Document Type : Research Article
Master student of Horticulture Department, Urmia University
Associate Professor, Department of Horticulture, Urmia University
Strawberry with the scientific name Fragaria × ananassa Dutch from the Rosaceae family is an important commercial fruit in the world, which is widely considered in terms of nutrition due to its rich content of vitamins, minerals and phytochemicals. Water scarcity stress is one of the important sources of abiotic stresses, so that it reduces growth, development and yield during the vegetative, reproductive and maturing stages of the crop. Studies have shown that application of nano-fertilizers can be useful in order to achieve high yield while reducing the amount of fertilizer consumption due to its higher absorption due to its high specific surface area. Despite its low consumption, zinc is involved in chromosome synthesis, carbohydrate metabolism, photosynthesis, sugar-to-starch conversion, protein metabolism, auxin metabolism, pollen grain formation, biological membrane preservation, and resistance to infections by pathogens. Zinc is also needed for chlorophyll production, pollen grain yield, fertility and pollen grain germination. Zinc as a coenzyme is also involved in the activation of many enzymes in the biosynthesis pathway of secondary metabolites. The use of zinc nanoparticles can have very positive effects on the quantitative and qualitative properties of strawberry fruit during low solubility
Materials and Methods
The present study was conducted in the greenhouses of the Department of Horticulture, Urmia University.Sabrina cultivar strawberry seedlings were planted in culture bags containing 50% cocopeat, 25% pithomass and 25% perlite in three rows containing 27 plants and evenly pruned. The first week was used to establish the plants from water, the second week to the sixth week for vegetative growth of half-concentrated Hoagland solution and from the seventh week to the end of the harvest period, depending on the stages of flowering to fruiting, modified Hoagland nutrient solution was used. By calculating the amount of solution output from each nozzle and the amount of each plant need, the time required for solution was calculated and this time was divided into 5 times a day and was automatically pumped to the foot of each plant. To apply low solubility stress, the first row (without stress) was used with solution 5 times a day, the second row with solution 4 times a day and the third row with solution 3 times a day. Foliar application of different concentrations of zinc chelate nanoparticles was performed once a week (5 times) after pruning of primary flowers, from the fourteenth to the eighteenth week. Zinc chelate nanoparticles were used in three levels (0, 1 and 1.5 g / l) and nutrient solution treatment was performed in three levels (90, 110 and 130 ml) daily. Then fruits that were more than 70% colored were harvested and different quantitative and qualitative characteristics were measured. At the end of the experiment, fruit weight was measured using a digital scale, fruit length and width by caliper, fruit acidity by pH meter, titratable acids by titration method and TSS by refractometer. Chlorophyll a, b and total carotenoids were also measured using Dynamica spectrophotometer (HALODB-20) according to Lichtanthaler & wallborn (1985). Also, fresh weight of shoots and roots were measured in the last stage after fruit harvest. For this purpose, the plants were completely removed from the bed and the roots were washed with water and then exposed to air to remove moisture. The aerial parts were then separated from the roots and weighed 0.001 g by digital scale. To measure dry weight, the roots and aerial parts were placed separately in the bag and then placed in a 70 ° oven for 72 hours and then weighed 0.001 g with a digital scale.
Results and Discussion
The results showed that the interaction effect of low solubility treatment and zinc chelate nanoparticles treatment on fruit weight, shoot dry weight and yield was significant, so that the highest amount was in the treatment of 130 ml of nutrient solution and concentration of 1.5 g / l of zinc chelate nanoparticles. Also in fruit length and width, pH, TA, TSS, chlorophyll a and b and carotenoids, the main effects of low solubility treatment and of chelate nanoparticles were significant. As in the treatment of chelate nanoparticles, the highest amount of these traits was observed in the concentration of 1.5 g / l nanoparticles and in the low solubility factor, the highest amount was observed in the control treatment (complete solubility).
Low solubility stress reduced the quantitative and qualitative characteristics of strawberry fruit. The use of different concentrations of nano-chelate zinc improved these properties, so that the greatest effect was related to the concentration of 1.5 g per liter of nanoparticles. This concentration increased the yield of the product more than 1.6 times compared to the control sample in complete solution and more than 1.7 times compared to the low solution. Also, the growth traits studied were significantly increased by the use of nanoparticles. These nanoparticles also improved the taste of the fruit by reducing the acidity and increasing the soluble solids.