Submitted to: Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 11, 1995
Publication Date: N/A
Interpretive Summary: Fresh fruits and vegetables can incur heat stress if they are not cooled to remove "field heat" soon after harvest. Heat stress may result in water loss and tissue damage which ultimately reduce the quality of fresh produce in marketing channels. The ability of plant tissues to adapt to and survive at elevated temperatures is at least partly determined by the capacity to rapidly alter the structure of cell membranes, and thereby prevent loss of water and nutrients. In this study, changes in membrane structural components after transfer to heat-stress temperature were investigated in carrot root cells. The major change in response to high temperature was attributable to altered activity of a single enzyme. This work will help scientists to determine the important parameters of acclimation to heat stress, and ultimately enable the development of more heat-tolerant plant products.
Heat-stressed (30 degrees C) cell suspension cultures of carrot (Daucus carota L.) attained a lower maximum cell density and showed browning earlier when compared with control cultures (22 degrees C) over a 16 day growth period. Phospholipid class profiles did not differ between cells grown at 30 and 22 degrees C. The fatty acids of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from microsomes of heat-stressed cells were less unsaturated than those of PC and PE from microsomes of control cells. In particular, there was a marked increase in the proportion of oleate [18:2(9,12)] at the higher growth temperature. This difference could result from inhibition or loss of the microsomal lipid-linked desaturase which inserts the double bond between carbons 12 and 13 of oleate esterified to the glycerol moiety of PC and PE.