Distribution of Three Auxin Protector Substances in Seeds and Shoots of the Japanese Morning Glory (Pharbitis nil)

Studies on Auxin Protectors. VII. Association of Auxin Protectors With Crown Gall Development in Sunflower Stems

“…There is a correlation between interference with auxin destruction and rate of internode elongation in young vines. Thus auxin protection is greatest in leaves and interriodes elongating most rapidly, and diminishes as the tissue matures (29,30). Similar substances have been identified in other plants such as tobacco (15,16), cocklebur, Kalanchoe, Nicotiana affinis, N. glauca, N. ri'stica, sunflower, and tomato (24, and (25).…”

“…This fact was implied initially in the observations of Phipps oni tobacco leaves (15,16). and high levels of protector have been found in the apexes of Japanese morning glory vines (30), and in growing Nicotiania tissue cultures (21). The association of high levels of auxin protectors with the juvenile state will be reported elsewhere, as will a more detailed discussion of why these substances are probably causally related to the juvenile state.…”

“…1(d). The secondary appearance of protector activity in verv old stems has alvo been observed in the Japanese morning glory (30). No explanation for this phenomenon is apparent, al--though it may relate to secondary cambial, or lateral bud activity.…”

Studies on Auxin Protectors

“…Our results indicate that auxin protectors are highly effective in blocking both of these peroxidase oxidations, and the greatest concentrations of auxin protectors are found associated with juvenile tissue. There exists, in fact, a gradient of Prs along the shoot axis of Japanese morning glories (33,34), Helianthus, Kalanchoe, Nicotiana, and Xantliiimin (26).…”

Studies on Auxin Protectors. V. On the Mechanism of IAA Protection by Protector-I of the Japanese Morning Glory

“…Experinments on young plants have indicated that the inhibition of enzymatic destruction of IAA varies inversely with the age of the tissue, i.e., inhibition decreases as one descends along the stem, and the interference with IAA destruction correlates with the rate of internode and leaf elongation. Thus auxin protection is greatest in leaves and internodes elongating nmost rapidly, and dimlinishes in maturing and senescing tissue (21,22). At least 3 substances (or comp)lexes or polymers of the same substance) appear to be involved: protector-A (Pr-A).…”