5-(1,2-Epoxy-2,6,6-trimethyl-1-cyclohexyl)-3-methyl-cis, trans-2,4-pentadienoic acid and its esters: New plant growth inhibitors structurally related to abscisic acid

5-(1,2-Epoxy-2,6,6-trimethyl-1-cyclohexyl)-3-methyl-cis,trans-2,4-pentadienoic acid and its esters were found to be potent plant growth inhibitors. Their activities were comparable to that of abscisic acid.

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.

Starfish gonad: action and chemical identification of spawning inhibitor

The gamete-shedding substance obtained from the radial nerves induces spawning when it is applied to the gonads of mature starfish in vivo and in vitro. A substance that inhibits the action of this spawning factor is present in both ovary and testis; it has been isolated from testis of Asterina pectinifera and chemically identified as L-glutamic acid.

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.

Isolation of (+)-abscisin II from dormant aerial tubers of Dioscorea batatas

The occurrence of at least three growth inhibitors was demonstrated in the dormant aerial tubers of Dioscorea. One of the inhibitors was isolated in crystalline form and identified as (+)-abscisin II by the infrared and ultraviolet spectra as well as by the optical rotatory dispersion.

IAA-oxidase activity in light grown cucumber hypocotyls treated with helminthosporol

Helminthosporol (H-ol) promoted the growth of light grown cucumber hypocotyls. The IAA-oxidase activity per dry weight of the hypocotyl of H-ol treated materials was less than that of controls. There was an inverse relationship between IAA-oxidase activity and H-ol induced elongation of the hypocotyl. However, when IAA-oxidase activity per plant was compared between H-ol treated materials and controls there was no essential difference. It is concluded that the apparent inhibitory effect of H-ol on IAA-oxidase activity is not directly related to the mechanism of H-ol action.

Physiological activities of helminthosporol in comparison with those of gibberellin and auxin

Helminthosporol, a metabolic product of Helminthosporium sativum, remarkably stimulated elongation of the second leaf sheath of rice seedlings of various varieties. It also stimulated the elongation of hypocotyls of cucumber seedlings. This substance did not have any effect on the growth of peas, tomato, sunflower and the dwarf mutants of maize. This substance did not have auxin-like activities.