Alignment of liquid crystals with periodic submicron structures ablated in polymeric and indium tin oxide surfaces

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Influence of Exogenous Glycinebetaine Application on Improving Chilling Tolerance in Corn Seedlings (Zea mays L.)

Abstract\ud Glycinebetaine (GB) as an osmoprotectant plays an important role in improving plant resistance to abiotic stresses. In order to assess the effect of GB spray on enhancing chilling tolerance in corn plants, an experiment with 7 concentration treatments (0, 2.5, 5, 10, 25, 50 and 100 mM) of glycinebetaine was carried out as randomized complete block design with three replications. Corn plants were sprayed by corresponding GB concentrations at 2 to 3- leaf stage and then were exposed to low temperature of 4ºC for 3 days. Following the chilling stress period, plants were located in the room temperature (25 ± 5ºC). Results showed that seedlings sprayed with GB concentrations of 10-100 mM were visually in a better status and more tolerant to chilling injuries. Moreover, chlorophyll content and root and shoot dry weight of seedlings sprayed with this range of GB were significantly higher than those sprayed with distilled water. In addition, electrolyte leakage was effectively declined by spraying the seedlings with GB in the range of 10-50 and further increase in GB concentration significantly enhanced electrolyte leakage. In total, the foliar application of GB resulted in relative improvement of chilling tolerance in corn seedlings.\ud \ud Keywords: Chilling stress; Chlorophyll content; Electrolyte leakag

Growth and physiological responses of balansa clover and burr medic to low levels of salinity

This study investigated a wide range of morphological and physiological responses of burr medic (Medicago polymorpha L. cv. Scimitar) and balansa clover (Trifolium michelianum L. cv. Frontier) to different levels of salinity. Balansa clover and burr medic plants were grown in the greenhouse at 25°C day temperature and 16°C night temperature. Salt treatments were applied 6 weeks after germination, and plants were grown for a further 6 weeks before harvest. The salt treatments included a control, 20 mm, 40 mm, and 80 mm of NaCl. The shoot biomass yield was significantly affected by the species × salt interaction (P = 0.04). For balansa clover, the shoot biomass yield was greatest for the control treatment and lowest for the 20 mm NaCl treatment. For burr medic, the shoot biomass yield did not differ among salt treatments. Sodium (Na+) and potassium (K+) concentrations in leaves and stems increased with salinity. Compared with a non-saline control, sodium concentration in leaves in the 80 mm NaCl treatment was 3-fold higher for balansa clover and 2-fold higher for burr medic. Under various saline treatments, leaf Na+/K+ ratio stayed relatively constant in balansa clover (0.3–0.4) and burr medic (0.4–0.5), whereas stem Na+/K+ ratios for both species increased with salinity. The most sensitive parameters to salinity were Na+/K+ and Na+/Ca2+ ratios, whereas biomass, chlorophyll fluorescence, net photosynthesis, stomatal conductance, transpiration, and δ13C and δ15N discrimination were least sensitive. Therefore, accumulation of sodium in the plant tissues did not reach the threshold for causing reduction in growth

Influence of Exogenous Application of Glycinebetaine on Reducing the Effect of Drought Stress at Germination and Early Seedling Growthof Corn (Zea mays L.)

Abstract In order to evaluate the effect of seed treatment with glycinebetaine, a factorial experiment with 5 glycinebetaine levels (0, 2, 4, 8 and 16 mM) and 6 drought stress levels (0, -0.1, -0.2, -0.4, -0.8 and -1 MPa) was conducted based on completely randomized design with 3 replications. Corn seeds were immersed in water for 24 hours at corresponding glycinebetaine concentrations. These seeds were placed in petri dish and were exposed to different drought stress levels using PEG 6000. Results showed that drought stress caused a significant reduction in all measured parameters at different glycinebetaine concentrations. However, glycinebetaine concentrations of 2 and 4 mM effectively decreased the drought stress impact on seeds. Seed treatment with glycinebetaine, however, could not alleviate the effect of drought stress on germination rate. The three-parameter logistic model fitted to germination percentage effectively successfully justified the advantageous effect of seed treatment with glycinebetaine under drought stress. According to the model estimation, the drought level which causes 50% reduction in germinability was happened at higher drought stress levels when seeds were treated with glycinebetaine. Seed treating with glycinebetaine could alleviate the effect of drought stress on germination percentage, radicle and coleoptile length and fresh weight. Nevertheless, increasing the glycinebetaine concentration above 8 mM negatively affected germination and related parameters. Keywords: Glycinebetaine, Germination percentage, Coleoptile length, Radicle length, Cor

Effect of insufficient on Qualitative Characterestics of Produced Kernels in spring Safflower Cultivars

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