ISHS Acta Horticulturae 239: VI International Symposium on Growth Regulators in Fruit Production
EFFECT OF NEW SYNTHETIC ABSCISIC ACID ANALOGUES IN COMBINATION WITH TETCYCLACIS ON CHILLING AND FREEZING RESISTANCE IN CROP PLANTS |
| Authors: | K. Dörffling, A. Flores, A. Grau, B. Capell |
| Abstract:
The protective effect against chilling and freezing of new abscisic acid analogues coded LAB 144 143 and LAB 173 711 in combination with tetcyclacis, a growth retarding derivitive of norbornadiazetine, was studied in various crop species. The compounds were applied either to the seeds prior to germination or as a spray to the leaves before the onset of a chilling or freezing treatment. The ABA analogues increased chilling as well as freezing resistance in a manner similar to ABA. The compound LAB 144 143 proved to be nearly as active as ABA, whereas LAB 173 711 was less active. Tetcyclacis applied alone also exhibited protective properties. Combinations of one of the ABA analogues with tetcyclacis had additive effects. The manner in which the ABA analogues protect against chilling was studied in more detail in cucumber. A main effect seems to be stomatal closure which reduces water loss during the chilling period. Moreover, membrane injury and membrane degradation, measurable as electrolyte leakage and phospholipid degradation during the chilling period, was greatly reduced. Proline levels increased. Possibilities for practical use of the ABA analogues in combination with tetcyclacis in horticulture and agriculture are discussed. | |
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