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Materiałem roślinnym były cięte kwiaty 10 odmian powojników (Clematis L.) z grupy odmian botanicznych i wielkokwiatowych. Bezpośrednio po zbiorze kwiaty chłodzono w temperaturze 8-10°C przez 24 godz. w wodzie, po czym wstawiano je do wody lub roztworu pożywki (8HQC + 2%S lub Chrysal Professional® - w zależności od odmiany). Kwiaty niechłodzone, bezpośrednio po zbiorze wstawiano do wody lub pożywki. Trwałość kwiatów określano w dniach na podstawie wyglądu zewnętrznego. Wykazano, iż chłodzenie przebadanych odmian nie miało wpływu na ich trwałość, bądź nawet ją skróciło. Zastosowanie preparatu Chrysal Professional® nie wpłynęło na trwałość kwiatów badanych odmian, a w niektórych przypadkach ją nawet skróciło. Zastosowanie pożywki standardowej dla kwiatów ciętych, tj. 8HQC + 2%S tylko u odmiany wielkokwiatowej ‘Ville de Lyon’ zwiększyło trwałość o 23%, ale jedynie u kwiatów wstępnie nie schładzanych.
Root meristem nucleoli from soybean (Glycine max. cv. Aldana) seedlings germinated for 3 days at 25°C and then for 4 days at 10°C or still at 25°C (control) were examined. Chill was observed to reduce root meristematic zone growth 15-fold. Nucleoli doubled their volume at 10°C. Autoradiographic studies showed that after 20 min 3H-uridine incubation at 10°C, incorporation of this precursor (postincubation time 0) into nucleoli of chilled seedlings was 4.7 times weaker than in the control. After 80 min postincubation in nonradioactive medium, the cytoplasm became the most intensely labelled cell area in the control material, while in chilled roots the nucleoli were still most intensely labelled and the cytoplasm was 11 times less labelled than in the control. The increase in nucleoli volume at 10°C is suggested to result from greater cold-induced inhibition of the dynamics of maturation and transport of ribosome subunits than of rRNA synthesis dynamics. Ultrastructural studies of chilled seedling nucleoli showed a significant decrease in the fibrillar component and an increase in the granular component, forming characteristic clusters. They are supposed to correspond to shortened and condensed pre-rRNA transcription complexes (compacted "Christmas trees").
Mung bean CYP90A2 is a putative brassinosteroid (BR) synthetic gene that shares 77% identity with the Arabidopsis CPD gene. It was strongly suppressed by chilling stress. This implies that exogenous treatment with BR could allow the plant to recover from the inhibited growth caused by chilling. In this study, we used proteomics to investigate whether the mung bean epicotyl can be regulated by brassinosteroids under conditions of chilling stress. Mung bean epicotyls whose growth was initially suppressed by chilling partly recovered their ability to elongate after treatment with 24-epibrassinolde; 17 proteins down-regulated by this chilling were re-up-regulated. These up-regulated proteins are involved in methionine assimilation, ATP synthesis, cell wall construction and the stress response. This is consistent with the re-up-regulation of methionine synthase and S-adenosyl-L-methionine synthetase, since chilling-inhibited mung bean epicotyl elongation could be partially recovered by exogenous treatment with DL-methionine. This is the first proteome established for the mung bean species. The regulatory relationship between brassinosteroids and chilling conditions was investigated, and possible mechanisms are discussed herein.
This paper is a continuation of our studies related to the response of two tomato cultivars: Robin and New Yorker to chilling: the later is more tolerant to chilling than the former one (Starck et al. 1994). The concentration of ABA in the xylem sap and ABA delivery rate (calculated as the amount of ABA exuded in 2h from the cut stump, following shoot removal) were estimated by ELISA. The relative water content (RWC) of the leaf blades and stomatal resistance (RS) were also measured. Tomato plants were grown in a greenhouse, under noncontrolled conditions. Before chilling some of the plants were drought hardened for 10 days (H). As an consequence of water deficit only New Yorker growth slightly decreased. Plants were chilled to 2–5 °C during three consecutive, 16-h nights, preceded by warm days, which caused a decrease in the RWC of leaf blades. Chilling did not decreased leaf blade hydration significantly, but drastically increased the concentration of ABA in the xylem sap in more chilling tolerant cv. New Yorker only. The delivery rate of ABA was markedly enhanced in both cultivars, but much more in New Yorker. Drought hardening increased ABA delivery rate in cv. Robin only, especially after chilling. The lack of correlation between changes in the RWC of leaf blades after low temperature treatment and the concentration of ABA in the xylem sap as well as its delivery rate suggest, that in both tomato cultivars chilling increased ABA level directly, not as an secondery effect of temperature-induced water deficit.
In pot experiments on cucumber cv. Śremski F1, the effect of short-term chilling on plants earlier treated with triacontanol (TRIA) and Asahi SL was investigated. These plants were grown in a phytotron at an air temperature of 27/22ºC (day/night), using fluorescent light with far flux density of 220 μmol x m-2 x s-1, with a photoperiod 16/8. At the 4th true leaf stage, the respective experimental series were sprayed with: 1) H2O – control, 2) TRIA 0.01, 3) TRIA 0.1, 4) TRIA 1.0 mg x dm-3, 5) Asahi SL 0.2, 6) Asahi SL 0.3%. After 24 hours one half of the plants from each experimental series was treated for a period of 3 days at a temperature of 12/6ºC, with all the other growth conditions unchanged. The obtained results have shown that short-term chilling stress caused a significant increase in electrolyte leakage, free proline content and in the activity of guaiacol peroxidase in leaves, but a decrease in chlorophyll a+b content, stomatal conductance, transpiration, photosynthesis, leaf area and in the activity of catalase in leaves. The application of TRIA or ASAHI SL on leaves in the pre-stress period reduced the values of the traits which had been increased as a result of chilling and increased those which had reduced. Generally, TRIA was most effective at a concentration of 0.1 mg x dm-3, and Asahi SL at a concentration of 0.3%.
Omówiono nową technologią produkcji chłodzonych posiłków „sous vide" ze szczególnym uwzględnieniem parametrów procesu oraz bezpieczeństwa mikrobiologicznego przy stosowaniu tej technologii
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