Hsa_circ_0001707 regulates endothelial-mesenchymal transition in esophageal squamous cell carcinoma via miR-203a-3p/Snail2 pathway.

Esophageal squamous cell carcinoma (ESCC) is a malignant tumor with high mortality and poor prognosis. Despite intensive research focused on tumor suppression, the 5-year survival rate of ESCC is lower than 15%. Therefore, investigate fundamental mechanisms involved in ESCC is on-demand crucial for diagnostics and developing targeted therapeutic drugs. Circular RNAs (circRNAs), as an emerging class of non-coding RNA, have been elucidated that circRNAs participated in regulating a variety of pathological processes and tumorigenesis. Nevertheless, the functional role of circRNAs in the occurrence and development of ESCC remains unclear. We identify a novel circRNA (hsa_circ_0001707), which was highly expressed in ESCC patients' tissues and cell lines. Furthermore, gain- and loss-of-function assays were performed and found that overexpression of hsa_circ_0001707 significantly promote tumor proliferation, metastasis, and invasion. By functioning as a competing endogenous RNA (ceRNA), the dual-luciferase activity assay verified that hsa_circ_0001707 can endogenously bind with miR-203a-3p and regulate its downstream gene Snail2. Rescue assay further confirms that hsa_circ_0001707 downregulation could partially attenuate the facilitation effect of miR-203a-3p, thereby inhibiting the endothelial-mesenchymal transition (EMT) process of ESCC. Our results suggested that hsa_circ_0001707 play an oncogenic role in the pathogenesis of ESCC, which might be a potential biomarker for diagnostics and targeting therapy.

N-nitrosamines-mediated downregulation of LncRNA-UCA1 induces carcinogenesis of esophageal squamous by regulating the alternative splicing of FGFR2.

Concerns are raised over the risk to digestive system's tumors from the N-nitrosamines (NAs) exposure in drinking water. Albeit considerable studies are conducted to explore the underlying mechanism responsible for NAs-induced esophageal squamous cell carcinoma (ESCC), the exact molecular mechanisms remain largely unknown, especially at the epigenetic regulation level. In this study, it is revealed that the urinary concentration of N-Nitrosodiethylamine is higher in high incidence area of ESCC, and the lncRNA-UCA1(UCA1) is significantly decreased in ESCC tissues. In vitro and in vivo experiments further show that UCA1 is involved in the malignant transformation of Het-1A cells and precancerous lesions of the rat esophagus induced by N-nitrosomethylbenzylamine (NMBzA). Functional gain and loss experiments verify UCA1 can affect the proliferation, migration, and invasion of ESCC cells in vitro and in vivo. Mechanically, through binding to heterogeneous nuclear ribonucleoprotein F (hnRNP F) protein, UCA1 regulates alternative splicing of fibroblast growth factor receptor 2 (FGFR2), which promotes the FGFR2IIIb isoform switching to FGFR2 IIIc isoform, and the latter activates epithelial-mesenchymal transition via PI3K-AKT signaling pathways impacting tumorigenesis. Therefore, NAs-mediated downregulation of UCA1 promotes ESCC progression through targeting hnRNP F/FGFR2/PI3k-AKT axis, which provides a new chemical carcinogenic target and establishes a previously unknown mechanism for NAs-induced ESCC.

Identification and function of circular RNA hsa_circ_0071106: A novel biomarker for differentiation degree of esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) has a high degree of malignancy, and there is currently no effective treatment. Circular RNA is a novel endogenous noncoding RNA with a stable loop structure. Several theories have been proposed regarding its biogenesis and usefulness as a biomarker in various cancers. Here we explore the predictive value and potential functions of a candidate circRNA (hsa_circ_0071106) in ESCC. METHODS: The altered expression of hsa_circ_0071106 was validated in clinical tissue samples from 64 patients with ESCC. The correlation between the clinical characteristics of these patients and the expression of hsa_circ_0071106 was analyzed by the chi-square test. The receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were used to evaluate the diagnostic value of hsa_circ_0071106. The human esophageal carcinoma cell lines ECA109 and ECA9706 and the normal human esophageal epithelial cell line (HET-1A) were applied for functional analysis of hsa_circ_0071106. qRT-PCR, sanger sequencing, agarose gel electrophoresis, RNase R digestion assay, Actinomycin D inhibition assay, nucleoplasm separation assay, and FISH assays were utilized to verify the circular characteristics and subcellular localization of hsa_circ_0071106. SiRNA and circRNA interference lentivirus was constructed to inhibit the expression of hsa_circ_0071106 in the ECA109 and ECA9706 cell lines. We used the EdU assay, Transwell assay, and flow cytometry to detect changes in cell proliferation, invasion, migration, and apoptosis. RESULTS: We identified that hsa_circ_0071106 showed significantly decreased expression levels in ESCC cells (P < 0.001) and tissue samples (P < 0.001). The correlation analysis of clinicopathological features and gene expression revealed that low expression of hsa_circ_0071106 was related to poor differentiation grade (P < 0.05). ROC curves indicated that hsa_circ_0071106 might have a diagnostic value for ESCC (AUC = 0.826, 95% CI: 0.748-0.904) and a predictive value for a high degree of histological differentiation (AUC = 0.730, 95% CI: 0.607-0.854). Hsa_circ_0071106 has a stable circular structure and was primarily localized in the cytoplasm. A transient knockdown of hsa_circ_0071106 by siRNA promotes proliferation, migration, and invasion and inhibits apoptosis of ESCC cells. A steady knockdown of hsa_circ_0071106 by a lentivirus knockout vector significantly promoted cell migration and invasion in ECA109 and ECA9706 cell lines. CONCLUSION: Hsa_circ_0071106 was a downregulated circRNA related to ESCC and promoted ESCC progression by regulating cell migration and invasion. These findings suggest that hsa_circ_0071106 could be a promising diagnostic biomarker and potential therapeutic target and might predict ESCC's histological differentiation degree.

[Effects of foliar spraying with low concentration NaCl on the growth and physiological responses of cucumber seedlings under temperature regulation in solar greenhouse]. / 设施调温模式下叶施低浓度NaClå¯¹é»„ç“œå¹¼è‹—ç”Ÿé•¿å’Œç”Ÿç†æŒ‡æ ‡çš„å½±å“.

In order to clarify the effects of foliar spraying the solution with low concentration NaCl on the growth and matter accumulation of vegetables under the temperature-regulated solar greenhouse, we carried out an experiment on cucumber seedlings with two cotyledons, under two tempera-ture regimes and four concentrations of NaCl. Low-medium temperature zone (L) and medium-high temperature zone (H) were set by low tunnel with plastic film in the greenhouse. The solutions with different concentrations of NaCl, 0 mmol·L-1 (L0 and H0), 5 mmol·L-1 (L5 and H5), 10 mmol·L-1 (L10 and H10) and 15 mmol·L-1 (L15 and H15), were sprayed every day to the cucumber seedlings. The seedling growth, plant biomass, nutrient accumulation and photosynthetic gas exchange parameters of cucumber seedlings were measured at the 21th day of spraying treatment. Compared with the control groups (L0 and H0), NaCl spraying significantly increased dry matter and plant water content by 38.6% (L5)-50.2% (L10) and 20.8% (L5)-52.2% (L10) in L zone, 8.9% (H5)-23.3% (H10) and 8.7% (H5)-10.1% (H10) in H zone, respectively. The treatment of 10 mmol·L-1 NaCl (L10 and H10) under both temperature regimes increased dry matter accumulation and plant water content than other treatments. Nevertheless, the highest normalized strong seedling index (SI) with the highest stomatal conductance (gs) and photosynthetic rate (Pn) was only found in L5 treatment. L10 treatment promoted foliar expansion much more than H10 treatment. In addition, foliar spraying NaCl with concentrations from 5 mmol·L-1 to 10 mmol·L-1 under both temperature regimes significantly increased the accumulation of soluble sugar, free amino acids and soluble protein, which were preferentially allocated to the stem or root of cucumber seedlings. Results of two-way ANOVA showed significant effects of both temperature and NaCl concentration on dry biomass, leaf area, Pn, plant water content, SI, gs and free amino acid content. On the contrary, there were significant interactions between temperature and NaCl concentration in affecting plant water content, SI, gs and free amino acid content (except leaf). In conclusion, foliar spraying with 5-10 mmol L-1 NaCl could promote growth and physiological indices of cucumber seedlings, with the effect being higher under low temperature regime. More importantly, foliar spraying of proper concentration (L5 and H10) of NaCl could stimulate biomass accumulation more than water retention in cucumber seedlings, which would provide a relevant breeding target for high water-use efficiency in cucumber.

Linc-ROR regulates apoptosis in esophageal squamous cell carcinoma via modulation of p53 ubiquitination by targeting miR-204-5p/MDM2.

The long intergenic noncoding RNA, regulator of reprogramming (linc-ROR) has been reported to participate in tumorigenesis, while its functions and fundamental mechanisms in esophageal squamous cell carcinoma (ESCC) remain unclear. In this study, gain-of-function assays showed that linc-ROR upregulation enhanced cell viability, promoted cell proliferation, and inhibited apoptosis. Mechanistically, the regulatory network of linc-ROR/miR-204-5p/MDM2 was established with bioinformatics analysis and online databases, then validated via dual-luciferase reporter assays, RNA immunoprecipitation assays in ESCC cells. Linc-ROR positively regulates the expression of MDM2 as a molecular sponge of miR-204-5p. Moreover, results of western blot and coimmunoprecipitation indicated that linc-ROR overexpression enhanced the ubiquitination level of p53, and its downstream apoptosis-related genes have showed higher bcl-2 expression, lower bax, and cleaved caspase-3 expressions, while miR-204-5p could counteract with this effect. Finally, small interfering RNAs tailored to linc-ROR were established to further evaluate its effects on ESCC comprehensively. In summary, this study revealed that linc-ROR modulated cell apoptosis and regulated p53 ubiquitination via targeting miR-204-5p/MDM2 axis, which provides a novel therapeutic insight into treatments for ESCC.

Identification of Cancer Stem Cell Molecular Markers and Effects of hsa-miR-21-3p on Stemness in Esophageal Squamous Cell Carcinoma.

Cancer stem cells (CSCs) are closely related to tumor resistance and tumor recurrence in esophageal squamous cell carcinoma (ESCC). The lack of specific biomarkers to identify and isolate CSCs has led to the slow progression of research on CSCs in ESCC. Here, we established a method to identify and isolate CSCs in ESCC using fluorescence-activated cell sorting with combined surface biomarkers including CD71, CD271, and CD338. CD71-/CD271⁺/CD338⁺ subpopulation cells possessed more stem cell properties in proliferation, self-renewal, differentiation, metastasis, drug resistance, and tumorigenesis. We further explored possible roles that microRNAs played in stem cells. Using microarrays, we identified that has-miR-21-3p was highly expressed in positive sorted cells, and further functional and Luciferase reporter assays verified that has-miR-21-3p promoted proliferation and anti-apoptosis by regulating TRAF4. We further analyzed the relationship between hsa-miR-21-3p and ESCC in 137 patients with ESCC. Statistical analysis showed that up-regulation of hsa-miR-21-3p was associated with a high risk of ESCC. Collectively, we identified surface biomarkers of stem cells in esophageal squamous cell carcinoma, and discovered thathsa-miR-21-3p may be involved in stemness maintenance by regulating TRAF4.

Novel-miR-4885 Promotes Migration and Invasion of Esophageal Cancer Cells Through Targeting CTNNA2.

Esophageal cancer is one of the most common cancers worldwide. It is critical to find early diagnostic biomarkers for esophageal cancer. MicroRNAs (miRNAs) play important regulatory roles in occurrence and development of esophageal cancer, which has the diagnostic and prognostic values. The aim of the study was to evaluate the potential diagnostic value of the novel miRNA. The novel miRNA was predicted using miRDeep2 software and validated by quantitative reverse transcription PCR (qRT-PCR) and the TA-cloning sequencing of the PCR products. The expression of the novel miRNA in esophageal cancer tissues and adjacent tissues was also analyzed by qRT-PCR. The EdU staining and transwell method were used to detect the capacity of cell proliferation, migration, and invasion. Besides, the target gene CTNNA2 of novel-miR-4885 was verified via qRT-PCR, western blot, luciferase reporter assay, and RNA immunoprecipitation. We identified the novel-miR-4885, the expression level was confirmed by qRT-PCR in the esophageal cancer cells. The result of TA-cloning sequencing was consistent with the prediction and the pre-miRNA had a standard hairpin stem-loop structure. In addition, the expression of novel-miR-4885 was upregulated in esophageal cancer tissue compared with that in adjacent tissue (p < 0.05). Further, the assays showed that overexpression novel-miR-4885 could improve the cell proliferation, migration, and invasion with an average fold change of 1.19, 1.59, and 2.34, respectively. Novel-miR-4885 can bind to 3' untranslated region of CTNNA2 to reduce cell adhesion and promote epithelial-mesenchymal transition in esophageal cancer cell. The expression of N-cadherin, ß-catenin, Vimentin, and α-smooth muscle actin was upregulated, while that of E-cadherin and ZO-1 proteins was downregulated through western blot. Novel miRNA present in esophageal cancer cells was validated, supplementing the miRNA database. Meantime, the possible functional mechanisms were explored, and the results showed that the novel miRNA may serve as potential biomarker for the diagnosis of esophageal cancer.

miR-144/451 cluster plays an oncogenic role in esophageal cancer by inhibiting cell invasion.

BACKGROUND: miRNA clusters are widely expressed across species, accumulating evidence has illustrated that miRNA cluster functioned more efficiently than single miRNA in cancer oncogenesis. It is likely that miRNA clusters are more stable and reliable than individual miRNA to be biomarkers for diagnosis and therapy. We previously found low expression of miR-144/451 was closely related with the risk for esophageal cancer. Researches on miR-144/451 cluster were mostly focused on individual miRNA but not the whole cluster, the regulatory mechanism of miRNA cluster were largely unknown. METHODS: In present study, we firstly analysed biological functions of individual miRNAs of miR-144/451 in ECa9706 transfected with miRNA mimics. We further analysed the biological function of the whole cluster in stable transgenic cell overexpressing miR-144/451. We then performed genome-wide mRNA microarray to detect differentially expressed gene profiles in stable transgenic cells. RESULTS: Overexpression of miR-144-3p promoted early apoptosis of ECa9706 and inhibited cell migration, cell invasion and cell proliferation. miR-144-5p and miR-451a inhibited cell proliferation, at the same time, miR-451a inhibited cell migration. Overexpression of miR-144/451 leads to the arrest cell cycle from S to G2 and G2 to M,while the invasion ability was obviously inhibited. We further observed c-Myc, p-ERK were downregulated in cells overexpressing miR-144/451, while p53 was up-regulated. The downstream effectors of c-Myc, MMP9 and p-cdc2 were downregulated in miR-144/451 stable transgenic cell. miR-144/451 may or partly inhibited cell cycles and invasion of ECa9706 through inhibiting ERK/c-Myc signaling pathway. CONCLUSION: Collectively, we analysed the function of miR-144/451 cluster from individual to overall level. miR-144/451 cluster played proto oncogene role in esophageal cancer by inhibiting cell invasion.

LincRNA-ROR promotes metastasis and invasion of esophageal squamous cell carcinoma by regulating miR-145/FSCN1.

BACKGROUND AND OBJECTIVE: In an attempt to discover a new biomarker for early diagnosis and prognosis of esophageal squamous cell carcinoma (ESCC), the regulation mechanism of large intergenic non-coding RNA-regulator of reprogramming (lincRNA-ROR) as a microRNA (miRNA) sponge was studied. PATIENTS AND METHODS: ROR expression in 91 pairs of ESCC tissue samples and matched adjacent tissues was quantified with real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The ROR-miRNA-mRNA regulatory network was built with 161 esophageal cancer (EC) tissues and 11 adjacent tumor tissues from The Cancer Genome Atlas (TCGA) database. A total of 96 cases of ESCC from TCGA database were collected for analysis on survival rates. The regulatory relationship between ROR, miR-145 and FSCN1 was verified in ESCC cells via qRT-PCR, dual luciferase reporter (DLR) assay, RNA immunoprecipitation (RIP) and Western blotting. The transwell method was used to detect cell migration and invasion. RESULTS: ROR expression in ESCC tumor tissues was significantly higher than in the adjacent tissues, p<0.001. The survival rate of ESCC patients with high ROR expression levels was lower than that of patients with low ROR expression levels (p<0.001). ROR overexpression could downregulate miR-145 by up to 50% was proven by RIP, DLR assay, and qRT-PCR. Two effective binding sites of ROR to miR-145 were verified by DLR assay. One of the sites has never been cited in the literature. The Western blotting results showed that FSCN1 was a downstream target of ROR/miR-145 (p<0.05). Transwell assays were used to show that overexpression of ROR enhanced migration and invasion behavior of ESCC and miR-145 hindered these effects. CONCLUSION: ROR acted as a competitive endogenous RNA (ceRNA) of miR-145 in ESCC. A novel, effective miR-145 binding site of ROR was discovered. The ROR/miR-145/FSCN1 pathway was shown to take part in the metastasis of ESCC. ROR is likely an oncogene biomarker for ESCC early diagnosis and prognosis.

Identification of extracellular matrix protein 1 as a potential plasma biomarker of ESCC by proteomic analysis using iTRAQ and 2D-LC-MS/MS.

PURPOSE: This study was aimed to conduct a proteomics profiling analysis on plasma obtained from ESCC patients with the goal of identifying appropriate plasma protein biomarkers in the progression of ESCC. EXPERIMENTAL DESIGN: Plasma from 28 ESCC patients and 28 healthy controls (HC) were analyzed by iTRAQ combined with 2D-LC-MS/MS. ProteinPilot software was used to identify the differentially expressed plasma proteins in ESCC compared to HC. Western blot was performed to verify the expression of selected proteins in 37 independent ESCC patients and 37 HC. Transwell and MTT assays were used to detect the biological function of ECM1 protein in vitro. RESULTS: Nineteen (four upregulated and fifteen downregulated) proteins were identified as differentially expressed between ESCC and HC (p <0.05). Biological functions of these proteins are involved in cell adhesion, cell apoptosis and metabolic processes, visual perception and immune response. Of these, extracellular matrix 1 (ECM1) and lumican (LUM) were selected further confirmation by Western blot (p <0.05), which were consistent with the iTRAQ results. Furthermore, the migration ability of EC9706 cell line after overexpressing ECM1 was increased significantly (p <0.05). The proliferation ability of HUVEC cell was enhanced when treated with the culture supernatants of EC9706 overexpressed ECM1(p <0.05). CONCLUSION AND CLINICAL RELEVANCE: This proteome analysis indicate that ECM1 is a potential novel plasma protein biomarker for the detection of primary ESCC and evaluation of neoplasms progression.

Possible tumor suppressive role of the miR-144/451 cluster in esophageal carcinoma as determined by principal component regression analysis.

MicroRNA (miRNA) clusters are expressed universally across different types of organisms, and an accumulating number of studies have demonstrated that miRNA clusters function more efficiently compared with single miRNAs during the development of certain cancer types. miRNA clusters may have increased stability and reliability over individual miRNAs as diagnostic or therapeutic biomarkers. In the present study, the expression levels of mature miRNAs within the miR-144/451 cluster were examined using stem­loop reverse transcription­quantitative polymerase chain reaction in 102 patients pathologically diagnosed with esophageal carcinoma. Bioinformatics tools were used to identify a possible miRNA­mediated network of the miR­144/451 cluster. The expression levels of hsa­miR­451a, hsa­miR­144­3p and hsa­miR­144­5p in tumor tissues were significantly lower compared with those in adjacent non­tumor tissues (P<0.05). Pearson correlation analysis demonstrated that the expression levels of individual miR­144/451 cluster members were correlated with each other, except for the pair of hsa­miR­144­3p and hsa­miR­4732­3p. In particular, hsa­miR­144­5p expression was highly associated with hsa-miR-4732­5p and hsa-miR-451a expression levels, with correlation coefficients of 0.729 and 0.608, respectively. Furthermore, the low expression levels of hsa­miR­144­3p [odds ratio (OR), 0.85; P<0.05] and hsa-miR-144-5p (OR, 0.84; P<0.05) were determined to be risk factors for esophageal carcinoma development. Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that miRNAs forming the miR­144/451 cluster may cooperate to regulate the cell cycle. Therefore, the miR­144/451 cluster may serve an important role in the progression of esophageal carcinoma and may be considered as a biomarker for the detection of esophageal carcinoma at an early stage.

lncRNA UCA1 inhibits esophageal squamous-cell carcinoma growth by regulating the Wnt signaling pathway.

Esophageal squamous-cell carcinoma (ESCC) is one of the most common tumors worldwide. Recent studies suggested that long noncoding RNAs (lncRNAs) might play a key role in regulating cellular processes and cancer progression. One of the lncRNAs, urothelial carcinoma associated 1 (UCA1), is known to be dysregulated in several cancers, including bladder carcinoma, colorectal, melanoma, breast, gastric, and ESCC. However, contributions of UCA1 to ESCC remain largely undiscovered. In order to understand the role and mechanisms underlying UCA1 in ESCC, the association of UCA1 expression with risk of esophageal cancer development was determined in 106 esophageal cancer tissues of ESCC patients and adjacent normal tissues using real-time reverse-transcription polymerase chain reaction (PCR). The relative expression of UCA1 was significantly reduced in cancer versus adjacent normal tissues suggesting an enhanced risk of esophageal cancer. To investigate the biological functions of UCA1 in ESCC, it was of interest to examine whether overexpression of UCA1 might influence cell proliferation, apoptosis, cell cycle distribution, migration, and invasion in vitro using EC109 cells. Our results demonstrated that UCA1 decreased cell proliferation, migration, invasion, and cell cycle progression of EC109 cells. Further, mRNA microarray analysis of overexpressed UCA1 in EC109 cells revealed that abnormal expression of UCA1 also inhibited the Wnt signaling pathway. Gene levels of DKK1 were elevated while C-myc fell significantly in overexpressed UCA1 EC109 cells. Interestingly, Western blot demonstrated no significant differences in relative expression of CTNNB1 (ß-catenin) but marked reduction in ß-catenin (active form) levels in both total and nuclear proteins. These results suggest that UCA1 may inhibit ESCC growth by regulating the Wnt signaling pathway. In conclusion, UCA1 may be a novel biomarker involved in ESCC development that may provide a potential therapeutic target for ESCC.

[Effects of bagging on light use efficiency of tomato fruit photosystem II].

In a greenhouse experiment, white laminating bags were applied to bag the tomato cultivar 'Baoluota' fruits, with the absorption spectra and chlorophyll fluorescence parameters of the fruits measured by optical spectrometer and Mini-Imaging-Pam after different bagging time, aimed to investigate the effects of bagging on the light use efficiency of photosystem II of the fruits. In the first 20 days of bagging, no significant effects of bagging were observed on the chlorophyll a (Chl a) content and the maximum quantum yield of PS II (Fv/Fm) of the fruits, but the relative absorption coefficient (A(670/780)) and the effective quantum yield of PS II (Y(II)) were reduced, compared with the control. In this period, the regulatory energy dissipation of PS II played, an important role. After then, the Chl a and Chl b contents of bagged fruits decreased markedly, but the Fv/Fm, Y(II), and A(670/780) had no significant differences with the control. On the 40th day of bagging, the Chl a and Chl b contents of bagged fruits decreased by 35.2% and 52.8%, but the Fv/Fm and Y(II) increased by 24.5% and 35.4%, respectively, suggesting that at this time, the PS II of bagged tomato fruits had a higher light use efficiency, which provided energy foundation for the earlier ripening of the bagged fruits via further reducing the quantum yield of non-regulatory energy dissipation (Y(NO)).

[Toxicological effects of omethoate on leaf photosystem II of cole].

After spraying different concentrations of two brands pesticide omethoate on cole (Brassica campestris L.) leaves, the leaf chlorophyll a fluorescence transients were measured by a Plant Efficiency Analyzer (PEA), and the toxicological effects and rudimental dynamic courses of omethoate on the leaf photosystem II (PS II) were investigated by JIP-test. The results showed that after spraying omethoate except at the concentration of 0.50% , the maximal efficiency of photochemistry (F(v)/F(m)) did not have a remarkable change. However, with increasing omethoate concentration, the minimal fluorescence F(o), maximal fluorescence F(m), relative variable fluorescence at the J-step (V(J)), and electron transport flux perreactive center in PS II (ET(o)/RC) increased remarkably, but psi(o), the efficiency that a trapped exciton in PS ]I moved an electron into the electron transport chain beyond Q(A)-, decreased remarkably. The test two brands of pesticide omethoate had almost alike effects on the PS II of cole, and the residual effect of the pesticide was the strongest at the third day after spraying and petered out from the ninth to twelfth day. The main targets of omethoate on the PS II of cole could be listed as promoting the reduction from Q(A) to Q(A) (-) (increasing of V(J)) and the electron transmission from Q(A) (-) to Q(B) (increasing of ET(o)/RC).

[Heat stress characteristics of photosystem II in eggplant].

With lower-and higher heat-resistant varieties of eggplant (Solanum melongena L.) Heibei I and Heibei II as test materials, and by using Plant Efficiency Analyzer (PEA) from Hansatech, this paper measured the fast chlorophyll a fluorescence transient and its parameters. The results showed that PS II construction became more sensitive to heat stress when ambient temperature was higher than 40 degrees C. The F0 went up slowly, and Fv/Fm and deltaF/Fm' came down dramatically. Heibei II had a longer semi-attenuation temperature of Fv/Fm (T50) and deltaF/Fm' (t50) than Heibei I. Under strong heat stress (5 min at 48 degrees C or 20-30 min at 44 degrees C), the K-step in relation to the inactivation of oxygen-evolving complex appeared in fluorescence rise at about 700 micros, and the regular O-J-I-P transient was transformed to O-K-J-I-P one. The K-phase of Heibei I and Heibei II appeared when the treatment time was up to 20 and 30 minutes at 44 degrees C, respectively. In comparing with 35 degrees C heat treatment, the DI0/RC in the parameters of Strasser's specific energy fluxes model was increased by a great extent under 48 degrees C or more heat stress, reflecting a strong safeguard of energy dissipation to PS II. When the temperature of heat stress increased from 35 degrees C to 52 degrees C, the Fvi/Fv of PS II silent reaction centers of Heibei I and Heibei II increased remarkably.

[Effects of arbuscular mycorrhizal fungi on the growth and fruit quality of plastic greenhouse Cucumis sativus L].

In this paper, arbuscular mycorrhizal fungi (AMF) Glomus versiforme (GV), Glomus mosseae (GM), Glomus intraradices (GI) and their mixtures were applied to inoculate plastic greenhouse Cucumis sativus seedlings to investigate the effects of AMF on C. sativus growth, development, yield, and quality. The results showed that all test AMF could form mycorrhiza with cucumber roots, and the infected rate reached 41.74% - 55.69%. Compared with the control, treatments GV, GM, GM + GV, GM + GV + GI and GV + GI enhanced the healthy seedling index by 58.14% - 123.6%, and increased early yield by 21.71% - 37.87% and total yield by 19.72% - 34.41%. AMF also improved fruit quality. The Vc content of cucumber fruit increased by 22.84% and 21.95% in treatments GM + GV and GV + GI, soluble sugar content increased by 13.29%, 8.25%, and 10.20% in treatments GV, GI and GV + GI, and amino acid content increased by 47.66% and 23.19% in treatments GV and GM + GI, respectively, while soluble protein content increased by 17.67% - 34.29% in all AMF treatments. The results suggested that AMF inoculation could significantly promote the seedling growth of cucumber and improve its fruit quality, and the effects differed with different AMF and their combinations.