Biomedical subjects

Huaqin He

Publications and source records attributed to Huaqin He.

14 recordsLinked to original sources

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

[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↗

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

[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

[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↗

PubMed2003

[Molecular ecological basis of high-yielding formation of rice and its application].

This paper introduced the developmental genetics and its molecular ecological basis of high yielding formation of rice in the past decade, and analyzed the advantage and the shortage of comparative physiological approach traditionally used in the research work on crop cultivation. It was emphasized to actively introduce the research contents and its methodology from relative disciplines to deeply understand the scientific issue, and suggested that the key to realize stable and high yielding of rice was to develop a rational cultivation system based on the properties of genetic effects on the traits in different developmental stages by controlling and regulating the traits governed by dominant effect genes and additive effect genes x environment in same direction, which was considered as the main characteristics and the technological innovation of modern crop genetic ecological cultivation science. Finally, the development trend of crop cultivation science shifting to molecular crop cultivation science was predicted and discussed.

Carbohydrates↗

PubMed2002

[Effect of enhanced UV-B radiation on polyamine metabolism and endogenous hormone contents in rice (Oryza sativa L.)].

The results showed that the activities of Agrinine decarboxylase(ADC), Ornithine decarboxylase(ODC) and s-Adenosylmethionine decarboxylase(SAMDC) were increased by 165.74%, 104.60% and 89.60% in the leaves of Shan You63(Sy63) and by 59.91%, 41.30% and 23.68% in the leaves of Nancheum(NC). Only ADC and ODC activities were increase by 115.93%, 14.45%, but SAMDC activity was decreased by 33.01% in the leaves of IR65600-85 respectively in the exposure to enhanced UV-B radiation for 7-14 days. In late treatment time course(21-28 d), the activities of ADC and ODC were increased by 89.72% and 3.71% in the leaves of Sy63 exposed to UV-B radiation for 21-28 days and by 73.95% and 27.38% in the leaves of NC. The activity of ADC was also increased by 94.41%, but ODC activity was decreased by 13.57% in the leaves of IR65600-85 compared with the controls. As far as SAMDC was concerned, the enzymic activities in the leaves of Sy63, NC and IR65600-85 were reduced by 40.06%, 19.20% and 38.21% respectively in the exposure to enhanced UV-B radiation for 21-28 days. The reverse was true in the case of Polyamine Oxidase (PAO), this in turn resulted in increased contents of Polyamine(PA) especially putrescine(Put). In addition, the result also indicated that the contents of IAA and GA1/3 were significantly reduced in all rice cultivars used for this experiments with enhanced UV-B radiation treatments for 7-28 days, in which the contents of IAA and GA1/3 were decreased by 58.92% and 45.48% in the leaves of Sy63, by 43.31% and 56.20% in the leaves of NC, and by 38.60% and 47.33% in the leaves of IR65600-85. The contents of ZRs in the leaves of the three cultivars concerned were lower in earlier treatment time courses (7-14 d), but much higher in late courses(21-28 d) compared with the their counterparts. With regard to the endogenous hormone of ABA, the content was significantly increased by 14.4%, 99.6% and 56.7% respectively in the three rice cultivars concerned exposed to enhanced UV-B radiation for 7-28 days, thereby led to decreased values of IAA/ABA, GA1/3/ABA and ZRs/ABA, consequently suppressed growth and development of rice.

Adenosylmethionine Decarboxylase↗

PubMed2002

[Developmental genetic analysis of panicle dry weight of indica hybrid rice oryza sativa under different environmental conditions].

Four indica sterile lines (A) and corresponding maintainer lines (B) as well as five indica restorer lines, which varied in panicle dry weight, were used to create genetic populations of two generations according to incomplete diallel cross design (4 x 5). Analysis on panicle dry weight at different developmental stages based on tow-years experimental data was conducted by using additive-dominant developmental genetic models with genotype effects and genotype x environment interaction effects. The results showed that panicle dry weight was controlled by both genetic main effects and genotype x environment interaction effects in the whole developmental process. During the early-middle developmental periods (15 days after flowering), panicle dry weight was mainly governed by dominant effects, and dominant genes expressed with large amount. The meanwhile, positive effects produced by environmental factors appeared to be significant. Proper cultivation measure to create good external environment conditions for rice panicle was helpful to promote the expression of heterosis potential completely. Within the middle-late developmental periods (from the fifteenth day to the thirtieth days after flowering), additive effects played major role, and its genes expresed in the most active state. Genetic selection for panicle conducted in this period was expected to gain better genetic advancement.

Crops, Agricultural↗

PubMed2002

[Genetic ecology of rice allelopathy on receiver plant].

In this study, 5 parental rice lines with different allelopathic potential were employed in partial diallel cross (4 x 5) to get 10 groups of F1 seeds. After testing the inhibitory effects of 5 parents and 10 F1s under different environment at different leaf stage on the shoot length of receiver plant lettuce(Lactuca sativa L.), dynamic genetics of rice allelopathy and its genotype x environment effects were analyzed by using additive-dominant developmental genetic models. The results showed that additive and dominant effect genes expressed alternatively during 3-leaf stage to 8-leaf stage in rice seedling. As additive effect genes were pronounced at 7-leaf stage, dominant effect genes appeared to play the most important role at 3-leaf stage and 6-leaf stage but the two effect genes were equally important at 5-leaf stage and 8-leaf stage. Heritabilities analysis indicated that the general heritability in the narrow sense(HN2) was significant at 5-, 7- and 8-leaf stage, and decreased with increasing leaf stage. Rice allelopathy was significantly affected by genotype x environment (GE) interaction, suggesting that the environment of allelopathic rice development must be controlled for practical use.

Ecology↗

PubMed2002

[Screening methodology for rice (Oryza sativa) genotypes with high phosphorus use efficiency at their seedling stage].

Under hydroponic culture, the responses of rice (Oryza sativa) genotypes to low P stress were respectively evaluated by means of relatively-higher P concentration in a controlled system with insoluble phosphate source (Ca3 (PO4)2) and of relatively-lower concentration with 0.5 mg P/L in which NaH2PO4 was the soluble phosphate. Relative indices such as relative dry weight of tillers (RTW), total relative plant dry weight (RPW), relative number of tillers (RTN), relative dry weight of root (RRW), relative dry weight of shoot (RSW), relative leaf age (RLA) and relative plant height (RPH) were used to screen as the tolerant indices to P deficiency, and the correlations among screening criteria per se were analyzed. The results showed that there were significant differences of tolerant indices to P deficiency in the test rice genotypes. When the rice cultivars were exposed to low P stress with the relatively-higher P concentration to be screened, the relative tiller dry weight (RTW), relative shoot dry weight (RSW) and total relative plant dry weight (RPW) could be used as the better screening criteria, especially RTW was considered as a sensitive and reliable screening criterion because its coefficient of variation (CV) and the variable range of data among the test varieties should be large. However, when rice genotypes were grown in the stress condition with relatively-lower P concentration, the screening criteria were different, and it suggested that relative shoot dry weight (RSW) or total relative plant dry weight (RPW) was the best single screening criterion.

Genotype↗