Sex-related differences in the dioecious species Rumex thyrsiflorus Fingerh : analysis of the content of phenolic constituents in leaf extracts

Rumex thyrsiflorus Fingerh. is mentioned as a European folk medicinal plant. This species has also been traditionally used as an edible plant in Eastern Europe because of its nutritional value. During the study, qualitative and quantitative sex-related differences of phenolic constituents in methanolic leaf extracts of R. thyrsiflorus were evaluated. The presence of the same substances (nine phenolic acids before, and six phenolic acids after acid hydrolysis, nine flavonoids, and a catechin) was estimated in both female and male specimens, using the HPLC-DAD method. A statistically significant higher content of eleven constituents in female plant extracts (acids: chlorogenic, p-coumaric, cryptochlorogenic, gallic, protocatechuic, neochlorogenic, vanillic; flavonoids: quercitrin, rhamnetin, rutoside; and a catechin) was shown. This is the first report concerning the relation between the sex and the content of biologically active phenolic secondary metabolites in leaf extracts of R. thyrsiflorus. Female plants of R. thyrsiflorus could be useful for pharmaceutical purposes as a preferential source of bioactive phenolic acids, flavonoids and especially catechin

Rooting affects the photosystem II activity : in vitro and ex vitro studies on energy hybrid sorrel

Rumex tianschanicus x Rumex patientia is a high-biomass-yielding plant suitable for fuel and biogas production. The protocol of the hybrid sorrel micropropagation was used to study the changes in the photosystem II (PSII) activity as well as to analyse the ultrastructure of the chloroplasts. The lowest effective PSII quantum yield [Y(II)] and an apparent electron transport rate of PSII [ETR(II)] were observed for adventitious shoots that had been regenerated in vitro, before rooting. These fluorescence parameters were higher and similar for both the leaves of the same adventitious shoots that had been rooted under in vitro conditions and for the shoots that had been acclimated and grown in ex vitro conditions. The analysis indicated that the PSII activity strongly depends on the formation of properly functioning roots and that in vitro or ex vitro culture conditions are, at least to some degree, less important. TEM analysis revealed that chloroplasts from plants rooted in vitro were sufficiently mature and acclimatization processes have less impact on their devel- opment. This is the first report concerning the analysis of PSII activity and the ultrastructure of the chloroplasts at all of the stages of micropropagation, i.e. adventitious shoot formation in vitro, rooting in vitro and acclimation to ex vitro conditions. It strongly indicated that rooting under in vitro conditions, rather than the acclimation to ex vitro conditions, plays a key role in the development of a completely functional photosynthetic apparatus in hybrid sorrel

Male adventitious roots of Rumex thyrsiflorus Fingerh. as a source of genetically stable micropropagated plantlets

Rumex thyrsiflorus Fingerh. is one of the few dioecious plant species that have sex chromosomes. The chromosome constitution of females is 2n = 12A + XX and 2n = 12A + XY1Y2 of males. It is a medicinally important plant species and has also been the object of studies on the structure and function of sex chromosomes and sex ratio. An efficient plant regeneration protocol was developed from karyologically stable male roots that had been derived from a long-term liquid culture. The root segments were grown on MS medium supplemented with the following plant growth regulators: 2.4-D, NAA, kinetin, BAP and TDZ. The highest frequency (81.73 %) of adventitious shoot formation (16.27 shoots/explant) was obtained on MS + 0.5 mg/l TDZ. Regenerated shoots were successfully rooted on ½ MS + 2 % sucrose + 0.5 mg/l IBA and acclimated to in vivo conditions. Histological analysis revealed indirect (via callus) adventitious shoot formation. The cells of the morphogenetic callus were surrounded by a fibrillar structure that was similar to the extracellular matrix. Molecular analysis based on genetic sex markers confirmed that all of the root explants were male. The genetic stability of the regenerated plantlets was confirmed using random amplified polymorphic DNA analysis. This is the first report concerning the micropropagation protocol for R. thyrsiflorus Fingerh. from male roots derived from a long-term liquid culture, which offers a unique opportunity to obtain true-to-type plants of the same sex

Female versus male : Rumex thyrsiflorus Fingerh. under in vitro conditions : does sex influence in vitro morphogenesis?

Rumex thyrsiflorus Fingerh. is a dioecious plant with polymorphic sex chromosomes (XX in females, XY_{1}Y_{2} in males). This species is an interesting plant for study on the structure and function of sex chromosomes, the sex ratio, and is also a valuable source of bioactive constituents. A procedure for the micropropagation of R. thyrsiflorus from hypocotyl explants, which can be useful for analyses of sex-specific morphogenetic reactions under in vitro conditions, was developed. The molecular analysis, based on genetic sex markers, allowed the sex of explants to be determined in order to create male or female in vitro cultures. Regeneration primarily occurred via indirect adventitious shoot formation as well as via somatic embryogenesis, which was confirmed by histological and scanning electron microscope (SEM) analyses. The highest frequency of explants that revealed a morphogenetic response with the highest number of regenerated adventitious shoot buds (average 11.5 shoots per explant) was obtained on a Murashige and Skoog (MS) medium supplemented with 2.27 \mu M thidiazuron (TDZ). Molecular analysis revealed a female-biased sex ratio under these conditions. The relationship between the sex of the explants and their morphogenetic potential was studied. The efficiency of morphogenesis varied between the two sexes and depended on the ratio of auxin and cytokinin in the medium. The germination pattern of male and female seeds under in vitro conditions was also analysed. No differences in germination time between male and female seeds and in terms of male and female seedling length were observed, which indicated that there was no competition between the sexes during seed germination when grown under uniform growth conditions

Extracellular matrix surface network is associated with non-morphogenic calli of Helianthus tuberosus cv. Albik produced from various explants

Helianthus tuberosus is economically important species. To improve characters of this energetic plant via genetic modification, production of callus tissue and plant regeneration are the first steps. A new, potentially energetic cultivar Albik was used in this study to test callus induction and regeneration. Callus was produced on leaves, petioles, apical meristems and stems from field-harvested plants but was totally non-morphogenic. Its induction started in the cortex and vascular bundles as confirmed by histological analysis. The surface of heterogeneous callus was partially covered with a membranous extracellular matrix surface network visible in scanning and transmission electron microscopies. The results clearly indicate that: (i) the morphogenic capacity of callus in topinambur is genotype dependent, (ii) cv. Albik of H. tuberosus proved recalcitrant in in vitro regeneration, and (iii) extracellular matrix surface network is not a morphogenic marker in this cultivar