Tocotrienols in Vellozia gigantea leaves: occurrence and modulation by seasonal and plant size effects

Abstract

Vitamin E occurs in all photosynthetic organisms examined to date. Tocopherols predominate in photosynthetic tissues (α-tocopherol being the major form), while either tocopherols or tocotrienols (or both) are present in seeds. Tocotrienols have not been described in photosynthetic tissues thus far. Here, we report on the presence of tocotrienols in leaves of higher plants. Both tocopherols and tocotrienols accumulated in leaves of Vellozia gigantea, an endemic plant found in the rupestrian fields of Serra do Cipó, Brazil. Increased plant size had a remarkable effect on the vitamin E composition of leaves, α-tocopherol and β-tocotrienol levels being highest in the largest individuals, but only during the dry season. Vitamin E levels positively correlated with lipid hydroxyperoxide levels, which also increased in the largest individuals during the dry season. However, the maximum efficiency of PSII photochemistry (F v/F m ratio) kept above 0.75 throughout the experiment, thus indicating absence of photoinhibitory damage to the photosynthetic apparatus. It is concluded that higher plants, such as V. gigantea, can accumulate tocotrienols in leaves, aside from tocopherols, and that the levels of both tocopherols and tocotrienols in the leaves of this species are strongly modulated by seasonal and plant size effects.

Ecology and evolution of plant diversity in the endangered campo rupestre: a neglected conservation priority

“…Whilst leaves of resurrection plants are physiologically inactive during the dry season, they differ from deciduous species in that they retain leaf nutrients during the dry season (Griffiths et al 2014). A recent study reported that leaves of Vellozia gigantea plants not only accumulate tocopherols, but also tocotrienols (vitamin E compounds) as antioxidants, which can protect the photosynthetic apparatus from oxidative stress especially during the dry season (Morales et al 2014).…”

“…Because plants from campo rupestre usually show traits related to greater resource conservation ) compared with those in lowland close relatives in the Atlantic rainforest and cerrado (Lusa et al 2014), many plant traits in the campo rupestre are thought to be adaptations to cope with high irradiance, strong winds, and the seasonal distribution of rainfall. All these filters combine with the nutrient-impoverished shallow soils with a low water-holding capacity that leads to long periods of severe water limitation for plant productivity (Lüttge et al 2007;Morales et al 2014Morales et al , 2015Miola and Fernandes 2015).…”

Adaptation of the Long-Lived Monocarpic Perennial, Saxifraga longifolia to High Altitude

“…A number of recent studies with trees, shrubs, and herbs, including vascular epiphytes (Mencuccini and Grace 1996;Zotz, 1997;Munné-Bosch and Lalueza, 2007;Morales et al, 2014), point out, however, to another source of intraspecific variation that many studies in the past have inadvertently missed, i.e. substantial variation in physiological traits related to plant size rather than changing environmental conditions .…”

Ecophysiological performance of a threatened shrub under restored and natural conditions in a harsh tropical mountaintop environment

“…A recent study with Vellozia gigantea in the same region led by Morales et al (2014) reported that differences in leaf contents of tocopherols and tocotrienols depend on plant size. However, the authors did not find differences in Fv/Fm values or in stomata conductance between taller and smaller individuals.…”

“…A decline in stomatal conductance coupled with an osmotic adjustment in response to water stress was observed in an experimental study with Lavoisiera campos-portoana, an endemic species of rupestrian grasslands (França et al 2012). Although Lüttge et al (1998), Lemos-Filho & Mendonça-Filho (2000) recorded damage to photosystem II (PSII) in some species under excessive light in the natural environment of the rupestrian grassland, although no significant photoinhibition was observed in some species of Velloziaceae even during the dry season (Lüttge et al 2007;Morales et al 2014). The limited ecophysiological data, in contrast to the high species richness of rupestrian grasslands, indicates the need for additional study in order to identify strategies that can lead to the use of more species in restoration programs, as well as to understand their physiological behavior under the current scenario of climate change.…”