Postharvest physiology
S. Shiukhy
Abstract
Introduction
Inefficient management of strawberry fields is one of the important factors in significantly reducing the strawberry fruit yield and quality. Nowadays application of polyethylene soil mulch is widely considered in the cultivation of fruits and vegetables, with various purposes such ...
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Introduction
Inefficient management of strawberry fields is one of the important factors in significantly reducing the strawberry fruit yield and quality. Nowadays application of polyethylene soil mulch is widely considered in the cultivation of fruits and vegetables, with various purposes such as improving quality, increasing yield and reducing weeds. The thermal and light environment around the plant due to the use of polyethylene mulch, can affect the quality and yield of strawberry fruit.
Material and Methods
In this study, In order to investigate the effect of colored polyethylene mulch on fluorescence parameters, leaf chlorophyll and strawberry fruit yield (cv. Camarosa), an experiment was carried out as completely randomized block design with four experimental treatments including; colored polyethylene mulch (black, red, white) and control (traditional cultivation without mulch) in three replication in the Caspian Sea region, Iran during the 2016-17 and 2017-2018 years. The experimental plots were 5 m long and 1.5 m wide, with 4 planting rows separated by 30 cm in each plot. Then polyethylene mulch was laid on the ridge and the plants were planted at a distance of 20 cm in a row (1 October). Three harvest times (170, 185 and 200 days after planting) were determined to assess the characteristics of harvested fruits.
Result and Discussion
Based on the results, the effect of mulches color on fruit yield was significantly (P ≤ 0.01). Considering fruit yield at the first harvest (175 DAP) and the second (185 DAP), red mulch showed the highest fruit yield and the lowest was observed in the control treatment. While at the third harvest time (200 DAP), it was the black and white mulches that resulted in the largest amount of yield. The effect of colored polyethylene mulch on the acidity (pH) and titratable acid (TA) of the fruit was not significant, but the amount of soluble solids (TSS) of the fruit at different harvest times showed a significant difference between the experimental treatments. So that in the first harvest time (170 DAP) and the second (185 DAP), the highest amount of soluble solids was observed in treatments with colored polyethylene mulch. The results also showed that colored polyethylene mulches effect on fluorescence parameters and leaf chlorophyll content was significant (P ≤ 0.05). The results showed that mulch color had a significant effect on Fv/Fo ratio, Fo and leaf chlorophyll content. During the both years, the highest Fv/Fo ratio, Fo and leaf chlorophyll were related to colored polyethylene mulches, and the lowest was observed in the control treatment, while colored mulches did not affect the Fv/Fm ratio. In fact, it can be explain that the plant's response to the colored polyethylene mulches, compared to the control treatment, improves fruit yield and increases the strawberry photosynthetic system.
Conclusion
Comparison of the average effect of polyethylene mulch on strawberry fruit yield during the growing season in both years, showed similar results. Polyethylene mulches can increase yields by increasing soil temperature, increasing nutrient availability, increasing root uptake in nutrients and increasing the efficiency of soil microorganisms. Based on the results, in the first harvest time (170 DAP), second harvest time (185 DAP) and third harvest time (200 DAP), the yield of strawberry fruit in both growing season showed that the highest yield was related to treatments with The colored polyethylene mulch and the lowest yield was observed in the control treatment. Red mulch had the highest fruit yield during the first and second harvests, but gradually decreased during the third harvest. It seems that red color, in addition to increasing yield, has also caused early ripening of the fruit. The amount of soluble solids (TSS) of the fruit at different harvest times showed a significant difference between the experimental treatments. During the first harvest (170 DAP) and the second (185 DAP), the highest amount of soluble solids was observed in treatments with colored polyethylene mulch. Based on the findings, the effect of colored polyethylene mulch on fluorescence parameters and chlorophyll content of leaves indicated that the color of polyethylene mulch had a significant effect on the amount of Fo and chlorophyll content of leaves. Therefore, the use of polyethylene mulch due to the increase in yield and quality of strawberry fruit compared to its traditional cultivation method seems very beneficial.
Mohammad Mahmoodi Sourestani
Abstract
Introduction: Spearmint (Mentha spicata L.) is an aromatic plant belonging to the Lamiaceae family. The ground fresh biomass and dried leaves of the plant are used as spice and herbal tea, and cultivated commercially in the entire world. Spearmint oil also has economic importance and is used in perfumery, ...
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Introduction: Spearmint (Mentha spicata L.) is an aromatic plant belonging to the Lamiaceae family. The ground fresh biomass and dried leaves of the plant are used as spice and herbal tea, and cultivated commercially in the entire world. Spearmint oil also has economic importance and is used in perfumery, confectionary and pharmaceutical preparations. Major components in cultivated spearmint oil are carvone, limonene, and 1,8-cineole. Essential oil compositions of aromatic plants depend on their genetic structure, the climatic factors and the agronomical practices as well as harvest and post-harvest managements. A climate with adequate and regular rainfall and good sunshine during its growing period ensures a good yield. Climatic condition is one of the most important factors influencing the growth and accumulation of active ingredients that its effect is concealed at the harvesting time of plants. In addition, harvest time (cut) and phonological stages can affect herbage yield and oil content and composition of perennial medicinal plants.
Materials and Methods: Plant materials were harvested from a farm in Safiabad city, Khuzestan province, Iran. Five samples from each ecotype of spearmint (Kashan and Shushtar) were collected during growth season at the beginning of flowering stage, from May to the end of November. Plants were hand-harvested by cutting the herbage at 5 cm above the soil. Then the plants were dried at room temperatures (approximately 40 °C). Spearmint essential oil was extracted via steam distillation using a Clevenger apparatus. The distillations were carried out on a sample size of 50 g of dry aerial parts with a distillation time of 180 min. The oil was dried over anhydrous sodium sulfate and was kept in a refrigerator until further analysis. The essential oil’s chemical composition was analyzed by GC and GC/MS.
Results and Discussion: The results showed that temperature and humidity conditions prevailing in the area at the time of harvest had significant effect on plant growth and ultimately leaf dry weight, oil content and composition. The highest leaf dry weight of the Kashan (250.67 g.m-2) and the Shushtar (290.23 g.m-2) were observed at the third and fifth harvest time, respectively. There was no significant difference between the first to fourth harvest times of the Kashan and the first, third, fourth and fifth harvest time of the Shushtar. The highest (3.33%) and the lowest (1.72%) amounts of essential oil of the Kashan ecotype were obtained from the third and the first cuts, respectively. The Shushtar ecotype had lower oil than the Kashan ecotype. The second harvest time of the Shushtar ecotype had the highest (2.53%) amount of essential oil and the lowest (1.36%) amount was observed at the first harvest time that had no significant difference with the third and fifth harvest times. The highest amount of oil yield of the Kashan (8.34 g.m-2) and the Shushtar (4.89 g.m-2) ecotypes was recorded at the third and the fourth cuts, respectively. It seems that plants during the second to the fourth harvests encouraged with hot stress and they produced more essential oil in response to high temperature. Limonene, cis-dihydrocarvone, carvone and caryophyllene were the main oil components at five harvest times. Both ecotypes were similar in regards of main oil components but the Shushtar had more oil composition than the Kashan. In the Kashan ecotype, limonene was at the lowest amount (12.22%) and reached to the maximum amount (20.55%) at the second harvest time. In contrast, cis-dihydrocarvone decreased from 4.95% to 2.34% at the second harvest time and finally the maximum amount (11.14%) was recorded at the fifth harvest time. Carvone content was 68.94% at the first harvest and after that increased to the highest level (74.21%) and finally decreased to the minimum level (65.15%) at the fifth harvest time. In the Shushtar, limonene increased from the first until the fourth harvest and ultimately declined in the last cut. The maximum amount of carvone (72/67%) was observed in the first harvest and then was relatively constant during the second to fourth harvests, and reached to the lowest level (56/58% ) at fifth harvest. The Kashan ecotype had more carvone than the Shushtar ecotype. The fluctuation of carvone and cis dihydrocarvone were in opposite of each other and it seems that lower temperatures in the fifth harvest caused to carvone convert to cis-dihydrocarvone. However, the amount of carvone was more than 50 % at all harvest times.
Conclusion: Although harvest times had a significant effect on the traits, both ecotypes showed a good oil content and yield at five cuts. Oil composition was also changed during different harvest times. Nevertheless, Carvone content was up to 50% at all harvest times and it seems that we can recommend harvesting of plants from May to the end of November.
M. Hamedani; H. Moradi; A. Ghanbari
Abstract
The different factors such as harvest time, product handling, temperature and storage duration can be influenced on the different properties of citrus fruits and has considerable economic consequences. Therefore a factorial experiment based on completely randomized design with 3 replications was performed ...
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The different factors such as harvest time, product handling, temperature and storage duration can be influenced on the different properties of citrus fruits and has considerable economic consequences. Therefore a factorial experiment based on completely randomized design with 3 replications was performed to evaluate the effects of harvest times (start of color change, 50% of color change and full color change of fruits), storage period (0, 25, 50 and 75 days) at 7ºC on total soluble solids, titrable acidity, ascorbic acid, total phenol content, flavonoid, antioxidant capacity, anthocyanin and activity of L-phenylalanin ammonia-lyase. The results showed that the harvest times and storage period had significant effect on the measured properties. So that the after 75 days of storage, peak phenylalanin ammonia-lyase activity and total flavonoid observed concomitantly with the accumulation of anthocyanin in ripe blood orange fruit but decreased antioxidant capacity and total phenol after 25 days of storage. Also, the highest vitamin C content and total soluble solids were measured in full ripening of fruits before storing and decreased after 75 days storage. So, according to changes in all of measured characteristics, the apropriate time of harvesting of Moro blood orange was the stage of commercial maturity of fruits.
Hassan Hajnajari; M. Eshghi
Abstract
The investigations were carried out in 2007 on the fruit of 7 native early-ripening apple cultivars grown in Karaj climatic conditions, harvested in two phenological stages of maturity and ripenning. The harvested samples were stored at (0 ± 0.5) C and (85 ± 5) % of humidity. The measured sensorial ...
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The investigations were carried out in 2007 on the fruit of 7 native early-ripening apple cultivars grown in Karaj climatic conditions, harvested in two phenological stages of maturity and ripenning. The harvested samples were stored at (0 ± 0.5) C and (85 ± 5) % of humidity. The measured sensorial traits consisted in: aroma, flavor, sweetness, flesh quality and general acceptability achieved by an experienced group of panelists in the predefined temporal intervals during cold storage. Biochemical tests were computed for determination of pH, TA and TSS. The factorial experiment was defined within completely randomized design. The results showed significant differences at 1% probability for most of the evaluated sensorial traits between two picking phases, among cultivars and also in temporal intervals of cold storage. The highest level of storage potential meaning as quality conservation was found in 'Mashad', 'Gol Bahar' and 'Golab-e-Kohanz' descentely for the first picking or maturity phase, while it was shown that the fruit picked at ripening better sensorial qualities were determined in the decreaing order as: 'Golab-e-Isfahan', 'Golab-e-Kohanz', 'Gol Bahar', 'Ghermez-e-Rezaieh', 'Mashad' and 'Assali'. More oscillations of sensorial traits were assessed in the first harvest samles of the early cultivars related to the ripening time. Considering, genetic variability of the plant material and observed qualitative oscillations during different temporal stages of storage it was concluded that highest climacteric point was always occurred at the middle intervals of storage. Higher flavor index was registered in the first intervals of storage for the samples picked at second phase. Ulterior comparative results of panel tests in different temporal intervals for maturity and ripening phases demonstrated that superior levels of sensorial quality registered at riprning was gradually decreased, meaning that no significant difference were observed in the long storage periods of the sensorial values for both of the picking phases.
