BRASSINOSTEROIDY A JEJICH ÚLOHA V ŘÍZENÉ TVORBĚ VÝNOSU

Brassinosteroidy a jejich úloha v řízené tvorbě výnosu

Brassinosteroids and their role in cereal yield control

Dana Hradecká1, Ludmila Staszková2, Ladislav Kohout3

1) Department of Plant Production CAU Prague,

2) Department of Chemistry CAU Prague,

3) Inst.of Org. Chem and Biochem., ASCR Prague 6, Fleming sq. 6

Souhrn, klíčová slova

V příspěvku nabízíme možnosti využití aplikace brassinosteroidů (BRST) k řízení tvorby výnosu obilnin. Brassinosteroidy jsou přírodní látky odvozené od substancí nalezených v pylu řepky, a později i v četných dalších planých rostlinách, takže aplikace nezatěžuje životní prostředí a jeví se výhodně zejména na chudých, méně příznivých až extrémních stanovištích.Ošetření omezuje stresovou zátěž a příznivě ovlivňuje strukturu tvorby výnosu, zvyšuje obsah chlorofylu (obr.1 a tab.1) a zvyšuje aktivitu enzymu glutamátkinázy jak je patrné z tabulky 1, a optimalizuje využití energie, jak je poukázáno na příkladu hodnot red/ox potenciálu měřeného metodou rychlé fluorescenční analýzy (obr.2).

Klíčová slova: brassinosteroidy, růstová analýza, glutamátkináza, chlorofyl, rychlá fluorescenční analýza.

Summary, keywords

In this paper are given the results of research made in spring wheat Sandra treated by brassinosteriods BRST, which are native substances based on eluate from rape polen grains. Late there were found in more wild plants. Optimal functionning was observed in poor lands and non convenient stands where the treatment remove stress.Treatment affected all growth processes and afforded positive effect on yield elements and farming yield. With regard to higher yield the preparations differ each other by the intensity and duration of action which has relation to metabolic degradation as is explained tab.I. Treatment enhanced chlorophyll content in leaves (Fig.1) and optimized energy balance in cell membranes (Fig.2).

Key words: brassinosteroids, growth analysis, glutamate kinase, chlorophyll content, quick fluorescent analysis

Introduction

Brassinosteroids (BRST) are biological and native substances.They were found in 1979 in polen grains of Brassica napus, whence their name (YOKOTA.1987), and later in approximately 30 tribe of high spermatophyts, e.g. Aesculus, Alnus, Secale, Zea, Phaseolus, Vicia etc. Mitchell Mandava (1970), Mandava, Mitchell (1991), Marumo (1968), Abe, Marumo (1991), Sakurai,Yokota, Clouse (1999) described their steroid character. Brassinosteroids are active especially in small doses. Multiple interaction of BrST with auxin, giberellin cytokinin, ethylene and abscisic acid are characteristic of BrST. Therefore mixed treatment effects of BrST and other plant hormones are expectet to be important for the purpose of the growth control of field crops.Treatment by doses 10-100mg/ha lead out of stres by low temperature. Kamuro (1991) and Watanabe (1997) described positive effect of BrST on rooting and vegetative growth. Young plant contain more BRST than older one. KEFELI (1993) described enhences of nitrate reductase activity. The object of our research was to compare chlorophyll content and balance of energy in photosynthesis and cumulation of dry matter as indicators of preconditions for higher yield crop production.

Methods

Experiments were made in Prague - Suchdol. (Sowing rate: 400 grains per m2 after cereal forcrops. Sowing date: 7.4+5 days. Germinated: 23.4+8 days. Aplication of brassinosteroids in a stage 49DC /phase of transition from columning to heading/ 10.5+3days).In regular 14 days intervals during the whole vegetative periode dry matter cumulation, leave area, stem length, micro-, macro-phenology and chlorophyll content in 30 plants were tested. After the harwest farming yield (amount of grain per ha), length of the ear, number grains per ear, TKW (=1000 kernells weight) as a constant of the quality were analysed.Chlorophyll content was measured in acetone extract according to ŠESTÁK, ČATSKÝ (1966) by spectrophotometer and paralelly by non destructive method using chlorophylometer instrument Hydro-Minolta.The method was described by JOZEFYOVÁ (1998). The activity of enzyme (glutamate kinase) was determined from powder, plant extract obtained with aceton from which aceton was evaporated, and buffer extraction with subsequent centrifugation on day 10 after the treatment. A fraction with enzyme was achieved from supernatant on salting out with crystalline amonium sulphate, and consecutive purification by chromatography on a Sephadex G-100 Superfine. The activity of enzyme was determined spectrophotometrically according to modificated hydroxamate method (VAŠÁKOVÁ 1980). The method of analyzing QFA is described by Strasser (2000).Brassinosteroids used for treatment were prepared in Inst.of Org. Chem+Biochem., ASCR by L.Kohout as semiochemicals by the structure of native compounds present in polen grains of rape.

Results and discussion

All preparations compared enhanced the productivity and grain yield. The effect was induced by enlargement of assimilative area,chlorophyll content and optimalisation of enzymatic activity as is described on example of the activity of glutamate kinase (Table I and Fig. 1).

Fig. 1

Tab. I: Average of characters measured in vegetative periode on wheat SANDRA, increments by BRST treatment

Treatment affected all growth processes and afforded positive effect on yield elements and farming yield. With regard to higher yield the preparations differ each other by the intensity and duration of action which has relation to metabolic degradation as is explained in Fig. 2. This figure shows that even first time of measuring QFA in vegetative period, when red/ox activity was measured (day 14 after treatment), brassinosteroids were metabolised on different level.This effect causes differences in duration of the activity. Tested brassinosteroids exhibited various impact to plastoquinons as demonstrated by quick fluorescency induction activities. Fig.2 shows that brassinosteroid 4812 was nearly fully reduced. Growth process is controled in each of them by own specific manner which is without the possibility of dynamic analyse during whole vegetative periode, only in a stage of the hypotheses which has to be verified in the future.Movement of substances, e.g. nutrients from roots, or assimilates from sources to sinc, is induced by action related to stress inhibition.That argue indicate enzyme glutamate kinase which catalyses transformation glutamate to g -glutamyl phosphate. Reaction is the first chemical response of synthesis proline from glutamate. It is known (Vašáková, Štefl 1982) that proline plays significative role in metabolism, on adaptation of plants to stressors such as unconvenient stand conditions, droughtness, salinity, coolness etc. but also in the control of the productivity, in relation to onthogenesis and to develop- ment stage. Both applications markedly diminished the number of sterile shoots, immediately after the treatment, by changing them to fertile ones.These affect dry matter cumulation during whole vegetative periode and manifest themself on grain yield increments. Leave area per plant and leave area index (LAI; m2/m2) especially if measured in upper flag leaves, as chlorophyll content, and vertical stratification of chlorophylls in growth from the bottom to ear, were positivelly influenced during first 14 days after spraying. These changes were accompanied by increases of ear length, increments of spikes, spikelets and florets numbers, lately increased grain number per ear and kernell weight (TKW). Substances applied affected production of enzyme glutamate kinase, as accumulation underground and above ground dry matter (measured in preliminary plot experiments), length and robustness of root systems, especially in poor soils from ecological stand of view, non farmed by conventional or extensive farming.

Fig. 2

Conclusion

These changes were accompanied by increases of ear length, increments of spikes, spikelets and florets numbers, lately increased grain number per ear and kernell weight (TKW). Substances applied affected production of enzyme glutamate kinase, as accumu- lation underground and above ground dry matter (measured in preliminary plot experiments), length and robustness of root systems, especially in poor soils from ecological stand of view, non farmed by conventional or extensive farming.

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This work was supported by Research.Aim MSM No. 412100002 and 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