บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

The role of sensitivity to ethylene in pollination-induced corolla senescence syndrome.

Halevy, A. H.

Acta Horticulturae Year: 1995 Issue: No. 405 Pages: 210-215 Ref: 21 ref.

1995

บทคัดย่อ

The role of sensitivity to ethylene in pollination-induced corolla senescence syndrome.

 

Treatment of cut Phalaenopsis flowers with cholera toxin or guanosine-5-O-(3-thiotriphosphate), compounds that modulate GTP-binding protein activity, increased the sensitivity of flowers to ethylene. Guanosine-5-O-(2-thiotriphosphate) which does not affect the activity of GTP-binding proteins, had no effect on the sensitivity to ethylene. Western blot analysis of microsomal proteins revealed that a peptide with a molecular mass of about 42 kDa cross-reacts with antibodies against well-conserved amino acid sequence of mammalian G-proteins. Calcium ions, known as cofactors of protein kinases, also increased the sensitivity of the flowers to ethylene, while EGTA, a chelator of calcium, decreased it. Protein phosphorylation in petal microsomal membranes was doubled in the presence of calcium ions. Ten hours after pollination, at the peak of ethylene sensitivity, a significant increase was measured in the binding of of GTP to the membranes. This increase was unrelated to the effect of pollination on

ethylene production, since it occurred also in flowers treated with AOA. Protein phosphorylation in flowers increased significantly following pollination, with a single peptide of about 30 kDa most heavily phosphorylated. These observations indicate a direct involvement of GTP-binding proteins, calcium and protein phosphorylation, major components of the cellular signal transduction pathway, in the regulation of pollination-induced ethylene sensitivity in Phalaenopsis petals. The most likely candidates as the transmissible sensitivity factor are short chain saturated fatty acids (C7-C10). The concentration of these acids, especially C8 in the perianth increased soon after pollination and application of octanoic acid to the stigma of unpollinated flowers greatly increased the sensitivity of the flowers to ethylene. Pollination as well as application of octanoic acid increased the fluidity of the gynoecium and perianth membranes indicating these agents had an effect via membrane function.