Aida Shomali; Oksana Vladimirovna Lastochkina; Mohammad Mohammadian; Anshu Rastogi; Massimo Bosacchi; Tao li; Sasan Aliniaeifard
Abstract
Acclimation to the privileged lighting environment is an important step for the survival of newly developed horticultural plants such as transplants, tissue culture-generated plants, and mature plants when a change occurs in light intensity during the growth period or even during one full day. Capturing ...
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Acclimation to the privileged lighting environment is an important step for the survival of newly developed horticultural plants such as transplants, tissue culture-generated plants, and mature plants when a change occurs in light intensity during the growth period or even during one full day. Capturing excess light energy without an antecedent to acclimation imposes photooxidative cellular damage and photoinhibition in plants. Since carbon utilization may not keep pace with reductive energy production, it renders electron acceptors in the electron transfer chain oversaturated. However, plants are usually equipped with photoprotective mechanisms to attenuate the detrimental effects of excess light energy on the photosynthesis apparatus. In this review, we discussed how different controlled environment horticulture (CEH) systems are embedded with immense opportunities for improving yield and quality. Current understandings of the direct and indirect functional roles of light spectra are discussed in the context of photoinhibition, photoprotection, and their regulatory mechanisms.
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.
Fahimeh Aghakarim; Hassan Sarikhani; Ali Azizi
Abstract
Increasing day length during the short photoperiod in fall and winter is a beneficial method of increasing biomass production and altering plant morphology and phytochemistry. The objective of this study was to examine the effects of light quality at the end of the day (EoD) on the growth and phytochemical ...
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Increasing day length during the short photoperiod in fall and winter is a beneficial method of increasing biomass production and altering plant morphology and phytochemistry. The objective of this study was to examine the effects of light quality at the end of the day (EoD) on the growth and phytochemical characteristics of lemon balm. During shortday photoperiods in autumn, lemon balm (Melissa officinalis L.) seedlings were exposed to red, blue, and combined red/blue light using light-emitting diodes for 2 hours at the EoD. The results showed that exposure to red light significantly increased biomass. Plants grown under blue light yielded the highest percentage of dry matter and their leaves had the highest chlorophyll content and flavonoids. The highest carotenoid content was found in plants irradiated with blue light and later with red+blue light. The highest levels of total phenols, anthocyanins, and antioxidant activity were found in plants grown under red light. In addition, light quality had a significant effect on essential oil content. The highest essential oil content was obtained in the red and red+blue light treatments. The light quality at the EoD significantly changed the essential oil composition. The blue light significantly increased the citronellal content but decreased the geranial and linalool content. This study provided insights into the effects of EoD light quality on plant growth and metabolite accumulation in lemon balm with a short photoperiod. In conclusion, supplemental light at the EoD can effectively improve plant growth and secondary metabolite quality in medicinal plants.
Hassan Sarikhani; Hassan Sarikhani-Khorami
Abstract
Cadaman Avimag rootstock is widely used for almonds and peaches. The purpose of this studywas to investigate the effect of light quality on micropropagation, and some morphological andphysiological properties of this rootstock. Single node explants were cultured on WPM and MSmedia containing three levels ...
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Cadaman Avimag rootstock is widely used for almonds and peaches. The purpose of this studywas to investigate the effect of light quality on micropropagation, and some morphological andphysiological properties of this rootstock. Single node explants were cultured on WPM and MSmedia containing three levels of BA (0, 1 and 2 mg L-1) and three levels of NAA (0, 0.05 and0.1 mg L-1). WPM medium containing 2 mg L-1 BA and 0.1 mg L-1 NAA was selected fordifferent light quality treatments including fluorescent, red, and red+blue lights. Results showedthat light quality had a significant effect on shoot proliferation, length and diameter, nodenumber, shoot fresh and dry weights, leaf thickness, stomata number, and chlorophyllconcentration. Red light resulted in higher shoot diameter, but crunchiness and lack of propershoot growth. Moreover, red light produced the lowest amount of chlorophyll in the explants.Leaf thickness and its structural layers under the red light were the lowest among differenttreatments. Combined red+blue light in many factors resembled fluorescent light but inducedmore chlorophyll and a larger stomata size. The quality of light influenced the growth of thisrootstock in vitro, and affected the stem and leaf vegetative traits.
