The long-term effect of cold on the metabolism of winter wheat seedlings. I. Growth and hydration of seedlings at in vitro conditions
1994
Dubert, F. | Skoczowski, A. | Biesaga-Koscielniak, J.
1. Growth rate, hydration and distribution of dry matter between the particular organs in seedlings of winter wheat grown under in vitro conditions at the vernalization temperature (2 degrees C) and at 20 degrees C have been compared. 2. At the end of the cold period an inhibition of the increase of the fresh weight in seedlings was observed, whereas fresh weight of control seedlings continued to increase. 3. At both temperatures the dry weight of upper parts of seedlings (coleoptile and first true leaves) and roots became stabilized at the end of the examined growth period. Mesocotyl attained its maximum dry weight in the initial growth period, which was significantly higher in seedlings grown in cold. At 20 degrees C the upper part represented about 73% of the total dry weight of the seedling, whereas at 2 degrees C, its dry weight was only equal to approx. 60%. 4. The hydration of the seedlings decreased during the growth at 2 degrees C, and increased at 20 degrees C. At 2 degrees C the hydration of the roots was higher than that of upper part whereas at 20 degrees C a reversed dependence was observed. 5. Transfer of the seedlings from 2 to 20 degrees C enabled further increase in their dry weight, reaching values observed in the controls. However, the hydration of these seedlings was still lower, although the interrelations between the hydration of the roots and that of the upper parts approached the values observed in control plants, 6. It has been demonstrated that neither fresh nor dry weight can be used as parameters allowing for equalization between the development stage of plants grown at high temperature and that of plants grown in cold, which is of fundamental importance in studies of vernalization or frost hardening processes.
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