Clomazone对中国红豆杉细胞培养的影响

以中国红豆杉 (Taxuschinensis)悬浮细胞为材料 ,研究了Clomazone(广灭灵 )对培养细胞生长及紫杉醇和类胡萝卜素合成的影响 ,探讨紫杉醇生物合成途径人工调控的方法 .结果表明在细胞培养第 2 0d添加终浓度为 2 0mg L的Clomazone ,对细胞生长影响较小 ,紫杉醇含量最高 ,达 4 2 6 3μg L ,约为对照的 3倍 .Clomazone可以抑制红豆杉细胞类胡萝卜素的合成 ,其对紫杉醇产量的提高可能与其抑制类胡萝卜素的合成有关 .Cloma zone与Methyljasmorale (MJ)及Chloroholinechloride (CCC)

Clomazone dissipation, adsorption and translocation in four paddy topsoils

Laboratory experiments about the dissipation, adsorption and translocation in four paddy topsoils were conducted in this paper. From the results it can be concluded as follows: the dissipation rate of clomazone differed greatly in different paddy soil derived from different parent materials. The half-lives for clomazone degradation in paddy soils ranged from 5.7 to 22.0 d. The order of clomazone dissipation rate was reddish yellow paddy soil > alluvial sandy paddy soil > yellow clayey paddy soil > purple sandy paddy soil. Clomazone sorption quantity was significantly correlated with organic carbon(R2=0.62) and clay content(R2=0.67) in the tested paddy soils. Positive correlation was found between apparent K d value and cation exchange content(CEC). The consequences for the adsorption of different soils were purple sandy paddy soil>yellow clayey paddy soil>reddish yellow paddy soil>alluvial sandy paddy soil. Under the simulated rainfall of 200 mm through four different unsaturated soil lysimeters over 24 h, clomazone was readily to be leached into lower surface soil and there was about 2.6%—4.2% of applied clomazone leached out of 20 cm cultivated soil layer. Translocation experiments showed that the order of clomazone leaching ability was: alluvial sandy paddy soil > reddish yellow paddy soil > yellow clayey paddy soil > purple sandy paddy soil. Simple regression results manifested that factors like CEC, organic carbon, clay, and adsorption rate constant had been negatively correlated with the percentage of clomazone loss from soil lysimeters.

Hydrolysis and Photolysis of Herbicide Clomazone in Aqueous Solutions and Natural Water Under Abiotic Conditions

The hydrolysis and photolysis of clomazone in aqueous solutions and natural water were assessed under natural and controlled conditions. Kinetics of hydrolysis and photolysis of clomazone were determined by HPLC-DAD. Photoproducts were identiifed by HPLC-MS. No noticeable hydrolysis occurred in aqueous buffer solutions （（25±2）°C, pH （4.5±0.1）, pH （7.4±0.1）, pH （9.0±0.1）;（50±2）°C, pH （4.5±0.1）, pH （7.4±0.1）） or in natural water up to 90 d. At pH （9.0±0.1） and （50±2）°C the half-life of clomazone was 50.2 d. Clomazone photodecomposition rate in aqueous solutions under UV radiation and natural sunlight followed ifrst-order kinetics. Degradation rates were faster under UV light （half-life of 51-59 min） compared to sunlight （half-life of 87-136 d）. Under UV light, four major photoproducts were detected and tentatively identiifed according to HPLC-MS spectral information such as 2-chlorobenzamide, N-hydroxy-（2-benzyl）-2-methylpropan-amide, 2-[2-phenol]-4,4-dimethyl-3-isoxazolidinone and 2-[（4,6-dihydroxyl-2-chlorine phenol）]-4,4-dimethyl-3-isoxazolidinone. These results suggested that clomazone photodegradation proceeds via several reaction pathways：1） dehalogenation;2） substitution of chlorine group by hydroxyl;3） cleavage of the side chain. Photosensitizers, such as H2O2 and ribolfavin, could enhance photolysis of clomazone in natural sunlight. In summary, we found that photoreaction is an important dissipation pathway of clomazone in natural water systems.

Synergistic Effect of Adjuvants on Clomazone

Adjuvants have the potential to improve the weed control efficacy of herbicides. The synergistic effects of different types of adjuvants on clomazone and the safety of soybean were studied systematically by bioassay, instrumental analysis and field trial methods. The results showed that the five different types of adjuvants all differentially enhanced the herbicidal effects of clomazone;the compound adjuvant had the best synergistic effect on clomazone, and the plant control effect and the fresh weight control effect of clomazone on weeds could be increased by 24.2% and 24.11%, respectively. Through the study of the physical properties of the solution, the results showed that the adjuvants reduced the surface tension by 15.66%-33.23%, increased the expansion diameter by 11.56%-63.19%, reduced the contact angle by 8.40%-71.49%, and shortened the drying time by 3.1%-37.75%. Among the adjuvant options, the compound adjuvant exhibited the best effect, reducing the surface tension by 26.03%-33.23%, increasing the expansion diameter by 39.81%-63.19%, reducing the contact angle by 33.22%-71.49%, and shortening the drying time by 28.85%-37.75%. All the adjuvants had no significant effect on soybean plant height and yield and were safe for soybean. The reasonable development and application of adjuvants in China’s agricultural practices had good practical basis and significant value.

Management of Grass and Broadleaf Weeds in Processing Potatoes (Solanum tuberosum L.) with Clomazone, in the Argentinian Pampas

Weed competition in the potato crop could cause up to a 95% yield reduction depending on the variety, the weed species and the competition period. In this work the effect of Clomazone (Command 36 CS®), when applied alone or in combination with Metribuzin (Sencorex® 48) upon grass and broad-leaved weeds was assessed. The work was carried out under the environmental conditions of the Argentinian Pampas, where close to 50% of the potatoes produced in the country are grown. The field trial was performed during the spring-summer crop, season 2008/09, with cv. Innovator, in a completely randomized design of the following treatments: (a) control, without weed control;(b) Clomazone 1.6 l·ha-1;(c) Clomazone 2.0 l·ha-1;(d) Clomazone 1 l·ha-1 + Metribuzin 0.75 l·ha-1;(e) Clomazone 1.6 l·ha-1 + Metribuzin 0.5 l·ha-1;and (f) Metribuzin 1.35 l·ha-1. Treatment effectiveness (TE), crop competition level (CCL) and weed suppression index (WSI) were assessed at 38, 53 and 72 days after planting (DAP), while yield and quality were also evaluated, following industry protocols. In those treatments were Clomazone was used alone, at 2 l·ha-1, or combined (Clomazone 1 l·ha-1 + Metribuzin 0.75 l·ha-1), a higher yield was observed. Besides, a high correlation between TE, WSI and tuber yield was also achieved. Clomazone improved TE, CCL and WSI, which was not only reflected in higher tuber yields, but also on better tuber quality.

Alleviation of Pesticide Residue in Surface Water

Reduction of environmental pollution incurred from pesticide use is very important. Zeolite is a natural mineral capable of removing certain chemical contaminants from water. This study was carried out to test the effect of zeolite treatment on pesticide residue alleviation in surface water. Ten surface water samples were treated with natural zeolite by filtering through. An EPA method was used to extract pesticide residue from the water samples and the surfactant used to modify the net charge on the zeolite was hexadecyltrimethylammonium chloride (HDTMA-Cl). Gas chromatography-mass spectrometry was used to analyze water samples. Alleviation was achieved in all the 10 water samples that were filtered through zeolite. The highest removal of pesticides from water with zeolite included 100% of bifenthrin in sample CLC, atrazine in BPH, CDG and LBT;metolachlor in CLC, LBT, BCH, TRH2 and BPI;acetolachlor in BBH and BCH;azoxystrobin in BBH;desethylatrazine in BCH and BPI;metribuzin in BCH, TRH2 and BPI;and both clomazone and bromacil in sample BDC. A minimum reduction of 10.9% was found for metolachlor in sample BRH. Further reduction of pesticide residues up to 50% was recorded in the SMZ treatment as the concentrations of 4 out of 8 pesticide residues were reduced. This study confirms the potential of both the natural zeolite-Clinoptilolite, and SMZ of alleviating pesticide residues in water.