In plant cells, the accumulation of K^+ plays a primary role in osmotic regulation,and high-affinity K^+ uptake and transport systems have been investigated. InEscherichia coli, Hesse et aI.isolated a specific K^+ upt...In plant cells, the accumulation of K^+ plays a primary role in osmotic regulation,and high-affinity K^+ uptake and transport systems have been investigated. InEscherichia coli, Hesse et aI.isolated a specific K^+ uptake system known as Kdpwhich has a K_m of 2 μmol/L, and it was induced by osmotic stress. Its kdpABCgenes encode three membrane-binding proteins whose molecular weights are 47, 90 and22 kD, respectively, and kdpDE genes produce two regulatory factors. Gaber et al.展开更多
This study was carried out to investigate the effects of silicon (Si) 3.6 mM (as calcium silicate) under drought stress induced by polyethylene glycol “PEG” at 15% (MW 8000), in addition to the control treatment on ...This study was carried out to investigate the effects of silicon (Si) 3.6 mM (as calcium silicate) under drought stress induced by polyethylene glycol “PEG” at 15% (MW 8000), in addition to the control treatment on growth and some biochemical constituents of date palm cv. Barhee cultured in vitro. Drought stress (15% PEG) depressed the growth of shoot and decreased protein content and chlorophyll concentration. Addition of 3.6 mM Si could improve the growth of shoot and increase the protein content and leaf chlorophyll concentrations of stressed plants. The inclusion of Si to the PEG containing medium significantly increased the catalase (CAT) and superoxide dismutase (SOD) activity in regenerated shoot, compared to other treatments. As well as drought stress 15% PEG induced significant accumulation of shoots proline, which were decreased by added silicon. Moreover, the results were also supported by the observation that PEG stress-induced decrease the response percentage of root induction and root lengths was reversed by added silicon. Addition of Si obviously significantly increased the wax content in leaves, response percentage of root induction and root lengths of plantlets under drought stress. The results of this study indicate that the application of silicon improved growth attributes, effectively mitigate the adverse effect of drought, and increase tolerance of date palm plants for drought stress during the course of date palm tissue cultures.展开更多
文摘In plant cells, the accumulation of K^+ plays a primary role in osmotic regulation,and high-affinity K^+ uptake and transport systems have been investigated. InEscherichia coli, Hesse et aI.isolated a specific K^+ uptake system known as Kdpwhich has a K_m of 2 μmol/L, and it was induced by osmotic stress. Its kdpABCgenes encode three membrane-binding proteins whose molecular weights are 47, 90 and22 kD, respectively, and kdpDE genes produce two regulatory factors. Gaber et al.
文摘This study was carried out to investigate the effects of silicon (Si) 3.6 mM (as calcium silicate) under drought stress induced by polyethylene glycol “PEG” at 15% (MW 8000), in addition to the control treatment on growth and some biochemical constituents of date palm cv. Barhee cultured in vitro. Drought stress (15% PEG) depressed the growth of shoot and decreased protein content and chlorophyll concentration. Addition of 3.6 mM Si could improve the growth of shoot and increase the protein content and leaf chlorophyll concentrations of stressed plants. The inclusion of Si to the PEG containing medium significantly increased the catalase (CAT) and superoxide dismutase (SOD) activity in regenerated shoot, compared to other treatments. As well as drought stress 15% PEG induced significant accumulation of shoots proline, which were decreased by added silicon. Moreover, the results were also supported by the observation that PEG stress-induced decrease the response percentage of root induction and root lengths was reversed by added silicon. Addition of Si obviously significantly increased the wax content in leaves, response percentage of root induction and root lengths of plantlets under drought stress. The results of this study indicate that the application of silicon improved growth attributes, effectively mitigate the adverse effect of drought, and increase tolerance of date palm plants for drought stress during the course of date palm tissue cultures.
