Buhara Yücesan

In Vitro Regeneration of Achillea millefolium L from Shoot-tips and Root Segments of Seedlings

This report describes, for the first time, an efficient plant regeneration system for Achillea millefolium L (yarrow), a medicinal plant, via shoot multiplication from shoot-tips and adventitious shoot regeneration from root segments. Higher numbers of shoots were obtained when shoot-tips were cultured on MSMO medium supplemented with 3.0 mg l−1 BA and 0.5 mg l−1 IAA, or 5.0 mg l−1 KIN and 1.0 mg l−1 IBA, producing 17.3 and 17.0 shoots per explant at 100% frequency, respectively. For adventitous shoot regeneration, only root segments developed shoots when cultured on medium containing a combination of 1 mg l−1 TDZ, 0.5 mg l−1 IAA and 0.5 mg l−1 GA3 (18.9 shoots per explant at 100% frequency), while other types of explants (i.e., cotyledons, leaf lamina and petiole segments) or hormonal combinations tested were found ineffective. Regenerated shoots rooted readily on MSMO medium containing different concentrations of IAA, IBA, NAA or 2,4-D, however, NAA at 0.5 mg l−1, or IBA at 0.5 or 1.0 mg l−1 were found to be the most productive. Nearly all of the regenerated plants (98%) survived through the hardening process when the rooted plantlets were kept at 55–65% relative humidity for 2 weeks, which were then planted in pots containing potting soil and kept at 25–35% humidity.

An efficient in vitro regeneration system for Lythrum salicaria

This report describes an efficient plant regeneration system for the medicinal plant Lythrum salicaria via direct adventitious shoot development from leaf and stem explants. Leaf explants were much more responsive to regeneration than stem segments. Of the hormonal combinations tested, those involving thidiazuron (TDZ; 0.1, 0.3 or 0.5 mg dm−3) were more effective than the combinations of other hormones and 0.1 mg dm-3 TDZ combined with either indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA) was the most productive. Rooting was readily achieved when multiple shoots were singled out and cultured on medium containing different auxins. IAA was the most effective on root development in terms of both the number of roots per shoot and the frequency of rooted shoots. More than 90 % of the regenerants survived after hardening for four weeks at gradually decreased air humidity.

Effect of Phytohormones on Micropropagation of Self-Heal (Prunella vulgaris L.)

Self-heal (Prunella vulgaris L.), a medicinal plant with strong antiviral activities, was regenerated from seedling shoot-tips cultured on medium containing selected concentrations and combinations of various plant growth regulators. The highest frequency of multiple shoot regeneration was obtained with 3.0 mg L−1 BA with 0.1 mg L−1 IAA. Regeneration tests with leaf lamina, petiole, stem internodes, and root explants cultured on medium containing combinations of plant growth regulators at various concentrations were unsuccessful. Regenerated shoots obtained from shoot-tips readily rooted on media containing IAA, IBA, NAA, or 2,4-D, with medium containing 3.0 mg L−1 IAA or 3 mg L−1 IBA being the most effective. Rooted explants transferred to vermiculate in Magenta boxes and acclimated for 2 weeks could be planted into foam cups containing potting soil and maintained in an environmentally controlled plant growth room.

Thidiazuron (TDZ): A Callus Minimizer for In Vitro Plant Production

Thidiazuron (TDZ) seems to be quite suitable growth regulator for rapid and effective plant production in vitro. In many woody and herbaceous plants, lower TDZ concentrations induce less callus production around the explant. However, there is still insufficient number of studies how actually TDZ is effective on plant production in vitro and which biochemical and molecular genetic mechanism are involved in developmental physiology. Recent studies have shown that TDZ affects endogenous cytokinin and auxin production, and therefore morphogenetic identification of cells and tissues is downregulated by various genes acting on auxin regulation and transport as well as cytokinin response. These hormones that take a role in several metabolic pathways wherein more researches are required to identify the direct regulator and stress signaling factors during plant regeneration are induced by TDZ. A closer look on these subjects may bring about a better understanding on why urea derivative TDZ is more effective than adenine types of cytokinin on most species and how low concentration of TDZ has been found to be useful for micropropagation, especially in wood plants. Lastly, why does long exposure of TDZ have not been recommended and what are the possible reasons of hyperhydricity, abnormal shoot growth, and difficulty in rooting? The answers will be quite useful for management of culture conditions for the large-scale production and conservation of economical plants.

Differential effects of plant growth regulators on physiology, steviol glycosides content, and antioxidant capacity in micropropagated tissues of Stevia rebaudiana

Abstract Plants naturally produce secondary metabolites on exposure to abiotic/biotic stress. Production of secondary metabolites, like phenols or flavonoids, is a defence mechanism against different stresses. This study explores the influence of plant growth regulators (PGRs) on the growth and secondary metabolites of in vitro grown tissues of zero calorie sweetener, Stevia rebaudiana. An efficient regeneration of this valuable plant under the influence of PGRs was conducted, and quantification of physiology parameters, steviol glycosides (SGs) and various antioxidant activities in callus, shoots and regenerated plants was performed. Significantly highest explant response was achieved by 2 mg/L of 6-benzyl aminopurine (BAP) and 0.5 mg/L of 2,4-dichlorophenoxy acetic acid (2,4-D) combination in case of callogenesis, while shoot and root organogenesis was best illustrated by control and 0.5 mg/L of indole acetic acid (IAA) treatment, respectively. Regarding SGs formation in leaves, significantly greater content (2.07% and 0.93%) was obtained by control in case of rebaudioside A (Reb A) and 2 mg/L of BAP in case of stevioside (ST). Leaves of rooted-shoots produced significantly highest Reb A (4.21%) and ST (2.22%) content in case of 1 mg/L of IAA and 0.25 mg/L of IAA inoculation in Murashige and Skoog growth medium, respectively. Similarly, differential effects of PGRs were elucidated in case of all in vitro grown tissues on antioxidant properties. The study concludes that secondary metabolites can be efficiently produced in in vitro culture so can be employed in bioreactors.