ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Chilling-induced leaf abscission of Ixora coccinea plants. II. Alteration of auxin economy by oxidative stress.

Michaeli, R.; Riov, J.; Philosoph-Hadas, S.; Meir, S.;

Physiologia Plantarum Year: 1999 Vol: 107 Issue: 2 Pages: 174-180 Ref: 27 ref.

1999

บทคัดย่อ

Chilling-induced leaf abscission of I. coccinea pot plants was almost completely inhibited by NAA, even in the presence of exogenous ethylene (which enhanced the chilling effect on leaf abscission). Chilling reduced free IAA content, quantified immediately after chilling, in the abscission zone (AZ) and leaf blade. Free IAA content in chilling-treated plants continued to decrease gradually with time after chilling. Application of the antioxidant butylated hydroxyanisole (BHA) before or after chilling not only prevented the postchilling decline in free IAA content, but also restored the free IAA level during 6-48 h of the postchilling period almost to the control level. No significant effect of chilling on the endogenous content of ester- and amide-conjugates of IAA or the metabolism of exogenous labelled IAA were observed. Chilling enhanced the decarboxylation of IAA, particularly in the AZ tissue. Auxin transport capacity was significantly inhibited by chilling, and this effect was counteracted

 by BHA applied before chilling. The data indicate that chilling reduces free IAA content in the AZ, an effect that may lead to increased sensitivity to ethylene. The chilling-induced reduction in IAA content in the AZ appears to result, at least in part, from increased IAA decarboxylation and reduced auxin transport capacity. These processes seem to be triggered by the oxidative stress imposed on the tissues by chilling.