Physiological responses of Norway spruce (Picea abies) seedlings to drought stress

Abstract

Four-year-old seedlings of Picea abies [L.] Karst (Norway spruce) were grown in semi-controlled conditions with three watering regimes. The seedlings in the control group (c) were watered to prevent any dehydration effect. The two remaining groups were subjected to mild (ms) and severe water stress (ss), respectively. The following physiological variables were monitored until ss seedlings began to die: leaf water potential (psi(L)), stomatal conductance (g(s)), CO(2) exchange (P(N)), free proline content (Pro), total chlorophyll (a + b) concentration (Chl(t)) and the maximal photochemical efficiency of photosystem II (F(v)/F(m)). The results indicate that not all observed physiological parameters display the same degree of sensitivity to dehydration. After Day 12 of dehydration, psi(L) of ss seedlings was already significantly lower than that of the two other groups. On Day 26, significant differences in psi(L) were recorded among all treatments. Decreasing values of water potential were accompanied by early changes in P(N), g(s) and Pro. A significant decrease in Chl(t) and F(v)/F(m) were only observed during the more advanced stages of dehydration. These results demonstrate that the drought response of P. abies seedlings include a number of parallel physiological and biochemical changes in concert, enhancing the capability of plants to survive and grow during drought periods, but only to a point.

Monoterpene responses to interacting effects of drought stress and infection by the fungus Heterobasidion parviporum in two clones of Norway spruce (Picea abies)

“…Changes in chlorophyll fluorescence in young interior spruce trees during drought stress were found to reflect down-regulation of primary photochemistry and the augmentation of photoprotective mechanisms to avoid over-reduction and photoinhibitory damage (Eastman and Camm, 1995). A similar drop in the potential photochemical efficiency of PSII with drought stress was previously observed in Norway spruce (Pukacki and Kaminska-Rozek, 2005;Ditmarová et al, 2010); although, in contrast to our experiment, values did not recover to pre-stress conditions. Bigras (2005) observed an initial drop in the potential photochemical efficiency of PSII at leaf water potential ranging from −1 to −2 MPa.…”

“…Patterns of net photosynthesis and stomatal conductance were similar, resulting in the close coupling of gas exchange components, without differences in instantaneous water use efficiency between clones (though c171 showed a delayed response of stomatal conductance and net photosynthesis to decreasing water potential in comparison with c386). Stomatal conductance and net photosynthesis were found to be strongly correlated in four-year-old seedlings of Norway spruce subjected to drought stress (Ditmarová et al, 2010). Pronounced sensitivity to drought stress is well known in Norway spruce, although not all physiological parameters display the same degree of sensitivity to dehydration, and may change in concert, enhancing the capability of trees to withstand water stress to some extent (Ditmarová et al, 2010).…”

“…Stomatal conductance and net photosynthesis were found to be strongly correlated in four-year-old seedlings of Norway spruce subjected to drought stress (Ditmarová et al, 2010). Pronounced sensitivity to drought stress is well known in Norway spruce, although not all physiological parameters display the same degree of sensitivity to dehydration, and may change in concert, enhancing the capability of trees to withstand water stress to some extent (Ditmarová et al, 2010).…”

Drought and aluminium as stress factors in Norway spruce (Picea abies) seedlings

“…The plant water potential (Y) is a frequently used parameter in the assessment of the plant water regime. The drought effect on Y values has been confirmed by several studies (Aliasgharzad et al 2006;Ditmarová et al 2010). They are in good accordance with our results showing the decrease of water potential during progressive dehydration.…”

“…The increased proline accumulation as a response to drought has been reported for various tree species (Lei et al 2007;Ditmarová et al 2010). Higher levels of proline in the drought presence might contribute to osmotic adjustment allowing the plants to maintain their turgor pressure and to adapt themselves to the limited water availability (Lei et al 2007).…”