Eklund L, Cienciala E, Hallgren JE
No Relation between Drought Stress and Ethylene Production in Norway Spruce
Physiologia Plantarum: 1992 86:297-300
The relationship between water availability and ethylene production was studied in 24-year-old trees of Norway spruce [Picea abies (L.) Karst.] growing on experimental plots with different water availability. Ethylene and oxygen were collected from the cambial/xylem region and heartwood in the stem using non-destructive sampling methods. Xylem sap flow was measured-in stems using a heat-balance technique. Pre-dawn water potential of shoots was used to assess the water status of the trees. Growth was calculated from increments in stem basal area. The highest ethylene concentrations were found in irrigated trees that also, as compared to the other treatments, showed the most rapid flow rate of sap, the highest pre-dawn water potential, and the most rapid growth. By contrast, the lowest ethylene concentrations were measured in trees to which artificial drought was induced. Such trees also showed the lowest water transport, lowest water potential and relatively slow growth. Thus, no signs of drought-induced ethylene production were found in this study, contrary to the general contention of a positive relation between drought stress and ethylene production.
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