Effects of Music Acoustic Frequency on Indoleacetic Acid in Plants

[Objective] The aim was to study the effects of music acoustic frequency on the contents of indoleacetic acid（IAA） in 6 species of vegetables.[Method] Music acoustic frequency group and control group were designed to determine the related growth indicators of unified managed 6 species of vegetables regularly.The contents of indoleacetic acid were detected by the High Performance Liquid Chromatography（HPLC）.[Result] The music acoustic frequency had significantly increased the contents of indoleacetic acid in 6 species of vegetables,which were significantly higher than that in the control.[Conclusion] The music acoustic frequency could stimulate the IAA secretion in plants.

INHIBITION AND RADIATION SENSITIZING EFFECT OF INDOLEACETIC ACID COMBINED WITH HORSERADISH PEROXIDASE ON HELA CELLS

Objective To observe the inhibition and radiation-sensitizing effect of Indoleacetic acid (IAA) combined with horseradish peroxidase(HRP)on Hela cells. Methods Hela cells were cultured in vitro and classified into control group, drug group incubated with different doses of IAA(30, 60, 90μmol·L -1) plus 1.2μg·mL -1 HRP, radiation group (6MV-X, 4Gy ) and group of radiation plus IAA plus HRP(same dose as above). All the above were treated for 24-96 hours.The growth inhibition, radiation-sensitizing effect were observed with methyl thiazolyl tetrazolium (MTT) photocolorimetric assay and trypan blue dye assay. The-effect on cell proliferation cycle was determined by flow cytometry. Results The antiproliferation activities showed a significant time-effect and dose-effect relationship to some extent after Hela cells were treated with IAA combined with HRP. The group of radiation plus 60μmol·L -1 IAA plus 1.2μg·mL -1 HRP and radiation plus 90μmol·L -1 IAA plus 1.2μg·mL -1 HRP showed an obvious radiation sensitizing effect. After treatment with 90μmol·L -1 IAA plus 1.2 μg·mL -1 HRP for 72 hours, the determination of cell cycle showed that the percentages of the cells on stages G 2-M and S were all higher than those of the control group. For the group of radiation plus IAA combined with HRP, the percentages of the cells on stages G 2-M were higher than those of the radiation group. Conclusion The above findings suggest that IAA combined with HRP has an inhibitive and killing effect on Hela cells. The effect was stronger during the cell cycles of G 2-M and S. It also has a radiation sensitizing effect. Its mechanism might be that Hela cells were blocked on stages G 2-M, and it presents a collaborative killing effect during miototic time.

Studies on the plasma tryptophan and urinary 5-hydroxy-3-indoleacetic acid in expedition members residing in Antarctica

In order to clarify the possible relationship between the changes of behavior/personality and metabolic changes of 5 hydroxytryptamine (5 HT) in Antarctic expedition members, plasma tryptophan (Trp) and urinary 5 hydroxy 3 indoleacetic acid (5 HIAA) were studied for 24 winter over and 19 summer over members of the 8th and 11th CHINARE respectively. Results showed that plasma Trp decreased significantly after residing 1￣3 months at Great Wall Station and did not recover on returning back to Beijing from Antarctica by two weeks travelling. Urinary 5 HIAA increased significantly after residing 6 months at Great Wall Station, and recovered on returning back to Beijing from Antarctica in the winter over members. The decrease of plasma Trp may be related to the decline of brain 5 HT which might play a role in the changes of behavior/personality . Increase of urinary 5 HIAA might reflect metabolic changes of 5 HT as a whole, but cold weather involving in the release response of platelet should be considered. Therefore, supplement of related food rich in Trp or intervention of L Trp might be valuable.

Study of the mechanism on the apoptosis induced in Human leukemia cell line K562 by the combination of indole-3-acetic acid and horseradish peroxidase

Objective To investigate the mechanisms of apoptosis induced in Human leukemia cell line K562 by the combination of indole-3-acetic acid and horseradish peroxidase.Methods Human leukemia cell line K562 were exposed to indole-3-acetic acid(IAA) at 20,40,60,80 or 100mol/L and horseradish peroxidase(HRP) at 1.2g/mL for varying times.MTT assay was applied to detect the cell proliferation.Flow cytometry was performed to detect the arrest of cell cycle.Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay was used to measure apoptosis.2,7-dichlorofluorescin diacetate(DCFH-DA) uptake was measured to determine free radical by confocal microscope.Content of malondiadehyde(MDA) and activity of superoxide dismutase(SOD) were measured by biochemical methods.Results IAA/HRP initiated growth inhibition of K562 cells in a dose-and time-dependent manner.Flow cytometry revealed that cell cycle arrested at G_1/G_0 after 24 hours treatment.After 72 hours treatment,apoptotic rate of 100 mol/L IAA group increased to 43.9%,which was 5 times that of control(P<0.01).Content of MDA and activity of SOD increased respectively in treatments compared with control.Meanwhile,IAA/HRP stimulated the formation of free radical,which was increased by IAA concentration-dependently.Conclusion The combination of IAA and HRP can inhibit the growth of Human leukemia cell line K562 in vitro by inducing apoptosis which is associated with the increase of free radical.The combination of IAA and HRP might be a promising chemopreventive and chemotherapeutic agent against human leukemia.

Auxin distribution and transport during embryogenesis and seed germi-nation of Arabidopsis

Auxin distribution during embryogenesis and seed germination were studied with transgenic Arabidopsis plants expressing GUS gene driven by a synthetic DR5 promoter,an auxin responsive promoter. The results showed that GUS activity is higher in ends of hypophysis and cotyledon primordia of heart-, torpedo- and cotyledon-stage embryos, leaf tip area, lateral root primordia, root apex and cotyledon of young seedlings. And GUS accumulated in root apex of the seedlings grown on auxin transport inhibitor containing media. All these suggested that above-mentioned part of the organs and tissues have a higher level of auxin, and auxin polar transport inhibitor could cause the accumulation of auxin in root apex. And auxin transport inhibitor also resulted in aberration of Arabidopsis leaf pattern formation, root gravitropism and elongation.

Bio-Fertilizer,Ground Magnesium Limestone and Basalt Applications May Improve Chemical Properties of Malaysian Acid Sulfate Soils and Rice Growth

Acid sulfate soils are normally not suitable for crop production unless they are appropriately ameliorated. An experiment was conducted in a glasshouse to enhance the growth of rice, variety MR219, planted on an acid sulfate soil using various soil amendments.The soil was collected from Semerak, Kelantan, Malaysia. Ground magnesium limestone(GML), bio-fertilizer, and basalt(each 4t ha-1) were added either alone or in combinations into the soil in pots 15 d before transplanting. Nitrogen, P and potash were applied at 150, 30, and 60 kg ha-1, respectively. Three seven-day-old rice seedlings were transplanted into each pot. The soil had a p H of 3.8 and contained organic C of 21 g kg-1, N of 1.2 g kg-1, available P of 192 mg kg-1, exchangeable K of 0.05 cmol c kg-1,and exchangeable Al of 4.30 cmol c kg-1, with low amounts of exchangeable Ca and Mg(0.60 and 0.70 cmol c kg-1). Bio-fertilizer treatment in combination with GML resulted in the highest p H of 5.4. The presence of high Al or Fe concentrations in the control soil without amendment severely affected the growth of rice. At 60 d of growth, higher plant heights, tiller numbers and leaf chlorophyll contents were obtained when the bio-fertilizer was applied individually or in combination with GML compared to the control. The presence of beneficial bacteria in bio-fertilizer might produce phytohormones and organic acids that could enhance plant growth and subsequently increase nutrient uptake by rice. Hence, it can be concluded that addition of bio-fertilizer and GML improved rice growth by increasing soil p H which consequently eliminated Al and/or Fe toxicity prevalent in the acid sulfate soil.

An Overview of the Biology of Reaction Wood Formation

Reaction wood possesses altered properties and performs the function of regulating a tree＇s form, but it is a serious defect in wood utility. Trees usually develop reaction wood in response to a gravistimulus. Reaction wood in gymnosperms is referred to as compression wood and develops on the lower side of leaning stems or branches. In arboreal, dicotyledonous angiosperms, however, it is called tension wood and is formed on the upper side of the leaning. Exploring the biology of reaction wood formation is of great value for the understanding of the wood differentiation mechanisms, cambial activity, gravitropism, and the systematics and evolution of plants. After giving an outline of the variety of wood and properties of reaction wood, this review lays emphasis on various stimuli for reaction wood induction and the extensive studies carried out so far on the roles of plant hormones in reaction wood formation. Inconsistent results have been reported for the effects of plant hormones. Both auxin and ethylene regulate the formation of compression wood in gymnosperms. However, the role of ethylene may be indirect as exogenous ethylene cannot induce compression wood formation. Tension wood formation is mainly regulated by auxin and gibberellin. Interactions among hormones and other substances may play important parts in the regulation of reaction wood formation.

Research Progresses on Auxin Response Factors

Auxin response factors （ARFs）, a family of transcription factors, have been discovered recently. The ARFs bind specifically to the auxin response elements （AuxREs） within promoters of primary auxin responsive genes and function as activators or repressors. The ARFs contain three domains, namely a conserved Nterminal DNA-binding domain, a non-conserved middle region, and a conserved C-termlnal dlmerlzatlon domaln. The ARFs can form a protein complex with auxin/indoleacetic acid through homodimerization or heterodlmerization. The particular protein-protein interaction may play a key role in moduiating the expression of early auxin responsive genes. The identification of ARF mutations in Arabidopsis helps to demonstrate/dissect the function of ARFs in the normal growth and development of plants. Phylogenetic analysis also reveals some interesting protein evolution points in the ARF family.