was consistently found in the year 2014, with the excess mortality rate for all-cause death reaching 17.47 per 100000 population. The sex differences in influenza-associated mortality were not statistically significant (p>0.05). CONCLUSIONS: The mortality burden of influenza has been substantial in Hefei since the 2009 influenza pandemic, while the evidence on sex differences in mortality burden is limited. The severity profile of influenza type/subtypes in China needs to be assessed and confirmed in more cities in future studies.

Nonlinear and Interactive Effects of Temperature and Humidity on Childhood Hand, Foot and Mouth Disease in Hefei, China.

BACKGROUND: Hand, foot and mouth disease (HFMD) is one of the major infectious diseases among children and remains a health threat, especially among Asian countries. Many epidemiologic studies suggested significant association of air temperature and humidity with childhood HFMD; however, evidence on the temperature effects on childhood HFMD in temperate cities is limited, and the interactive effects of temperature and humidity have not been studied yet. METHODS: Daily counts of HFMD in children younger than 15 years of age and daily meteorologic variables during 2010 to 2012 were obtained in Hefei, China. A distributed lag nonlinear model was applied to estimate the potential nonlinear association between temperature and childhood HFMD. The interactive effects between temperature and humidity on childhood HFMD were also investigated. RESULTS: Temperature rise was associated with higher risk of childhood HFMD. Within the incubation period of HFMD, temperature rise appeared to have the acute effects on childhood HFMD, and a 5°C increase of temperature at lag 0-6 days was associated with 24.8% (95% confidence interval: 11.94%-39.10%) increase of childhood HFMD. Females and children of 0-4 years of agewere more vulnerable to temperature rise. Notably, there were obvious combined effects between temperature and humidity on childhood HFMD-the risk of childhood HFMD elevated at higher temperature and humidity level. CONCLUSIONS: This study provides evidence that temperature and humidity may jointly affect childhood HFMD, and such interactive impact needs to be considered when evaluating the temperature-childhood HFMD relationship.

The association between diurnal temperature range and childhood bacillary dysentery.

Previous studies have found that mean, maximum, and minimum temperatures were associated with bacillary dysentery (BD). However, little is known about whether the within-day variation of temperature has any impact on bacillary dysentery. The current study aimed to identify the relationship between diurnal temperature range (DTR) and BD in Hefei, China. Daily data on BD counts among children aged 0-14 years from 1 January 2006 to 31 December 2012 were retrieved from Hefei Center for Disease Control and Prevention. Daily data on ambient temperature and relative humidity covering the same period were collected from the Hefei Bureau of Meteorology. A Poisson generalized linear regression model combined with a distributed lag non-linear model (DLNM) was used in the analysis after controlling the effects of season, long-term trends, mean temperature, and relative humidity. The results showed that there existed a statistically significant relationship between DTR and childhood BD. The DTR effect on childhood bacillary dysentery increased when DTR was over 8 °C. And it was greatest at 1-day lag, with an 8% (95% CI = 2.9-13.4%) increase of BD cases per 5 °C increment of DTR. Male children and children aged 0-5 years appeared to be more vulnerable to the DTR effect. The data indicate that large DTR may increase the incidence of childhood BD. Caregivers and health practitioners should be made aware of the potential threat posed by large DTR. Therefore, DTR should be taken into consideration when making targeted health policies and programs to protect children from being harmed by climate impacts.

[Effects of electromagnetic radiation on health and immune function of operators].

OBJECTIVE: To investigate the effects of electromagnetic radiation on the physiological indices and immune function of operators. METHODS: The general conditions and electromagnetic radiation awareness rate of 205 operators under electromagnetic radiation were evaluated using a self-designed questionnaire. Physical examination, electrocardiography, and routine urine test were performed in these operators. Peripheral blood was collected from the operators under electromagnetic radiation for blood cell counting and biochemical testing, and their peripheral blood lymphocytes were cultured for determination of chromosomal aberrant frequency and micronucleus frequency. The data from these operators (exposure group) were compared with those of 95 ordinary individuals (control group). RESULTS: The chief complaint of giddiness, tiredness, dizziness, and amnesia showed significant differences between the exposure group and control group (P < 0.01), and the difference in headache became larger with an increase in working years. The awareness rate of electromagnetic radiation damage was significantly higher in the exposure group than in the control group. The difference in bradycardia was significant between the two groups (P <0.01), and the incidence was higher with longer working years. Significant differences between the two groups were also found in the numbers of individuals with elevated alanine aminotransferase, total bilirubin, and direct bilirubin (P < 0.01), populations with increased lymphocyte ratio and decreased neutrophil ratio (P < 0.01), populations with positive occult blood, urobilinogen, and bilirubin tests, and the number of individuals with increased micronucleus frequency of cultured peripheral blood lymphocytes (P < 0.01). In addition, the exposure group had significantly increased complement C3 and C4 (P < 0.01), significantly increased IgG (P < 0.05), and significantly decreased IgM (P < 0.01), as compared with the control group. CONCLUSION: Electromagnetic radiation may lead to the changes in physiological indices, genetic effects, and immune function and affect the health and immune function in operators. The adverse effects are increased as the working years increase. So it is important to strengthen occupational protection of operators under electromagnetic radiation.

Growth response to ionic and osmotic stress of NaCl in salt-tolerant and salt-sensitive maize.

Salt-tolerant maize (STM) and salt-sensitive maize (SSM) were treated with 100 mM NaCl for 1, 3 and 6 d and the contents of Na+ and Cl(-) (cps) of different organelles of leaf cells determined by X-ray microanalysis. The results showed that Na+ and Cl(-) entered the cytoplasm, vacuole, chloroplast and apoplast simultaneously. When STM and SSM were treated in 100 mM NaCl at atmospheric pressure (-P) and with pressure equivalent to the osmotic pressure of the NaCl (+P), the dry weights of STM (+P) and SSM (+P) plants were greater than that of STM (-P) and SSM (-P) plants, showing that the inhibitory effect of salt on plant growth was at least partially due to the osmotic effect of the NaCl. When STM and SSM were treated with NaCl and iso-osmotic polyethlene glycol, the dry weights of plants given the iso-osmotic polyethlene glycol treatment were lower for both maize lines than that of the NaCl-treated plants. Our data show that under NaCl stress, both STM and SSM seedlings simultaneously suffered from osmotic and ion stresses.

Association between transforming growth factor-beta1 T869C polymorphism and rheumatoid arthritis: a meta-analysis.

OBJECTIVE: The results of studies on association between TGF-beta1 T869C polymorphism and susceptibility to RA are controversial. The absence of a replication of linkage might be due to different ethnicities. The aim of this study was to perform a preliminary investigation on the effect size of TGF-beta1 T869C polymorphism on RA susceptibility through a meta-analysis. METHODS: Case-control studies on the association of TGF-beta1 T869C with RA were searched up to March 2009, and the genotype frequencies in the control group were found to be consistent with the Hardy-Weinberg equilibrium. The effect summary odds ratio (OR) and 95% CIs were obtained. Publication bias was tested by funnel plot with Egger's regression test, and heterogeneity was assessed. RESULTS: Seven studies comprising 1122 cases and 1132 controls were included. Heterogeneity was observed (chi(2 )= 17.16; P = 0.009). Under the random effects model, the common OR was 1.38 (95% CI 0.95, 2.01; P = 0.09). In the subgroup meta-analysis, there was an association between TGF-beta1 T869C polymorphism and RA in the people of Asian descent (OR = 1.93; 95% CI 1.42, 2.62; P < 0.0001), but not in the people of non-Asian descent (OR = 0.88; 95% CI 0.65, 1.19; P = 0.41). There was no evidence of publication bias according to Funnel plot and Egger's regression test (a = 4.778; P = 0.14). CONCLUSIONS: There was heterogeneity between studies, and no clear evidence of an association on a worldwide population was observed. Subgroup analysis results suggest that TGF-beta1 T869C might play a role in RA susceptibility for Asians but not for non-Asians. Further studies are required for definite conclusions.

Self-concept and mental health status of 'stay-at-home' children in rural China.

AIM: To describe the self-concept and mental health status of 'stay-at-home' children and to explore the differences between stay-at-home children and non-stay-at-home children. METHODS: A cross-sectional survey was conducted in Changfeng County to collect information on self-concept and mental health status. Children were classified as 'stay-at-home' or 'non-stay-at-home' for data analysis. RESULTS: Stay-at-home children accounted for 55.1% of children. The two groups of children differed significantly on the total scores of self-concept (stay-at-home, 52.48 +/- 14.29; non-stay-at-home, 55.24 +/- 15.10). The mental health status of stay-at-home children was poor, with significant difference between them (stay-at-home, 41.17 +/- 12.25; non-stay-at-home, 40.14 +/- 13.11). Using multivariate linear regression analysis, we found that the total P-H score, gender, low family economic status, stay-at-home status and being cared for by an uncle/aunt or an older sibling were independent variables for mental health of the children. CONCLUSION: This study suggests that stay-at-home children have a greater risk of mental health problems than their counterparts in rural Anhui province, China. In addition, this study provides useful baseline information on childhood mental health and has identified important risk factors that would be important in planning strategies for prevention of mental health problems for stay-at-home children.

[Study on the distribution and risk factors of injuries among home-stranded children in rural area of Anhui province].

OBJECTIVE: To explore the distribution and risk factors of injuries among home-stranded children and living in rural area of Anhui province and to provide basic information for the development of injury intervention program. METHODS: 3617 students were recurited from Changfeng county of Anhui province with stratified sampling method and a survey was conducted using questionnaires. Unconditional univariate and multivariate logistic regression analysis were performed to evaluate the situation of unintentional injuries among 1614 home-stranded children during the past one year and on its influencing factors. RESULTS: The number of home-stranded children accounted for 45.83% of the total number of students with the main type of guardianship was single-parent (55.82%). The incidence of injuries of students was 32.25%. The incidence of injuries of boys (36.43%) was higher than that of girls (27.44%) (chi2 = 32.340, P = 0.000). The incidence of injuries among children was 32.25% but among children away from it was 40.90%, significantly higher than that of children with parents (24.95%) (chi2 = 101.730, P = 0.000). Seven kinds of injures including fall, transportation or animal-related factor for children who were away from their parents, were higher than that of children with parents around. Data from Univariate analysis showed that injuries of children without family around were associated with gender, monthly income, education level of mother, type of guardianship, introversion-extroversion, neuroticism, cohesion, conflict, independence, active-recreational orientation, intellectual-cultural orientation. Results from multivariate analysis indicated that injuries of home-stranded children were associated with gender (OR = 0.598), being the only child (OR = 1.445), introversion-extroversion (OR = 1.062), cohesion (OR = 0.933), conflict (OR = 1.150), independence (OR = 1.110), intellectual-cultural orientation (OR = 0.928), active-recreational orientation (OR = 1.096) and ability of self-control (OR = 0.917). CONCLUSION: Many factors were found to be involved in injuries among children who were away from parents, especially regarding family environment and the individual personality. Special preventive measures should be taken to reduce the incidence of injuries among rural children who were away from their parents.

[Effects of salt stress on the contents of chlorophyll and organic solutes in Aeluropus littoralis var. sinensis Debeaux].

After seedlings of Aeluropus sinensis var. sinensis Debeaux were treated with different NaCl concentrations (0-200 mmol/L) for 14 days, some physiological indexes were measured. The higher the NaCl concentration, the more the growth of A. sinensis was inhibited. The increase in root/shoot ratio suggests that the shoots are more sensitive to salinity than the roots. The diminished leaf area may reduce the transpiration rate, and the root mainly grew longitudinally, which may help the root to reach the water source under the high salinity conditions. Chl a contents increased, so did Chl b, but the Chl a/Chl b ratio declined, which implies the stimulation of Chl a accepted from NaCl is smaller than that of Chl b. After salt treatment, the organic solute contents increased (P<0.05), the proline, amino acids and soluble sugar contents increased more than organic acids, the increase in soluble carbohydrate may inhibit photosynthesis in feedback. The percentage of sucrose in soluble carbohydrates increased too. Although the organic dry weight of whole plant declined, the proportion of organic dry weight in total dry weight increased, and the osmotic potential of plant cell juice declined, which implies that the contribution of organic matter to osmotic adjustment increased with salinity. That is, A. sinensis had ability to tolerate salinity to a certain degree.

[The morphological structure of salt gland and salt secretion in Aeluropus littoralis var. sinensis Debeaux].

The leaves of Aeluropus littoralis var. sinensis Debeaux were scanned with a scanning electron microscope, it showed that the upper-epidermis had almost the same number of salt glands as the lower-epidermis (Plate I-1, 2), and the salt gland is the typical bicelluar gland, which consists of a large basal cell inlaid into the epidermis and a small cap cell (Plate I-6). These salt glands were distributed mainly on the leaf veins, which favors the rapid collection of salts from the roots. Ion X-ray microanalysis indicated that the salt glands could effectively absorb Na(+) from the epidermal cells and mesophyllous cells (Table 1), then secreted Na(+) from the cap cells (Plate I-4), which would decrease the salinity of plant. After the plants were treated with various salts for 17 d, the ion contents of the leaves and the secretion were measured, and the results implied that salt glands had different selection in absorbing and secreting Na(+) , K(+) and Ca(2+), that is, the plants first selected K(+) when absorbing ions, while first selected Na(+) when sending ions out, but Ca(2+) was fewer in both absorbed and secreted, and the order of secretion of the three ions was found to be Na(+)>K(+)>Ca(2+) (Figs. 1-6). The secretion of Na(+) or three ions were respectively higher than that of leaves within 24 h (Figs. 1, 2, 7, 8), while K(+) situation was completely opposite with them (Figs. 3, 4). At the same time, the total ion content and composition inside the leaves remained more or less constant (Fig. 8).

[Effects of salt stress on the growth and the nitrate reductase activity in Thellungiella halophila].

The results showed that when Thellungiella halophila was treated with NaCl, the fresh and dry weight, the water content, the succulency of whole plant and the root/shoot ratio were decreased (Figs. 2-4, 7); the organic matter content in roots was increased and the inorganic matter content in roots was decreased, while those in shoots changed in the opposite direction (Fig. 6); osmotic adjustment ability, the Na+ content, the root activity were increased (Figs. 5, 7, 8); the nitrate reductase activity increased significantly; the O(-)(2*) content decreased at about NaCl 50 mmol/L but increased at about NaCl 100-400 mmol/L (Fig. 10). The micrographs of T. halophila leaf surface by scanning electron microscope (SEM) indicate that there is no salt gland or bladder on the surface of T. halophila (Fig. 1), so it is not a salt-secreting halophyte. The determination of growth parameters, the Na(+) content and Na(+) X-ray (Table 1) microanalysis of T. halophila indicate that T. halophila is not a salt-exclusing halophyte but it probability is a salt-dilution halophyte.

[Osmotica accumulation and its role in osmotic adjustment in Thellungiella halophila under salt stress].

Thellungiella halophila was treated with different concentrations of NaCl (0, 50, 100, 200, 300 and 400 mmol/L). Water content, osmotic potential, various organic and inorganic osmotica contents in the leaves and roots were determined and the calculated osmotic potential (COP) of osmotica in the osmotic adjustment was calculated (Figs.1-10 and Table 1). The result showed that water content, osmotic potential decreased with the increase of salinity; Na(+) and Cl(-) were the accumulated inorganic osmotica in roots and leaves; soluble sugar, organic acid and free amino acid were the accumulated organic osmotica in roots; and proline was the accumulated organic osmotica in both root and leaf. Na(+) X-ray microanalysis indicated that vacuole in the cell was the main organelle of accumulation toxic ions (Table 2).