S. Afr. J. Bot. , 1987,53(2): 125 - 128 125

Effects of seaweed concentrate on grain yield in barley

B.C. Featonby-Smith and J. van Staden* UNICSIR Research Unit for Plant Growth and Development, Department of Botany, University of Natal, Pietermaritzburg,

3200 Republic of South Africa

Accepted 14 November 1986

Winter barley (Hordeum vulgare L. cv. Clipper) was grown in pots in a growth chamber providing 12-h photoperiods and diurnal temperatures of 17/10°C. Seaweed concentrate was applied as a foliar spray and soil drench at dilutions of 1 :250 and 1 :500 two weeks after seedling emergence and as a seed dip (1 :250) prior to planting. Grain mass per plant was increased in the order of 50% irrespective of the concentration of seaweed concentrate applied or whether applied as a foliar spray or soil drench. The increase was largely due to a greater number of fertile spikelets per ear. The total nitrogen content of the seed produced by seaweed-treated plants remained within the parameters laid down by the malting industry.

Gars (Hordeum vulgare L. cv. Clipper) is in potte in 'n groeikamer met 'n ligperiode van 12 uur en 'n dag/nag­temperatuur van 17/10°C gekweek. Seewierkonsentraat is aangewend as 'n blaarbespuiting en grondbenatting by verdunnings van 1 :250 en 1 :500 twee weke na saailingverskyning en as 'n saad-dompeling (1 :250) voor planting . Graanopbrengs per plant is in die omgewing van 50% verhoog ongeag van die konsentrasie en of seewier konsentraat as 'n grondbenatting of blaarbespuiting aangewend is. Hierdie verhoging was grootliks toe te skryf aan 'n groter aantal vrugbare blompakkies per aar. Die stikstofgehalte van die graankorrels van seewierbehandelde plante was binne die perke wat deur die bierbrouersindustrie vereis word.

Keywords: Hordeum vulgare, seaweed concentrate

*To whom correspondence should be addressed

Introduction Variation in the yield of barley is closely correlated with variation in grain number (Gallagher et al. 1975; Willey & Holliday 1971; Williams & Hayes 1977) and must therefore depend on variation in the number of shoots which survive to produce ears and on the mean number of fertile spikelets per ear (Williams & Cartwright 1980). The selective survival of the dominant tillers and spikelets is thought to be a hormone-controlled phenomenon (Langer et al. 1973), re­gulated in vitro through the maintenance of 'priority sinks' monopolizing a limiting supply of cytokinins originating in the roots. The involvement of cytokinins in nutrient mobi­lization has been established (Mothes & Engelbrecht 1961; Luckwill 1977). It has been suggested that the presence of high levels of cytokinins in reproductive organs (Letham 1973; Davey & Van Staden 1977; Summons et al. 1980; Van Staden & Dimalla 1980) may be associated with nutrient mobilization (Wareing & Seth 1967). Mothes & Engelbrecht (1%1) showed that sugars and amino acids could be transported preferentially to regions of high cytokinin activity. Thus, if the cytokinin supply is augmented either through an improved nutritional status or by feeding exogenous cytokinins more and/or larger sinks could result (Williams & Cartwright 1980). The beneficial effects of cytokinins on spring wheat (Herzog & Geisler 1977) and on barley (Ruckenbauer & Kirby 1973; Williams & Cartwright 1980) are consistent with such an hypothesis.

The presence of cytokinins in extracts and/or concentrates prepared from marine algae (Brain et al. 1973; Featonby­Smith & Van Staden 1983a, 1984b; Tay et al. 1985) and the implication of this group of hormones in the response of plants to seaweed application is well documented (Booth 1966; Blunden & Wildgoose 1977; Blunden et al. 1978; Featonby­Smith & Van Staden 1983a, 1983b). This investigation con­centrated on the effects of seaweed concentrate (Kelpak 66), on grain yield and quality in winter barley.

Materials and Methods Barley (Hordeum vulgare L. cv. Clipper) plants were grown in a growth chamber providing 12-h photoperiods and diurnal temperatures of 171l0°C. Three seeds, thinned to one plant per pot at emergence were grown in 1,0 dm - 3 pots. The potting medium used was sand:loam (1 :2). Each pot was fertilized 1 week after germination and every 2 weeks thereafter with a liquid fertilizer containing 11070 nitrogen, 7,3% phosphorus and 3,7% potassium. The pots were arranged in a randomized block design with ten replicates per treatment.

The trial consisted of five treatments, these were (1) 20 cm3

of a 1 :250 dilution of seaweed concentrate plus Tween 20 (0,25%) applied as a foliar spray 2 weeks after emergence of the seedlings, (2) 20 cm3 of a 1 :500 dilution of seaweed concentrate plus Tween 20 (0,25%) applied as a foliar spray 2 weeks after emergence, (3) 100 cm3 of a 1:250 dilution of seaweed concentrate applied directly to the soil as a single application 2 weeks after emergence, (4) 100 cm3 of a 1:500 dilution of seaweed concentrate applied as a single application directly to the soil 2 weeks after emergence of the seedlings, (5) seeds were dipped for 1 hour prior to planting in a 1 :250 dilution of seaweed concentrate, (6) control, plants received 20 cm3 water plus Tween 20 as a foliar spray 2 weeks after emergence, (7) control, plants received a single application of 100 cm3 water applied directly to the soil two weeks after emergence, (8) control, seeds were dipped in water for 1 hour prior to planting.

Plant material was harvested ± 4 months after planting. After harvesting, the mass of the plant parts was determined. Least significant differences (P < 0,05) for all data were biometrically calculated (Rayner 1967). The results obtained from the various control treatments were not significantly different from one another and are thus considered as a single treatment.

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Nitrogen determination The total nitrogen content of malted seed from the various treatments was determined using a method adapted from Ballentine (1957). Analyses were performed in the laboratories of Southern Associated Maltsters (Pty) Limited, Caledon, South Africa.

Results Irrespective of whether seaweed concentrate was applied as a foliar spray, soil drench or seed treatment prior to planting, a ± 500/0 increase in grain yield over the control plants was recorded (Table 1). Grain yield was greatest in those plants which received seaweed concentrate at a dilution of 1 :500 applied directly to the soil (Table 1). Although the number of ears produced by these plants did not increase significantly (Table 2), the grain mass per ear and the number of grains per ear showed an increase over the controls of 52% and 36% respectively (Tables 1 & 2). Grain mass per ear was even greater in those plants which received seaweed concentrate at a dilution of 1 :500 applied as a foliar spray (Table 1). Plants from this treatment also produced significantly more grains per ear (35%) than did the control plants (Table 2). Seaweed concentrate at a dilution of 1 :250, irrespective of whether it was applied directly to the soil, as a foliar spray or seed dip, resulted in significant increases in grain yield over the control plants (Table 1). The number of grains and grain mass per ear were, however, not significantly different from the controls (Tables 1 & 2). Of importance was the fact that the number of ears produced by these plants was significantly higher than both the control and those plants which received seaweed concentrate at a 1 :500 dilution (Table 2).

Table 3 shows the total nitrogen content of the grain from the various treatments. It is evident from these results that when seaweed concentrate was applied, there was a reduction in the total nitrogen content of the seed produced. The moisture content of the seed from the various treatments remained unchanged (Table 3).

S.-Afr. Tydskr. Plantk., 1987, 53(2)

Table 2 The effect of seaweed concentrate appli­cations on the grain yield of H. vulgare plants. Means for the parameter measured followed by the same letter do not differ Significantly (P < 0,05). Figures in brackets represent percentage increase over the control

Parameter

No. of No. of 070 fertile No. of spikelets grains spikelets

Treatment ears ear- I ear- I ear- I

Control 2,4a IS,7a 1O,9a 5S Seaweed concentrate 3,4bc 16,7a 12,9a 77 (I :250) foliar (41) (IS)

Seaweed concentrate 2,Sa 17,9a 14,Sb S2 (I :500) foliar (16) (35)

Seaweed concentrate 3,6c 17,5a 12,Ia 6S (I :250) soil (50) (10)

Seaweed concentrate 2,6a IS,2a 14,9b SI (I : 500) soil (S) (36)

Seaweed concentrate 3,Ob 16,9a 14,Ia S2 (I :250) seed dip (25) (2S)

Total x ± SE 2,96±O,23 17,7± 1,01 13,3 ± 1,32

Discussion The seaweed concentrate used in this investigation caused a substantial increase in grain yield irrespective of whether it was applied as a foliar spray, soil drench or seed dip. Although the controls did not receive the additional micro nutrients present in seaweed preparations, they were apparently not nutrient deficient as there were no significant differences in straw yield and total shoot mass between the control and the treatments.

The presence of cytokinins, auxins and gibberellins in

Table 1 The effect of seaweed concentrate applications on grain dry mass (g) of H. vulgare plants. Means for the parameter measured followed by the same letter do not differ Significantly (P < 0,05). Figures in brackets represent percentage increase over the controls

Parameter

Grain Grain Straw Individual mass mass mass Total shoot

Treatment grain mass ear- I plant - I plant - I mass plant - I

Control O,063a 0,69a 1,71a 2,06a 3,76a Seaweed concentrate O,063a O,Sla 2,64b 1,90a 4,54a (I :250) foliar (0) (17) (54) (20)

Seaweed concentrate O,075a I,lIb 2,59b 1,73a 4,39a (I :500) foliar (19) (60) (51) (17)

Seaweed concentrate O,070a O,S4a 2,54b l,85a 4,39a (I :250) soil (II) (21) (4S) (17)

Seaweed concentrate O,070a 1,05b 2,67b 1,61a 4,27a (I :500) soil (II) (52) (56) (14)

Seaweed concentrate O,06Sa O,95a 2,59b 1,63a 4,23a (I :250) seed dip (S) (37) (51) (12)

Total x ± SE O,9I±O,II 2,44±O,23 I,S±0,I6 4,27±O,32

S. Afr. 1. Bot., 1987, 53(2)

Table 3 Concentration of nitrogen and the moisture content of the grain from plants treated with seaweed concentrate

Treatment

Control Seaweed concentrate (I :250) foliar Seaweed concentrate (I :500) foliar Seaweed concentrate (I :250) soil Seaweed concentrate (I :500) soil Seaweed concentrate (I :250) seed dip

Parameter

Moisture Nitrogen content (OJo) content (OJo)

12,1 12,0 11,9 12,1 12,2 12,0

1,68 1,59 1,40 1,46 1,48 1,41

seaweed extracts is reasonably well documented (Abetz 1980), while cytokinins (Blunden & Wildgoose 1977; Booth 1966; Featonby-Smith & Van Staden 1983a & b, 1984a) and ethylene (Nelson & Van Staden 1984) have been implicated in the response of plants to seaweed concentrate application. Pre­vious studies have shown that when foliar applications of benzyladenine (10- 5 M) a synthetic cytokinin and seaweed concentrate (1 :500 dilution) were applied to barley plants grown in liquid culture, similar yield responses were achieved (unpublished data). The presence of relatively high concen­trations of cytokinins in the seaweed concentrate used in this investigation (Featonby-Smith & Van Staden 1983a) and the similarity between the results achieved here and those obtained when cytokinins were applied to barley plants (Williams & Cartwright 1980) suggests the possible involvement of this group of hormones in the responses observed. In addition, research has shown that foliar applications of seaweed con­centrate to bean plants (Featonby-Srnith & Van Staden 1984a) resulted in high levels of cytokinin activity detected within the fruit. It was postulated that a direct correlation exists between the increase in fresh mass of the fruits of treated plants and the high levels of cytokinin activity detected within these fruits. These results are in agreement with those of Jameson eta!. (1982) who showed that peaks of cytokinin activity within the developing grains of wheat corresponded closely with sub­sequent cell division within the developing endosperm and the phase of rapid starch accumulation. Although the cytokinin levels within the grain of barley plants were not determined, the increase in the number of fertile spikelets and the overall grain yield would suggest the possible involvement of this group of hormones in he responses observed in plants treated with seaweed concentrate. The significant increase in the number of fertile tillers produced by those plants which received seaweed concentrate applications at dilutions of 1:250 and 1 :500 could be a cytokinin-related phenomenon. It has been demonstrated in other plants and tissues that applications of a synthetic cytokinin not only caused buds to be initiated (Skoog & Miller 1957; Schraudolf & Reinert 1959) but will also release buds that are inhibited (Wickson & Thimann 1958; Sachs & Thimann 1967).

It was significant that although grain yield was improved whenever seaweed concentrate was applied, the moisture content of grains remained unchanged and the total nitrogen levels remained low, which is essential for a good quality malting barley.

Acknowledgements The Council for Scientific and Industrial Research are ack­nowledged for their financial assistance, and Mrs I. Esbach,

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Southern Associated Maltsters (Pty.) Limited, Caledon, 7230 South Africa, for conducting the nitrogen analyses.

References ABETZ, P . 1980. Seaweed extracts, have they a place in

Australian agriculture or horticulture? J. Aust. Jnst. Agric. Sci. 46: 23-29.

BALLENTINE, R. 1957. Determination of total nitrogen and ammonia. Methods Enzymol. 3: 984-995.

BLUNDEN, G., JONES, E.M. & PASSAM, H.C. 1978. Effects of post-harvest treatment of fruit and vegetables with cytokinin­active seaweed extracts and kinetin solutions. Bot. Mar. 21: 237-240.

BLUNDEN, G. & WILDGOOSE, P .B. 1977. The effects of aqueous seaweed extract and kinetin on potato yields. J. Sci. Food Agric. 28: 121- 125.

BOOTH, E. 1966. Some properties of seaweed manures. Proc. 5th Int. Seaweed Symp. pp. 349- 357, Pergamon Press, London.

BRAIN, K.R., CHALOPIN, M.C., TURNER, T.D., BLUNDEN, G. & WILDGOOSE, P .B. 1973. Cytokinin activity of commercial aqueous seaweed extract. Plant Sci. Lett. I: 241-245.

DAVEY, J .E. & VAN STADEN, J. 1977. A cytokinin complex in the developing fruits of Lupinus a/bus. Physiologia Pl. 39: 221-224.

FEATONBY-SMITH, B.C. & VAN STADEN, J. 1983a. The effect of seaweed concentrate on the growth of tomatoes in nematode infested soil. Sci. Hortic. 20: 137 - 146.

FEATONBY-SMITH, B.C. & VAN STADEN, J. 1983b. The effect of seaweed concentrate and fertilizer on the growth of Beta vulgaris. Z. Pjlanzenphysiol. 112: 155- 162.

FEATONBY-SMITH, B.C. & VAN STADEN, J. 1984a. The effect of seaweed concentrate and fertilizer on growth and the endogenous cytokinin content of Phaseolus vulgaris. S. Afr. J. Bot. 3: 375-379.

FEATONBY-SMITH, B.C. & VAN STADEN, J . 1984b. Identification and seasonal variation of endogenous cytokinins in Ecklonia maxima (Osbeck) Papenf. Bot. Mar. 27: 527- 531.

GALLAGHER, J.N., BISCOE, P.V. & SCOTI, R.K . 1975. Barley and its environment. V. Stability of grain weight. J. Appl. Ecol. 12: 319 - 336.

HERZOG, H. & GEISLER, G. 1977. Der einfluss von Cytokininapplikation auf die Assimilateintagerung und die endogene Cytokininaktivitiit der Karyopsen bei zwei Sommerweizensorten. Z. Acker- und Pjlanzenbau. 144: 230 - 242.

JAMESON, P.E., McWHA, J.A. & WRIGHT, G.J. 1982. Cytokinins and changes in their activity during the development of grains of wheat (Triticum aestivum L.). Z. Pjlanzenphysiol. 106: 27-36.

LANGER, R.H.M., PRASAD, P .C. & LAUDE, H.M. 1973. Effects of kinetin on tiller bud elongation in wheat (Triticum aestivum L.). Ann. Bot. 37: 565-571.

LETHAM, D.S. 1973. Cytokinins from Zea mays. Phytochem. 12: 2445-2455.

LUCKWILL, L.C. 1977. Growth regulators in flowering and fruit development. In: Pesticide chemistry in the 20th century, eds. Plimmer, J.R. pp. 293-304, A.C.S. Symposium Series.

MOTHES, K. & ENGELBRECHT, L. 1961. Kinetin induced directed transport of substances in excised leaves in the dark. Phytochem. 1: 58-62.

NELSON, W.R. & VAN STADEN, J. 1984. The effect of seaweed concentrate on wheat culms. J. Plant Physiol. 115: 433-437.

RAYNER, A.A. 1967. A first course in biometry for agricultural students, pp. 203-219, University of Natal Press, Pietermaritzburg, South Africa.

RUCKENBAUER, P. & KIRBY, E.J.M. 1973. Effects of kinetin on the growth and development of barley and its interaction with root size. J. Agric. Sci. Camb. 80: 211-217.

SACHS, T. & THIMANN, K.V. 1967. The role of auxins and cytokinins in the release of buds from dominance. Am. J. Bot. 54: 136-144.

SCHRAUDOLF, H. & REINERT, J. 1959. Interaction of plant growth regulators in regeneration processes. Nature 184: 465-466.

128

SKOOG, F. & MILLER, C.O. 1957. Chemical regulation of growth and organ formation in plant tissues cultured in vitro. Soc. Exptl. BioI. Symp. 11: 118 - 131.

SUMMONS, R.E. , ENTSCH, B., LETHAM, D.S., GOLLNOW, B.!.P., MACLEOD, 1.K. 1980. Metabolites of zeatin in sweetcorn kernels: purification and identification using HPLC and chemical-ionization mass spectrometry. Planta 147: 422 - 434.

TAY, S.A.B., MACLEOD, 1.K., PALNl, L.M .S. & LETHAM, D.S. 1985. Detection of cytokinins in seaweed extract. Phytochem. 24: 2611-2614.

VAN STADEN, 1. & DIMALLA, G.G. 1980. The effect of silver thiosulphate preservative on the physiology of cut carnations. II . Influence of endogenous cytokinins. Z. Pflanzenphysiol. 99: 19 - 26.

S.-Afr. Tydskr. Plantk ., 1987, 53(2)

WAREING, P.F. & SETH, A.K. 1967. Ageing and senescence in the whole plant. Symp. Soc. expo BioI. 21 : 543 - 548.

WICKSON, M.E . & THIMANN, K.V. 1958. The antagonism of auxin and kinetin in apical dominance. Physiologia PI. II : 62 - 74.

WILLEY, R.W. & HOLLIDAY, R. 1971. Plant population and shading studies in barley. 1. Agric. Sci. Camb. 77: 445 - 452.

WILLIAMS, R.H . & CARTWRIGHT, P .M. 1980. The effect of applications of synthetic cytokinin on shoot dominance and grain yield in spring barley. Ann. Bot. 46: 445 - 452.

WILLIAMS, R.H . & HAYES, 1.D. 1977. The breeding implications of studies on yield and its components in contrasting genotypes of spring barley. Cereal Res. Commun . 5: 113 - 118.