| Autor: |
Zahedi M; Department of Agronomy and Plant Breeding, Isfahan University of Technology, Isfahan, Islamic Republic of Iran., Sharma R; Department of Plant Science, The University of Adelaide, Waite Agricultural Research Institute, PMB 1 Glen Osmond, SA 5064, Australia., Jenner CF; Department of Plant Science, The University of Adelaide, Waite Agricultural Research Institute, PMB 1 Glen Osmond, SA 5064, Australia. Corresponding author; email: colin.jenner@adelaide.edu.au. |
| Jazyk: |
angličtina |
| Zdroj: |
Functional plant biology : FPB [Funct Plant Biol] 2003 Mar; Vol. 30 (3), pp. 291-300. |
| DOI: |
10.1071/FP02205 |
| Abstrakt: |
The effects of a sustained period of moderately high temperature were evaluated on the availability of substrate and the activity of starch synthase (ADP-glucose: 1,4-α-D-glucan 4-α-D-glucosyltransferase, EC 2.4.1.21) in the developing grains of two wheat Triticum aestivum L. cultivars differing in their tolerance to high temperature. Final grain weight was reduced by 33% in the least sensitive (cv. Kavko) and by 40% in the most sensitive (cv. Lyallpur) cultivar as post-anthesis temperature was raised from 20/15°C (day/night) to 30/25°C. The difference in the response of the two cultivars was mainly due to changes in the rate of grain filling at high temperature. The response of the rate of grain filling at high temperature, and the differential effects on the two cultivars, did not seem to be explained by an effect of temperature on the supply of assimilate (sucrose) or on the availability of the substrate for starch synthesis (ADP-glucose) in the grains. In vitro, but not in vivo, the differential responses of the efficiency (V max /K m ) of soluble starch synthase in the two cultivars to an increase in temperature were associated with differences in the temperature sensitivity of grain filling. In vivo, the most remarkable difference between the two varieties was in the absolute values of the efficiency of soluble starch synthase, with the most tolerant cultivar having the highest efficiency. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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