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- Author or Editor: James A. Bryan x
- HortScience x
Foliar application of the synthetic growth regulator BA was evaluated for increasing the duration and extent of Fraser fir [Abies fraseri (Pursh.) Poir.] seedling growth. Aqueous solutions of 0, 222, or 444 μm BA (0, 50, or 100 ppm) were sprayed on the shoots of Fraser fir seedlings biweekly from 18 until 38 weeks after planting. Foliar sprays of 444 μm BA increased seedling height 19%, increased shoot weight 57%, reduced root weight 22%, and increased total weight 27%. Apical meristem activity was stimulated and the long periods of dormancy typical of Fraser fir seedlings were avoided. Chemical name used: 6-benzylaminopurine (BA).
The relationship between fruit maturation and accumulation of hydrogen peroxide (H2 O2), lipid peroxidation, ethylene (C2 H4) production, antioxidant activity (hydrophilic, lipophilic and total) and the antioxidant enzyme ascorbate peroxidase (APX, EC 1.11.1.11) in fruit pericarp tissue of `Chandler' (Fragaria × ananassa Duch.) strawberry were measured. `Chandler' fruit pericarp maturation and ripening were accompanied by a decline in H2 O2 content early in fruit development followed by a rapid accumulation. An increase in membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS) coincided with accumulation of H2 O2, which preceded a rise in C2 H4 production. In general, antioxidant activity declined as fruit matured and ripened. APX enzyme activity increased by 2-fold and peaked at the pink stage of development and then gradually declined with ripening. H2 O2 may serve as a signal molecule to initiate the cascade of oxidative processes during maturation and ripening. APX enzyme activity during maturation and ripening was not substantial and thus, may not have a role in alleviating accumulation of H2 O2 and subsequent events related to oxidative senescence in fruit pericarp. To our knowledge, this is the first study to present fractionated antioxidant activities (HAA, LAA and TAA) from strawberry pericarp as assessed by the ABTS∼+ radical cation assay. A fundamental understanding of the mechanisms involved in the senescent related-oxidative changes during strawberry fruit ontogeny in relation to quality and nutrition is discussed.