Effect of water deficit and application of 24-epibrassinolide on gas exchange in cauliflower plants
2010
Hnilicka, F.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Botaniky a Fyziologie Rostlin | Koudela, M.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Zahradnictvi | Martinkova, J.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Botaniky a Fyziologie Rostlin | Hnilickova, H.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Botaniky a Fyziologie Rostlin | Hejnak, V.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Botaniky a Fyziologie Rostlin
Under partly controlled greenhouse conditions, an experiment was initiated with cauliflower (cv. Chambord F1) to monitor the long-term effect of water deficit and the effect of the application of 24-epibrassinolide on the photosynthesis and transpiration rates. Plants were grown in pots at 25 deg C during the day and 18 deg C at night, and were irrigated with Knop's nutritional solution once a week and with distilled water on the remaining days of the week. The plants were provided with a solution containing microelements according to Benson twice during the vegetation period. Irrigation was controlled according to the results obtained by the apparatus AT Theta Kit. The experimental plan contained 4 groups as follows: control group irrigated with 25% of full water capacity (FWC); in the second group irrigation was limited to 20% of FWC throughout the vegetation period; 24-epibrassinolide in the concentration of 10*-9 M was applied to the third and fourth groups with control plants and stressed plants at the stage of 6-7 leaves. Water deficit provably reduced the rate of exchange of gases. The application of 24-epibrassinolide reduced the photosynthesis and transpiration rates in control plants apparently due to unbalanced endogenous level of phytohormones, whereas it increased the photosynthesis rate and reduced the transpiration rate in stressed plants. In conclusion, the application of 24-epibrassinolide reduced the transpiration rate in the monitored plants and had an effect similar to that of abscisic acid.
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