Physiological and morphological responses of dormant and growing Norway spruce container seedlings to drought after planting

Abstract

-Survival, root egress, height growth, xylem water potential, and chlorophyll fluorescence of dormant and growing Norway spruce (Picea abies (L.) Karst.) container seedlings exposed to postplanting drought periods (1, 2, 3 and 4 weeks) in the field were studied. Growth stages were created by terminating overwinter frozen storage 5 weeks (growing) or 5 days (dormant) before planting. Without postplanting drought, root egress of growing seedlings during the 6-week study period was twice that of dormant seedlings. When exposed to postplanting drought, growing seedlings showed a greater decline in root egress and xylem water potential than dormant seedlings. Postplanting drought had no effect on chlorophyll fluorescence in dormant seedlings, whereas in growing seedlings chlorophyll fluorescence decreased after the 3-week drought period. The results indicate that planting seedlings kept dormant by prolonged frozen storage in summer is beneficial only if very long dry periods occur after planting. chlorophyll fluorescence / drought / growth stage / Picea abies / root egress Résumé -Réaction physiologique et morphologique à la sécheresse après plantation de semis dormants ou en croissance de Picea abies cultivés en conteneurs. La survie, la production de nouvelles racines, la croissance de la pousse, le potentiel hydrique du xylème et la fluorescence de la chlorophylle ont été étudiés sur des semis de Picea abies (L.) Karst, dormants ou en croissance, cultivés en conteneurs et exposés à des périodes (1, 2, 3 et 4 semaines) de sécheresse après plantation au champ. Pour préparer les divers stades de croissance, le stockage hivernal des semis au froid a cessé 5 semaines (en croissance) ou 5 jours (dormants) avant la plantation. Quand les semis n'ont pas été exposés à la sécheresse après plantation, la production de nouvelles racines des semis en croissance a doublé comparativement aux semis dormants pendant les 6 semaines d'étude. Pour les semis exposés à la sécheresse après plantation, la production de nouvelles racines et le potentiel hydrique ont davantage baissé pour les semis en croissance que pour les semis dormants. La sécheresse après plantation n'a pas affecté la fluorescence de la chlorophylle des semis dormants, mais après une sécheresse de 3 semaines la fluorescence de la chlorophylle des semis en croissance a baissé. Les résultats montrent que la plantation des semis qui ont été conservés dormants par un stockage au froid plus long en été est bénéfique dans le cas où la sécheresse continue très longtemps après plantation. fluorescence de la chlorophylle / sécheresse / stade de croissance / Piceas abies / production de nouvelles racines

Early development and nutrition of Norway spruce (Picea abies(L.) Karst.) seedlings on different seedbeds in the Bavarian limestone Alps – a bioassay

“…temperature, moisture, pathogenic fungi, or light are important factors for Norway spruce (Picea abies (L.) Karst.) seedling development in natural forests [5,14,34]. It has recently been shown that the recruitment of a new spruce generation strongly depends on the quality of the seedbed [14,15,46].…”

Nursery fertilisation affects the frost-tolerance and plant quality of Eucalyptus globulus Labill. cuttings

“…The plants were taken out of their containers, making every effort to keep their root balls intact. White pre-existing roots (usually less than 5 and shorter than 2 cm long) grown out from each ball were cut [23,56]. It was previously ascertained, using the plants harvested for the dry weight measurements, that there were not white roots inside the root ball at this time.…”

Late termination of freezer storage increases the risk of autumn frost damage to Norway spruce seedlings

“…The risk of autumn frost damage can be studied in field experiments by varying the date of storage termination of the planting stock (Ericsson et al 1983, Raulo et al 1994, Luoranen et al 2005. As this experimental design simulates real-life practice, the method produces reliable results.…”

“…One traditional way to overcome this problem has been to plant part of the seedlings in the autumn, after they have attained dormancy (Antola and Lehto 1969). More recently, plantings with actively growing seedlings have also produced promising results (Revel et al 1990, Grossnickle and Folk 2003, Luoranen et al 2005, 2006.…”

“…This method has been successfully used in northern Europe and North America for more than fifty years (Yli-Vakkuri et al 1968, Brown 1973, Camm et al 1994. The viability of the seedlings is sustained relatively long in freezer storage, so that there are normally no problems about the onset of growth even in late plantings (Ericsson et al 1983, Luoranen et al 2005, Helenius et al 2005) except after very long storage, which may decrease the carbohydrate reserves (Ritchie 1982, Jiang et al 1994) and dry out the seedlings through transpiration. In their development over the growing season, however, freezer-stored seedlings lag behind seedlings planted earlier in the spring.…”