Paclobutrazole

Most of the GA-synthesis inhibitors characterized so far affect two segments of the compHcated pathway from MVA to the many different GAs identified. The cycHzation reactions that produce / Akaurene are inhibited by the onium growth retardants, and the oxidations of /-kaurene to /-kaurenoic acid are sensitive to heterocycHc triazoles such as paclobutrazol and similar compounds. Other enzymes in the pathway are points for pathway dismption by as yet undeveloped GA biosynthesis inhibitors (236). 

The technique of purification based on seeded crystallization of the desired isomer and simultaneous racemisation of the undesired isomer, termed crystallization induced asymmetric transformation , has been covered by Davey (1994) with the example of a chiral pesticide, paclobutrazol (P). 

Triazole derivatives of the dichlobutrazole and paclobutrazole types are closely related chemically to the triazolyl-0,N-acetals previously mentioned. The oxygen atom of the acetal function was merely replaced by a methylene group. Dichlobutrazole (ICI) was developed for the control of powdery mildew, rust and scab in cereals. Paclobutrazole is under development as a growth regulator. 

As In the use of dichlobutrazole and paclobutrazole, the biological spectrum of the two experimental compounds S 3307 and S 3308, whether fungicide or growth regulator, Is dictated only by the substitution pattern In one part of the molecule. Triapenthenol, which Is of particular Interest as a growth regulator in rice and rape, also possesses a marked fungicidal activity. 

Pinacolone bitertanol, diclobutrazol, diniconazole, metribuzin, paclobutrazol, pindone, thiofanox, triadimenol, triadimefon, triapenthenol, uniconazole Piperazine triforine... 

Sodium borohydride brodifacoum, diclobutrazol, difenacoum, difethialone, diniconazole, fenpropidin, flocoumafen, imidacloprid, imizalil, inabenfide, paclobutrazol, penconazole, triadimenol, uniconazole Sodium butyl mercaptide see Butyl mercaptan Sodium chlorate cloroneb... 

Figure 3. Total proteins secreted by callus which was treated with paclobutrazol. 12.5% SDS-PAGE stained with Coomassie blue. Lane A, 0.0 mg/L Lane B, 0.5 mg/L Lane C, 5.0 mg/L Lane D, 20 mg/L and Lane E, 50 mg/L paclobutrazol. Alpha-amylase is the predominant band at 44 kDa.

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