Domestic grape germination behaviour: the ‘Chardonnay’ and ‘Syrah’international cultivars’s study case

The domestic grape germination eco-physiology is a little studied aspect since reproduction occurs predominantly agamically, despite the sexual reproduction remains the main form for the selection of new cultivars. In this study, two international cultivars grown all over the world-Chardonnay and Syrah-were chosen as models of the domestic grape for the experiments in the eco-physiology of germination. The experimental design consisted of chemical, mechanical pre-treatments and combination of them as the bird ingestion pre-treatment that simulates the transit through the digestive tract of birds. Furthermore, seeds were submitted to different periods of cold stratification -0, 15, 30, 60 and 90 days -to simulate the winter effect. Seeds were placed to germinate at different incubation temperatures, to find the optimal germination protocol. The results showed that domestic grapes retain the need for cold stratification, and the best germination temperature is represented by the fluctuating temperature that simulates spring conditions. Our results help to understand what the best germination conditions of domestic grapes are and offer a contribution to extend the knowledge on how the process of domestication may have affected the biology of Vitis vinifera L. subsp. vinifera

In Vitro Preservation of Transgenic Tomato (Solanum lycopersicum L.) Plants Overexpressing the Stress-Related SlAREB1 Transcription Factor

In vitro preservation of transgenic tomato lines overexpressing the stress-responsive transcription factor SlAREB1 was studied by using slow growth and cryopreservation techniques. Slow growth preservation was performed by using different concentrations of sucrose (0, 100, 200, 300 mm) and abscisic acid (0, 4, 8, 12 μm) in Murashige and Skoog (MS) media, while cryopreservation was conducted by using encapsulation dehydration, V-cryoplates and seeds. Significant differences were observed between tested lines grown on MS media supplemented with 200 mm sucrose where transgenic lines overexpressing SlAREB1 showed improved growth when compared with negative control. The addition of abscisic acid (ABA) to the preservation media affected negatively transgenic lines growth and development when compared with ABA-free media. In encapsulation dehydration, non-cryopreserved transgenic lines overexpressing SlAREB1 pretreated in 0.8 M sucrose for 1 day and subjected to different dehydration periods showed significantly higher survival percentages when compared with negative control. For V-cryoplates technique, cryopreserved transgenic lines overexpressing SlAREB1 treated in 0.3 M sucrose for 3 days with or without cold acclimatization showed significantly higher survival percentages when compared with the negative control. Seed cryopreservation was performed successfully with a clear reduction in germination percentage in transgenic lines overexpressing high levels of SlAREB1. In conclusion, transgenic tomato lines overexpressing SlAREB1 were found to improve tolerance against different abiotic stresses associated with different in vitro preservation protocols

Improving solanine production in in vitro cultures of Solanum nigrum L. using different chemical and physical factors

Solanum nigrum L. is a medicinal plant of solanaceae family with distinguished therapeutic properties. Traditionally, S. nigrum. had been used as an anti-tumorgenic, antioxidant, hepatoprotective, diuretic, and antipyretic agent. The most important alkaloid member in this plant is solanine. Therefore, this study was conducted to utilize tissue culture techniques for the enhancement of solanine production in the in vitro grown cultures of this promising neglected plant. For callus growth and development experimental part, the highest callus growth parameters (callus diameter (21.4 mm) and callus fresh weight (2202.4 mg) were obtained in callus grown on Murashige & Skoog MS media supplemented with 2,4-Dichlorophenoxyacetic acid (2.0 mg·L-1) plus 1.5 mg·L-1 Thidiazuron. Similar trend was also obtained in cell suspension culture experiment, as maximum growth was recorded at similar hormone combination. Moreover, High-performance liquid chromatography analysis revealed that, solanine was affected by growth regulator type and concentration. The highest solanine levels were obtained when the explants were treated with 6-benzylaminopurine at level of 2.0 mg·L-1, as solanine content reached up to (2.61, 1.53 mg.g-1) for callus and cell suspension, respectively, while, microshoot contained the highest solanine (4.52 mg.g-1 DW) at 6-benzylaminopurine level of 1.6 mg.L-1. Additionally, carbon source had positively affected solanine level, where 0.2 M sucrose resulted in production of the highest amounts (3.13, 2.03 and 1.20 mg.g-1 DW) of solanine in microshoots, callus and cell suspension, respectively. Also, exposing microshoots and callus to light intensity of (100 µmol.m -2 s-1) yielded the highest solanine content (4.03 and 1.26 mg.g-1 DW, respectively),while the lowest solanine levels (1.50 and 0.48 mg.g-1 DW) were observed in plant material exposed to the lowest light intensity treatment (25 µmol.m -2 s-1)