THE EFFECT OF SUNFLOWER ALLELOPATHICS ON GERMINATION AND SEEDLING VIGOUR OF WINTER WHEAT AND MUSTARD. Introduction

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1 THE EFFECT OF SUNFLOWER ALLELOPATHICS ON GERMINATION AND SEEDLING VIGOUR OF WINTER WHEAT AND MUSTARD Waldemar Bernat 1, Helena Gawronska 1, Franciszek Janowiak 2, Stanislaw W. Gawronski 1 1 Department of Pomology and Basic Natural Sciences in Horticulture, Faculty of Horticulture and Landscape Architecture, Warsaw Agricultural University, Nowoursynowska 166, Warsaw, Poland 2 Institute of Plant Physiology, Polish Academy of Sciences, Podluzna 3, Cracow, Poland Introduction Sunflower (Helianthus annuus L.) is well known from high allelopathic activity [MACIAS et al. 1999], and use of sunflower mulch is considered as an alternative strategy for weed management especially in organic farming [GAWRONSKI et al. 2002; GAWRONSKI 2003]. High allelopathic - inhibitory effectiveness of sunflower against most common weeds reported Leather [1983] and Ciarka et al. [2002a]. In laboratory study we observed that, wheat germination is almost unaffected by sunflower allelopathics [CIARKA et al. 2002b], while in the field substantial reduction in wheat germination and seedling establishment took place when sunflower mulch was used [GAWRONSKI et al. 2002; GAWRONSKI 2003]. Increase in abscisic acid (ABA) level under various stresses is often reported [QUARRIE, LISTER 1983; DAVIES, JONES 1991; JANOWIAK, DÖRFLING 1996; GAWRONSKA, KIELKIEWICZ 1999; GAWRONSKA et al. 2003] and it was also observed under the allelopathy stress in mustard at autotrophic growth stage [GAWRONSKA et al. 2002]. An attempt was made to elucidate differences between wheat and mustard, model plants for monocotyledonous crops and dicotyledonous weeds in our studies, in the response to sunflower allelopathics both at the hetero- and autotrophy growth stages. The aim of this work was to evaluate the effect of sunflower allelopathics on: (i) seed germination, (ii) early seedling growth, and on (iii) changes in the level of ABA in seedlings. 1

2 Material and methods Seeds and seedlings of winter wheat (Triticum aestivum L.) cv. Zyta and of mustard (Sinapis alba L.) cv. Nakielska were used. Seeds were germinated on Petri dishes layered with filter paper (mustard) or on rolled filter paper (wheat), moistened with 7 ml of distilled water (control) or with aqueous extract of air-dried leaves of sunflower (Helianthus annuus L.) cv. Lech. Extract concentrations were 5.0 and 10.0% DM w/v (wheat, experiment 1 st ) and 2.5, 5.0 and 10.0% DM w/v (wheat, experiment 2 nd and mustard both experiments). The seeds were incubated for 6 days in controlled cabinet at 20ºC in darkness. In experiment 1 st germinating seeds were counted and samples of roots and of coleoptiles (wheat) and of hypocotyls (mustard) for ABA assay were collected. Plant tissues were immediately frozen in liquid nitrogen and kept in 30ºC until ABA analysis. In the 2 nd experiment, number of roots (wheat), length and fresh weights of coleoptiles, hypocotyls and of roots were recorded. In both experiments, for every combination at least 4 replications (with 25 seeds in each) were used. ABA determination was performed in crude water extract of seedling by an indirect ELISA immunotest according to the protocol of [WALKER-SIMMONS 1987], modified by [HANSEN, DÖRFLING 1999], using the antibody MAC 252, of John Innes Centre, Norwich, UK. For each sample three measurements in independent ELISA plates, each with three replicates, were performed. Data were analysed with ANOVA. Values of HSD (Tukey test) at P < 0,05 are provided when differences between combinations were significant. Data are mean ± SE, n = 4 or 12 (ABA assay). Results and discussion In the presence of sunflower allelopathics seed germination was delayed and reduced in both species but these effects substantially differed depending on a species as mustard was extremely, while wheat only slightly affected. At highest concentration, less than 7% of sown mustard seeds germinated whereas in case of wheat over 90% of sown 2

3 seeds still germinated (Fig. 1, 2). This study clearly showed that differences in the tolerance to sunflower allelopathics between wheat and mustard exist already at the germination stage. It also confirmed results of our earlier studies, in which germination of mustard was reduced while of wheat was almost unaffected by allelocompounds contained in water extracts of sunflower leaves [CIARKA et al. 2002b]. Osmotic potential of used extracts, measured by dew point micro voltmeter (WESCOR RH 33T), were as follows: -0.28, -0.41, and 0.70 MPa for the concentrations of 2.5, 5.0, and 10.0% DM w/v respectively. According to Ciurzynska [personal communication, Ph.D studies] mustard Nakielska cv. (the same as used here), under osmotic stress induced by NaCl, at osmotic potentials of 0.50 MPa and of 0.75 MPa germinated above 90% and 70% respectively. Mustard germination in the presence of sunflower extract of osmotic potential MPa was about 10 fold lower (7%) in comparison with the above data. This, suggest that lower water availability for seeds germination, due to binding water by compounds contained in aqueous extracts of sunflower, plays, in the extreme reduction of seed germination, minor role, if any and only in the highest concentration. Therefore, we postulate that in case of mustard the mode of action of sunflower allelochemicals is mainly of toxic nature. Seedling vigour (based on length and fresh matter), at lowest concentrations, was significantly stimulated in both species (Fig. 3, 4, 5, and 6) what, according to definition, is an allelopathic effect as well [MOLISH 1937]. In fact, many synthetic compounds, including herbicides and stress factors, if at lower levels show stimulatory effects. Seedling length at 5.0% of extract concentration was either unchanged or slightly reduced (Fig. 3, 4). Fresh matter of mustard seedlings was also reduced at this concentration while in case of fresh matter of wheat seedlings stimulation still took place (Fig. 5, 6). At highest extract concentration mustard seedling growth was almost completely inhibited (Fig. 4, 6) while wheat seedlings continue to grow though, their length as well as fresh matter were strongly reduced (Fig. 3, 5). Growth inhibition in response to allelochemically active compounds according to [WÓJCIK-WOJTKOWIAK et al and references therein] is due both to restrained cell division and inhibited cell elongation and is often used as a parameter in studies on allelopathy. Reduced wheat seedling vigour by sunflower allelopathics recorded in this work partially explained, mentioned above, differences between our earlier results on germination in the lab and germination and seedling stand establishment in the field. As in most germination test only germination was evaluated and they were performed in optimal conditions. In the 3

4 field not only seedling vigour influenced the crop stand establishment but also environmental conditions often are far from optimum. Besides, in the field, interactions between allelocompounds, microorganisms, and environmental conditions influencing germination and seedling growth are also responsible for these differences. It is worthwhile to note that, in case of wheat seedlings, which develop adventitious secondary, tertiary and so on roots, an increase in number of roots took place along with an increase of allelopathics concentration (Tab. 1). Consequently, there was an essential difference in the reduction of total root(s) length between wheat and mustard. At highest concentration, root length of mustard, was only about 2% of control seedling while length of wheat roots was still around 30% of control ones (Tab. 1). This increase in roots number in wheat might be considered as an acclimation process to the stress of allelopathy. It can be also in response to poliphenols contained in sunflower extracts, which are auxine cofactors that are known as stimulator in rhizogenesis. As shown in our other studies on germination and seedling growth of 10 winter wheat cultivars under osmotic stress, along with lowered osmotic potentials (at comparable levels to used sunflower extracts) number of roots per seedling was in all cultivars reduced (data not presented). This character of wheat growth, at least partially, explains higher wheat tolerance to sunflower allelopathics. Higher wheat tolerance to sunflower allelopathics, than of most dicotyledonous weeds, would be an advantage in agro-ecosystems, if allelopathically active sunflower mulch to control weeds would be considered for application, because (i) the total roots size is greater what is beneficial in coping with stress, and (ii) later developing roots would be exposed to lowered, along with time, activity of allelopathic compounds in surrounding soil environments [YENISH et al. 1995]. Morris and Parrish [1992] similarly to us also found that wheat germination was not while early seedling growth was affected by aqueous extract of sunflower and that sunflower residues depending on cultivation have variable effect on wheat yield. Abscisic acid level, in control seedlings both of wheat and mustard was similar. In both species ABA level was higher in roots than in hypocotyls or coleoptiles (Fig. 7, 8) and it is in agreement with results of Wlodkowski et al. [1995] who also reported higher concentration of ABA in roots of three genotypes of triticale. In response to sunflower allelochemicals, ABA level increased in both organs manifold and in dose dependent manner (Fig. 7, 8). However, significant increase in ABA level was recorded in roots for both species and at all concentrations of allelopathics, whereas the increase in coleoptiles/hypocotyls was small being significant only in mustard hypocotyls at the 4

5 highest concentration. Similarly to us comparable increase of ABA, both in roots and in coleoptiles of triticale seedlings, in response to osmotic stress (at relative osmotic potentials) was reported by Wlodkowski et al. [1995]. Different pattern of ABA accumulation in roots and hypocotyls or coleoptiles, in studied species, suggests that the roots, as the first developing organs during germination, are presumable more protected than coleoptiles. If so, it would be in agreement with result of [SHARP 2002 and references therein] who showed that increased ABA level is necessary for root growth under stress conditions. For both organs, increase in the level of ABA was greater in case of mustard (Fig. 8 vs. Fig. 7), on which, as described above, the negative impact of sunflower allelopathics was evidently more severe. Different pattern of ABA accumulation in both studied species and in both organs suggest that these species and organs have different mechanism of protection or/and sensitivity against the stress caused by sunflower allelochemicals. This study also showed that ABA is involved, as in many other stresses, in the defence mechanism(s) against allelopathy stress. Conclusions 1. Compounds contained in water extracts of sunflower leaves, possess allelopathic activity, which depending on species of the acceptor plant, evaluated process and, on used concentrations are both of inhibitory and stimulatory nature. 2. There are substantial differences between wheat and mustard in response to sunflower allelopathics with wheat being evidently more tolerant. 3. Mode of action of sunflower allelochemicals against mustard is mainly of toxic nature. 4. Abscisic acid is involved in the defence processes against allelopathy stress both in wheat and mustard seedlings. References Ciarka D., Gawronska H., Gawronski S. W. 2002a. Weed species reaction to sunflower allelopathics. Abstract of Third World Congress on Allelopathy: Challenge for the New Millennium, Tsukuba, Japan, , s

6 Ciarka D., Prawicz U., Gawronska H., Gawronski S. W. 2002b. Genotypical differences of allelopathic potential of sunflower. Abstract of Third World Congress on Allelopathy: Challenge for the New Millennium, Tsukuba, Japan, , s 78. Davies W.J., Jones H.G Abscisis acid, physiology and biochemistry. BIOS Scientific Publisher Limited, Oxford, UK. pp 63-77, , , Gawronska H., Bernat W., Ciurzynska M., Garwonski S.W Photosynthesis and water status of mustard plants as influenced by sunflower allelopathics. Abstract of Third World Congress on Allelopathy: Challenge for the New Millennium, Tsukuba, Japan, , s 65. Gawronska H., Deji A., Sakakibara H., Sugiyama T Hormone-mediated nitrogen signaling in plants: implication of participation of abscisic acid in negative regulation of cytokinin-inducible expression of maize response regulator. Plant Physiol and Biochem. 41: Gawronska H., Kielkiewicz M Effect of the carmine spider mite (Acardia: Tetranychidae) infestation and mechanical injury on the level of ABA in tomato plants. Acta Physiol. Plant. 21: Gawronski S.W Allelopathy as a strategy for weed control in organic farming. Abstract of Fifth International Conference, Ecophysiological Aspects of Plant Responses o Stress Factor Cracow, Poland. Acta Physiol. Plant. 25, 3. p. 25. Gawronski S.W., Bernat W., Garwonska H Allelopathic potential of sunflower mulch in weed control. Abstract of Third World Congress on Allelopathy: Challenge for the New Millennium, Tsukuba, Japan, , s 160. Hansen H., Dörffling K Changes in free and conjugated abscisic acid and phaseic acid in drought-stressed sunflower plants. J. Exp. Bot. 50:

7 Janowiak F., Dörffling K Chilling of maize seedling in the field during cold period in ten genotypes differing in chilling tolerance. J. Plant Physiol. 147: Leather G.R Sunflowers (Helianthus annuus) are Allelopathic to Weeds. Weed Sci. 31: Macias F.A., Molinillo J.M.G., Varela R.M.,Torres A., Galindo J.C.G Bioactive compounds from the genus Helianthus. In: Recent advences in allelopathy. Eds Macias F.A., Galindo J.C.G., Molinillo J.M.G., Cutler H.G Servicio De Publicaciones-Universidad De Cádiz, ss Molisch H Der Einfluss einer Pflanz auf die andere Allelopathige. Fischer Jena. Germany. Morris P.J., Parrish D.J Effects of sunflower residues and tillage on winter wheat. Field Crops Res. 29: Quarrie S.A., Lister P.G Characterization of spring wheat genotypes differing in drought-induced abscisic acid accumulation. J. Exp. Bot.34: Sharp R.E Interaction with ethylene: Changing views on the role of abscisic acid in root and shoot growth responses to water stress. Plant Cell Environ. 25: Walker-Simmons M.K ABA level and sensitivity in developing wheat embryos of sprouting resistant and susceptible cultivars. Plant Physiol. 84: Wlodkowski M., Grzelak K., Lukasinski A., Gawronska H Influence of osmotic stress on seedlings vigour and ABA content in triticale. Materialy Konferencji i Sympozjów 50 Zjazdu PTB Kraków, p Wójcik-Wojtkowiak D., Politycka B., Weyman-Kaczmarkowa W Allelopatia. Wydawnictwo AR Poznan, ss 90. 7

8 Yenish J.P., Worsham A.D., Chilton W.S Disapperance of DIBOA- glucoside, DIBOA and BOA from rye (Secale cereale L.) cover crop residue. Weed Sci. 43: Acknowledgement: We thank to Dr. Steve Quarrie from John Innes Centre, Norwich, UK for providing us with monoclonal antibodies MAC 252 against ABA. These researches were financially supported by: 1/ European Commission, 5FP # QLK5-CT / State Committee for Scientific Research, kbn # 117/E-385/SPUB-M/5PRUE Key words: allelopathy, sunflower, wheat, mustard, germination, seedling growth, ABA Summary In this work the influence of sunflower allelochemicals on germination, seedling vigour and ABA levels was studied. Wheat and mustard seeds and seedlings were incubated on Petri dishes (mustard) layered with filter paper or rolled filter paper (wheat) moistened with aqueous extract of sunflower (2.5, 5.0 and 10.0% DM w/v) or water at 20 C for 6 days. In 1 st experiment, number of germinating seeds was counted and samples for ABA were collected. In 2 nd experiments, number of roots was counted (wheat) and length and fresh weights of coleoptiles/hypocotyls and roots were recorded. In response to allelopathics germination was delayed and reduced but germination of wheat was slightly affected, while of mustard extremely reduced (to 90%). Allelopathic effect on seedling growth was diverse: at lower concentration stimulatory, and at higher inhibitory. At highest concentration growth of mustard was almost completely inhibited while wheat seedlings continue to grow though, their vigour was strongly reduced. ABA levels in response to allelopathics increased manifold and the increase was greater in roots. This suggests ABA involvement in seedlings acclimation to allelopathy stress. Results showed essential differences between wheat and mustard in tolerance to sunflower allelopathics with wheat being more tolerant. 8

9 WPLYW ALLELOPATYCZNYCH WLASCIWOSCI SLONECZNIKA NA KIELKOWANIE I WZROST SIEWEK PSZENICY I GORCZYCY Waldemar Bernat 1, Helena Gawronska 1, Franciszek Janowiak 2, Stanislaw W. Gawronski 1 1 Katedra Sadownictwa i Przyrodniczych Podstaw Ogrodnictwa, Nowoursynowska Warszawa, Polska 2 Instytut Fizjologii Roslin. Polska Nauk, Podluzna 3, Kraków, Polska Slowa kluczowe: allelopatia, slonecznik, pszenica, gorczyca, kielkowanie, wzrost siewek, ABA Streszczenie Celem badan byla ocena wplywu allelozwiazków zawartych w wodnych wyciagach slonecznika na: (i) kielkowanie, (ii) wigor siewek i (iii) poziom ABA w siewkach. Nasiona pszenicy ozimej odm. Zyta oraz gorczycy odm. Nakielska kielkowaly na szalkach Petriego (gorczyca) oraz w zrolowanych paskach bibuly zwilzanych 7mL wody destylowanej (kontrola) lub wyciagami z lisci slonecznika w stezeniach 2.5, 5.0 i 10.0% w temperaturze 20 0 C w ciemnosci. Po 6-sciu dniach w doswiadczeniu 1-szym zliczano nasiona kielkujace i pobrano próby do oznaczen poziomu kwasu abscysynowego, a w doswiadczeniu 2-gim liczono korzenie (pszenica), mierzono dlugosc koleoptyla (pszenica), hypokotyla (gorczyca), oraz korzeni i wazono ciezar tych organów. W obecnosci allelozwiazków slonecznika stwierdzono opóznienie oraz istotna redukcje zdolnosci kielkowania u gorczycy (az o 90%) natomiast u pszenicy efekt ten byl znikomy. Wigor siewek byl, zaleznie od stezenia, zarówno stymulowany jak i zmniejszany, z tym ze w najwyzszym stezeniu wzrost siewek gorczycy byl niemal zupelnie zahamowany a pszenicy tylko zredukowany. Poziom ABA byl wielokrotnie wyzszy w siewkach traktowanych zwlaszcza w korzeniach, co wskazuje na udzial ABA w reakcjach obronnych przed stresem allelopatii. Badania wykazaly, ze pszenica cechuje sie wyraznie wyzsza niz gorczyca tolerancja allelozwiazków zawartych w wodnych wyciagach slonecznika. 9

10 Dr hab. Helena Gawronska, prof. nadzwyczajny SGGW Katedra Sadownictwa i Przyrodniczych Podstaw Ogrodnictwa Szkola Glówna Gospodarstwa Wiejskiego ul. Nowoursynowska Warszawa Table 1. Root growth of winter wheat (Triticum aestivum L.) cv. Zyta and of mustard (Sinapis alba L.) cv. Nakielska as influenced by allelochemicals derived from sunflower (Helianthus annuus L.) cv. Lech. Data are mean ± SE, n = 4 Tabela 1. Wzrost korzeni pszenicy ozimej (Triticum aestivum L.) odm. Zyta pod wplywem substancji allelopatycznych zawartych w sloneczniku (Helianthus annuus L.) odm. Lech. Dane przedstawiaja srednie z 4 powtórzen ± SE. Extract concentration % DM w/v Stezenie ekstraktu % s.m. g/v Roots number Average root length Total root length (Liczba korzeni) (Srednia dlugosc korzenia) (Laczna dlugosc korzeni) N o seedling -1 (N o siewka -1 ) mm root -1 (mm korzen -1 ) mm seedling -1 (mm siewka 1 ) wheat (pszenica) mustard (gorczyca) wheat (pszenica) mustard (gorczyca) wheat (pszenica) mustard (gorczyca) 0.0 (Control) 3, ,27-231,66 44, , ,71-296,87 62, , ,27-176,35 36, , ,69-68,19 1,00 10

11 Figure 1. Germination of winter wheat (Triticum aestivum L.) cv. Zyta in the presence of allelochemicals contained in aqueous extract of sunflower. Data are mean ± SE, n=4 Wykres 1. Kielkowanie nasion pszenicy ozimej (Triticum aestivum L.) odm. Zyta w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika Dane przedstawiaja srednie z 4 powtórzen ± SE. Figure 2. Germination of mustard (Sinapis alba L.) cv. Nakielska in the presence of allelochemicals contained in aqueous extract of sunflower. Data are mean ± SE, n=4. Wykres 2. Kielkowanie nasion gorczycy bialej (Sinapis alba L.) odm. Nakielska w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 4 powtórzen ± SE. Figure 3. Length of winter wheat (Triticum aestivum L.) cv. Zyta seedlings as influenced by allelochemicals derived from sunflower. Data are mean ± SE, n=4. Wykres 3. Dlugosc siewek pszenicy ozimej (Triticum aestivum L.) odm. Zyta rozwijajacych sie w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 4 powtórzen ± SE. Figure 4. Length of mustard (Sinapis alba L.) cv. Nakielska seedlings as influenced by allelochemicals derived from sunflower. Data are mean ± SE, n=4. Wykres 4. Dlugosc siewek gorczycy (Sinapis alba L.) odm. Nakielska, rozwijajacych sie w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 4 powtórzen ± SE. Figure 5. Fresh matter of winter wheat (Triticum aestivum L.) cv. Zyta seedlings as influenced by allelochemicals derived from sunflower. Data are mean ± SE, n=4. Wykres 5. Swieza masa siewek pszenicy ozimej (Triticum aestivum L.) odm. Zyta rozwijajacych sie w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 4 powtórzen ± SE. Figure 6. Fresh matter of mustard (Sinapis alba L.) cv. Nakielska, seedlings as influenced by allelochemicals derived from sunflower. Data are mean ± SE, n=4. 11

12 Wykres 6. Swieza masa siewek gorczycy (Sinapis alba L.) odm. Nakielska, rozwijajacych sie w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 4 powtórzen ± SE. Figure 7. Concentration of ABA in winter wheat (Triticum aestivum L.) cv. Zyta seedlings cultured in the presence of sunflower allelopathics. Data are mean ± SE, n=12. Wykres 7. Zawartosc ABA w siewkach pszenicy ozimej (Triticum aestivum L.) odm. Zyta rozwijajacych sie w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 12 powtórzen ± SE. Figure 8. Concentration of ABA in mustard (Sinapis alba L.) cv. Nakielska seedlings cultured in the presence of sunflower allelopathics. Data are mean ± SE, n=12. Wykres 8. Zawartosc ABA w siewkach gorczycy bialej (Sinapis alba L.) odm. Nakielska rozwijajacych sie w obecnosci substancji allelopatycznych zawartych w wodnych wyciagach slonecznika. Dane przedstawiaja srednie z 12 powtórzen ± SE. 12

13 100 HSD 0,05 = Germination (%)cc Kielkowanie (%) Extract concentration (% DM w/v) Stezenie ekstraktu (% s.m. g/v) 13

14 100 HSD 0.05 = Germination (%)cc Kielkowanie (%) Extract concentration (% DM w/v) Stezenie ekstraktu (% s.m. g/v) 14

15 400 HSD 0,05 = (coleoptile, koleoptyl) HSD 0,05 = (roots, korzenie) Length (mm seedling -1 ) Dlugosc (mm siewka -1 ) Extract concentration (% DM w/v) Stezenie ekstraktu % (s.m. g/v) Coleoptile (Koleoptyl) Whole seedling (Cala siewka) Roots (Korzenie) 15

16 HSD 0,05 = 9.49 (hypocotyls, hypokotyl) HSD 0,05 = 9.58 (root, korzen) Length (mm seedling -1 ) Dlugosc (mm siewka -1 ) Extract concentration (% DM w/v) Stezenie ekstraktu (% s.m. g/v) Hypocotyls (Hypokotyl) Root (Korzen) Whole seedling (Cala siewka) 16

17 HSD 0,05 = (roots, korzenie) HSD 0,05 = (coleoptile, koleoptyl) FM (mg seedling -1 ) Swieza masa (mg siewka -1 ) Extract concentration (% DM w/v) Stezenie ekstraktu (% s.m. g/v) Coleoptile (Koleoptyl) Roots (Korzenie) Whole seedling (Cala siewka) 17

18 60 50 HSD 0,05 = 8.86 (hypocotyls, hypokotyl ) HSD 0,05 = 3.52 (root, korzen) FM (mg seedling -1 ) Swieza masa (mg siewka -1 ) Extract concentration (% DM w/v) Stezenie ekstraktu (% s.m. g/v) Hypocotyls (Hypokotyl) Root (Korzen) Whole seedling (Cala siewka) 18

19 HSD 0,05 = (coleoptile, koleoptyl) HSD 0,05 = (roots, korzenie) ABA (pmol g -1 FM) ABA (pmol g -1 s.m.) Extract concentration (% DM w/v) Stezenie ekstraktu (% s.m. g/v) Coleoptile (Koleoptyl) Roots (Korzenie) 19

20 2500 HSD 0,05 = (hypocotyls, hypokotyl) 2000 ABA (pmol g -1 FM) ABA (pmol g -1 s.m.) HSD 0,05 = (root, korzen) Control Extract concentration (% DM w/v) Stezenie ekstraktu % s.m. g/v) Hypocotyls (Hypokotyl) Root (Korzen) 20