The effect of ε-aminocaproic acid on self-incompatibility and incongruity in Phaseolus

Summary

The effects of ε-aminocaproic acid (EACA) on self-incompatibility was tested in a Phaseolus coccineus line which failed to form pods in controlled pollinations. Scanning electron microscope (SEM) and fluorescence miscroscopy confirmed problems in pollen-germination and pollen-tube growth but EACA-treated self- pollinations resulted in fairly normal pollen germination and pollen tube growth. In a few cases, pollen tubes were seen entering the embryo sac and occasionally pods were formed. Incongruity barriers also exist in crosses of P. coccineus × P. vulgaris, P. acutifolius × P. coccineus and their reciprocals. Effects of EACA on flower abscission, pod development and pod abscission were studied. Increased pod formation was observed in EACA treated materials, except in P. acutifolius × P. coccineus and P. coccineus × P. vulgaris cv. Jacobs Cattle. EACA seems to act at the stigmatic and stylar levels, thereby enhancing pollen germination and pollen tube growth and delaying flower abscission. The net result is fertilization and delayed senescence which permit the pod to grow for a longer period of time.     

Research progress of organic solute transporter α/β in bile acid metabolism

The organic solute transporter α/β （OSTα/β） is a recently discovered transporter that controls bile acid secretion into portal blood stream in the basal lateral membrane of intestinal epithelial cells. OSTα/β is a compound composed of 2 subunits, OSTα and OSTβ. Only when the 2 subunits are expressed at the same time, they exist stably and function properly. It is responsible for the transmembrane transport of organic solutes such as bile acids in a way of easy diffusion. OSTα/β is regulated by bile acid receptor, also named as farnesoid X receptor （FXR）. Studies showed that the bile acid synthesis in OSTα deficient mice is decreased, while the bile acid content in the urine is increased. It is worth mentioning that the single gene mutation leads to OSTβ deficiency in the patients with clinical symptoms such as chronic diarrhea and cholestatic liver disease. This paper reviews the structure, function and role of OSTα/β in enterohepatic circulation and the diseases caused by loss of OSTα/β.     

Jasmonic acid effects on gibberellic acid-induced seedlessness in ‘Neo Muscat’ table grapes

Summary

The effect of jasmonic acid (JA), applied alone or in combination with gibberellin A3 (GA₃), on the induction of seedlessness in ‘Neo Muscat’ (Vitis vinifera) was investigated. Endogenous JA levels in the florets of ‘Neo Muscat’ and ‘Delaware’ (Vitis vinifera x Vitis labrusca) were also studied. The proportion of seedless berries induced by application of GA₃ alone 12 d before full bloom (DBB) was 17.0%, and at 6 DBB it was 62.7%. The proportion of seedless berries induced by GA₃ + JA applied 6 DBB increased significantly with increasing JA concentration, while pollen germination decreased quadratically with increasing JA concentration. JA did not affect seed number per berry or the seed’s fresh weight. Treatment with JA alone also induced seedlessness effectively. Although the fresh weight of the seedless berries induced by the application of GA₃ + JA 12 DBB decreased quadratically with increasing JA concentration, there were no significant differences between the treatments at 6 DBB. Fruit soluble solids and titratable acidity were not affected by JA. There were no obvious differences in the amounts of JA in the florets of ‘Delaware’ and ‘Neo Muscat’.     

Protective effect of astragaloside Ⅳ on acute tubular injury induced by aristolochic acid I

AIM: To study the effect of astragaloside Ⅳ (AS Ⅳ) on acute aristolochic acid nephropathy (AAN). METHODS: MTT assay was used to observe the viability of human proximal tubule epithelial cell line HK-2 in vitro. In in vivoexperiments, Kunming mice were intra peritoneally injected with aristolochic acid I (AAⅠ) for 6 d to induce acute AAN model.AS Ⅳ at dose of 50 mg·kg^-1·d^-1 was gavaged for 6 d, and the levels of urine protein, urine γ-glutamyltransferase (γ-GT), serum creatinine (SCr) and blood urea nitrogen (BUN) were measured. The histological changes of the kidneys were observed under microscope by HE and periodic acid-silver methenamine (PASM) staining at the 7th day. RESULTS: The cell viability was significantly inhibited by AA I. However, the cell viability increased when AA I combined with AS Ⅳ was given as compared with control group, indicating that AS Ⅳ plays a dose-dependent protective role in HK-2 cells against the injury of AA I. The results of in vivo experiments showed that the levels of urine protein, urine γ-GT, SCr and BUN were decreased in AA I combined with AS Ⅳ group compared with AA I renal injury group. Histological study showed that AA I-induced kidney injury was improved with the decrease in the area of tubule necrosis and nude tubular basement membrane. CONCLUSION: AS Ⅳ has a protective effect on renal tubular damage induced by AA I.     

Application timing and concentration of abscisic acid affect the quality of ‘Redglobe’ grapes

Summary

The plant hormone abscisic acid (ABA), the concentration of which increases in grape berry skins at the onset of maturation (veraison), appears to be involved in the regulation of anthocyanin accumulation. Preliminary tests suggested that exogenous applications of ABA could improve grape berry colour, but its high cost precluded the development of commercial applications. Recently, a lower-cost ABA production method was developed, which led to the evaluation of different concentrations of ABA, applied at or around veraison, on the quality of ‘Redglobe’ grapes. In two of three years of tests, several ABA treatments enhanced the anthocyanin content of grape skins. ABA, applied at approx. 300 mg l^–1 at veraison, may be required to reliably increase pigmentation, and improve the colour of ‘Redglobe’ grapes. Although the total anthocyanin content was increased by ABA treatment, anthocyanin composition was not affected. Applications of ABA had few effects on fruit size or composition, although they did cause fruit softening, which is undesirable. A secondary objective of this study was to determine how the anthocyanin content of berry skins affected berry colour characteristics. Strong curvilinear relationships between anthocyanin content and lightness and hue showed that these colour characteristics were saturated by anthocyanin contents over 0.02 mg cm^–2 of skin. These data suggest that colour measurements may be needed to evaluate the effect of cultural practices on colour in table grapes.     

Nicotinic acid promotes lysosomal free cholesterol efflux via LXRα/NPC1 pathway in macrophages

AIM To explore the effects of nicotinic acid (NA) on lysosomal free cholesterol efflux in macrophages and its underlying mechanism. METHODS Macrophages induced from human monocytic leukemia cell line THP-1 by phorbol myristate acetate served as the cell model. Laser scanning confocal microscopy was applied to observe the effects of NA on lysosomal free cholesterol efflux in macrophages loaded with oxidized low-density lipoprotein (oxLDL). The influences of nicotinic acid adenine dinucleotide phosphate (NAADP) antagonist Ned-19, Ca²⁺ chelator BAPTA, liver X receptor α (LXRα) siRNA and Niemann-Pick C1 protein (NPC1) siRNA on NA effects were also evaluated. RT-qPCR and Western blot were conducted to evaluate the influence of NA, Ned-19 and BAPTA on LXRα mRNA and NPC1 protein expression. RESULTS NA dose-dependently promoted lysosomal free cholesterol efflux in macrophages. This effect was markedly inhibited by Ned-19 and BAPTA. NA increased NPC1 protein and LXRα mRNA expression. These effects were also attenuated by Ned-19 and BAPTA remarkably. LXRα siRNA significantly inhibited the promoting effect of NA on NPC1 protein expression. Silencing of LXRα and NPC1 with siRNA remarkably abolished the effect of NA on lysosomal free cholesterol efflux. CONCLUSION NA promotes lysosomal free cholesterol efflux in macrophages. This effect may be mediated by the increased production of NAADP, which subsequently promotes Ca²⁺ release through lysosomal transient receptor potential mucolipin 1 (TRPML1) channel and finally up-regulates NPC1 protein expression via LXRα.     

Effects of light on flavonoid and chlorogenic acid levels in the skin of ‘Jonagold’ apples

The objective of our work was to determine how fruit position on the tree affects flavonoid and chlorogenic acid contents. Light was measured at different positions within the canopy of 10-year-old ‘Jonagold’ apple trees on M.9 rootstock raised as slender spindles. Fruit from the top of the canopy contained the highest percentage of blush and the highest levels of cyanidin 3-galactoside (anthocyanin) and quercetin 3-glycosides, followed by fruit from the outside of the canopy, and then those from the canopy interior. There were no significant differences in the levels of catechins, phloridzin and chlorogenic acid among fruit from the different canopy positions. Light level was directly correlated with the levels of cyanidin 3-galactoside and quercetin 3-glycosides and with the percentage of blush in the fruit skin. Light in the interior of the canopy was poorer in UV-A, blue, green and red but richer in far-red light than at all other positions. Consequently, the FR/R ratio was much larger at the interior of the canopy than at all other positions. Both anthocyanin and quercetin 3-glycoside concentrations were clearly related to light level, and there was a critical FR/R ratio of about 1 below which no anthocyanin and only minimal quercetin 3-glycosides were formed.     

Effects of phosphorylation-defective retinoic acid receptor α1 on proli-feration of human multiple myeloma cells in vitro

AIM: To investigate the effect of phosphorylation-defective retinoic acid receptor α1 (RARα1) on the proliferation of human multiple myeloma cells. METHODS: The mRNA expression of RARα subtypes in U266 cells was detected by RT-PCR. Lentiviral plasmid construction, viral production, titer determination and cell transfection were carried out by the general methods of molecular biology. Proliferation analysis was performed with CCK-8 assay. The U266 cells were treated with all-trans retinoic acid (ATRA,0~100 μmol/L) or transfected with lentivirus RARαS77A. The expression levels of proliferation-related proteins, P53 and Rb, in U266 cells treated with ATRA or transfected with lentivirus RARαS77A were detected by Western blotting. RESULTS: RARα1 was positively expressed in U266 cells and RARα2 expression was negative. ATRA significantly inhibited the proliferation of U266 cells in a dose- and time-dependent manner. Proliferation of U266 cells was significantly inhibited 48 h after transfection with lentivirus RARαS77A, and the inhibitory rate was 15.16%±3.84%. The up-regulated expression of Rb and down-regulated expression of P53 were detected in U266 cells not only in the cells treated with ATRA, but also in the cells transfected with lentivirus RARαS77A. CONCLUSION: Phosphorylation-defective RARα1 (RARαS77A) mimics the growth inhibitory effect of ATRA on U266 cells that express RARα1 (+) and RARα2 (-) via down-regulating the expression of P53 and up-regulating the expression of Rb, suggesting that the antiproliferative effect of ATRA is mainly mediated by decreasing the phosphorylation of RARα1.     

Hormone and antioxidant responses of Lilium Oriental hybrids ‘Sorbonne’ bulblets to humic acid treatments in vitro

The lily cultivar introduction is a very long process and bulblet development a limiting element in the entire cycle. The aim of the present study was to acquire a highly synchronized model system to gain insight into the bulbing process. Subsequently, this system was implemented to quantify the efficacy of humic acid applications to evaluate the hypothesized positive effect on bulblet growth. Based on weight, bulblet production was promoted with low humic acid concentration treatment (0.2 mg/L, LHA), showing 0.47 g weight and 11.68 mm diameter, while inhibitory effects were observed with increased doses. LHA significantly decreased the gibberellic acid content, and a pronounced phytohormone balance (promotive/inhibitive) was observed, which might be beneficial for the translocation of assimilates from the shoot to sink organs (bulblets). Intriguingly, LHA increased superoxide dismutase, peroxidase, ascorbate peroxidase, catalase, and glutathione reductase activities compared with the control during the early development stages, implicating a possible role for elimination of reactive oxygen species, thereby favouring cell expansion. In conclusion, we initially reported the effects of HA on the development of bulbous plants, showing that a relatively low dose markedly increased the bulblets size via positive GA and antioxidant responses. However, the mechanism of action needs further evaluation.     

Evaluation of an alternative D-amino acid/DAAO selection system for transformation in apple (Malus × domestica Borkh.)

Summary

The conventional selection system for apple transformation is based on the selectable marker gene, nptII, encoding antibiotic resistance against kanamycin. We tested an alternative selection system based on the use of D-amino acids using the gene, D-amino acid oxidase 1 (dao1) as the selectable marker, in order to avoid the presence of antibiotic resistance genes in the resulting transgenic apple plants. In addition, dao1 allowed the selection as well as the elimination of dao1-transgenic plants, based on differences in the toxicity of different D-amino acids. Regeneration experiments using apple leaf explants revealed that 2 mM D-serine or D-alanine inhibited shoot regeneration. We performed transformation experiments using the apple cultivars ‘Gala’, ‘Holsteiner Cox’, and a progeny of the apple cultivar ‘Pinova’, and the vector p35S::dao1-intron, containing the dao1 and nptII selectable marker genes. Several shoots regenerated successfully on selection media containing various concentrations of D-serine or D-alanine, but transgenic shoots were not obtained. However, three dao1/nptII transgenic apple lines were obtained after selection with kanamycin, indicating that the vector was functional. Furthermore, we showed that 20 mM D-serine could be used to select dao1-transgenic shoots from non-transgenic in vitro shoots, whereas 13 mM D-isoleucine had the opposite effect.     

Cultivar identification of ‘Yuzu’ (Citrus junos Sieb. ex Tanaka) and related acid citrus by leaf isozymes

Leaf extracts of 27 ‘Yuzu’ and related acid citrus cultivars were analyzed using polyacrylamide gel electrophoresis for isozyme variation of glutamate oxaloacetate transaminase (GOT) and shikimate dehydrogenase (SDH). SDH yielded 12 different isozyme phenotypes and six cultivars were discriminated by this enzyme alone. GOT produced 10 different isozyme phenotypes and four cultivars were separated. When both enzyme systems were taken together, 16 cultivars (59%) were uniquely discriminated and the rest could be classified into four groups of 2–4 cultivars each. Mutation originated cultivars could not be discriminated. Differences between cultivars suggested that isozymes may provide useful markers for cultivar identification.     

Effect of 3,5,6-trichloro-2-pyridyl-oxyacetic acid on fruitlet abscission and yield of ‘Mauritius’ litchi (Litchi chinensis Sonn.)

Summary

‘Mauritius’, the main cultivar in Israel’s litchi industry, tends to suffer from massive fruitlet drop. Recently, spraying ‘Mauritius’ trees with 2,4,5-TP at the ca. 2 g fruitlet stage was shown to improve greatly productivity due to a reduction in fruitlet drop. Here we examine another synthetic auxin, 3,5,6-trichloro-2-pyridyl-oxyacetic acid (3,5,6-TPA), used in the commercial product Maxim^®. We found it to be as effective as 2,4,5-TP in reducing ‘Mauritius’ fruitlet drop. In seven commercial-scale trials, spraying with 25 or 50 ppm 3,5,6-TPA consistently and significantly increased ‘Mauritius’ yields relative to non-sprayed controls.Therefore 3,5,6-TPA is recommended for routine use in ‘Mauritius’ orchards.     

Role of retinoic acid X receptor in regulation of autophagy in rat alveolar type Ⅱ epithelial cells induced by hypoxia/reoxygenation

AIM To investigate the regulatory effect of retinoic acid X receptor （RXR） on autophagy induced by hypoxia/reoxygenation （H/R） in rat alveolar type Ⅱ epithelial cells （AEC Ⅱ） and its molecular mechanism. METHODS AEC Ⅱ were cultured in normoxia. The cells growing to logarithmic growth phase were randomly divided into 5 groups： （1） control （Con） group： cells were cultured for 30 h under normal operation; （2） H/R group： cells were cultured in hypoxia condition for 6 h and then in reoxygenation condition for 24 h; （3） DMSO group： cells were pretreated 1.5 h with medium containing less than 0.1% DMSO before modeling, and the rest were treated the same as the H/R group; （4） 9-cis-retinoic acid （9-RA） group： cells were pretreated for 1 h with 9-RA （100 nmol/L） before hypoxia; （5） HX531 group： cells were treated with 9-RA （100 nmol/L） for 0.5 h, then treatment with HX531 （2.5 μmol/L） for 1 h. CCK-8 assay was used to detect the cell viability. Immunofluorescence staining was used to observe the expression of RXRα. Transmission electron microscope was used to observe the changes of intracellular ultrastructure, and the mRNA expression of adenosine AMP-activated protein kinase （AMPK）, beclin 1, LC3, mammalian target of rapamycin （mTOR） and P62 was detected by RT-PCR. Western blot was used to detected the protein levels of p-AMPK, beclin 1, LC3-Ⅱ, p-mTOR and P62. RESULTS Compared with Con group, the cell viability in H/R, DMSO, 9-RA and HX531 groups were significantly decreased. The mRNA expression of AMPK, beclin 1 and LC3 was significantly increased, and the protein levels of p-AMPK, beclin 1 and LC3-Ⅱ were also increased. The mRNA expression of mTOR and P62 was decreased, and the protein levels of p-mTOR and P62 were also decreased （P<0.05）. The cell injury in 9-RA group was alleviated and autophagy level was significantly lower than that in H/R, DMSO and HX531 groups （P<0.05）, and no significant difference among H/R, DMSO and HX531 groups was observed （P>0.05）. CONCLUSION H/R induces autophagy of AEC Ⅱ. Activating RXR reduce the damage of AEC Ⅱ cells induced by H/R, and its mechanism may be related to the inhibition of autophagy.     

Effect of salvianolic acid B on expression of TGF-β1 receptors and Smad2 in activated mesangial cells

AIM: To study the mechanisms of salvianolic acid B (Sal B)antagonizing mesangial cell activation and kidney fibrosis through investigating the effect of Sal B on expression of transforming growth factor-β₁ (TGF-β₁) receptors and Smad2 in TGF-β₁-stimulated renal mesangial cell activation. METHODS: Mesangial cells was isolated and purified from rat kidney. TGF-β₁ was used to establish rat primary mesangial cell activation model and Smad2,Smad7 protein expression was detected. Sal B (10^-6 mol/L and 10^-5 mol/L) was employed to treat the cells; α-smooth muscle actin(α-SMA) expression was analyzed by immunofluorescence staining and Western blotting. Mesangial cells were treated with Sal B alone or additional with TGF-β₁,and TGF-β₁ receptor Ⅰ (TβRⅠ),TGF-β₁ receptorⅡ (TβRⅡ),Smad2 phosphorylation and Smad2 protein expression was determined by Western blotting. RESULTS: Cell ular model was established by incubating with 5 μg/L TGF-β₁ for 24 h,and in early stage Smad2 was significantly phosphorylated. Sal B (10^-6 mol/L and 10^-5 mol/L) could inhibit α-SMA expression,which was the biomarker of activated mesangial cells. In addition,in Sal B group,the protein expression of TβRⅠand TβRⅡ was significantly down-regulated while Smad2 phosphorylation in mesangial cells was inhibited. CONCLUSION: Sal B inhibits the TGF-β₁-Smad pathway,the protein expression of TβRⅠ,TβRⅡ and Smad2 phosphorylation in mesangial cells,which is probably one of the mechanisms of Sal B alleviating kidney fibrosis.     

Micropropagation of the bromeliad Guzmania ‘Hilda’ via organogenesis and the effect of α-naphthaleneacetic acid on plantlet elongation

This study established a highly effective micropropagation system to obtain good plantlet proliferation from floral organs via callus induction and bud differentiation in Guzmania ‘Hilda’ bromeliad. The best frequencies of organogenic callus formation (20% in petal and 35% in ovary explants) were obtained on media containing a combination of 1.0 mg l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) with 1.0 mg l⁻¹ α-naphthaleneacetic acid (NAA) and 1.5 mg l⁻¹ 2,4-D with 0.5 mg l⁻¹ NAA, respectively. Organogenic calli were cultured on medium with 1.0 mg l⁻¹ NAA and 0.5 mg l⁻¹ 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea (TDZ) induce the differentiation and regeneration of adventitious buds into plantlets. When the plantlets were cultured in a medium with optimum NAA concentration (0.5–1.0 mg l⁻¹) significant improvement in regeneration and elongation was achieved within one month. This overcame the difficulty of delayed elongation in Guzmania plantlets. More than 99% of the regenerated and acclimatized plantlets developed to the flowering stage.     

Lysophosphatidic acid (LPA) induces the proliferation of astrocytes in rat via pathway of protein kinase C-α and calcium ion in vitro

AIM: To determine if lysophosphatidic acid (LPA) regulates the proliferation of astrocytes (AS) and to approach the mechanism of the process.METHODS: The cerebral AS of the neonatal SD rats were cultured in vitro and divided randomly into control group, PKC excitomotor (PMA) group, LPA group, PKC-α inhibitor (Ro31-8220) group, Ro31-8220+PMA group and Ro31-8220+LPA group. The proliferation of the cells was detected by MTT assay and flow cytometry (FCM). The concentration of intra-cellular calcium ion of the cells (［Ca2＋］i) which were labeled with Fura-2/AM was determined by ultraviolet spectrophotometer. The change of PKC-α inside the cells was observed by Western blotting.RESULTS: LPA and PMA stimulated the proliferation of AS, they also enhanced the expression of PKC-α and increased the concentration of ［Ca2＋］i. After pretreated with Ro31-8220, the abilities of LPA that mentioned above were decreased. The change of ［Ca2＋］i was associated with the diversity of PKC-α.CONCLUSION: LPA promotes the proliferation of AS via the way of PKC-α and Ca2＋.     

Roles of protein phosphatase 4 in down-regulation of eNOS Ser633 phosphorylation induced by palmitic acid in human umbilical vein endotheli?al cells

AIMTo investigate the roles of protein phosphatase 4 (PP4) in down-regulation of endothelial nitric oxide synthase (eNOS) Ser633 phosphorylation induced by palmitic acid (PA). METHODSHuman umbilical vein endothelial cells (HUVECs) were treated with PA at 25 μmol/L, 50 μmol/L, 100 μmol/L and 200μmol/L for 36 h, or treated with PA at 100 μmol/L for 12 h, 24 h, 36 h and 48 h. Protein phosphatase 2A (PP2A) family inhibitor fostriecin (FST, 20 nmol/L) or okadaic acid (OA, 5 nmol/L) was selected to pretreat the HUVECs for 30 min. Protein phosphatase 4 catalytic subunit (PP4c) siRNA or protein phosphatase 2A catalytic subunit (PP2Ac) siRNA was transfected into the HUVECs. The protein expression levels of of eNOS, PP4c and PP2Ac, as well as the level of eNOS Ser633 phosphorylation, were detected by Western blot. The intracellular nitric oxide (NO) content was measured by DAF-FM DA. RESULTS(1) Compared with control group, the levels of eNOS Ser633 phosphorylation were decreased in PA groups in which the HUVECs were treated with 25 μmol/L, 50 μmol/L, 100 μmol/L and 200 μmol/L PA for 36 h (P<0.05) and 100 μmol/L PA for 24 h, 36 h and 48 h (P<0.05). No significant difference in the level of total eNOS protein expression among all the groups was observed. (2) Compared with control group, both FST and OA pretreatment reversed the reduction of eNOS Ser633 phosphorylation (P<0.05) and the decrease in intracellular NO content (P<0.05) induced by PA. No significant difference in the level of total eNOS protein expression among all the groups was observed. (3) Compared with si-Control group, the PP4c protein expression was significantly reduced (P<0.05), while the level of eNOS Ser633 phosphorylation was significantly increased in si-PP4c group (P<0.05). Although the levels of PP2Ac protein expression declined significantly (P<0.05), the level of eNOS Ser633 phosphorylation remained unchanged in si-PP2Ac group. No significant differencein the level of total eNOS protein expression among all the groups was found. CONCLUSION PA significantly reduces the level of eNOS Ser633 phosphorylation and the content of NO in the HUVECs, which may be due to PA inducing the activation of the PP2A family member PP4 rather than PP2A.     

Effect of agar,galactomannan and indole-butyric acid on in vitro rooting of the pear cultivar ‘Durondeau’ and apple rootstock cultivar ‘Marubakaido’

Summary

The influence of partial substitution of agar by galactomannans in culture media supplemented with different concentrations of indole-3-butyric acid (IBA) was studied on in vitro rooting of pear (Pyrus communis L.) cultivar ‘Durondeau’ and apple rootstock (Malus prunifolia Borkh.) cultivar ‘Marubakaido’. The galactomannans applied were obtained from Cassia fastuosa (cassia) and Cyamopsis tetragonolobus (guar gum) seeds. The results obtained with mixtures of agar and galactomannan (3 g l^–1 each) were compared with those from media solidified with a standard concentration of agar (6 g l^–1). The rooting of pear shoots was enhanced significantly in the presence of a mixture of agar plus cassia galactomannan compared to medium solidified with agar only. The modified media promoted a higher number of roots than the control, and increased the percentage of rooted shoots. A maximum of 84.8% rooting was obtained on half-strength MS medium (¹?2MS) supplemented with 0.49 µM IBA and solidified with a blend of agar plus cassia galactomannan. For the apple rootstock, only the number of roots per shoot was influenced significantly by the addition of galactomannan to the rooting medium. The highest number of roots per shoot was 16.67 on ¹?2MS medium gelled with a mixture of agar plus guar galactomannan supplemented with 4.90 µM IBA. The behaviour of the agar-galactomannan gel and the possibility of reduced costs when compared with systems containing only agar, suggest new biological and commercial applications for galactomannans.