Within- and trans-generational plasticity: seed germination responses to light quantity and quality.

Plants respond not only to the environment in which they find themselves, but also to that of their parents. The combination of within- and trans-generational phenotypic plasticity regulates plant development. Plants use light as source of energy and also as a cue of competitive conditions, since the quality of light (ratio of red to far-red light, R:FR) indicates the presence of neighbouring plants.

Phytochrome A increases tolerance to high evaporative demand.

Stresses resulting from high transpiration demand induce adjustments in plants that lead to reductions of water loss. These adjustments, including changes in water absorption, transport and/or loss by transpiration, are crucial to normal plant development. Tomato wild type (WT) and phytochrome A (phyA)-mutant plants, fri1-1, were exposed to conditions of either low or high transpiration demand and several morphological and physiological changes were measured during stress conditions.

Expression of seed dormancy in grain sorghum lines with contrasting pre-harvest sprouting behavior involves differential regulation of gibberellin metabolism genes.

Grain sorghum [Sorghum bicolor (L) moench] exhibits intraspecific variability for the rate of dormancy release and pre-harvest sprouting behavior. Two inbred lines with contrasting sprouting response were compared: IS9530 (resistant) and RedlandB2 (susceptible). Precocious dormancy release in RedlandB2 is related to an early loss of embryo sensitivity to ABA and higher levels of gibberellins in imbibed grains as compared with IS9530.

Gene expression analysis of light-modulated germination in tomato seeds.

Tomato (Solanum lycopersicum) seed germination can be inhibited by continuous irradiation with far-red light (FRc) and re-induced by a subsequent red light pulse. In this study, we carried out a global transcript analysis of seeds subjected to FRc inhibitory treatment, with and without a subsequent red light pulse, using potato cDNA microarrays. We also identified and characterized genes involved in light-modulated germination as elements of the phytochrome signalling pathway.