ISSN 00063509, Biophysics, 2015, Vol. 60, No. 1, pp. 135–137. © Pleiades Publishing, Inc., 2015. Original Russian Text © O.A. Kalmatskaya, V.A. Karavaev, L.E. Gunar, A.G. Myakinkov, 2015, published in Biofizika, 2015, Vol. 60, No. 1, pp. 169–172.
COMPLEX SYSTEMS BIOPHYSICS
Luminescent and Physiological Indices of Triticale Plants under Treatment of Seeds with Growth Regulators O. A. Kalmatskayaa, V. A. Karavaeva, L. E. Gunarb, and A. G. Myakinkovb a
Moscow State University, Moscow, 119991 Russia Russian State Agrarian University, ul. Timiryazevskaya 49, Moscow, 127550 Russia email:
[email protected]
b
Received March 26, 2014; in final form, June 26, 2014
Abstract—It is shown that beforesowing treatment of triticale seeds with the growth regulators epin and zir con resulted in an increase in the F742/F686 ratio of the stationary fluorescence intensities of plant leaves at the wavelength bands of 742 and 686 nm corresponding to the maxima in the leaf fluorescence spectrum. Triticale under the treatment of seeds with growth regulators showed higher chlorophyll content, higher productivity, and higher indices of crop yield. Keywords: triticale, growth regulators, chlorophyll fluorescence spectra DOI: 10.1134/S0006350915010157
INTRODUCTION The fluorescent indicators of photosynthetic objects depend on a wide range of biotic and abiotic factors and are very attractive for monitoring the state of the photosynthetic apparatus and the assessment of its functional activity [1–3]. An important advantage of fluorescent research methods is that they usually can detect changes in the photosynthetic apparatus in the early stages of the impact of one or another factor, even before the appearance of typical morphological changes [1, 4–6]. Establishing the relationship between fluorescent and physiological characteristics of plants is an important and urgent task. It has been reported in previous studies [6, 7] that there was an increase in the (FM–FT)/FT indicator of fluorescence slow induction of barley leaves treated with physiologically active substances (FM is the max imum and FT the stationary value of fluorescence intensity at a wavelength of 686 nm) that resulted ulti mately in higher yields and main indices of yield struc ture of the experimental plants. Along with induction changes in the fluorescence at a fixed wavelength, the interest of researchers is focused on studying the fluo rescence spectra of green leaf [8, 9]. It was found in [8, 9] that the fluorescence spectra of chlorophyll in the leaves of plants tend to have two broad peaks in the red spectrum, one at a wavelength of 680–690 nm (F1) and the other at a wavelength of 730–740 nm (F2). It was shown in [8] that the ratio ω = F2/F1 and F2 and F1 stationary values recorded at the end of the induction process depend on several factors—the nature of mineral nutrition, CO2 concentration, intensity of illumination and duration of daylight, soil
and air humidity, and others—and the optimal condi tions for the development of plants, as a rule, corre spond to the maximum values of ω. In all cases studied in [8], the value of ω and the relative rate of biomass growth depended on the same factors and their changes were always unidirectional. In this paper, we investigated the luminescent and physiological indices of triticale, a hybrid of wheat and rye. Triticale has a high nutritional value and is increasingly being used as food and a fodder crop. Epin (active substance epibrassinolide) and zircon (a mixture of cinnamic acids) were used to stimulate the growth processes of triticale. The growthregulatory effect of these compounds has been shown earlier for barley, but it depended, however, on the weather con ditions of the year [10]. The goals of this study were (1) to study the effect of epin and zircon on the growth and development of triticale plants during beforesow ing treatment of seeds, as well as (2) to establish the relationship between the values of the luminescent index ω = F2/F1 in the leaves of triticale, on the one hand, and physiological indices (chlorophyll content, biometric parameters, plant productivity), on the other hand. MATERIALS AND METHODS The test was performed at the field experimental station of Russian State Agricultural University in 2012–2013. We used the triticale variety Valentin. The seeds were treated with EpinExtra and Zircon (Nest M, Russia) according to the manufacturer’s recom mendations immediately before sowing (August 2012). The application rate of compounds based on 1 t
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Luminescent (F742/F686) and physiological indices of triticale after treatment of seeds with epin and zircon Parameter F742/F686 Plant height, cm Chl a + Chl b, mg per 1 g of leaf raw weight Chl a/Chl b Yield, t/ha
Control
Epin
1.38 ± 0.09 41.0 ± 3.0 1.97 ± 0.09 2.34 ± 0.06 4.52 ± 0.25
of seeds was 200 mL for EpinExtra and 2 mL for Zir con. Specific quantities of compounds were diluted in 10 L of water to obtain the working solution. Changes in plant height, chlorophyll content, and fluorescence parameters were measured at the begin ning of June 2013. The fluorescence of triticale leaves was measured with a Solar SM2203 spectrofluorome ter. Leaves were cut from the middle layer, placed in the holder, kept in the dark for 5 min, and then illumi nated at a wavelength of 450 nm with an intensity of about 150 W/m2. Fluorescence was recorded simulta neously at two wavelengths: 686 and 742 nm, corre sponding to the maxima in the fluorescence spectrum of the leaf. Stationary values of fluorescence intensities F686 and F742 were detected after 20 min of illumina tion, and the ratio ω = F742/F686 was used as a fluores cent indicator. The content of chlorophyll in the leaves was mea sured using acetone extractions in accordance with [11]. The average height of the aboveground part of triticale was determined from ten plants. The yield and main indices of yield structure were determined in accordance with [12]. Fluorescent indices were mea sured in three replications, and productivity was mea sured in four replications. The table shows standard deviations from the mean values. RESULTS AND DISCUSSION Triticale plants under the treatment of seeds with epin and zircon were significantly better developed compared with the control plants, being 45–50% higher than the reference values (table). The content of chlorophyll a and b in the leaves of experimental plants, based on raw weight, was also higher with a simultaneously increased ratio of Chla/Chlb (table). It was known that chlorophyll a is part of both core com plexes of reaction centers and peripheral antennas of photosystems I and II (PS I and PS II), whereas chlo rophyll b is more likely a component of the mobile lightharvesting complexes that provide consistent functioning of both photosystems [13]. Thus, the increase in the ratio of Chla/Chlb in the leaves of trit icale under the treatment of seeds with epin and zir con, may indicate a change in the stoichiometric ratio between the complexes of photosystems and lighthar
Zircon
1.75 ± 0.10 61.0 ± 6.0 2.30 ± 0.12 2.49 ± 0.07 5.22 ± 0.25
1.69 ± 0.10 60.0 ± 5.0 2.30 ± 0.12 2.49 ± 0.07 5.12 ± 0.15
vesting complexes. A similar effect has been observed previously in barley, treated with epin and zircon [10]. Stationary values of luminescent index ω = F742/F686 in triticale plants under the treatment of seeds with growth regulators were approximately 25% higher than the control plants (table). Unidirectional changes in this parameter and chlorophyll content in the leaves of plants have been observed earlier in cucumber in the leaves of different layers [14], in plants grown under different kinds of mineral nutri tion [15] and low illumination [16], during the autumn degradation of chlorophyll [17], and in number of other cases. It was assumed that the dependence of the stationary value of ω on the content of chlorophyll was associated with the effect of reabsorption of fluores cence of chlorophyll within the leaf [9]. Analysis of fluorescence induction curves showed that F742 and F686 values were almost identical for all studied variants within the first minute of illumination until it reached the second peak of slow fluorescence induction. The quenching of fluorescence was observed at both wavelengths during the subsequent illumination; at the same time, the ratio F742/F686 increased gradually from values close to 1 to the sta tionary values given in the table. An increased F742/F686 ratio in the induction period is believed to be an indi cator of regulatory processes, affecting the photosyn thetic apparatus [9]. One such process includes the redistribution of excitation energy between the photo systems in favor of PSI. The classical mechanism of these changes involves reversible phosphorylation of specific lightharvesting chlorophyllprotein complex with protein kinase, the activity of which depends on the degree of reduction of the plastoquinone pool of electron carriers between the photosystems [18–20]. Taking into account changes in the pigment complex of plants, seeds of which were treated with epin and zircon, it cannot be excluded that increased stationary values of ω = F742/F686 in the experimental plants com pared with control ones are associated with changed coefficients of photochemical and nonphotochemical quenching of chlorophyll fluorescence, which is caused in turn by increased functional activity of the photosynthetic apparatus [21]. Thus, increased value of ω = F742/F686 in triticale during treatment of seeds with growth regulators may indicate an increased photosynthetic activity of the BIOPHYSICS
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experimental plants. This conclusion is consistent with the results of [22, 23], in which the method of slow fluorescence induction was used and an increase was observed in the photosynthetic activity of cereals (rye, barley) under the action of epin and zircon dur ing both beforesowing treatment of seeds and spray ing of plants during the phase of their most intense growth and development. Enhancement of the growth processes in triticale under the treatment of seeds with growth regulators resulted in higher yields (12–15% compared with con trol; see table) with a simultaneous increase in the number of yield structure indices—in particular, total and productive tillering and thousandkernel weight. CONCLUSIONS Thus, increase in physiological parameters (chlo rophyll content, plant height) of triticale plants under the treatment of seeds with epin and zircon was accompanied by an increase in the fluorescent index F742/F686 and ultimately in increased yield of triticale. The results obtained indicate the prospects of using the fluorescence spectra of a green leaf to evaluate the effectiveness of various growthstimulating com pounds used in agriculture. REFERENCES 1. Chlorophyll a Fluorescence: A Signature of Photosynthe sis, Ed. by G. C. Papageorgiou and Govindjee (Springer, Dordrecht, 2004). 2. T. V. Nesterenko, A. A. Tikhomirov, and V. N. Shikhov, Zh. Obshch. Biol. 68, 444 (2007). 3. N. R. Baker, Annu. Rev. Plant Biol. 59, 89 (2008). 4. M. K. Solntsev, H. P. F. Ekobena, V. A. Karavaev, and T. P. Yurina, J. Luminesc. 76–77, 349 (1998). 5. S. A. Glazunova, V. V. Ptushenko, L. E. Gunar, V. A. Karavaev, M. K. Solntsev, and A. N. Tikhonov, Biophysics (Moscow) 54 (3), 343 (2009).
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6. V. A. Karavaev, L. E. Gunar, A. G. Myakinkov, M. S. Gins, S. A. Glazunova, I. P. Levykina, and F. D. Lepeshkin, Biophysics (Moscow) 57 (4), 502 (2012). 7. L. E. Gunar, A. G. Myakinkov, S. A. Glazunova, and V. A. Karavaev, Izv. TSKhA 2, 91 (2009). 8. K. B. Aslanidi, A. A. Shalapionok, V. N. Karnaukhov, et al., A Method for Evaluating the Functional State of Plants from Chlorophyll Fluorescence Spectra (ONTI NTsBI, Pushchino, 1988) [in Russian]. 9. C. Buschmann, Photosynth. Res. 92, 261 (2007). 10. L. E. Gunar, A. G. Myakinkov, V. A. Karavaev, et al., Vestn. Mosk. Gos. Univ. Lesa (Lesnoi Vestn.) 34, 132 (2004). 11. M. V. Gusev, Initrial Practical Sourse in Plant Physiol ogy (Mosk. Gos. Univ., Moscow)\, 1982) [in Russian]. 12. B. A. Dospekhov, Methodology of Field Experiments (Kolos, Moscow, 1985) [in Russian]. 13. G. F. Peter and G. P. Thornber, J. Biol. Chem. 266, 16745 (1991). 14. V. V. Zavoruev, E. N. Zavorueva, and A. V. Shelegov, Biophysics (Moscow) 45 (4) 685 (2000). 15. S. M. Kochubei, T. M. Shadchina, and N. S. Odinokii, Fiziol. Biokhim. Kul’t. Rast. 18, 35 (1986). 16. O. A. Kalmatskaya, I. P. Levykina, S. V. Patsaeva, et al., Moscow Univ. Phys. Bull. 6, 466 (2013). 17. N. D’Ambrosio, K. Szabo, and H. K. Lichtenthaler, Radiat. Environ. Biophys. 31, 51 (1992). 18. J. F. Allen, Biochim. Biophys. Acta 1098, 275 (1992). 19. J. Minagava, Biochim. Biophys. Acta 1807, 897 (2011). 20. M. Tikkanen and E.M. Aro, Biochim. Biophys. Acta 1817, 232 (2012). 21. U. Schreiber, U. Schliva, and W. Bilger, Photosynth. Res. 10, 51 (1986). 22. V. A. Karavaev, L. E. Gunar, A. G. Myakinkov, and M. K. Solntsev, Collection of Scientific Papers, Faculty of Agriculture in Ceske Budejovice, Series for Crop Sciences 21, 195 (2004). 23. L. E. Gunar, A. G. Myakinkov, and V. A. Karavaev, Dokl. TSKhA 281, 294 (2009).
Translated by M. Shulskaya
