Biomedical subjects

Wenxiong Lin

Publications and source records attributed to Wenxiong Lin.

At least 19 recordsLinked to original sources

PubMed2006

[Effects of allelopathic rice on rhizosphere microbial flora and enzyme activity].

This paper studied the dynamics of microbial flora and enzyme activity in the rhizosphere of allelopathic rice PI312777 (PI) and non-allelopathic rice Lemont (LE) at the growth stage of 3 - 7 leaves. The results showed that in the rhizosphere of PI, the amounts of bacteria, actinomycetes and azotobacter were 11.2% - 28.3%, 40% - 78.6% and 111.5% - 173.9%, respectively, while that of fungi was lower, with the maximum being 25.5% of that in the rhizosphere of LE, suggesting that allelopathic rice PI promoted the growth of bacteria, actinomycetes and azotobacter, but inhibited that of fungi. Further analysis on the physiological groups of microbial flora showed that PI favored the growth of ammonifier, aerobic azotobacter, aerobic cellulose - decomposer, sulphate - reducer, nitrite - bacteria and nitrate - bacteria, among which, ammonifier and aerobic azotobacter increased by 53.7% and 57.6%, respectively, while inhibited the growth of desulphate bacteria and denitrifyier. Moreover, PI increased the activities of urease, phosphatase and sucrase, but decreased the catalase activity in its rhizosphere.

Actinobacteria↗

PubMed2006

[Energy accumulation and caloric value in yield-forming process of different rice cultivars].

Based on the determination of dry matter and caloric value, this paper studied the characteristics of energy accumulation and the dynamics of caloric value in the yield-forming process of rice cultivars Shanyou 63 ( three-line hybrid rice) , Liangyou 2186 (two-line hybrid rice) , and IR64 (conventional rice). The results showed that at fully grain-maturing stage, the amount of dry matter in Shanyou 63, Liangyou 2186 and IR64 was 1926. 38 g x m(2), 1933.80 g x m(-2) and 1842.30 g x m(-2), and that of accumulated energy was 31,137.05 kJ x m(-2) 31 060.63 kJ x m(-2) and 30 454.89 kJ x m(-2) , respectively, showing no significant difference among the cultivars. In the process of grain filling, the apparent transformation ratio of energy in Shanyou 63, Liangyou 2186 and IR64 was about 38. 95% , 28. 38% and 32. 66% , respectively, implying that the energy flow in Shanyou 63 and IR 64 was smoother than that in Liangyou 2186, and the output of energy from stem to the sink of grain was blocked in Liangyou 2186. The ratio of energy partitioning to the sink of grain was 53. 03% , 46. 43% and 50. 11% for Shanyou 63, Liangyou 2186 and IR64, respectively, showing the energy partitioning heterosis in three-line hybrid rice Shanyou 63. As for the caloric value, it had no significant difference among the three cultivars, but decreased in the order of leaf> grain > sheath > stem > root, ranging from 16.81-17.25 kJ x g(-1) , 15.89-16.54 kJ x g (-1) 14.33-15.49 kJ x g(-1) , 14.23-15.15 kJ x g , and 11.51-13.25 kJ x g(-1), respectively. It was also shown that there was a significant positive correlation of caloric value with carbon content, chlorophyll a content, and nitrogen content in rice plant, with the determination coefficient R(2) being 0.609, 0.471 and 0.485, respectively.

Biomass↗

PubMed2005

[Terpenoids in root exudates of different allelopathic rice varieties].

In this paper, a strong allelopathic rice variety PI312777 and a weak allelopathic rice variety Lemont were used as test materials, and the root exudates of two rice varieties grown in the media of sand and soil were respectively collected by using circulation system approach. The terpenoids in ether-extracts were detected by GC-MS, and characterized by spectrum database. The results showed that some terpenoids such as limonene oxide, limonene dioxide, carvone oxide, carveol, and cedrol were detected in the ether-extracts. Different rice varieties had the similar kinds of terpenoids, but their existing modes and quantities were different. The differences between different various cultural methods and between rice varieties were further discussed.

Oryza↗

PubMed2005

[Allelopathy and resources competition of rice under different nitrogen supplies].

In order to explore the bio-interference of allelopathic rice with barnyardgrass under different nitrogen supplies, a new bioassay method, i.e., allelopathy-competition separation based (ACS) approach was recommended in this study. The results indicated that ACS could be successfully used to distinguish the rice allelopathy from its resources competition in rice-weed co-culture system, and to evaluate its response characteristics under different N supplies. The test rice accession PI312777 had a higher ability in interfering target weed barnyardgrass (BYD), represented by its stable and higher ability in resources competition, as well as its increasing allelopathic potential in suppressing companion weed BYD when the N supply decreased in the co-cultured system. The reverse was true in the case of rice accession Lemont, which had a lower allelopathic potential under all N supply levels, and a lower ability in resources competition under normal or rich N supply. But, Lemont had an obviously increased ability in resources competition under lower N supply, which was considered as the result of econiche competition in rice-weed system.

Echinochloa↗

PubMed2005

[Interactive effects between allelochemical substitutes].

In order to understand the allelopathic mechanisms of rice on weed, the allelochemical substitutes salicylic acid, p-hydroxybenzonic acid, cinnamic acid, vanillic acid and ferulic acid were used in an orthogonally gyrating regression experiment to study their interactive effects on the growth of barnyardgrass. The results indicated that whether the interactive effects between two substitutes, e.g., between salicylic and cinnamic acid or between salicylic and p-hydrobanzonic acid, were synergistic or antagonistic depended on the concentrations of each substitutes in the mixture. In the mixture of salicylic acid and p-hydrobanzonic acid, the effect of salicylic acid was synergistic at < 0.14 mmol.L(-1) but antagonistic at > 0.14 mmol.L(-1), while p-hydrobanzonic acid showed an antagonistic effect at > 0.425 mmol.L(-1). Salicylic acid at all test concentrations exhibited antagonism to cinnamic acid, while cinnamic acid had a synergistic at < 0.14 mmol.L(-1), but an antagonistic effect at >0.14 mmol.L(-1) on alicylic acid. The interactive effects between cinnamic and ferulic acid were all synergistic at test concentrations.

Cinnamates↗

PubMed2005

[Corresponding analysis on rice grain heavy metal pollution in Fujian province].

By the methods of environmental statistics and corresponding analysis, this paper collected 38 early and late rice grain samples from the middle, southern, northern, western and eastern parts of Fujian Province to detect their Hg, As, Cr, Cd and Pb contents, and to search for the main factors resulting in the difference of rice cropping type in different regions, aiming at further understanding the relationships between heavy metal pollution and rice cropping type. The results showed that among the test heavy metals in grain, Pb had the highest percentage (100%) beyond the standard level, followed by Hg (78.95%), Cd (50.5%) and Cu (2.63%), while As did not surpass the standard level. It therefore could be concluded that Pb and Cd were the main factors resulting in the difference of rice cropping type in different regions. The results also showed that 38 rice grain samples could be clustered into 7 groups, indicating that different rice cropping types would significantly cause different degrees of heavy metal pollution, which suggested that the best way in controlling and preventing rice grain heavy metal pollution could be the approach of combining site-controlling with variety selection, based on the situation of different regions and rice cropping systems.

Cadmium↗

PubMed2005

[Screening of phytase-producing strain and its optimal solid state phytase-producing conditions].

Phytase can catalyze phytate hydrolyzed into inositol and phosphoric acid, and its application could make the phytic acid in animal feeds become more available, decrease feed cost, and at the same time, protect eco-environment. In this paper, a phytase-producing strain Trichoderma Viride LH374 was obtained through isolation and mutation, and its optimal conditions for solid state fermentation and phytase production were investigated. The results suggested that the optimal conditions of solid state fermentation were straw:rice bran ratio 8:2, medium initial pH 6.5, temperature 30 degrees C, culture duration 96 h, and moisture content 60%. Under the optimal conditions, LH374 could accumulate phytase up to 1,580 U x g(-1).

6-Phytase↗

PubMed2005

[Changes of key enzyme activities in rice cultivars with different photooxidation-tolerance during grain-filling stage in early and late seasons].

Four rice cultivars with different photooxidation-tolerance characteristics during grain-filling stage in early and late seasons were selected to uncover the physiological and biochemical mechanisms of the correlation between rice photooxidation-tolerance and grain quality. The results showed that the parameters mean grain-filling rate (Gmean), time arrived to maximum grain-filling rate (T(max. G)), and 100-grain weight at the maximum grain-filling rate (T(max. G)) were relatively stable for the varieties adaptable to high light intensity, while on the contrary for those sensitive to photooxidation. The ADP glucose pyrophosphorylase and starch synthase activities of the varieties adaptable to high light intensity after grain-filling peaks had a less difference between early and late seasons than those sensitive to photooxidation, and the relative enzyme activities in the varieties adaptable to high light intensity changed coequally in early and late seasons.

Edible Grain↗

PubMed2005

[Chemical components of root exudates from allelopathic rice accession PI312777 seedlings].

In this study, allelopathic rice accession PI312777 seedlings were grown on a paddy soil under near natural condition, and their root exudates were collected by using circulation method, with the solution collected from no seedlings- planted soil as the control. The ether extracts of the root exudates and soil solution were detected by GC-MS, and identified with the mass spectral database of NIST and WILEY Library. The results showed that there were 36 compounds in the rice root exudates, including 9 terpenoids (peak area 10.97%), 8 phenols or quinones (5.87%), 6 esters (10.68%), 3 aldehydes or ketones (1.44%), 4 heterocycles (68.04%), 2 alcohols (1.23%), 2 ethers (0.57%), and 2 others (1.20%). A distinctly similar structure was observed among the terpenoids and among the phenols or quinones. In the soil solution, 39 compounds were detected, and 7 of them were the same of the root exudates. The difference of the compounds in rice root exudates and soil solution, and the possible allelopathic mechanisms of these compounds were discussed in this paper.

Heterocyclic Compounds↗

PubMed2005

[Chemical components and antimicrobial activity of essential oils in Cunninghamia lanceolata heartwood].

In this study, the essential oils in Cunninghamia lanceolata heartwood were water-steam distilled, and their chemical components were analyzed by column chromatography and GC-MS, with their antimicrobial activity tested. The results showed that the essential oils content was 1.794-2.076 (w/w), and 47 peaks were separated. 27 compounds, accounted for 99% of crude essential oils, were identified. The essential oils had an obvious antimicrobial activity against Escherichia coli, Staphylococcus aureus, Bacillus sabtills and Salmonella typhi, and cedrol, occupying 76.27% of essential oils, was the major component with antimicrobial activity.

Anti-Bacterial Agents↗

PubMed2004

[Relationship between wheat root activity and leaf senescence].

A field trial on the wheat root activity, chlorophyll content and photosynthetic rate showed that the decline of root activity was earlier and faster than that of flag leaf chlorophyll content and photosynthetic rate, and there was a positive correlation between root activity and leaf photosynthetic rate (r = 0.8006). Topdressing nitrogen fertilizer at elongation stage could obviously improve root activity and photosynthetic rate, decrease leaf ABA content, increase ZRs content and SOD activity, and delay the peak value of MDA for 8-10 days, which suggested that the variation of root activity was closely related to the senescence of flag leaf. Improving root nutrition and root activity at earlier growth stages could delay the senescence of wheatleaf.

Biomass↗

PubMed2004

[Evaluation efficiency of different bioassay methods on allelopathic potential of Oryza sativa].

In this paper, three bioassay methods, i.e., relay seeding in agar (RSA), relay seeding in silica (RSS) and seeding in rice root-exudation (SRE), were used to test the allelopathic potential of 8 rice cultivars on the target weed barnyardgrass (Echinochloa crusgalli). The results indicated that RSA was the ideal method for the bioassay, showing the highest efficiency in the evaluation of allelopathic potential. RSS and SRE had a lower efficiency than RSA, but these two methods showed the same tendency in evaluating the allelopathic potential of rice. RSA, the considered best bioassay method in this experiment, was used for 57 allelopathic rice germplasm screening, and 5 of them, i.e., Iguape Cateto, PI312777, Azucena, Taichung Native 1 and IAC25 performed the strongest allelopathic potential in the suppression on barnyardgrass.

Echinochloa↗

PubMed2004

[Effect of hormones on regulating and controlling photosynthesis rate of wheat nag leaf at their different development phases].

By the method of ELASA, this paper measured the ABA/ZRs ratio in wheat flag leaf at the relative steady phase (RSP), end steady phase (ESP) and sharply descending phase (SFP) of chlorophylls. The ABA, ZRs and their mixture were led to the transpiration current of plant to measure the changes of photosynthesis rate at these three phases. The results showed that the ABA/ZRs ratio in flag leaf was 4.20, 41.83 and 14.40 at RSP, ESP and SFP, respectively. The time that the photosynthesis rate reduced by ABA to zero was 49.5, 39.1 and 38.0 min, and that reduced by ZRs to half was 65, 49 and 31 min, respectively. The two preceding phases could be regulated, and the changes were reversible.

Abscisic Acid↗

PubMed2004

[Weed-suppressive effect of phenolic acids].

Allelochemical substitutions salicylic acid, p-hydroxybenzonic acid, cinnamic acid, vanillic acid and ferulic acid were tested in a gyrating regression experiment to study the weed-suppressive effect of phenolic acids on the root growth of barnyardgrass. The results showed that cinnamic acid had a significant inhibitory effect, its square item regression coefficient being -6.18; salicylic acid, p-hydroxybenzonic acid and ferulic acid had the same trend of weed-suppressive potential as cinnamic acid, while vanillic acid had a different weed-suppressive effect from the others. The inhibition rate (IR) on the root growth of barnyardgrass reached its highest level (78.5%) when 0.06 mmol x L(-1) salicylic acid, 0.60 mmol x L(-1) p-hydrobenzonic acid, 0.24 mmol x L(-1) cinnamic acid, 0.02 mmol x L(-1) vannillic acid and 0.02 mmol x L(-1) ferullic acid were mixed together to apply.

Cinnamates↗

PubMed2003

[Physiological adaptability of seeding rice genotypes with different P uptake efficiency under low P-deficient stress].

The genotypic differences in P uptake efficiency of three rice varieties (IR74, IR71331 and IR71379) were studied under the P-deficiency condition with hydroponics, and their adaptability to low phosphorus stress about physio-biochemical mechanisms was further studied. The results showed that rice genotypes tolerated low P stress resulted from the co-ordination of P uptake efficiency, internal utilization efficiency and its translocation efficiency. The higher P-efficiency type IR74 and the middle type IR71331 had a higher P uptake efficiency. The rice genotype with higher P-efficiency was characterized by higher activity and desirable kinetic parameters of H2 PO4- uptake, showing lower Km and Cmin, but higher Imax values and relative APase activity, small amount of Km and Cmin. Moreover, under low P stress, the activity of RNase was about ten to fifteen times as high as that of the control (CK), but it had little genotypic differences.

Acid Phosphatase↗

PubMed2003

[Molecular responses of rice (Oryza sativa L.) to the stress of lowly enhanced UV-B radiation].

The approach of mRNA differential display (DD) was used to analyze the gene differential expression of rice seedling subjected to lowly enhanced Ultraviolet-B radiation. The results showed that of the eighteen differential fragments, fifteen ones were different in expressional levels, another one was depressed, and the other two, named as RUVB1 and RUVB2 respectively, which could be recovered and re-amplified, were specifically induced. Sequence analysis for RUVB2 through Internet BLAST searching indicated that it was more than 95% identities with three rice ESTs, but very low similarity to others in the GenBank, and was mapped on the OSJNBb0091N21BAC(GenBank accession No.: AC091122) in Oryza sativa L.

Oryza↗

PubMed2003

[Application of endolaser in vitrectomy for retinal vascular disease].

PURPOSE: To discuss the usage and effectiveness of endolaser in vitrectomy for retinal vascular disease. METHODS: Twenty-four cases (28 eyes) of vitrectomy for retinal vascular disease were treated with endolaser. The methods of endolaser: 21 eyes were treated with panretinal scatter therapy; 2 eyes with endolaser ring-intercepting around retinal and sealing retinal breaks; 5 eye with focal therapy. RESULTS: After follow-up for 1-24 months (mean 9 months), retinal hemorrhage recurred in 3 eyes; the other 25 eyes, retinas were totally reattached, retinal breaks were sealed, and vision had considerable recovery, no hemorrhage. The ratio of recovery is up to 89.2%. CONCLUSIONS: Endolaser is an important adjuvant in vitreous operation nowadays and an effective procedure in vitrectomy for the cases of retinal hemorrhage.

Adolescent↗

PubMed2003

[Heterosis and genetic correlation analysis of rice (Oryza sativa L.) grain weight development under different environmental conditions].

Two sets of test materials were derived from diallel cross among nine different types of selected rice varieties (lines). Based on the experimental data at different development stages of early and late rice, the estimation of heterosis and genetic correlation of rice grain weight at some development stages (0-->t) or at some special development phases (t--1-->t) was conducted by using additive-dominant genetic model and developmental genetic model for quantitative traits. The results indicated that the heterosis over mid-parent value based on population mean was not significant at 5% level at the early stages (1-12 d), and turned to positively significant as the development process proceeded in early rice. The heterobeltiosis based on population mean appeared to be small negative during the entire courses of grain filling. The heterosis over mid-parent based on population mean appeared to be positively significant at the early and middle grain filling stages (1-18 d), but became insignificant at the late stages (19-28 d) in late rice. The heterobeltiosis based on population mean appeared to be positively significant at the early grain filling stages (1-12 d), but turned to be significantly negative as the development process proceeded in late rice. It also indicated that the heterosis of grain weight development was beneficial to improve the quality of grain filling in late rice, compared to that in early rice. The genetic correlation between the grain weights per se at different stages and the final grain weight was mainly controlled by dominant effects, and became closer with the development process in the early rice, while by additive effects in the late rice. It's suggested that indirect selection of final grain weight throughout the process of grain filling would be more effective in late rice.

Edible Grain↗