Isolation of gibberellins A26 and A 27 and their glucosides from immature seeds of Pharbitis nil

Two new gibberellins, gibberellins A26 and A27 (GA26 and GA27), and their glucosides have been isolated from immature seeds of Japanese morning-glory (Pharbitis nil), together with GA8 and its glucoside. GA26, GA27 and their glucosides showed only slight growth-promoting activities on seedlings of rice, dwarf maize and cucumber.

Isolation of two new gibberellins from immature seeds of Canavalia

Two new gibberellins, Canavalia gibberellin-I (CG-I) and Canavalia gebberellin-II (CG-II), were isolated from immature seeds of sword bean, Canavalia gladiata DC. The molecular formulas C19H22O7 and C19H22O6, were assigned to CG-I and CG-II, respectively, on the basis of high resolution mass, infrared and NMR spectra. The growth-promoting effects of CG-I and CG-II on dwarf maize mutants d 1 and d 5, rice seedlings and dwarf peas, Progress No. 5, are reported.

Isolation of water-soluble gibberellins from immature seeds of Pharbitis nil

The presence of three water-soluble gibberellins was confirmed in immature seeds of morning-glory (Pharbitis nil). The structure of the main component has been elucidated as 2-O-β-glucosyl-gibberellin A3. It shows marked growth-promoting activity on rice seedlings but is far less active on dwarf maize mutants d 1, d 2 and d 5.

Elemental Sulfur as a Plasticizer for Polysulfide Polymers and Other Polymers

So-called elastic sulfur obtained by quick-quenching molten sulfur from a temperature of 250° C to a temperature of about −10° C is really a mixture of polymeric sulfur and monomeric S8 sulfur, the latter in a metastable condition, Quick-quenched sulfur is elastic because of the plasticizing effect of the liquid S8 sulfur on the polymeric sulfur. In this publication we show that large concentrations of S8 can exist dissolved in a liquid condition in other polymers where it also acts as a plasticizer. In many cases these compositions appear completely stable, i.e., there is no tendency for the dissolved sulfur to crystallize out. The best example is crosslinked polyethylene tetrasulfide polymers. These polymers can retain 40 per cent of dissolved sulfur in the form of liquid S8 over indefinitely long periods of time. We prove that the sulfur is in its elemental form by quantitative extraction with CS2. The specific volume of the dissolved sulfur shows it is in a liquid condition. The mechanical properties of the sulfur plasticized crosslinked polymers are just what would be expected from this type of structure. Preliminary information concerning sulfur in other polymers is presented.