The effect of foliar application of Ascophyllum nodosum (L.) Le Jol. seaweed extract on biochemical traits related to abiotic stresses in pistachio (Pistacia vera L. cv. Kaleh-Ghoochi).

BACKGROUND: Due to the important economic role of pistachio (Pistacia vera L.) the cultivation of this valuable crop has been extended. Various abiotic stresses harm the growth and performance of pistachio. Seaweed extract containing various substances such as pseudo-hormones that stimulate growth, nutritional elements, and anti-stress substances can cause more resistance to abiotic stresses, and increase the quantity and the quality of the fruit. The present study was conducted to evaluate the effect of foliar application of Ascophyllum nodosum (L.) Le Jol. seaweed extract on some biochemical traits related to abiotic stress in Pistacia vera L. cv. Kaleh-Ghoochi. The first factor of foliar spraying treatment included A. nodosum seaweed extract at four levels (0, 1, 2, and 3 g/L), and the second factor was the time of spraying solution which was done at three times (1- at the beginning of pistachio kernel growth period at the end of June, 2- at the stage of full kernel development at the end of August, and 3- Spraying in both late June and August). RESULTS: The results showed that all investigated traits were significant under the treatment of seaweed extract compared with the control. The seaweed extract concentrations had a significant effect on all traits except soluble carbohydrates, but the time of consumption of seaweed extract on soluble carbohydrates, protein, peroxidase, ascorbate peroxidase, and superoxide dismutase enzymes was significant, while had no significant effect on the rest of the traits. According to the interaction effect of time and concentration of consumption of seaweed extract, the highest values of the biochemical characters were as follows: total phenol content: 168.30 mg CAE/g DW, flavonoid content: mg CE/g DW, catalase: 12.66 µmol APX min- 1 mg- 1 protein, superoxide dismutase: 231.4 µmol APX min- 1 mg- 1 protein, and ascorbate peroxidase: 39.53 µmol APX min- 1 mg- 1 protein. CONCLUSIONS: Based on the results of this study, it seems that it is possible to use fertilizers containing A. nodosum seaweed extract with a concentration of 3 g/L in August to increase the tolerance of the pistachio cultivar "Kaleh-Ghoochi" to abiotic stresses.

Impact of chitosan in combination with potassium sorbate treatment on chilling injury and quality attributes of pomegranate fruit during cold storage.

The impact of chitosan (CH) and potassium sorbate (PS) on quality attributes of pomegranate fruits (cv. Malas e Saveh) was evaluated during 90 days of storage at 4°C and 85%-90% relative humidity. The CH as well as the combined treatments (CH + PS) were effective in decreasing the chilling injury (CI) symptoms, electrolyte leakage, and malondialdehyde contents of fruit peel. Furthermore, CH, PS, and CH + PS treatments enhanced the activity of DPPH radical scavenging, and antioxidant enzymes of arils, and preserved the ascorbic acid content at high levels during the storage period. Fruits treated with CH1% + PS10% and CH2% + PS10% exhibited the lowest decay incidence and weight loss. Higher content of arils' phenols, flavonoids, and anthocyanin was observed in treated-fruits as a result of more activity of phenylalanine ammonia-lyase (PAL) and low activity of polyphenol oxidase (PPO). Consequently, CH + PS showed positive effects on the storage life of pomegranate fruits in terms of CI, decay incidence, and also nutritional values. PRACTICAL APPLICATIONS: Enhancement of chilling tolerance of pomegranate fruits during cold storage condition is a crucial issue. Application of CH coating alone or in combination with potassium sorbate could decrease the CI symptoms and preserved peel cell membrane integrity by maintaining electrolyte leakage (EL) and malondialdehyde in lower levels. Also, these treatments prevent weight loss and decay incidence in peel, and increase the activity of phenylpropanoid pathway and antioxidant systems in arils. All in all, usage of CH edible coating (2%) plus PS (10%) illustrated high efficiency in alleviating CI, decay incidence, and preserving nutritional quality of pomegranate fruits.