บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Role of ethylene sensitivity in mediating the chilling-induced leaf abscission of ixora plants.

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

Biology and biotechnology of the plant hormone ethylene II. Proceedings of the EU-TMR-Euroconference Symposium, Thira (Santorini), Greece, 5-8 September, 1998. Year: 1999 Pages: 235-242 Ref: 18 ref.

1999

บทคัดย่อ

Role of ethylene sensitivity in mediating the chilling-induced leaf abscission of ixora plants.

Exposing intact Ixora coccinea plants or petiole explants to chilling (3 days at 3, 7 or 9 deg C) resulted in 20-80% abscission of mature, non-senescent leaves, manifested only 2 days after transfer to 20 deg C. The degree of leaf abscission increased with decreasing temperature. Chilling exposure induced a significant increase in ethylene production rates in petiole explants during the initial 4 h after transfer to 20 deg C. A similar pattern of increased ethylene production was observed in petiole explants treated with NAA or with the antioxidant butylated hydroxyanisole (BHA), although these compounds significantly reduced chilling-induced leaf abscission. Application of the ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), which reduced ethylene production of petiole explants by 60%, inhibited leaf abscission by 70%. Treating intact plants with the ethylene action inhibitor, 1-methylcyclopropene (1-MCP) prior to chilling, completely prevented chilling-induced leaf abscission. E

ndogenous ethylene was essential for chilling-induced leaf abscission. Exposure of intact plants to exogenous ethylene (3-10 micro l/litre) for 1-3 days, or treating petiole explants with 1-aminocyclopropane-1-carboxylic acid (ACC), significantly enhanced leaf abscission only when they had been pre-exposed to chilling. Abscission induced by chilling was closely correlated with increased sensitivity of the abscission zone (AZ) to ethylene. NAA and BHA inhibited both chilling-induced and ACC-enhanced leaf abscission of petiole explants. This indicated the possible involvement of oxidative processes, probably IAA, in chilling-induced leaf abscission. It was proposed that chilling induced oxidative processes in the AZ which reduced IAA levels, resulting in increased sensitivity of the AZ to ethylene and leaf abscission.