Acidic mist and nitrogen fertilization effects on growth, nitrate reductase activity, gas exchange, and frost hardiness of red spruce seedlings

Abstract

SUMMARYAcidic deposition may contribute to the decline of red spruce (Picea rubens Sarg.) in eastern North America; response to acidic mist may depend on mist content and plant nutrient status. We grew red spruce seedlings with high or low nitrogen fertilization to roots (other elements in constant proportion to N), exposed only shoots to pH 30, high sulphate (10:1, S:N) or high nitrate (1 :10, S:N) mist for 5 wk, then moved seedlings outdoors for cold acclimation. Effects of mist content were found until the third week of cold acclimation. Foliar necrosis was higher after exposure to sulphate than to nitrate mist and greater in older than new needles. Sulphate-misted seedlings had lower new-shoot biomass, shoot water content, and nitrate reductase activity, and higher foliar sulphur levels than nitrate-misted seedlings. They also had greater needle frost hardiness (estimated by electrolyte leakage) at the start of cold acclimation. Effects of fertilization were found throughout the experiment. High-N fertilization increased biomass, tissue N level, and shoot water content, and decreased foliar necrosis from mist. During cold acclimation, high-N seedlings had lower transpiration and photosynthetic rates and higher water use efficiency than low-N seedlings. High-N fertilization increased needle frost hardiness after 5 wk of acclimation and decreased visible needle injury after an outdoor frost. However, high-N seedlings had fewer needle primordia in terminal buds and more bud frost-damage than low-N seedlings. Fertilization, mist content, and their interaction strongly affected seedlings, showing that nutrient status can influence the response of red spruce to acidic deposition and frost.

Effects of nitrogen addition on the stress sensitivity of Calluna vulgaris

“…In spring of 1994-1996, bud-burst was significantly more advanced in high-N plots than in those receiving only artificial rain solution. Similar results have been reported elsewhere, with, for example, earlier budbreak in fertilized seedlings of red spruce (L'Hirondelle et al, 1992).…”

“…Freer-Smith (1984) ; Mansfield, Lucas & Wright (1988) ; Aerts (1993)) and can have an impact on the plant and its mycorrhizal symbiosis (Van der Eerden et al, 1992 ;Caporn et al, 1995 b), both of which can affect plant water and nutrient relations. In addition to effects on drought sensitivity, increased N availability can enhance plant sensitivity to early winter and late spring frosts by delaying winter hardening and by accelerating physiological activity in the following season (Dueck et al, 1990 ;L'Hirondelle, Jacobson & Lassoie, 1992) Another effect of increased N availability is an increase in plant palatability to insect herbivores, with shoot concentrations of this nutrient being the principal determinant of insect growth rates and reproductive success (McNeill & Southwood, 1978 ;Crawley, 1983). The heather beetle (Lochmaea suturalis (L.) Thompson) feeds monophagously on Calluna, relying on the plant for all stages of its life cycle (Cameron, McHardy & Bennett, 1944) ; both larval and adult stages feed upon the young shoots, while pupation and over-wintering generally take place in the litter layer.…”

Effects of excess nitrogen on frost hardiness and freezing injury of above‐ground tissue in young oaks (Quercus petraea and Q. robur)

“…In Picea abies, N fertilization did not affect the frost hardiness of the needles (Wiemken et al, 1996). In Picea rubens, N fertilization even increased the frost hardiness of the needles, which exhibited significantly higher N concentrations after the N treatment (DeHayes et al, 1989 ;L'Hirondelle et al, 1992). However, the N status of the plants before the treatments exerts a great influence on the extent and direction of the alteration in frost hardiness.…”

“…This is consistent with our observation that buds of Q. petraea, but not those of Q. robur, were damaged by freezing at k25mC for 21 d. However, the N status of the plants had no effect on the frost hardiness of the buds. By contrast, buds of Picea rubens bear a higher risk of frost injury when the foliar N concentrations are elevated, even if the frost hardiness of the needles remains unaffected (L'Hirondelle et al, 1992 ;Hadley et al, 1993). F. M. Thomas and U. Ahlers The water supply during the preceding vegetation period and the type of freezing treatment had a distinctly greater influence on the frost hardiness of bark and buds than the N supply.…”

Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development

“…In contrast, N or NPK fertilization enhanced cold hardiness in red spruce (Picea rubens Sarg.) (DeHayes et al, 1989;L'Hirondelle et al, 1992) and white spruce (Picea glauca (Moench) Voss) seedlings (Calmé et al, 1993). Additionally, N application during fall increased cold hardiness in Douglas-fir, whereas phosphorus (P) applied without N decreased hardiness (Thompson, 1983).…”