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 ...
Read More
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; Mohammad-Sadegh Safariyan-Nejad
Abstract
One of the most important problems of strawberry cultivation in temperate regions is winter cold injuries. Current study investigated impacts of foliar application of glycine betaine (GB) at 0, 0.5, 1, 2 and 4 mM concentrations on the cold hardiness of strawberry. The plants were divided into two groups: ...
Read More
One of the most important problems of strawberry cultivation in temperate regions is winter cold injuries. Current study investigated impacts of foliar application of glycine betaine (GB) at 0, 0.5, 1, 2 and 4 mM concentrations on the cold hardiness of strawberry. The plants were divided into two groups: one group for evaluation of cold hardiness at temperatures of -6, -9, -12, -15 and -18 °C; and the other for study of some biochemical characteristics. Results showed that GB treatment increased soluble carbohydrate and proline concentrations in both leaf and crown tissues, total protein concentration in leaf, and relative water content in leaf as compared to those in control. Based on LT50 calculated from electrolyte leakage and tetrazolium staining test, the GB application increased cold hardiness in strawberry plant based on its concentration. The highest cold hardiness was found in the 2 mM GB concentration based on electrolyte leakage and tetrazolium staining tests at -13.3 and -15.3 °C. Meanwhile, the lowest values of cold hardiness were observed in the control treatments based on electrolyte leakage and tetrazolium staining tests at -10.2 and -11.0 °C. Significant correlations were found between soluble carbohydrate and proline concentrations in leaf and crown, and total protein concentration with LT50 calculated from electrolyte leakage and tetrazolium staining test. We conclude that application of 2 mM GBhas the capacity to increase the freezing tolerance of strawberry and could be used as a prophylactic tool to reduce winter cold injury.
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 ...
Read More
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.
