Pre-harvest Gibberellic Acid Research Articles

Preharvest Gibberellic Acid Treatment Increases Both Modulus of Elasticity and Resistance in Sweet Cherry Fruit (cv. ‘Bing’ and ‘Lapins’) at Harvest and Postharvest During Storage at 0 °C

Fruit firmness in sweet cherries (Prunus avium L.) is a critical quality parameter highly valued by consumers as it is associated with fruit freshness. In general, firm fruit also cope better with storage and handling. Gibberellic acid (GA) is commonly used by sweet cherry producers to increase firmness, soluble solids content and fruit size. This study evaluated the effects of GA on the rheological properties of sweet cherry fruit at harvest and postharvest storage. Specifically, GA’s influence on susceptibility to mechanical damage during handling was evaluated. The following GA treatments were applied to two sweet cherry cultivars ‘Bing’ and ‘Lapins’: T0, control, T30—GA at 15 ppm applied at pit-hardening and straw-colour stages; T45—GA at 25 ppm at pit-hardening and GA at 20 ppm at straw-colour; and T60—GA at 30 ppm applied at pit-hardening and straw-colour. The results indicate that GA delayed harvest by two to four days in both cultivars, with ‘Lapins’ also showing a significant increase in fruit size. Regardless of spray concentration, GA increased the modulus of elasticity and fruit resistance evaluated as stress at the maximum point at harvest. These effects persisted after 35 days of storage at 0 °C and an additional three days of shelf-life at 15 °C. While the strain or deformation capacity of the fruit at bioyield at harvest was constant across treatments, it was, however, lower in the GA-treated fruit than in the controls during storage at 0 °C under the high-humidity conditions of modified atmosphere packaging. The less mature fruit harvested at colour 3.0 (red/mahogany) were stiffer (reduced deformation) and more sensitive to induced mechanical injury than the fruit harvested later at colour 3.5 (mahogany). The GA treatments increased fruit resistance to damage without increasing tissue deformability. Other questions associated with stiffer tissues and lower deformability during storage at 0 °C under high humidity should be further studied, specifically cultivars that are naturally high in box-cracking sensitivity during storage.

Effects of GA3, CACl2 and Modified Atmosphere Packaging (MAP) Applications on Fruit Quality of Sweet Cherry at Cold Storage

ABSTRACT The aim of this study was to investigate the effects of pre-harvest gibberellic acid (GA3) and calcium chloride (CaCl2) and post-harvest modified atmosphere packaging (MAP) applications on fruit quality of sweet cherry during the cold storage. At the end of the cold storage, GA3+CaCl2 applications in MAP-applied fruit and CaCl2 in non-MAP-applied fruit significantly delayed weight loss compared to the control. During the cold storage, the decay of CaCl2-applied fruit has not been observed. At the end of cold storage, the a* and firmness values of the fruit treated with GA3 and CaCl2 were significantly higher than the control. The CaCl2-applied fruit had less soluble solids than the control, but they had significantly higher acidity compared to other applications. In MAP, GA3- and CaCl2-applied fruit had higher vitamin C and antioxidant activity values than the control fruit, but their total phenolics were higher. However, the total flavonoids of CaCl2-applied fruit were higher than the control. On fruit in non-MAP, with GA3 application, less anthocyanin was obtained compared to the control. As a result, GA3-treated fruit had a relatively lower bioactive compound content compared to the fruit of the CaCl2 and control applications both during the harvest and the cold storage. However, it has been revealed that GA3 and CaCl2 applications can be used as significant pre-harvest tools to delay the loss of the fruit firmness.

Influence of Pre-Harvest Gibberellic Acid and Post-Harvest 1-methyl Cyclopropane Treatments on Phenolic Compounds, Vitamin C and Organic Acid Contents during the Shelf Life of Strawberry Fruits.

In recent years, significant portions of the fresh fruits and vegetables produced worldwide have been decaying before reaching the consumer because of insufficient preservation after harvest. In this direction, we carried the study out to investigate the effect of gibberellic acid (GA3) and 1-methyl cyclopropane (1-MCP) applications on phenolic compounds and organic acid contents of the strawberry fruits (cv. Albion) during shelf-life. Gibberellic acid treatments, which prepared in two different concentrations (50 and 100 ppm), were performed by spraying the leaves before harvest. 1-methyl cyclopropane applied after harvest. The results of the study showed a greater decrease in organic acids (except oxalic and succinic acid) in Gibberellic acid-applied fruits during shelf-life. Citric acid was recorded as the most abundant organic acid in the control group. In phenolic compounds, gallic acid (15.22 mg 100 g−1) and ellagic acid (9.38 mg 100 g−1) were recorded as the highest phenolic compounds on the third day. 1-MCP and GA3 (50 ppm) + 1-MCP treatment reduced the breakdown of vitamin C during the shelf-life of strawberry fruits compared to the control group. As a result, phenolic compounds, vitamin C, and organic acids decreased during the shelf-life, and 1-MCP applications slowed down the breakdown of these compounds.

Effects of pre-harvest gibberellic acid spray on endogenous hormones and fruit quality of kumquat (Citrus japonica) fruits

ABSTRACT Gibberellic acid (GA3) is important in plant growth, development, ripening, and senescence. In the present study, we evaluated the effect of pre-harvest GA3 application on the maintenance of postharvest fruit quality in kumquat (Citrus japonica). On-tree fruits were sprayed with 20 mg/L GA3. Unsprayed harvested fruit stored at 6 °C were used as the control. The contents of indoleacetic acid, GA3, and zeatin ribosides in the GA3-sprayed fruits were significantly higher than those in the control, while the contents of both abscisic acid and titratable acid in sprayed fruits were lower than those in the control. Regarding peel colour, GA3 treatment resulted in a lower decrease in hue angle value, with a slow increase in citrus colour index and browning index. Additionally, GA3 treatment inhibited the accumulation of malondialdehyde. In conclusion, pre-harvest application of GA3 may represent a novel strategy for the preservation of fruits on trees, by maintaining nutritional quality and prolonging the postharvest life of kumquat fruits.

Changes of quality traits and phytochemical components of jujube fruit treated with preharvest GA3 and Parka during cold storage

The study aimed to assess the effects of pre-harvest gibberellic acid (GA3) and Parka applications on fruit quality and bioactive components of jujube (Ziziphus jujuba Mill. cv. ‘Li’) fruit during the storage. Fruit were kept at 0±0.5 °C and 90±5% RH for 45 days. Parka and GA3 applications delayed weight losses and respiration rate in the cold storage. While the effect of the Parka application on the decrease in fruit firmness values depending on the storage time was not significant, it can be said that GA3 application was effective in maintaining the fruit firmness in the cold storage. The increase in soluble solids content (SSC) during cold storage was less with GA3 application. The decrease in titratable acidity with ripening in the cold storage was similar in the Parka and control applications. It can be said that GA3 application was effective in maintaining the titratable acidity during storage and this effect increased with the combination of Parka+GA3. The highest vitamin C at the end of the storage was recorded in fruit treated with Parka. Total phenolics, total flavonoids and antioxidant activity decreased in all applications during the storage. GA3 and Parka applications retarded the losses in total phenolics, total flavonoids and antioxidant activity in the storage. As a result, it can be said that the pre-harvest GA3 and Parka applications give positive results in maintaining the quality properties of jujube fruit in the cold storage.

Influence of Preharvest Gibberellic Acid Treatments on Postharvest Quality of Minimally Processed Leaf Lettuce and Rocket

Plant growth regulators are used in high-value vegetable crops during cultivation and after harvest to increase yield, enhance crop management, and improve or retain the produce quality. The aim of this work was to evaluate the quality characteristics during cold storage of minimally processed leaf lettuce and rocket, obtained from plants grown in a hydroponic floating system with mineral nutrient solutions (MNS) containing different levels of gibberellic acid (GA3). Plants were grown in greenhouse conditions on nutrient solutions containing 0, 10−8, and 10−6 M GA3. At harvest, lettuce and rocket were immediately processed as fresh-cut vegetables and stored for 21 d at 4 °C. After processing, weight loss, total soluble solids, titratable acidity, ascorbic acid and nitrate content, leaf color characteristics, and overall quality were evaluated. Adding 10−6 M GA3 to the MNS of a floating system significantly increased the yield of leaf lettuce and rocket plants and of minimally-processed leaves. In addition, preharvest GA3 treatments had positive effects on delaying senescence and enhancing shelf-life of minimally processed lettuce and rocket. The slowed senescence of GA3-treated samples maintained an overall quality over the threshold of marketability in both lettuce and rocket for up to 21 d of cold storage.

Effect of Pre-Harvest Gibberellic Acid and Calcium Application on Post-Harvest Behaviour of Subtropical Peaches

Shorter shelf life and faster deterioration of fruits after harvest are the major constraints with the peach production in the subtropical regions. Pre-harvest application of GA3 and chloride & nitrate of calcium were tried in a RBD experiment for enhancing peach fruit quality and reducing fruit deterioration during shelf life studies of five subtropical peach cultivars. At harvest fruit quality parameters viz. TSS, acidity, firmness etc. were influenced greatly by the treatments. Other physical properties of the fruit such as fruit weight, size and yield were not influenced much. Physiological weight loss during storage and the deterioration of other fruit characteristics were considerably lowered by calcium treatments. Foliar application of Calcium nitrate (1%) was found to be superior over calcium chloride (2%) for improving fruit quality and shelf life.

Pre-harvest gibberellic acid (GA3) treatments play an important role on bioactive compounds and fruit quality of sweet cherry cultivars

The effects of pre-harvest GA3 treatments at different concentrations (0, 30 and 60mgL−1) on fruit quality attributes [geometric mean diameter, flesh firmness, hue angle, fruit removal force (FRF), soluble solids content (SSC) and titratable acidity] and bioactive compounds (total phenolics, total anthocyanin and total antioxidant capacity) of 0900 Ziraat, Regina and Sweetheart sweet cherry (Prunus avium L.) cultivars were investigated in 3 different harvest periods. GA3-treated Sweetheart fruits were significantly larger than the control fruits. Considering the hue angle values, it was observed that GA3 treatments retarded red color development in all three cultivars. The loss in flesh firmness throughout the ripening period was significantly retarded with GA3 treatments in all three cultivars. Fruit removal force was significantly higher in GA3-treated Regina and Sweetheart sweet cherries than in control fruits. The SSC values of GA3-treated fruits were generally lower than the control fruits. Total phenolics, total anthocyanin and total antioxidant capacity of GA3-treated fruits were also significantly lower than the control fruits. As compared to control treatment, total phenol content of Regina fruits with a week retarded harvest was 22 and 25% lower respectively in 30 and 60mgL−1 GA3 treatments. Similar results were observed.

The effect of different concentrations of pre-harvest gibberellic acid on the quality and durability of ‘Obilnaja’ and ‘Black Star’ plum varieties

The research work aimed at investigating the effect of pre-harvest gibberellic acid (GA3) treatment on the quality of ‘Obilnaja’ and ‘Black Star’ Japanese plum varieties. GA3 was sprayed onto the trees during the fruit color break at 0, 25, 50, 75, and 100 ppm concentrations. After pre-cooling, the plums were placed in modified atmosphere packages and exposed to the following conditions as follows: short storage-transportation (ST) [20 days at 2 °C and 90% relative humidity (RH)]; distribution center (DC) (5 days at 6 °C and 80% RH), and shelf life conditions (SL) (2 days at 20 °C and 70% RH). Pre-harvest GA3 treatments increased the fruit weight and size. Treatment of GA3 at 50, 75, and 100 ppm increased the fruit flesh firmness and total soluble substances (TSS) values in both the plum varieties during storage, transport, and marketing; it also limited the weight loss during the marketing process. Treatment of GA3 had no significant effects on the color, titratable acidity (TA), and the total phenolic and antioxidant activity values of plums. Pre-harvest GA3 treatment at 50 ppm GA3 can be thus recommended for both the plum varieties due to its effect on the fruit quality.

The effect of preharvest gibberellic acid applications on fruit quality of ʽAngelinoʼ plums during storage

High-performance preharvest treatments can ensure maintenance of quality during storage. In this study, gibberellic acid (GA3) was applied on the trees in the preharvest stage to study its effects on the storage potential of the ʽAngelinoʼ plums. The treatment was applied at 50 and 75mg/L concentrations, on the 8th, 10th, 12th and 14th ʽweek after anthesisʼ (WAA). The results of the GA3 applications on the ʽAngelinoʼ plum quality after 90 days of storage and an additional 2 days of shelf life showed a decrease in weight loss, with a corresponding increase in fruit flesh firmness, total soluble solids and titratable acidity with the treatment. The fruit skin hue values were higher in the GA3 treated plums, whereas no change was observed in the total antioxidant activity and total phenol contents. Overall, the effect of the preharvest GA3 application on the ʽAngelinoʼ plum quality during storage at 0±0.5°C and 90–95% relative humidity for 90 days was positive.

Effects of pre-harvest gibberellic acid spraying on gene transcript accumulation during peach fruit development

In order to understand early molecular events associated with increase in fruit size and woolliness prevention induced by pre-harvest gibberellic acid (GA3) spraying, differential transcript accumulation of genes encoding proteins putatively involved in protein folding and protection, cell wall metabolism, and endomembrane transport was studied during fruit development of ‘Chiripá’ peach. Woolliness occurrence reached 100% in untreated peach, was reduced by 15% with GA3 spraying at the end of the pit hardening stage and was significantly reduced (by 78%) in peaches treated at the beginning of the pit hardening stage despite a significantly increased fruit size. Low incidence of woolliness after cold storage and fruit size increase in early GA3 treated peach was correlated with high transcript accumulation of genes encoding proteins putatively involved in protein folding, and protection of the endoplasmic reticulum (heat shock proteins—HSP40 er) and chloroplast (HSP17.8 ch), endomembrane transport (GTPase), as well as genes involved in cell wall loosening (expansins—Exp1, Exp2, Exp3, Exp4).

Effects of Preharvest Gibberellic Acid Applications on Fruit Quality of ‘0900 Ziraat’ Sweet Cherry

The objective of this study was to determine the effects of gibberellic acid (GA3) applications on fruit quality of ‘0900 Ziraat’ sweet cherry (Prunus avium), a low cropping and a large-fruited variety. ‘0900 Ziraat’ trees were sprayed with 0, 15, 20, and 25 ppm GA3, when the fruit were at their straw-yellow color stage. Fruit quality was evaluated at harvest in terms of size, firmness, pedicel length, and soluble solids content (SSC) to determine the optimum application. Fruit treated with GA3 were significantly larger and firmer than the controls. There were no differences in fruit firmness within the different levels of GA3 treatment; however, fruit treated with 20 and 25 ppm GA3 were significantly larger than the fruit treated with 15 ppm GA3. Trees treated with the optimum concentration of GA3 (25 ppm) in two different locations yielded fruit with 13.4% and 14.1% greater weight and 38% and 25% higher firmness. GA3 treatments did not affect pedicel length. The effect of GA3 application on SSC was complex; there was a significant interaction between GA3 and location. Being firmer than the controls, the GA3-treated fruit could be harvested at a later date than the controls.

719 PB 429 EFFECT OF GIBBERELLIC ACID ON CERTAIN PHYSICAL AND CHEMICAL PROPERTIES OF GRAPEFRUIT PEEL

Preharvest gibberellic acid (GA) applications at 10 ppm in 0.1% L-77 (v/v) surfactant or 20 ppm in 0.05% L-77 (v/v) caused `Marsh' grapefruit (Citrus paradisi Macf.) to be significantly more resistant to puncture and significantly delayed yellow color development. There was no difference between the two GA rates and applications in July were not found to be as effective as August or September applications. There was an overall significant increase in peel oil content in flavedo tissue as a result of GA treatment, but no significant difference between GA treatments. Limonin contents in GA-treated grapefruit albedo tissue were generally higher at both GA levels than in control fruit. GA treatments had no effect on juice quality characteristics and there was no difference in taste preference between GA-treated and control fruit. Because citrus fruit are resistant to attack by tephritid fruit flies prior to the occurrence of peel senescence and GA delays peel senescence, GA treatment should provide a biorational addition to existing fruit fly control strategies.

Tuber development, storage and germination in yams (Dioscorea spp.) in response to pre-harvest application of plant growth regulators

SummaryWhen pre-harvest foliar applications of growth regulators were made to vines of Dioscorea esculenta cv. Chinese Yam and D. alata cv. White Lisbon there were no obvious effects on tubers of D. alata, but dramatic effects on tuber development, storage and germination were obtained with D. esculenta tubers. Gibberellic acid caused marked extensions in tuber dormancy, 2,4-dichlorophenoxyacetic acid resulted in marked callus development, delayed germination and abnormal shoot and root development and indole acetic acid resulted in fingering of the tubers. It was concluded that there was potential for commercial exploitation of pre-harvest gibberellic acid treatments in extension of dormancy in Chinese Yam tubers and that the lack of response of D. alata tubers to foliar application of growth regulators warranted further investigation.