Dormancy of Plants

This course will be held on 7 and 8 June 2010 at the Regardz Berghotel, Amersfoort, the Netherlands.

Course Introduction and Aims

Dormancy, diapause, rest and quiescence are terms that describe a state of (temporarily) lowered metabolic activity or 'hypometabolic state'. Dormancy is a state of suspended animation of life functions and is found in many species, ranging from bears to mice and frogs, from fish to buds and seeds and from crustaceans to yeast and bacteria. It is an adaptation to survive future unfavourable conditions for prolonged periods of time.

Dormancy and stress responses are closely linked. Many organisms become dormant before they are exposed to stress conditions. The timing may depend on developmental phase (e.g. sexual versus asexual), seasonal rhythms, environmental cues and food supply, among others. Common denominators appear to be a controlled reduction of metabolic activity, arrest of the cell cycle and the initiation of protective mechanisms.

Studies of dormancy may ultimately result in improved methods for the long-term biopreservation and storage of cells, tissues, organs and organisms.

• Because of the vastness of the subject and its acknowledged importance to agriculture and horticulture, our first ever post-experience course on DORMANCY will be limited to plants. It is planned to address the following topics:
• Definitions, classification and nomenclature
• Regulation and control of post-harvest environments
• Treatments to induce dormancy and/or germination
• Genetic, physical and physiological aspects
• Predictive laboratory testing

Course Agenda

• Definitions and nomenclature
• Dormancy as a process and a quantitative phenomenon
• Dormancy: a relative phenomenon
• Dormancy types (eco-, endo-, paradormancy), buds and seeds
• Primary and secondary dormancy in seeds

• Dormancy and inactivity as general phenomena in other organisms.
• Water and responses to water stress during inactivity
• Common and distinct features of dormancy and inactivity
• Quiescence/inactivity/hibernation/dormancy terminology
• Distinction from cold hardiness

• Methods to evaluate dormancy state
• Simple tests for growth inactivity and its potential causes
• Reduction of complexities in dormancy studies
• Interpretation of experimental data (eco-, endo-, paradormancy, embryo dormancy and seed-coat imposed dormancy)

• Development of seed dormancy
• Hormonal/metabolic/molecular regulation
• Causes for seed dormancy (seed coat, embryo dormancy, secondary dormancy)
• Dormancy under field conditions (seed banks; weed control)
• Meaningful/informative hormone measurements
• Preharvest sprouting in cereals – absence of dormancy
• Malting industry – deep dormancy

• Dormancy release in seeds
• Recalcitrant seeds
• Breaking of dormancy under natural conditions
• Breaking of dormancy by artificial treatments (ethylene, GA3, scarification)

• Induction and release of bud dormancy
• Bud types (bulbs, twigs, stolons, tubers etc)
• Environmental/hormonal/molecular/cellular aspects
• Tuber dormancy and potato storage
• Understanding dormancy for purposes of weed control

• Seasonal growth cycle in trees in temperate and tropical regions; different and similar pathways
• Seasonal growth cycle and its dilemma resulting from climatic change
• Assisted transfer strategies in plantation forest
• Out-of-season production of berries
• Whole-year-round production of woody ornamentals

• Regulation of ‘paradormancy' (branching)
• Hormonal regulation by auxin, cytokinin and strigolactones
• Uses of mutants in discovering the pathway downstream of auxin.
• Rational training of plant form, with examples of apple trees and pot azaleas

Who should attend

The course on plant dormancy is aimed at professionals and post-graduate students with a general background in life sciences or agriculture and at nonprofessionals with a strong interest in plant science and technology. The course will reveal mechanisms of dormancy induction, maintenance and release in plants, particularly in seeds and buds. The course addresses environmental, physiological, developmental, and molecular aspects of dormancy phenomena. A broad spectrum of case studies will serve to illustrate the industrial and economic importance of a comprehensive understanding of dormancy for agriculture and horticulture and for ecosystems research. Participants will enhance their knowledge of plant dormancy so as to assess the common features of different dormancies and inactive states. They will be provided with methods to apply knowledge on dormancy in their own research field. Interaction between participants on dormancy related problems that they might have from their own experience will be encouraged.