Overview
Bud dormancy is poorly understood compared with flowering or fruit ripening, despite governing yield potential: poor dormancy can cause necrosis of the inflorescence primordium and uneven bud burst and fruitfulness across a vineyard. This report investigates respiratory control in dormant grapevine buds, developing techniques to localise superoxide and hydrogen peroxide accumulation and measure whole-organ respiration across a developmental series from cold storage to bud burst. Results show tightly regulated, spatially distinct oxidative changes, with elevated activity in developing vascular tissue, providing a platform for further work on temperature's role in dormancy, with relevance to other stresses such as drought and salinity. A significant amount of research has been conducted since publication; refer to more recent Wine Australia resources.
Grapevine is a temperate perennial, with a reproductive cycle spanning two seasons (ca. 18 months). Normal, or optimal transitions from dormancy to bud burst, flowering, fruit ripening, senescence and so on, act in synchrony with seasonal changes in climate. The optimal regulation of bud dormancy is poorly understood by comparison to flowering or fruit ripening, despite bearing the floral organs that determine yield potential. Current knowledge is limited to either agronomic data, at one end of the scale, or gene expression data at the other. This project sought to bridge this gap by translating knowledge and technology from the more fundamental plant sciences, to the more complex grapevine bud. There was a need for basic understanding of how primary metabolism is regulated by temperature, and the work this project supported provides a firm platform. This project has enabled techniques in whole organ respiration, and the oxidative state of bud tissue to be developed and applied during bud burst.
Abstract
Respiration is the fundamental driver of metabolism, growth and adaptation in plants. Currently, there is very little understanding of respiration in grapevine buds, despite their importance in fruitfulness and spatial variation in development in vineyards.
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