Freezing Resistance and Cryopreservation of Cell Strains of Rhaponticum carthamoides and Thalictrum minus

Effects of long-term (few months) culturing and short pregrowth (up to 7 days prior to deep freezing) in the presence of mannitol (5–6%), ABA (5.0–7.5 × 10^–5 M), or both substances on cryogenic resistance of leusea (Rhaponticum carthamoides, strains Rhs-2 and Rhs-8) and meadow rue (Thalictrum minus L., strain B-233) cell suspension cultures were studied. Cryoprotective capacities of 48 solutions were studied at slow (0.33°C/min) freezing to the temperature of liquid nitrogen with an automatic initiation of crystallization. Cells were stored in liquid nitrogen for several days or months. ABA had a cryoprotective effect, provided that subculturing intervals were 12–14 days. At more frequent subculturing (every 7 days), pregrowth on ABA-containing medium did not increase survival percentage compared to pregrowth with mannitol. Successful cryopreservation of these strains has been achieved due to strict standardization of 7-day subculturing regime, pregrowth in the presence of mannitol prior to freezing, and cryopreservation with dimethyl sulfoxide, sucrose, trehalose, and glycerol. The cell survival rates after thawing were 60% (Rhs-8), 80% (Rhs-2), and 70% (B-233). The cell growth resumed on the third to seventh day. The growth indices and protoberberine synthesizing activity in B-233 strain reached their control values at the ninth subculturing after a post-thaw recovery.     

The Effects of Cold Acclimation of Winter Wheat Plants on Changes in CO<Subscript>2</Subscript> Exchange and Phenolic Compound Formation

We studied CO₂ exchange and phenolic compound production in various organs of unhardened and hardened winter wheat (Triticum aestivum L.) plants. The rates of CO₂ assimilation at saturating illumination (photosynthesis) and CO₂ evolution in darkness (respiration) declined substantially at the autumnal decrease of ambient temperature. However, because of a higher cold resistance of photosynthesis, the ratio of photosynthesis to respiration rates increased 1.5-fold. These gas exchange changes were accompanied by the accumulation of total soluble phenolics in leaves and a polymeric phenolic compound lignin in roots. We did not observe any changes in the production of either soluble or polymeric (lignin) phenolics in crowns.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 366–371.Original Russian Text Copyright © 2005 by Zagoskina, Olenichenko, Klimov, Astakhova, Zhivukhina, Trunova.     

Formation of phenol compounds in various cultivars of wheat (Triticum aestivum L.)

The formation of soluble phenol compounds, including flavonols, was studied in winter (Erythrospermum, Lutescens 230, and R 47-28) and spring cultivars (Lada) of wheat (Triticum aestivum L.). The contents of soluble phenol compounds and flavonols were 1.8-2.6 and 0.5-1.3 mg/kg fresh weight, respectively. These results illustrate the similarity of phenol metabolism in leaves of winter and spring wheat cultivars. The exception was the cultivar R 47-28 that accumulated the maximum amount of phenol compounds (e.g., flavonols). In this cultivar the ratio of flavonols reached 50% of total soluble phenol content. In other cultivars, this parameter did not exceed 25-35%. The data indicate that the cultivar R 47-28 differs from other wheat cultivars in the metabolism of phenol compounds. The observed differences are probably related to genetic modifications of the cultivar R 47-28 during selection.     

Formation of phenolic compounds in various cultivars of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

The formation of soluble phenolic compounds, including flavonols, was studied in winter (Erythrospermum , Lutescens 230, and R 47-28) and spring cultivars (Lada) of wheat (Triticum aestivum L.). The contents of soluble phenolic compounds and flavonols were 1.8–2.6 and 0.5–1.3 mg/g fresh weight, respectively. These results illustrate the similarity of phenol metabolism in leaves of winter and spring wheat cultivars. The exception was the cultivar R 47-28 that accumulated the maximum amount of phenolic compounds (e.g., flavonols). In this cultivar the ratio of flavonols reached 50% of total soluble phenol content. In other cultivars, this parameter did not exceed 25–35%. The data indicate that the cultivar R 47-28 differs from other wheat cultivars in metabolism of phenolic compounds. The observed differences are probably related to genetic modifications of the cultivar R 47-28 during selection.Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 1, 2005, pp. 113–116.Original Russian Text Copyright © 2005 by Zagoskina, Olenichenko, Chzhou Yunvei, Zhivukhina.