|Publication Type:||Journal Article|
|Year of Publication:||2011|
|Authors:||Šimkūnas, A, Valašinaitė, S, Švitra, D|
|Journal:||Journal of Agronomy and Crop Science|
|Keywords:||Festuca, Festuca pratensis, growth slowdown, Lolium, Lolium multiflorum, Lolium perenne, stress state, stress-tolerator|
Meadow fescue (Festuca pratensis), Italian ryegrass (Lolium multiflorum), their hybrid Festulolium braunii and perennial ryegrass (Lolium perenne) were grown hydroponically under vegetative (20 °C) and hardening (8 °C, 0 °C) regimes. The relative shoot/root growth ratio K, linear root growth rate and other parameters were estimated. When the temperature was lowered from 20 °C to 8 °C, the relative shoot/root growth ratio K of F. pratensis decreased to 0.6, i.e. much more than that of Lolium, suggesting that at 8 °C F. pratensis shoot growth blockage occurs. Further, by dropping the temperature from 8 °C down to 0 °C, the K ratio of F. pratensis increased significantly, while the linear root growth rate decreased much more markedly than in the other species – it suggests also a blockage of root growth. This growth slowdown of stress-tolerant F. pratensis shoots and at a lower temperature also of its roots is inadequate to the direct impact of temperature and, thus, indicates a two-step qualitative reorganization, i.e. transition into a qualitatively new state of stress. This phenomenon does not manifest itself in the less stress-tolerant Lolium and Festulolium species but is expressed in stress-tolerators, allowing them to achieve their strategic goal – to survive under extreme conditions.
|Short Title:||Journal of Agronomy and Crop Science|