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ARS Home » Research » Publications at this Location » Publication #89116
Title: CHANGES OF LIPID COMPONENTS DURING DORMANCY IN'HULL THORNLESS' AND 'TRIPLE CROWN' BLACKBERY CULTIVARS

Author
item IZADYAR, AMIR - VOLUNTEER
item Wang, Shiow

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Most deciduous fruit trees growing in temperate climates undergo a period of dormancy in the winter. However, the mechanism of dormancy is not very well understood. Factors controlling the onset and breaking of dormancy have not been defined. Our study shows Triple Crown and Hull Thornless blackberries are two short dormancy cultivars and Triple Crown requires lower chilling units than Hull Thornless to overcome dormancy. There was an increase in glycolipid and phospholipid content and unsaturation of fatty acids associated with termination of dormancy. This indicates that the breaking of dormancy and growth of blackberry buds probably is mediated through changes in membrane lipids. Basic knowledge on dormancy and bud break will help to lessen tree damage from spring frost. Information presented in this report will increase our understanding of the mechanism of dormancy and will stimulate further research in this field.

Technical Abstract: Changes in phospholipids, galactolipids, and fatty acid were determined in two cultivars of blackberries, Triple Crown and Hull Thornless, during dormancy and bud break. Under field conditions, Triple Crown required lower chilling units (CUs) than Hull Thornless to overcome dormancy. Triple Crown and Hull Thornless achieved full bud break after receiving 600 and 1000 CUs, respectively. Under cold temperature treatments, 'Triple Crown' needed 400 CUs, while Hull Thornless needed 600 CUs at 4 degrees C to obtain 100% bud break. The shoots kept at intermittent 6/24 degrees C (6 degrees C for 16 hr, and 24 degrees C for 8 hr) did not reach full bud break even after receiving 1000 CUs. An increase in phospholipids and glycolipids was observed during the termination of dormancy. The increase in phospholipids occurred earlier than the increase in glycolipids. The percentage of 18:2 fatty acid decreased while 18:3 increased and there was approximately a five-fold increase in the 18:3/18:2 ratio observed at the time of bud break. The increase in the 18:3/18:2 ratio could serve as an indicator of dormancy termination and growth resumption in blackberry.