The synthesis of short-chain saturated fatty acids and their role in the control of ethylene sensitivity in senescing petunia flowers

• Main Author: Botha, Marie Louise
• Published: 2012
• Subjects: Petunia; Plant hormones; Ethylene
• Online Access: http://hdl.handle.net/10210/4564

Ph.D. === The sensitivity of Petunia hybrida flowers to the plant hormone ethylene increases during the early stages of senescence and directly after pollination of the flowers. During these early stages .of senescence, ethylene production is very low and only increases after ethylene sensitivity had already increased. The increase in ethylene sensitivity is due to the forming of short-chain saturated fatty acids that accumulate in the petal tissue during the early stage of senescence. Following pollination, these acids are formed in the stylar tissue and transported to the corolla where it causes a rapid increase in ethylene sensitivity. The synthesis of short-chain saturated fatty acids is controlled by the enzyme acetyl-GoA carboxylase. As the acitivity of this enzyme decreases, the concentrations of short-chain fatty acids increase due to the lack of malonyl-GoA required for chain lengthening. During the early stages of senescence, the activity of this enzyme decreases simultaneously with an increase in short-chain fatty acids and ethylene-sensitivity. The results of this study indicate that acetyl-GoA carboxylase is a key enzyme involved in the control of ethylene sensitivity in petunia flowers.