The xanthophyll cycle and acclimation of Pinus ponderosa and Malva neglecta to winter stress

Abstract

Seasonal differences in the efficiency of open PSII units (F /F), leaf pigment composition and xanthophyll cycle conversion (Z+A)/(V+A+Z), leaf adenylate status, and photosynthetic capacity were investigated in Pinus ponderosa (Ponderosa pine) and Malva neglecta. In P. ponderosa, acclimation to winter involved a lower photosynthetic capacity, higher carotenoid to chlorophyll ratio, persistent reductions in F /F corresponding to persistent retention of Z+A, and no change in foliar ATP/ADP ratios. In contrast, M. neglecta characterized in winter exhibited higher rates of photosynthesis than in summer with no change in carotenoid to chlorophyll ratio, while small nocturnally persistent reductions in F /F were observed exclusively on colder winter nights when nocturnal retention of Z+A, and high ATP/ADP ratios were also present. Upon removal of winter-stressed leaves or needles from the field to room temperature, a portion of F /F relaxed within 15 min of warming and recovery was completed within 5 h in M. neglecta but required 100 h in P. ponderosa. In M. neglecta, the entire recovery of F /F correlated with decreases in the foliar ATP/ADP ratio, while in P. ponderosa this ratio remained unchanged. Possible ATP-dependent forms of sustained (Z+A)-dependent energy dissipation are discussed including a nocturnally retained pH gradient on cold winter nights. The slow recovery in pine involved not only retention of Z+A, but apparently also a persistent engagement of Z+A for energy dissipation via an unidentified mechanism.

Seasonal changes in the photosynthetic performance of two evergreen Nothofagus species in south central Chile

“…This highly efficient behavior of N. dombeyi in the utilization of absorbed energy in the photochemical and CO 2 assimilation processes at the highest PPFD (summer) coincides with higher contents in Z (8.2-fold higher) and slightly higher contents in A and L (1.9 and 1.7-fold higher, respectively) in relation to predawn (Table 2). Similar results are reported for other plants exposed to high light and to additional stresses such as drought or cold (Faria et al 1996, Logan et al 1998, Verhoeven et al 1999, García-Plazaola et al 2003. Differently as occurs in N. dombeyi, in upper canopy leaves of Nothofagus cunninghamii from an Australian rainforest subjected to high irradiance (by simulated sunflecks) the decrease of the Fv/Fm and the increase of Z, is associated with a transitory decrease of Φ PSII and net photosynthesis (Tausz et al 2005).…”

“…In N. nitida a conservation of some proportions of Z remained overnight until midday (Fig. 3 and Table 2), suggesting a nocturnal retention of dissipative pigments in this species as occurred in other plants (Logan et al 1998, Verhoeven et al 1999). This effect has been explained by a stimulating cold effect, which contributes to keep an acidic intrathylakoid pH, which could maintain active to some extent the enzyme violaxanthin de-epoxidase at night.…”

Protection and storage of chlorophyll in overwintering evergreens

“…However, photosynthetic efficiency in leaves of evergreens such as holly (1), pines (2,3), and snow gum (4,5), naturally declines to very low levels during winter and remains inhibited until conditions become favorable for growth in spring. These evergreen species maintain significant levels of chlorophyll (Chl), which exists in a state that has not been characterized previously with respect to the Chl electronic-excited state or fluorescence lifetimes, or the Chl excitation vs. emission spectra of photosystems I and II (PSI and PSII).…”

In vitro culture at low temperature and ex vitro acclimatization of Vriesea inflata an ornamental bromeliad

“…The plants of Malva neglecta Wallr. characterized in winter exhibited higher rates of photosynthesis than in the summer with no change in carotenoid to chlorophyll ratio (Verhoeven et al 1999). Thus, the higher value of dry mass that occurred in plants kept at 28 °c might not be related to chlorophyll tissue but rather to an increase in the number of reserve tissue cells (aquiferous parenchyma), thereby resulting in a higher capacity to store water.…”

“…in this sense, the use of low temperatures could induce a type of resistance in the plant necessary at the phase of climate adjustment to ex vitro conditions. Verhoeven et al (1999) observed that in Pinus ponderosa douglas ex Lawson & c. Lawson, the adjustment to a winter climate involved lower photosynthetic capacity and an increase in carotenoids rate in relation to that of chlorophylls and, on the other hand, Malva neglecta, presented higher photosynthesis rates in the winter than in the summer, and no alteration in the carotenoids/chlorophylls rate with the drop in temperature.…”