Significance of betaines in the increased chlorophyll content of plants treated with seaweed extract

Seaweed extract, prepared by alkaline extraction of Ascophyllum nodosum (L.) Le Jol., applied either to the soil or to the foliage of tomato plants, produced leaves with higher chlorophyll levels than those of control plants. The effects on leaf chlorophyll content were investigated using a cucumber bioassay procedure devised for cytokinins. The seaweed extract was shown to increase the chlorophyll levels of the cucumber cotyledons, but ‘peaks’ of activity were obtained when widely different concentrations were used. The possibility that these effects were the result of betaines present in the extract was considered. Glycinebetaine, γ-aminobutyric acid betaine and δ-aminovaleric acid betaine all produced significantly enhanced chlorophyll concentrations in the cotyledons. ‘Peaks’ of activity were observed for each betaine: for glycinebetaine at 10⁻⁶ and between 10⁻⁴ and 10¹ mg 1⁻¹, for γ-aminobutyric acid betaine at 10⁻⁶, between 10⁻⁴ and 10⁻¹, and 10¹ mg 1⁻¹, and for δ-aminovaleric acid betaine between 10⁻⁵ and 10¹ mg 1⁻¹. It was concluded that the effects of enhancing chlorophyll levels produced by the seaweed extract were due, at least in part, to betaines.     

Enhanced leaf chlorophyll levels in plants treated with seaweed extract

Application to the soil of an aqueous alkaline extract ofAscophyllum nodosum resulted in higher concentrations of chlorophyll in the leaves of treated plants in comparison to control plants treated with an equivalent volume of water. Positive results were obtained with all species tested (tomato, dwarf French bean, wheat, barley, maize). When the seaweed extract was applied as a foliar spray, similar effects on leaf chlorophyll contents were obtained, except in the case of dwarf French bean plants, for which no significant difference was recorded between test and control plants. When the betaines present in the seaweed extract were applied as a mixture in the same concentrations as those in the diluted seaweed extract (-aminobutyric acid betaine 0.96 mg L^–1, -aminovaleric acid betaine 0.43 mg L^–1, glycinebetaine 0.34 mg L^–1), very similar leaf chlorophyll levels were recorded for the seaweed extract and betaine treated plants. This suggests strongly that the enhanced leaf chlorophyll content of plants treated with seaweed extract is dependent on the betaines present.     

Improved methods of analysis for betaines in <Emphasis Type="Italic">Ascophyllum nodosum</Emphasis> and its commercial seaweed extracts

Beneficial effects of seaweeds and their extracts on crop performance have been attributed to a variety of compounds, including the betaines which are quaternary ammonium betaines. Methods of analysis of betaines published thus far suffer from low sensitivity, lack of baseline separation of individual betaines and from interference from other sample constituents. A rapid cleanup protocol and a sensitive LC-MS/MS method of analysis were developed to afford baseline separation of four betaines in the brown alga Ascophyllum nodosum and its commercial seaweed extract. Using this method, the presence of glycine betaine, δ-aminovaleric acid betaine, γ-aminobutyric acid betaine and laminine in A. nodosum, and commercial extracts derived from A. nodosum, were confirmed and quantified. The major betaine present was γ-aminobutyric acid betaine accounting for 0.008–0.014% of the dry weight of the seaweed and 0.014–0.027% of the dry weight of the commercial extracts. Seasonal variation in betaine content was observed. Differences in the total betaine content were observed between A. nodosum of the yellow (0.011–0.017% dry weight) and the olive green (0.017–0.021% dry weight) coloured morphologies.     

The effects of seaweed extract inclusion on gut morphology, selected intestinal microbiota, nutrient digestibility, volatile fatty acid concentrations and the immune status of the weaned pig

An experiment (complete randomised design) was conducted to investigate the effects of Laminaria hyperborea and Laminaria digitata seaweed extract inclusion on gut morphology, selected intestinal microbiota populations, volatile fatty acid concentrations and the immune status of the weaned pig. Twenty-eight piglets (24 days of age, 6.5 ± 1.4 kg live weight) were assigned to one of four dietary treatments for 7 days and then sacrificed: (T1) basal diet (control); (T2) basal diet and 1.5 g/kg L. hyperborea seaweed extract; (T3) basal diet and 1.5 g/kg L. digitata seaweed extract; and (T4) basal diet and 1.5 g/kg of a combination of L. hyperborea and L. digitata seaweed extract. The seaweed extract contained both laminarin and fucoidan. Digesta samples were taken from the caecum and colon to measure the enterobacteria, bifidobacteria and lactobacilli populations and for volatile fatty acid analysis. Tissue samples were taken from the duodenum, jejunum and ileum for morphological examination. Blood samples were taken to determine the cytokine gene expression profile and to measure the phagocytotic capacity of the blood. Pigs offered diets containing L. hyperborea seaweed extract had less bifidobacteria in the colon (P < 0.05) and lactobacilli in the caecum (P < 0.05) and colon (P < 0.001). The inclusion of L. digitata seaweed extract resulted in lower populations of enterobacteria in the caecum and colon (P < 0.01), bifidobacteria in the caecum (P < 0.05), and lactobacilli in the caecum (P < 0.05) and colon (P < 0.001). Pigs offered the combination of L. hyperborea and L. digitata seaweed extracts had less enterobacteria (P < 0.05) and lactobacilli (P < 0.01) in the caecum and colon. Pigs offered the L. digitata-supplemented diet had a reduced villous height in the duodenum and jejunum (P < 0.05). The inclusion of the L. digitata seaweed extract increased the molar proportion of butyric acid in the colon (P < 0.05). There was a significant reduction in the ammonia concentration in the colon with the inclusion of L. hyperborea (P < 0.01) and L. digitata (P < 0.05) seaweed extracts. An increase in the expression of the Interleukin-8 mRNA was observed on day 6 with the supplementation of the combination of L. hyperborea and L. digitata seaweed extract (P < 0.05). The inclusion of L. hyperborea seaweed extract resulted in an increase in total monocyte number (P < 0.05). In conclusion, the supplementation of L. hyperborea and L. digitata seaweed extract alone and in combination reduced the enterobacteria, bifidobacteria and lactobacilli populations in the caecum and colon, while only marginal effects on the immune response was observed.     

Effect of seaweed concentrate on hydroponically grown spring barley

Spring barley (Hordeum vulgare cv. Triumph) was grown hydroponically over a 6-week period. Two treatments were incorporated either into the hydroponic solution or sprayed onto the plants at rates of 1 ml per 3 litres. The treatments applied were: (i) a seaweed concentrate prepared fromAscophyllum nodosum (L.) Le Jolis (marketed as Maxicrop Triple), (ii) a ‘Trace element’ treatment incorporating the micro and macro nutrients added to the seaweed extract base to produce the formulated product Maxicrop Triple and (iii) a control treatment. Irrespective of the mode of application, plants treated with Maxicrop Triple grew faster than plants under either of the two other treatments. Elevated growth rates were also found for the ‘Trace element’ treated plants when incorporated into the hydroponic solution. At the final harvest, plants with Maxicrop Triple incorporated into the hydroponic solution showed increases from 56–63% over the control treatment for the growth characteristics measured. ‘Trace element’-treated plants produced increases of between 25–45%. When the treatments were sprayed the effect was less pronounced. Maxicrop Triple increased growth characters by 35–38% and the ‘trace element’ treatment gave increases in the range of 2–13%.     

Role of Kappaphycus alvarezii seaweed extract and its active constituents,glycine betaine,choline chloride,and zeatin in the alleviation of drought stress at critical growth stages of maize crop

Journal of Applied Phycology - Kappaphycus alvarezii seaweed extract (KSWE), an effective plant biostimulant, was investigated along with its active constituents, namely, glycine betaine (GB),...     

Strain selection and cell isolation of Ulvaria oxysperma (Kuetz.) Bliding (Chlorophyta) for net cultivation

North Carolina and Bermuda isolates of the green seaweed Ulvaria oxysperma (Kuetz.) Bliding were grown in cross-gradient light-temperature culture to determine the effects of varied photon fluence rates, temperature and photoperiod on their growth and reproduction. Results indicated significant genetic-based variation between the two populations. Spheroplast were obtained from the vegetative thallus of the North Carolina isolate following enzymatic digestion with abalone gut extract and maceration. Single cell isolates developed new cell walls in 2–3 days and attached to nylon net substrate. Cultured isolates regenerated into juvenile plants with normal development and morphology. Results are discussed in terms of the suitability of this economically important species for land-based mariculture.     

Evaluation of 28 marine algae from the Qingdao coast for antioxidative capacity and determination of antioxidant efficiency and total phenolic content of fractions and subfractions derived from Symphyocladia latiuscula (Rhodomelaceae)

The extracts obtained from 28 species of marine algae were evaluated for their antioxidant activity (AA) versus the positive controls butylated hydroxytoluene (BHT), gallic acid (GA), and ascorbic acid (AscA). Most of the tested samples displayed antioxidant activity to various degrees. Among them, the extract of Symphyocladia latiuscula exhibited the strongest AA, which was comparable to BHT, GA, and AscA in radical scavenging activity, as shown in the DPPH (α,α-diphenyl-β-picrylhydrazyl) assay, and higher than those of the positive controls in β-carotene-linoleate assay system. In addition, the ethyl acetate-soluble fraction isolated from the crude extract of S. latiuscula exhibited the highest antioxidant activity in both assay systems. This fraction was further fractionated into seven subfractions (F1-F7) by vacuum liquid chromatography (VLC). F1 and F4 were found to be the most effective subfractions in scavenging DPPH radical assay and in the β-carotene-linoleate assay, respectively. The total phenolic content (TPC) and reducing power (RP) for all of the extracts, fractions, and subfractions (F1–F7) were also determined. The TPC of the 28 extracts ranged from 0.10 to 8.00 gallic acid equivalents (mg/g seaweed dry weight) while the RP ranged from 0.07 to 11.60 ascorbic acid equivalents (mg·g⁻¹ seaweed dry weight). Highly positive relationships between AA and TPC as well as between AA and RP were found for the extracts and fractions, while for the subfractions F1–F7 only weak or no such relations were found. The results obtained from this study indicate that further analysis is needed of those marine algal species that contain the most antioxidant activity in order to identify the active principles.     

Betaine aldehyde dehydrogenase in sorghum.

The ability to synthesize and accumulate glycine betaine is wide-spread among angiosperms and is thought to contribute to salt and drought tolerance. In plants glycine betaine is synthesized by the two-step oxidation of choline via the intermediate betaine aldehyde, catalyzed by choline monooxygenase and betaine aldehyde dehydrogenase (BADH). Two sorghum (Sorghum bicolor) cDNA clones, BADH1 and BADH15, putatively encoding betaine aldehyde dehydrogenase were isolated and characterized. BADH1 is a truncated cDNA of 1391 bp. BADH15 is a full-length cDNA clone, 1812 bp in length, predicted to encode a protein of 53.6 kD. The predicted amino acid sequences of BADH1 and BADH15 share significant homology with other plant BADHs. The effects of water deficit on BADH mRNA expression, leaf water relations, and glycine betaine accumulation were investigated in leaves of preflowering sorghum plants. BADH1 and BADH15 mRNA were both induced by water deficit and their expression coincided with the observed glycine betaine accumulation. During the course of 17 d, the leaf water potential in stressed sorghum plants reached -2.3 MPa. In response to water deficit, glycine betaine levels increased 26-fold and proline levels increased 108-fold. In severely stressed plants, proline accounted for > 60% of the total free amino acid pool. Accumulation of these compatible solutes significantly contributed to osmotic potential and allowed a maximal osmotic adjustment of 0.405 MPa.     

Betaine Improves Freezing Tolerance in Wheat

The accumulation of the osmolyte betaine was found to be correlatedwith the development of freezing tolerance (FT) of two wheatcultivars where it increases by about three fold during thecold acclimation period. Exogenous betaine application resultedin a large increase in total osmolality mostly due to betaineaccumulation. Plants that accumulated betaine are more tolerantto freezing stress since a four day exposure to 250 mM betaineresulted in a LT₅₀ of –8°C (in spring wheat Glenlea)and –9°C (in winter wheat Fredrick) compared to –3°C(Glenlea) and –4°C (Fredrick) for control non-exposedplants. Betaine treatment (250 mM) during cold acclimation increasedFT in an additive manner since the LT₅₀ reached –14°C(Glenlea) and –22°C (Fredrick) compared to –8°C(Glenlea) and –16°C (Fredrick) for plants that arecold acclimated in the absence of betaine. These results showthat betaine treatment can improve FT by more than 5°C inboth non-acclimated and cold-acclimated plants. The betainetreatment resulted in the induction of a subset of low temperatureresponsive genes, such as the wcor410, and wcor413, that arealso induced by salinity or drought stresses. In addition tothese genetic responses, betaine treatment was also able toimprove the tolerance to photoin-hibition of PSII and the steady-stateyield of electron transport over PSII in a manner that mimickedcold-acclimated plants. These data also suggest that betaineimproves FT by eliciting some of the genetic and physiologicalresponses associated with cold acclimation. (Received April 23, 1998; Accepted September 4, 1998)     

Iota-carrageenan from a newly farmed, rare variety of eucheumoid seaweed—“endong”

A seaweed with the local name “endong” is a rare eucheumoid variety that has recently been farmed in Tawi-Tawi, southern Philippines. Local farmers describe it as “eel-like” because of its long, slender and smooth thalli. Being somewhat similar in appearance to the dominantly farmed seaweed “tambalang” (Kappaphycus alvarezii var. tambalangii), farmers mix their harvests of “endong” with those of “tambalang”. We analyzed the hydrocolloid extract from “endong” using spectroscopic and chemical techniques. The extract’s infrared and nuclear magnetic resonance (¹H and ¹³C) spectra, and sulfate and 3,6-anhydrogalactose contents revealed carrageenan of the iota-type, similar to extracts from another farmed species, Eucheuma denticulatum. This result implies that “endong” carrageenan exhibits physico-chemical properties different from those of kappa-carrageenan of “tambalang”. The findings of this study are of significance to the seaweed industry, as carrageenan quality problems could potentially arise from a mixed harvest. Seaweed farmers are advised to separate their harvests of “endong” and “tambalang”. Presented at the 19th International Seaweed Symposium, Kobe, Japan     

In vitro screening of seaweed extract on the proliferation of mouse spleen and thymus cell

A total number of 31 types of seaweed were assessed with regard to their effects on the proliferation of mouse spleen and thymus cells in a culture, using an MTT reduction assay. Acetone:dichloromethane (1∶1) extracts of three seaweed plants:Derbesia marina, Sargassum sp., andHisikia fuziformis, exhibited significantly positive effects on the survival of mouse spleen and thymus cellsin vitro. The acetone: dichloromethane (1∶1) extracts ofSargassum sp., in particular, much more potent effects on thymus cell activation than did any of the other types of seaweed. However, the methanol extracts ofSargassum ringgoldianium andChondrus crispus exerted a stimulatory influence only on the proliferation of mouse spleen cells, whereas the methanol extracts ofGrateloupia lanceolata exhibited significant cell proliferation properties in both spleen and thymus cells.     

大型海藻龙须菜抽提液对褶皱臂尾轮虫生命表参数的影响

大型海藻富含多种活性物质,具有抗衰老等生物活性;轮虫是良好的潜在抗衰老研究模式生物。本研究以褶皱臂尾轮虫(Brachionus plicatilis)作为实验对象,研究了不同浓度的大型海藻龙须菜抽提液(0,250,500,750,1000 mg/L)和不同浓度的食物(蛋白核小球藻和普通小球藻)对褶皱臂尾轮虫生命表参数的影响。结果表明:与对照组相比,食物浓度为1.0×10~6个/mL蛋白核小球藻时,不同浓度龙须菜抽提液对轮虫产卵数、平均寿命、净生长率以及世代时间有显著促进效应(P0.05);轮虫平均产卵数及寿命在龙须菜抽提液浓度750 mg/L处达到最高,分别为16只和13.9d(P0.05)。食物浓度为2.0×10~6个/mL普通小球藻时,轮虫平均产卵数和寿命在抽提液浓度为500 mg/L处达到最高,分别为16只和13.6d(P0.05),轮虫平均寿命和净生长率均有显著提高(P0.05)。相同龙须菜抽提液浓度下,食物浓度为1.0×10~6个/mL蛋白核小球藻下轮虫的净生长率、世代时间均显著高于食物浓度为2.0×10~6个/mL蛋白核小球藻培养的轮虫(P0.05);食物浓度为2.0×10~6个/mL时,普通小球藻培养轮虫的净生长率和世代时间均显著高于蛋白核小球藻实验组(P0.05)。交互作用分析显示,龙须菜抽提液与小球藻的交互作用对褶皱臂尾轮虫的内禀增长率有显著影响(P0.05)。研究结果表明,大型海藻龙须菜抽提液对褶皱臂尾轮虫的生长与生殖有促进作用,延长轮虫寿命。     

Protective effect of betaine on changes in the levels of lysosomal enzyme activities in heart tissue in isoprenaline-induced myocardial infarction in Wistar rats

Myocardial infarction is one of the most common manifestations of cardiovascular disease. In the present study, we investigated the protective effect of betaine, a potent lipotropic molecule, on changes in the levels of lysosomal enzymes and lipid peroxidation in isoprenaline-induced myocardial infarction in Wistar rats, an animal model of myocardial infarction in man. Male albino Wistar rats were pretreated with betaine (250 mg/kg body weight) daily for a period of 30 days. After the treatment period, isoprenaline (11 mg/100 g body weight) was intraperitoneally administered to rats at intervals of 24 h for 2 days. The activities of lysosomal enzymes (β-glucuronidase, β-galactosidase, β-glucosidase, and acid phosphatase) were significantly (p < 0.05) increased in plasma with a concomitant decline in the activities of these enzymes in heart tissue of isoprenaline-administered rats. Also, the level of lipid peroxidation was higher in heart lysosomes of isoprenaline-injected rats. Pretreatment with betaine daily for a period of 30 days to isoprenaline-induced rats prevented the changes in the activities of these lysosomal enzymes. Oral treatment with betaine (250 mg/kg body weight) to normal control rats did not show any significant effect in all the biochemical parameters studied. Thus, the results of our study show that betaine protects the lysosomal membrane against isoprenaline-induced myocardial infarction. The observed effects might be due to the free radical-scavenging and membrane-stabilizing properties of betaine.     

Isolation and biochemical characterization of collagens from seaweed pipefish, Syngnathus schlegeli

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the seaweed pipefish (Syngnathus schlegeli) and partially characterized. The amount of collagens isolated in the subsequent treatments was 5.5% of ASC and 33.2% PSC on the basis of lyophilized pipefish body weight, respectively. According to the electrophoretic pattern and CM-cellulose column chromatogram, the collagens might be classified as type I collagens, containing α1 and α2 chain. The imino acid content of collagen from pipefish was lower than those of mammalian collagens as also were the denaturation temperatures (Td) of collagens were 34.8°C and 35.1°C, respectively. This study shows that there is a possibility to use pipefish collagen as the alternative source of collagen from industrial purposes and subsequently it may evaluate the economical value of the seaweed pipefish.     

Performance of weanling piglets offered low-, medium- or high-lactose diets supplemented with a seaweed extract from Laminaria spp.

An experiment (3 × 4 factorial arrangement) was conducted to investigate the interaction between different levels of lactose (60 v. 150 v. 250 g/kg) and seaweed extract (0 v. 1 v. 2 v. 4 g/kg) containing both laminarin and fucoidan derived from Laminaria spp. on growth performance and nutrient digestibility of weanling pigs. In all, 384 piglets (24 days of age, 7.5 kg (s.d. 1 kg) live weight) were blocked on the basis of live weight and were assigned to one of 12 dietary treatments (eight replicates per treatment). Piglets were offered diets containing either low (60 g/kg), medium (150 g/kg) or high (250 g/kg) lactose levels with one of the following levels of seaweed extract additive: (1) 0 g/kg, (2) 1 g/kg, (3) 2 g/kg or (4) 4 g/kg seaweed extract. The pigs were offered the diets ad libitum for 21 days post weaning. There was a significant lactose × seaweed extract interaction (P < 0.05) in average daily gain (ADG) during the experimental period (days 0 to 21). At the low and medium levels of lactose, there was an increase in ADG as the level of seaweed extract increased to 2 g/kg (P < 0.05). However, at the high level of lactose there was no further response in ADG as the level of seaweed extract increased above 1 g/kg. There was a significant lactose × seaweed extract interaction during the experimental period (days 0 to 21) (P < 0.05) on the food conversion ratio (FCR). At the low level of lactose, there was a significant improvement in FCR as the levels of seaweed extract increased to 4 g/kg (P < 0.01). At the medium level of lactose, there was a significant improvement in FCR as seaweed extract increased to 2 g/kg. However, there was no significant effect of seaweed extract on FCR at the high levels of lactose (P > 0.05). There was a linear increase in average daily feed intake (ADFI) during the experimental period (days 0 to 21) (P < 0.05) as levels of seaweed extract increased. There was a linear increase in ash digestibility (P < 0.01) during the experimental period (days 0 to 21) as the level of lactose increased. There was a quadratic decrease (P < 0.01) in nitrogen (N) and neutral detergent fibre digestibility as the levels of lactose increased. In conclusion, pigs responded differently to the inclusion levels of seaweed extract at each level of lactose supplementation. The inclusion of a laminarin–fucoidan extract in piglet diets may alleviate the use for high-lactose diets (>60 g/kg) and would also alleviate some of the common problems that occur post weaning.     

Changes in cytokinin and auxin concentrations in seaweed concentrates when stored at an elevated temperature

Two seaweed concentrates were made from the kelps Ecklonia maxima and Macrocystis pyrifera using a cell burst method. Cytokinin- and auxin-like activities were measured using the soybean callus and mungbean bioassays, respectively. Cytokinin-like activity was detected in both seaweed concentrates, being equivalent to approximately 50 μg L⁻¹ kinetin. Auxin-like activity was also detected in both concentrates with the E. maxima derived concentrate having higher biological activity, equivalent to 10⁻⁵–10⁻⁴ M indole-butyric acid. Two replicates of each concentrate were stored at 54 °C for 14 days to accelerate the effects of storage. Both fresh and stored samples of the two seaweed concentrates were analysed for their endogenous cytokinin and auxin content. The samples were purified using a combined DEAE-Sephadex octadecylsilica column and immunoaffinity chromatography based on wide-range cytokinin and IAA specific monoclonal antibodies. These extracts were analysed by HPLC linked to a Micromass single quadrupole mass spectrophotometer. Eighteen and nineteen different cytokinins were detected, respectively, in the two concentrates, with trans-zeatin-O-glucoside being the main cytokinin present. Accelerated storage of the concentrates caused an increase in the total cytokinin concentration with a large increase in the aromatic meta-topolin. Indole-3-acetic acid was the main auxin in both seaweed concentrates. Indole conjugates, including amino acid conjugates, were also quantified. The total auxin concentration decreased with accelerated storage for both concentrates. This revised version was published online in August 2006 with corrections to the Cover Date.     

Salt Tolerance in the Halophyte, Suaeda maritima (L.) Dum.: The Influence of the Salinity of the Culture Solution on the Content of Various Organic Compounds

Plants of the halophyte Suaeda maritima were grown in tap wateror in a culture solution in the presence or absence of sodiumchloride and the levels of sugars, amino acids, organic acidsand quaternary ammonium compounds determined in relation tothe balance between cytoplasmic and vacuolar water potentials.The sugar content (some 7 µmol. g f. wt^–1) was unaffectedby the salinity of the growth medium as was the overall contentof amino acids (about 4 µmol. g f. wt^–1). The organicacid content was maximal in plants kept in tap water alone wherethe dominant acid was malic. Plants grown in culture solutioncontained the same acids, although addition of sodium chlorideto the medium brought about the apparent loss of glycolic acidand the appearance of oxalic acid. Only a single quaternaryammonium compound, glycinebetaine, was apparently present inthe tissues: the content of betaine doubled (to 37·5µrmol. g f. wt^–) when sodium chloride was addedto the culture solution. The content of these various compoundsis discussed in relation to the relative values of the cytoplasmicand vacuolar components of the overall tissue water potential Suaeda maritima, halophyte, salt tolerance, betaine, organic compounds, water potential     

The effect of seaweed concentrate on the growth and yield of potassium stressed wheat

The effects of the seaweed concentrate “Kelpak’ on the growth and yield of wheat grown under conditions of varying K supply were investigated. Kelpak had no significant effect on the yield of wheat receiving an adequate K supply, but significantly increased the yield of K stressed plants. The increase in yield was caused by an increase in both grain number and individual grain weight. Although the beneficial effects of seaweed concentrates have often been attributed to their cytokinin content, several lines of evidence suggested that this group of plant growth regulators may not be solely responsible for the observed effects of Kelpak on wheat. Irrespective of the physiological mechanism of action, Kelpak would appear to have considerable potential for increasing yield in K stressed wheat and may therefore reduce the requirement of wheat for K fertilization.