دانلود رایگان مقاله انگلیسی تأثیر سیستم های تهویه طبیعی و نور بر پارامترهای رشد و کارواکرول در کشت درون آزمایشگاهی - اشپرینگر 2018

Abstract

The aim of the current study is to investigate the influence of light intensity, quality of light and alternative membrane sytems on the growth and headspace-GC/ MS chemical analysis of Plectranthus amboinicus cultivated in  vitro. Nodal segments were grown under light intensities (26, 51, 69, 94 and 130 µmol m−2 s −1) provided by cool-white fluorescent lamps. Apical segments were grown under light-emitting diodes blue; red; 1 blue/2.5 red; 2.5 blue/1 red; 1 blue/1 red and white fluorescent lamps. Apical and nodal segments were grown under alternative membrane and membrane-free systems. One, two or four PTFE membranes were used on the lid of the culture vessel. The membranes provided natural ventilation and worked as filters. The results have shown significant differences in the growth and carvacrol content, as well as in the content of carvacrol precursors (γ-terpinene and p-cymene) in different treatments. Among all tested light intensities, the significant increase in the dry weight and in the carvacrol content of plantlets derived from the nodal segments was recorded at 69 µmol m−2 s −1. The monochromatic red led to greater shoot length and higher dry weight in plantlets derived from the apical segments, as well as to carvacrol accumulation greater than that provided by the fluorescent lamps. The culture vessel enclosure by one and two membranes led to higher dry weight in plantlets derived from the apical and nodal segments, respectively. They also showed higher carvacrol content. Thus, it is possible optimizing the growth and carvacrol content in P. amboinicus cultivated in vitro by adjusting these environmental parameters.

Conclusion

The light intensity and quality, as well as the natural ventilation of the culture vessel, should be controlled in P. amboinicus cultivation in  vitro, since these factors affect growth and carvacrol content, as well as the content of carvacrol precursors (γ-terpinene and p-cymene). The intensity 69 µmol m−2 s −1 was optimal for P. amboinicus growth in vitro. Such light intensity changes the profile of volatile compounds and increases the carvacrol content. The monochromatic red was the best for optimal growth in  vitro, whereas the monochromatic blue was the best for carvacrol content increase. The AMS1 and AMS2 natural ventilation systems have improved the species’ rooting. The apical segments should be cultivated under AMS1 and the nodal ones should be cultivated under AMS2 in order to provide the best growth. Thus, it was also possible obtaining good quality plantlets regarding their carvacrol content. The assessed environmental factors appeared to have caused changes in the γ-terpinene and p-cymene contents, which are carvacol precursors. The present study has contributed to the understanding about how light and ventilation affect terpenes in plants.