Mohammad Adibian; Yosef Hamidoghli; Sasan Aliniaeifard
Abstract
In the past decade, light-emitting diodes (LEDs) have been increasingly regarded as a suitable replacement for many other types of light source. They have attracted lots of attention. Supplemental lighting improves growth and yield of greenhouse vegetables such as sweet pepper, cucumber and tomato all-year ...
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In the past decade, light-emitting diodes (LEDs) have been increasingly regarded as a suitable replacement for many other types of light source. They have attracted lots of attention. Supplemental lighting improves growth and yield of greenhouse vegetables such as sweet pepper, cucumber and tomato all-year round. In the present study, the growth and photosynthetic functionality of two greenhouse sweet pepper cultivars, i.e. ‘Padra’ and ‘Shadleen’, were evaluated in response to the quality of LED lighting on sweet pepper seedlings. For this purpose, three combinations of red (R) and blue (B) LEDs (R90B10, R80B20, and R70B30 were used, with a light intensity of 200 μmol m-2 s-1 in all LED light treatments. Evaluations were done in two growing seasons, winter and summer, in Rasht, Iran. Seedlings exposed to supplemental light had thicker stems, wider leaf area, higher biomass, and greater photosynthetic functionality. We observed an increase in the ratio of B-light LED to the positive effects on the growth and photosynthesis functionality of the seedlings. However, no significant difference was observed between the cultivars. The effect of supplemental light was more emphasized in the winter. Thus, the control seedlings were weak and pale, while strong seedlings with dark green leaves were produced under the supplemental light. In conclusion, supplemental LED lighting appeared as a practical tool for the commercial production of greenhouse seedlings.
Farid Moradinezhad; Fatemeh Setayesh; Sohrab Mahmoodi; Mehdi Khayyat
Abstract
Jujube (Ziziphus jujuba Mill.) fruit is an important medicinal plant in Iran. The harvesting time is a crucial for jujube fruit quality. Several characteristics of jujube fruit when harvested at four development stages; white mature (light green), crisp mature (white-red), fully mature (red) and fully ...
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Jujube (Ziziphus jujuba Mill.) fruit is an important medicinal plant in Iran. The harvesting time is a crucial for jujube fruit quality. Several characteristics of jujube fruit when harvested at four development stages; white mature (light green), crisp mature (white-red), fully mature (red) and fully ripe (dehydrated brown) were evaluated. Fruit weight, diameter, volume, pulp to stone ratio, firmness, titratable acidity (TA), total soluble solids (TSS), ascorbic acid, total phenolics content, protein, ash and chlorophyll fluorescence parameters were determined. The results showed that fruit dry weight, TSS, TSS/TA were increased significantly, while firmness, protein content and ash weight were decreased as jujube fruit harvested at progressed development stages. Ascorbic acid in fruit was decreased from white to crisp mature stage and thereafter increased significantly to fully mature stage. However, the content of total phenol increased significantly from white to crisp mature stage and thereafter decreased at more maturity and ripening stages. Moreover, chlorophyll fluorescence parameters were influenced by harvesting time. The F0 and Fm showed a positive significant correlation with total phenolic, ascorbic acid and protein content and a negative significant correlation with DW. Therefore, chlorophyll fluorescence maybe a helpful, nondestructive technique to evaluate the nutritional quality changes in jujube fruit. Overall, jujube fruit harvested at crisp (white-red) and fully mature (red) stages, seem best in respect of postharvest handling and nutritional criteria.
