Photosynthesis and Photoprotection in Overwintering Plants

Abstract

Seasonal differences in the capacity of photosynthetic electron transport, leaf pigment composition, xanthophyll cycle characteristics and chlorophyll fluorescence emission were investigated in two biennial mesophytes (Malva neglecta and Verbascum thapsus) that grow in full sunlight, and in leaves/needles of sun and shade populations of several broad‐leafed evergreens and conifers (Vinca minor, Euonymus kiautschovicus, Mahonia repens, Pseudotsuga menziesii [Douglas fir], and Pinus ponderosa). Both mesophytic species maintained or upregulated photosynthetic capacity in the winter and exhibited no upregulation of photoprotection. In contrast, photosynthetic capacity was downregulated in sun leaves/needles of V. minor, Douglas fir, and Ponderosa pine, and even in shade needles of Douglas fir. Interestingly, photosynthetic capacity was upregulated during the winter in shade leaves/needles of V. minor, Ponderosa pine and Euonymus kiautschovicus. Nocturnal retention of zeaxanthin and antheraxanthin, and their sustained engagement in a state primed for energy dissipation, were observed largely in the leaves/needles of sun‐exposed evergreen species during winter. Factors that may contribute to these differing responses to winter stress, including chloroplast redox state, the relative levels of source and sink activity at the whole plant level, and apoplastic versus symplastic phloem loading, are discussed.

Impacts of drought and temperature stress on coffee physiology and production: a review

“…•− removal, as well as increases in both non-photochemical quenching and contents of photoprotective pigments (β-carotene, lutein and zeaxanthin), which act through thermal dissipation (Siefermann-Harms, 1988;Young, 1991;De Las Rivas et al, 1993;Krause, 1994;Krivosheeva et al 1996;Niyogi et al, 1997;Xu et al, 1999;Havaux and Kloppstech 2001;Adams et al, 2002;Foyer, 2002;Karpinski et al, 2002). These processes decrease the production of highly reactive compounds and prevent the over-reduction of the electron transport chain and the overacidification of the thylakoid lumen, which sensitize PSII to photodamage (Müller et al, 2001;Mano, 2002).…”

The role of antioxidant enzymes in photoprotection

“…Thus, chilling can perturb the balance between the production and consumption of photogenerated reductant in a manner that favors O 2 photoreduction. Many long-lived evergreens respond to the onset of wintertime cold temperatures by decreasing chlorophyll content (Adams and Demmig-Adams 1994;Verhoeven et al 1996;Logan et al 1998c;Burkle and Logan 2003) and reorganizing their light harvesting antennae into an energy dissipating state (Gilmore and Ball 2000; Matsubara et al 2002;Adams et al 2002Adams et al , 2004. However, profound up-regulation of levels of antioxidants is another hallmark of acclimation to cold temperatures (Scho¨ner and Krause 1990;Anderson et al 1992;Mishra et al 1993;Logan et al 1998cLogan et al , 2003.…”

Aspects of nitrogen metabolism in coffee plants

“…To prevent oxidative stress at the chloroplast level, due to the production of active forms of oxygen and chl, plants have evolved complex systems to remove such highly reactive chemical entities at their generation site. For that, the over-expression of antioxidative scavengers, such as enzymes (e.g., superoxide dismutase, ascorbate peroxidase), and hydrophilic (e.g., ascorbate, glutathione) and lipophilic (e.g., zeaxanthin, β-carotene and α-tocopherol) antioxidants, is of great importance (Foyer et al, 1994;Adams and Barker, 1998;Strand et al, 1999;Adams et al, 2002;Munné-Bosch, 2005).…”