The effects of chilling at 3 to 5 C on the nucleotide composition of roots and leaves of cotton (Gossypium hirsutum L.) seedlings were determined. Chilling decreased the concentration of nucleotides, especially di- and triphosphates, in both leaves and roots. Chilling also caused an increase in free nucleosides. The results are interpreted to mean that general phosphorolytic activity is associa...

A simple and efficient plantlet regeneration protocol via direct organogenesis was established for camphor tree (Cinnamomum camphora L.). Stem segments with one node (SN explants) from embryo-cultured seedlings (EC seedlings) were used as explants. Murashige and Skoog (MS) medium supplemented with 0.5 mg/L 2, 4-dichlorophenoxyacetic acid and 2.0 mg/L 6-benzyladenine was used to induce cotyledon...

One-year-old seedlings of silver birch (Betula pendula Roth.) were grown in pots filled with a soil substrate that originated from an area polluted by a phosphate fertiliser factory and characterised by a high soil Al level and low Ca/Al ratio or with a substrate from an area regarded as free from toxic pollution. In addition the effect of fertilisation with a mixture of nutrients was evaluated...

To identify new components in the phytochrome (phy) signaling network in Arabidopsis, we used a sensitized genetic screen for deetiolation-defective seedlings. Two allelic mutants were isolated that exhibited reduced sensitivity to both continuous red and far-red light, suggesting involvement in both phyA and phyB signaling. The molecular lesions responsible for the phenotype were shown to be m...

Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature...

Investigations into the biochemical processes and regulatory mechanisms of nitrogen (N) utilization can aid in understanding how N is used efficiently in plants. This report describes a deficiency in N utilization in an Arabidopsis (Arabidopsis thaliana) transfer DNA insertion mutant of the mitochondrial folylpolyglutamate synthetase gene DFC, which catalyzes the conjugation of glutamate residu...

Four-year-old seedlings of Picea abies [L.] Karst (Norway spruce) were grown in semi-controlled conditions with three watering regimes. The seedlings in the control group (c) were watered to prevent any dehydration effect. The two remaining groups were subjected to mild (ms) and severe water stress (ss), respectively. The following physiological variables were monitored until ss seedlings began...

Drought is one of the main constraints determining forest species growth, survival and productivity, and therefore one of the main limitations for reforestation or afforestation. The aim of this study is to characterize the drought response at the physiological and molecular level of different Pinus halepensis (common name Aleppo pine) seed sources, previously characterized in field trials as d...

Low concentrations of phosphate (Pi) in soil trigger alterations to the architecture of the root system that increase a plant’s capacity to absorb Pi. Many plants stimulate the uptake of this essential nutrient by promoting lateral root (LR) formation, increasing root hair length and density (see figure), and suppressing primary root growth. Auxin is a key player in LR development: exogenous au...