Effects of photooxidation on membrane integrity in Salix nigra seeds

Abstract

Salix nigra seeds were very susceptible to photooxidation. The thylakoid membranes appeared to be the first target of the photooxidative process since there were large decreases in galactolipids and both these lipids and the activated chlorophyll are contiguous in the structure of that membrane. Changes in normal germination and mean germination time could be explained by the deteriorative effects of oxidation.

Photo-oxidation modulates green fern spore longevity during dry storage

“…the presence of chlorophyll in green spores), we hypothesized that the exacerbation of oxidative stress typically associated with exposure to light could be responsible for the fast ageing of green spores. Similar findings have been reported for other dry chlorophyllous propagules such as Salix nigra seeds (Roqueiro et al 2010). Results of the present study show that when stored dry, green spores aged more rapidly than non-green spores under both light and dark conditions, but for green spores this ageing was exacerbated by (Fig.…”

“…In other organisms tolerant to desiccation that retain chlorophyll in the dry state light is absorbed by the pigments of the photosynthetic apparatus, and it is known that when water is absent, free radicals are produced and threaten to oxidise components of the photosynthetic apparatus (Heber et al 2006;Kranner et al 2008). In this sense, photo-oxidative stress has been related to ageing of dry chlorophyllous seeds through damage to thylakoid membranes (Roqueiro et al 2010). Hence, we test here the hypothesis that the fast ageing of green spores after drying and when in the dry state could result from an imbalance on free radicals and reactive oxygen species (ROS) and/or from a reduced antioxidant protection (Kranner et al 2010), particularly when spores are stored in the light.…”

Short storability of Caesalpinia echinata Lam. seeds as a consequence of oxidative processes

“…Photooxidation process shall be considered in the deterioration of C. echinata seeds in the same way as Salix nigra March. has been accounted for (Roqueiro et al 2010). Both species have desiccation tolerant seeds.…”

“…However, both S. nigra and C. echinata differ from typical orthodox seeds because they lose viability in few weeks at room temperatures. Roqueiro et al (2010) found that S. nigra seeds were very susceptible to photooxidation since there were large decreases in galactolipids which are contiguous in thylakoid membrane structure. Therefore, light and oxygen may promote strong photooxidation processes mediated by free radicals (FR) and ROS.…”

“…Roqueiro et al (2010) described that the embryonic tissues of S. nigra most damaged by FR were those of the abaxial side of the cotyledons and the most-external tissues of the axis and root tips. Therefore, the damage caused to seeds was evidenced by abnormal development in the roots and cotyledons, reducing the normal seedling development to zero level.…”