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Abstract The use of light-emitting diode (LED) technology represents a promising approach to improve plant growth and metabolic activities. The aim of this study was to investigate the effect of different light spectra: red (656 nm), blue (450 nm), red/blue (3:1), and white (peak at 449 nm) on biochemical properties, photosynthesis and gene expression in two lettuce cultivars (Lollo Rossa and Lollo Bionda) grown under different methods of nutrient solution replacement in hydroponics. Complete replacement and EC-based replacement of nutrient solution increased content of proline and soluble sugars and activity of antioxidant enzymes (CAT, GPX and SOD) under the red/blue LED and red LED light treatments in both cultivars. In addition, the red/blue and the monochromatic red light increased the soluble protein content and the antioxidant activity in the Lollo Rosa cultivar under the replacement method according to the needs of the plant. An increase in flavonoid content in the EC-based method in the Lollo Rosa variety treated with a combination of red and blue light was also observed. The red/blue light had the greatest induction effect on anthocyanin content, expression of the UFGT, CHS, and Rubisco small subunit genes, and the net photosynthetic rate. Data presented here will directly contribute to the development of nutrient solution and LED spectrum management strategies to significantly improve plant growth and metabolism, while avoiding water and nutrient waste, and environmental pollution.

Immature lentisk (Pistacia lentiscus L.) seeds from plants grown in Liguria (Italy) were collected and surface sterilized with ethanol (70%) and then NaOCl (1%). The outer pericarp of the immature fruits was removed and shells were opened. Enhancement of Embryo germination was examined through the use of five sucrose concentrations (0, 15, 30, 45, and 60 g L-1) combined with five concentrations of GA3 (0, 0.1, 0.3, 0.5, and 0.7 mg L-1). After 14 days, the germination frequency was detected and after 16 days, seedling development was evaluated. The embryo development into plantlets increased up to 54.37% when 45 g L-1 of sucrose was supplied; at this concentration, all the parameters, such as plantlet weight, height, and root length were high, while at 60 g L-1 of sucrose, the plantlets showed many lateral root formations. The root shape was completely different among the treatments. The percentage of embryo germination, plantlet weight and height, root length, and main lateral root number were enhanced when GA3 was used in the concentration of 0.7 (mg L-1). No rooting at all was observed when GA3 was used in a concentration of 0.3 or 0.5 (mg L-1) or medium without GA3. This research increases the possibility to obtain a massive number of plants to be used as rootstock for pistachio cultivation in difficult soils.

Genetic study of pistachio, especially male genotypes due to the effects of pollen on nut quality and quantity and next generation characterizations, help to improve its management and breeding programs. We studied the genetic diversity among 20 male and 36 female pistachio genotypes using ISSR marker. In total 178 DNA frgments were proliferated using 12 primers that 169 fragments were polymorphism. The average polymorphism information content (PIC) for the used primers were variable from 16 to up to 35%. Pistachio genotypes classified as five main categories by using cluster analysis. The most genetic similarity was between the ‘Poostkhormayee’and ‘Momtaz’ cultivars with 78% similarity and the lowest genetic similarity was between ‘Ravar3’ cultivar with ‘Ghazvini’cultivar and K40 genotype with 25% similarity. K38 male genotype had the lowest genetic similarity with female cultivars. Thus, it can be introduced as appropriate pollinizer for other studied cultivars. The results of analysis of molecular variance analysis showed that variability between male and female populations (8%) was lower than the variation within the populations (92%). Based on present results, ISSR marker was as a powerful tool to study the genetic variation among male and female pistachio genotypes.

Salinity is one of the most important abiotic stresses that limit crop growth and production. Salt stress influences plants in two ways: by affecting ion toxicity and increasing osmotic stress. Ion homeostasis, the excretion of Na+ and using antioxidant systems are the major strategies of salt tolerance in plants. Na+ and K+ transporters with enzymes that are involved in detoxification of reactive oxygen species play key roles in salt tolerance in plants. The aim of this study was to investigate the responses of high affinity K+ transporter2;1 gene (HKT2;1) which is involved in regulation of ion homeostasis and L-gulonolactone oxidase (GLOase) which is involved in the ascorbic acid biosynthesis pathway, under different concentrations of NaCl over different time points in Aeluropus littoralis shoots. Results from Real Time PCR data showed that expressions of both genes were influenced by external and internal concentrations of Na+ and the internal K+ content. AlHKT2;1 was significantly upregulated by increasing Na+ concentration at all time points. Furthermore, its highest expression level in shoots occurred after 6 days in 300mM NaCl in shoots which was 25folds more than untreated shoots. AlGLOase expression levels increased 54 h after initiation of salt stress. These results indicate that AlHKT2;1 and AlGLOase respond to different salinity conditions and probably are part of the mechanisms involved in tolerance to high salt concentrations in A. littoralis.