Abscisic Acid in the Response of ‘Fortune’ Mandarins to Chilling. Effect of Maturity and High-Temperature Conditioning
✍ Scribed by Lafuente, M T; Martínez-Téllez, M A; Zacarías, L
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 326 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
The possible role of abscisic acid (ABA) and peel colour in chilling tolerance of "FortuneÏ mandarins has been examined. Fruit stored at 2É5¡C, but not at 12¡C, showed pitting damage. The degree of damage changed considerably during development and maturity from November until May. Green fruit were more tolerant to chilling injury (CI). After colour break, chilling susceptibility increased from the beginning of December until January and February (the coolest season during the growing period) and declined towards May. This trend did not parallel changes in fruit colour index or free and bound ABA levels, which increased from November until May. At the time of chloroplast transformation to chromoplast a noticeable shift in free but not in bound ABA occurred. During storage, free ABA levels increased in fruits stored at 12¡C, but not at 2É5¡C. Changes in ABA with storage temperature depended on the stage of maturity of the fruits, but not on their susceptibility to CI. It has also been shown that there was no relationship between ABA content following exposure to 37¡C and chilling tolerance. At all stages of maturity, the susceptibility of the fruits to CI and the free ABA levels of the Ñavedo decreased after conditioning the fruits for 3 days at 37¡C. After storage at 2É5¡C, the ABA levels of the conditioned fruit were similar or even lower than those of non-conditioned fruit. Treatment of fruit for 3 days with 10 kl litre~1 ethylene increased free ABA about four times, whereas bound ABA remained nearly constant. This treatment enhanced cold-induced peel damage after prolonged storage. Thus, the ethyleneinduced changes in free ABA appear not to be related to the induced changes in chilling susceptibility. The results obtained indicated, therefore, that free and bound ABA appear not to be involved on the adaptative mechanism developed in "FortuneÏ mandarins to cope with chilling stress.