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Effect of summer irrigation on seasonal changes in taproot reserves and the expression of winter dormancy/activity in four contrastinig lucerne cultivars

Citation

Pembleton, KG and Cunningham, SM and Volenec, JJ, Effect of summer irrigation on seasonal changes in taproot reserves and the expression of winter dormancy/activity in four contrastinig lucerne cultivars, Crop and Pasture Science , 61, (11) pp. 873-884. ISSN 1836-0947 (2010) [Refereed Article]


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Copyright Statement

Copyright 2010 CSIRO

Official URL: http://www.publish.csiro.au

DOI: doi:10.1071/CP10030

Abstract

In the summer dry environment of cool temperate Tasmania, summer irrigation is used to maximise forage production. For lucerne (Medicago sativa L.) this irrigation is likely to interact with winter-dormancy genotypes to influence seasonal changes in taproot reserves and thus, the process of cold acclimation. To test this hypothesis four lucerne cultivars with contrasting levels of winter dormancy (DuPuits: winter-dormant; Grasslands Kaituna: semi winter-dormant; SARDI 7: winter-active: SARDI 10, highly winter-active) were grown in small plots at Elliott, Tasmania, under irrigated or dryland conditions. At each defoliation taproots were sampled and assayed for the concentration of soluble sugars, starch, amino acids, soluble protein, the abundance of vegetative storage proteins (VSP), and the abundance of mRNA transcripts associated with cold acclimation and VSP. Taproot-soluble protein concentrations in DuPuits significantly increased from summer to autumn when plants were grown under dryland conditions. When grown under irrigated conditions, taproot-soluble protein concentrations decreased over summer and increased in autumn for all cultivars. The abundance of VSP increased in summer in all cultivars grown under dryland conditions. Taproot-soluble sugar concentrations increased and starch decreased in autumn for all cultivars grown under both water regimes. Plants grown under dryland conditions showed little change in RNA transcript abundance of cold acclimation genes across all cultivars and sampling dates, while in those plants grown under irrigated conditions, transcript abundance was influenced by sampling date, and for some genes, by cultivar. There was a clear carry-over effect from the exposure of summer drought on the winter-dormancy response. The expression of winter dormancy at an agronomic and molecular level was greater under dryland conditions.

Item Details

Item Type:Refereed Article
Research Division:Agricultural and Veterinary Sciences
Research Group:Crop and Pasture Production
Research Field:Crop and Pasture Biochemistry and Physiology
Objective Division:Animal Production and Animal Primary Products
Objective Group:Pasture, Browse and Fodder Crops
Objective Field:Lucerne
Author:Pembleton, KG (Dr Keith Pembleton)
ID Code:60356
Year Published:2010
Web of Science® Times Cited:5
Deposited By:Agricultural Science
Deposited On:2010-02-01
Last Modified:2011-04-14
Downloads:0

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