Summarising, the objectives of the Coldtree project were:
To identify novel physiological, and genetic techniques indicative of the onset of winter hardiness and dormancy in woody species and, using cDNA microarrays, to postulate a conceptual model describing the molecular events underlying these processes.
To select a set of key genes, of which the expression patterns can be used to describe the stages of dormancy and hardiness.
To evaluate the merits of these key genes as molecular diagnostic tool for nursery practice and improved forestation.
Sustained yield from Europe's commercially exploited forests requires a supply of millions of seedlings annually. The planting stock for reforestation and urban horticulture, almost 1.7 billion tree seedlings and ornamental woody plants comprising a total value of about 2 billion Euro, is mainly produced by European forest tree nurseries. These nurseries rely on a tight scheduling of operations, to be able to deliver vital seedlings to the planting site. A critical step in a modern nursery production chain is the transfer of seedlings to cold or frozen storage. Cold storage is required to prevent winter damage, especially in containerised seedlings, to maintain planting stock in an inactive condition, and to ensure plant supply for geographically distinct planting sites, a requirement for large scaled or internationally operating nurseries.
Indoor storage has therefore become common practice, but poses a new dilemma for nurserymen. Efficient management requires that the handling of seedlings, such as transfer to cold storage, be carried out at the earliest possible time. However, lifting and storage of insufficiently hardened plants reduces vitality and may lead to cold damage, dehydration and fungal infection. To prevent this kind of damage, and its adverse economic effects on nurseries and end-users, it is of vital importance to be able to determine accurately the peak physiological condition for lifting or transfer.
Despite the economic importance of such decisions, nurserymen still predominantly rely on traditional (morphological) methods to identify this moment. Recently, several physiological measurement techniques have been proposed, and some of them have been used operationally. However, the number of nurseries in Europe utilising these techniques is limited, because the methods are either unreliable, labour intensive or technically demanding and the minimum test period (test dependent) can vary from 3 days to over 14 days. In nursery practice, where lifting opportunities can be severely limited by rainfall, frost and snow, such a delay may significantly reduce the number of plants lifted at peak physiological condition.
In addition to the onset of dormancy, dormancy release is also of economic importance. If plants growing out in the nurseries are put into cold storage too late in spring, they show evidence of damage, particularly to the root system. In spring, plants start reversing the processes that protect them during winter before there is a visible sign of regrowth.
So, efficient forestation and cost-effective nursery management require tools for rapid and reliable determination of the physiological condition of forest tree seedlings. To develop such tools, a thorough understanding of the cellular and molecular processes underlying cold hardiness is required. Unravelling the gene expression pattern as a seedling acquires the hardened state will reveal key processes that can be used as landmarks to describe the physiological condition of the tree. Eventually, this will result in molecular tests based on the presence or absence of specific messenger RNA's or proteins, that will allow a rapid evaluation of the physiological state and will facilitate forestation logistics. Such techniques are not yet available to forest tree nurseries and in this respect the forestry sector is lagging behind on horticulture and agriculture.
See also "The application of cDNA microarray technology for unravelling molecular events underlying dormancy and cold hardiness in forest tree seedlings. (COLDTREE)" (attached) Attribution statement: