Biomedical subjects

Yiping Tong

Publications and source records attributed to Yiping Tong.

5 recordsLinked to original sources

PubMed2006

Characterization of photosynthesis of flag leaves in a wheat hybrid and its parents grown under field conditions.

Two wheat cultivars, one with high yield and the other with a high tolerance against oxidative stress, were compared with a hybrid of these two cultivars by investigating their photosynthetic characteristics of flag leaves. From the beginning of flowering to the 17th day, CO(2) assimilation rate (P(max)) was maintained and there were no appreciable differences between the hybrid and its parents. P(max) showed no decrease at noon compared to that in the morning. From the 20th to the 30th day of flowering, P(max) decreased significantly, and this decrease was significantly less in the hybrid than in its parents. The actual photosystem II (PSII) efficiency (Phi(PSII)) and the maximal efficiency of PSII photochemistry (F(v)/F(m)) showed a significant decrease only on the 30th day after anthesis; this decline was much less marked in the hybrid relative to its parents, both in the morning and at noon. A decrease occurred in Phi(PSII) and F(v)/F(m) at noon when compared to that in the morning, but this decrease was less marked in the hybrid than in its parents. Rubisco activity decreased significantly from the 13th day of flowering and was higher in the morning than at noon both in the hybrid and its parents. However, the hybrid always showed a higher value of Rubisco activity. The activities of posphoenolpyruvate carboxylase and pyruvate phosphate dikinase showed similar changes to those in Rubisco activity, particularly from the 20th to 30th day. The results of this study suggest that the higher photosynthetic capacity of the flag leaf in the hybrid can help to accumulate more dry material, and may be the physiological basis for higher yield over its parents.

Biomass↗

PubMed2005

Evaluation of genotoxicity of combined soil pollution by cadmium and imidacloprid.

Cadmium (Cd) is one of the important pollutants of soil and the genotoxicity of Cd-contaminated soil was studied in combination with imidacloprid. The single cell gel electrophoresis or comet assay was used to quantify DNA strand breaks as a measure of DNA damage induced by Cd and imidacloprid contamination in soil. The soil was artificially contaminated by Cd (0.0, 0.2, 0.5, 1.0, 2.0 mg x kg(-1) dry soil) or Cd (0.0, 0.2, 0.5, 1.0, 2.0 mg x kg(-1) dry soil) and imidacloprid (0.5 mg x kg(-1) dry soil). Roots of Vicia faba were exposed to the contaminated soil for 2 h at 25 degrees C and were used in the comet assay. DNA damage was measured as the values of percentage of nuclei with tails, tail length, tail DNA, tail moment (TM), and Olive tail moment (OTM). DNA damages of root tips of Vicia faba increased after Cd treatment and there were dose-related increases in DNA damage measured as these parameters. However, the addition of imidacloprid further increased the DNA damage. These data confirmed the genotoxic effect of Cd to plants, and that the combined pollution with imidacloprid can enhance the genotoxicity of Cd.

Cadmium↗

PubMed2005

A two-component high-affinity nitrate uptake system in barley.

The analysis of genome databases for many different plants has identified a group of genes that are related to one part of a two-component nitrate transport system found in algae. Earlier work using mutants and heterologous expression has shown that a high-affinity nitrate transport system from the unicellular green algae, Chlamydomonas reinhardtii required two gene products for function. One gene encoded a typical carrier-type structure with 12 putative trans-membrane (TM) domains and the other gene, nar2 encoded a much smaller protein that had only one TM domain. As both gene families occur in plants we investigated whether this transport model has more general relevance among plants. The screening for nitrate transporter activity was greatly helped by a novel assay using (15)N-enriched nitrate uptake into Xenopus oocytes expressing the proteins. This assay enables many oocytes to be rapidly screened for nitrate transport activity. The functional activity of a barley nitrate transporter, HvNRT2.1, in oocytes required co-injection of a second mRNA. Although three very closely related nar2-like genes were cloned from barley, only one of these was able to give functional nitrate transport when co-injected into oocytes. The nitrate transport performed by this two-gene system was inhibited at more acidic external pH and by acidification of the cytoplasm. This specific requirement for two-gene products to give nitrate transport function has important implications for attempts to genetically manipulate this fundamental process in plants.

Amino Acid Sequence↗

PubMed2005

[Effects of land use type on soil nutrient distribution in northern agro-pasture ecotone].

Soil samples under five land use types were collected from Duolun County in the northern agro-pasture ecotone. Chemical analysis showed that soil nutrient content was the lowest in farmland, medium in grassland, and the highest in woodland, indicating that reclamation accelerated the decomposition of soil organic matter and the further loss of soil nutrients. To investigate the effects of land use type on soil organic matter, available phosphors, available nitrogen and total nitrogen, soils from four different land use types in the catchments with slopes steeper than 15 degrees were sampled and analyzed. Vertically, the content of soil nutrients from slope bottom to its top was two times higher in land use type cropland-grassland-woodland than in grassland-woodland-cropland. Such a difference indicated the positive effects of the former land use type on soil nutrient retention. Therefore, selecting this optimal land use type in studied area could improve local eco-environment and economic benefits.

Animal Husbandry↗

PubMed2003

Restricted spatial expression of a high-affinity phosphate transporter in potato roots.

Phosphorus deficiency limits plant growth, and high-affinity phosphate transporters, of the Pht1 family, facilitate phosphate uptake and translocation. The family is subdivided into root specific, phosphate deprivation induced members and those also expressed in leaves. An antibody to StPT2, a potato root specific transporter, detected two bands (52 kDa and 30 kDa) on western blots of root plasma membrane extracts that were most intense in whole extracts from the root tip and slightly increased throughout the root in response to phosphate depletion. RT-PCR, using StPT2 specific primers, confirmed these findings. Low power confocal immunofluorescent images showed StPT2 expression mainly in the elongation zone at the root tip. By contrast, a vacuolar pyrophosphatase and a plasma membrane ATPase antibody labelled the whole root. High power images showed, by comparison with alpha-tubulin, cell wall and plasma membrane ATPase labelling, that StPT2 was in the epidermal plasma membrane and restricted to the apical surface. This is the first evidence of polar plasma membrane localisation of a plant nutrient transporter and is consistent with a role for StPT2 in phosphate capture and uptake.

Adenosine Triphosphatases↗