CYTOKININY A BRASSINOSTEROIDY POMÁHAJÍ PŘEKONAT STRES BĚHEM RŮSTU FAZOLU

Cytokininy a brassinosteroidy pomáhají překonat stres během růstu fazolu

Cytokinins and brassinosteroids sustain overcame stress during bean development

Dana Hradecká, Department of Crop production CAU Prague

Radomíra Vaňková, Institut of Experimental Botany CAU Prague

Souhrn, klíčová slova

Práce porovnává vliv teplotního stresu na odrůdy fazolu Daysi, Salva, Prima, Jantar, Magna, a Katka v laboratorních podmínkách možnost regulace stresové reakce aplikací brassinosteroidu (BRST) a cytokininu 6-m-benzylaminopurinu (BAP). Fyziologické projevy jsou hodnoceny metodou rychlé fluorescenční analýzy.Jsou zachyceny odrůdové rozdíly i vertikální změny na rostlinách.

Klíčová slova: fazol obecný, rychlá fluorescenční analýza, cytokinin BAP, brassinosteroid.

Summary, keywords

Contribution give a possibility of comparison the physiological reaction of six bean cultivars (Daysi, Salva, Prima, Jantar, Magna, and Katka) to stress caused by low or high temperature in laboratory. There are described some possibilities of stress reduction by the application of brassinosteroid (BRST) or cytokinin (BAP). Physiologic expressions are evaluated by the method of quick fluorescent analyse. Cultivar specificities as vertical changes in stands are described in figures and tables.

Key words: bean, quick fluorescent analyse-QFA, cytokinin BAP, brassinosteroid.

Introduction

In ecophysiological studies question why measure fluorescence is often posed. (Richard, Gregory 1977). That is because fluorescent analyse give basal informations about presence and function of red/ox substances which constitute stroma and thylakoids of chloroplasts, their red/ox functionning in electron transfer during reception and binding of light amount, photon. (Lavorel 1959). Photons are absorbed in conjugated chemical binding, functioning as receptors or radioantens recipient of amount of energy.Two receptors (QA and QB) of energy distinguish one and other by chemical structure. They are present in systemPS II (=quinone) more often in ratio 1:7 (Richard, Gregory 1977).Their activity is in relation to number of izoprenoid binding in side chain of molecule chlorophyll. First step of the photosynthesis realises during absorption of electrons. Next connected represent electrone transport through quinons from PSI and PSII. System PSI is active on 700-730 nm accept light quantum and is active in energy transmission on short distances (= side-line transport). PSI donor of energy for system PSII, exploit light 250-320 nm. During electrone transmission to quinon reduction of PSII attends and the activity of fluorescencese increases on wave length 320 nm. Both systems PSI and PSII collaborate quickly in cyclic electron transfer realised in 1.10-2-1.10-5 sec., or merrily. Another electron transfer pursues through activity of ubiquinone, in respirative chain of mitochondrias where similar structures as PSI and PSII are present in haemic groups of chloroplasts, where they absorb electrons from PSI and PSII. (Davenport,1972 ,Hill 1963). Phenomenon is accompanied by Kautsky effect of increase fluerescence towards maximum, after which follow equilibratory. (Kautsky, Hirsch 1931). Transfer of electrons on molecular level is sensitive to outward stand factors (PSI and PSIto drought quinons to light and nitrogen). Well known tight correlation on molecular level exists between stressors (Synková 1997,Lichtenthaler, Rinderle 1968), but by some convenient agrotechnic we can restrain: or avoid stress by spraying of antistressors, as are cytokinins (BAP in experiment) or BRST, based on analyses of polen grains of colza (Chripac 1989). Comparison both thiese preparates was made in Depart- ment of Crop Production in Czech Agricultural University in Prague on beans.

Methods

Experiments were made on steady juvenille bean plants varieties Daysi, Salva, Prima, Jantar, Magna, and Katka sown in plots 10x10x10 cm (nine plots from variant). Measuring of quick fluorescent induction(QFI) was made in 45% of light intensity during 1 sec by the method suggested by Naus, Matoušková (2000) in Pea P02003 instrument, and data were evaluated by program Winpea 32, by which initial fluorescence Mo, bazal fluorescence Fo, ratio Fv/Fm, net fluorescence =“Area“, and time of accomplishing maximal fluorescence Tfm(ms) were calculated. Energetic balance was enumerated by Strasser (2000). After first measuring made in room temperature 20o C it was one third of plots treated by 1x10-6 mol BAP, and another one third by 1x10-6 mol by 4821/81K brassinosteroid, as antistressors. After the treatment plants were exposed for 60 min in temperature -5oC, and another one for 60 min in 35o C, for evaluation stresses and antistress reaction caused by treatment. In a variety Daysi alsosome changesof QFA parameters related to bazipetal leaf position in plant was tested.

Results

The results are collected in table 1-3. and Figs.1+2. In tab.1 there are described significative differences caused by various temperature and the effect of treatment by biological active substances in a variety Daisy.Large amount yield of fluorescence (as rate of stress) Fv/Fm slightly rise in low temperature -5oC to 20oC, but diminish in high temperature 35oC. Fo, in low temperature ascend slowly, in 35oC quickly.Brassinosteroid accelerates increases of Fo. Net fluorescent yield (evaluated by “A“-Area) decreases in-5oC more intensively than in 35oC.They indicate more diminution, than cytokinin. Similar trend show quinon metabolism, and inicial fluorescence Mo,or the value Sm, and energy transfer via Qa (=N),as requirement for electron transport y degree of the photochemical reduction Vi+Vj, and membrane consumption of energy (Eto/ABS). Appointed parameters vary according to varieties Salva, Prima, Jantar, Magna, Daysi and Katka (Tab.2), and to bazipetal leaf position in plant (Tab.3).Indices Fo, Fm, Fv, increase in relation to position significantly, while Fv/Fm are almost same,while time for acquirement maximal fluorescence, as on the contrary net fluorescence - area decreased. Initial fluorescence Mo oscillate, metabolic turn over Sm diminish from the bottom to apex, as “N“, and Sm/Tfmax, but energy for electron transport rise as also the requirement in membrane.Low temperature caused lower damage by stress than high. Stress can be expressed not only preliminary by the ratio Fv/Fm, but also by complementary factors as Eto/ABS, A, Sm and Mo.

Conclusion

The method used for evaluation is new and modern. It is available to describe varieties, stress reaction and the way how to aviod the stress by treatment the plants. QFA values are exploitable in genie genetic or for improovement of the varieties.

Literature

Chripac J.:Proceedings of the conference on BRSt.Minsk,168.(1989)

Davenport H.: Nature 170.,1112-1114(1972).

Hill R.:Comprehensive Biochemistry 9, Elsevier, Amsterdam 73-97. (1963).

Kautsky H., Hirsch A.:Naturwirtsch.19, 96 (1931).

Lavorell E.: Plant Physiol.,34, 204-209(1959).

Lichtenthaler H.K.:Nature 198, 1070-72 (1968).

Naus, J., Matouskova M.:Practical exercise book UFP,Olomouc 65.

Richard P.,Gregory F.: Biochemistry of Photosynthesis.Toronto, 221.(1977).

Strasser R.:Photochemistry 36, 168-200 (2000).

Synková H.: Photosynthetica 34(3),427-438, (1997).

This work was supported by the Grant No. 2060/21/05299/0.

Kontaktní adresa

RNDr. Dana Hradecká, CSc., Katedra rostlinné výroby, Agronomická fakulta ČZU Praha 165 21 Praha 6 -Suchdol, telefon 24382537, e-mail: Hradecka@af.czu.cz