Effects of Eight Herbicides on In Vitro Hatching of Heterodera glycines

Laboratory studies were conducted to evaluate effects of selected herbicides on hatching of free eggs of the soybean cyst nematode, Heterodera glycines. The herbicides used were Atrazine (atrazine), Basagran (bentazon), Bladex (cyanazine), Blazer (acifluorfen), Command (clomazone), Lasso (alachlor), Sonalan (ethalfluralin), and Treflan (trifluralin). Treatments comprised two concentrations of commercial herbicide formulations and deionized water and 3.14 mM zinc sulfate as negative and positive controls, respectively. Eggs were extracted from females and cysts, surface disinfested, and incubated in herbicide or control solutions at 25 ± 2 C in darkness. Hatched second-stage juveniles were counted every other day for 24 days. Hatching of H. glycines eggs in 50 and 500 μg/ml Blazer was 42 to 67% less than that in deionized water and 6l to 78% less than that in zinc sulfate solution. Zinc sulfate significantly increased hatching activity in 50 μg/ml but not 500 μg/ml Blazer. The other herbicides tested at various concentrations had no significant effect on egg hatching. The specific component of Blazer inhibiting egg hatching is unknown. Suppression of hatching by Blazer indicates that this postemergence soybean herbicide may have a potential role in managing H. glycines.     

Clomazone对中国红豆杉细胞培养的影响

以中国红豆杉（Taxus chinensis）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糊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20d加终浓度为20mg/L的Clomazone,对细胞生长影响较小,紫杉醇含量最高,达4263μg/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。Clomazone与Methyl jasmorale (MJ)及Chloroholine chloride（CCC）对紫杉醇含量的提高有协同作用。     

Suppression of Wolffia arrhiza growth by brassinazole, an inhibitor of brassinosteroid biosynthesis and its restoration by endogenous 24-epibrassinolide

The effect of the brassinosteroid (BR) 24-epibrassinolide (epiBL; 10(-13)-10(-6)M) on growth and levels of chlorophylls, carotenoids, sugars and protein in Wolffia arrhiza after 7 days of cultivation is reported. Application of epiBL to W. arrhiza cultures stimulates the growth and increases the content of photosynthetic pigments, sugar and protein. The greatest effect of epiBL is observed at a concentration of 10(-9)M. We tested the action of Brz2001, a specific BR biosynthesis inhibitor, in the range of 10(-6)-10(-4)M. Addition of Brz2001 to W. arrhiza cultures inhibits their growth after 7 days of cultivation. The inhibition of growth could be reversed by the addition of epiBL. Moreover, there was not complete recovery to the level of control, especially at 5 x 10(-5)-10(-4)M Brz2001. The effects of treatment with 10(-9)M epiBL mixed with a mevalonate pathway inhibitor (mevinolin), or a 2-methylerythritol 4-phosphate pathway inhibitor (clomazone), were also investigated. Mevinolin did not inhibit growth of W. arrhiza after 7 days of cultivation. However, clomazone did. Addition of epiBL overcame this inhibition. These results suggest that the mevalonate pathway may not function well in W. arrhiza and that biosynthesis of BRs through the non-mevalonate pathway in W. arrhiza could be possible.