Raphanus Sativus Cv Research Articles

Using a selective fast turn-around bioassay for population density determination of Heterodera schachtii

In Central Europe, Heterodera schachtii is kept below threshold levels by cover-cropping with resistant crucifers and crop rotation with non-hosts. Determining population densities of H. schachtii in soil is critical when implementing resistant and tolerant sugar beet cultivars in integrated pest management (IPM) programmes. Soil extraction of the cysts followed by egg counts or extraction of the second-stage juveniles (J2) facilitated by the chemical stimulant acetox can be unsatisfactory in mixed field populations of cyst nematodes. In contrast to H. schachtii, nematodes typically present in sugar beet soils, e.g., Globodera pallida, G. rostochiensis, H. avenae, H. filipjevi, Meloidogyne hapla, M. incognita and Pratylenchus penetrans, rarely penetrated radish roots. In this bioassay, equivalents of 50 g of soil dry weight were adjusted to 10-20% moisture, seeded with Raphanus sativus cv. Saxa 3, and incubated at a day-night (16:8 h) cycle of 28/23°C for 4 days before J2 in radish roots were enumerated. In different soil types, penetration by H. schachtii reflected the inoculation levels. When inoculated with mixes of H. schachtii with H. avenae or H. filipjevi, counts of H. schachtii were similar to those in soils with H. schachtii only. When comparing three methods in three soils spiked with H. schachtii cysts, the bioassay and the extraction method were lightly impacted by the soil texture but results of the acetox method varied with texture. When implemented for field samples from Franconia, the radish bioassay and the acetox method provided results related to cyst and egg extraction data. The radish bioassay provided a quick and easy method for quantifying H. schachtii in the presence of other nematode species in a wide range of soil types. Including this assay in IPM programmes may serve as an alternative to standard methods and will improve the decision making in sustainable production systems.

Identification and analysis of isothiocyanates and new acylated anthocyanins in the juice of Raphanus sativus cv. Sango sprouts

The freeze-dried sprouts’ juice of Raphanus sativus (L.) cv. Sango was prepared and analysed for the first time. HPLC analysis of total isothiocyanates, after protein displacement, resulted in 77.8±3.0μmol/g of dry juice while GC–MS analysis of hexane and acetone extracts showed E- and Z-raphasatin (8.9 and 0.11μmol/g, respectively) and sulforaphene (11.7μmol/g), summing up to 20.7±1.7μmol/g of free isothiocyanates. Sprouts’ juice contained an unprecedented wealth of anthocyanins and a new fractionation methodology allowed us to isolate 34mg/g of acylated anthocyanins (28.3±1.9μmol/g), belonging selectively to the cyanidin family. Analysis was performed by HPLC–PDA–ESI–MSn and extended to deacylated anthocyanins and aglycones, obtained, respectively, by alkaline and acid hydrolysis. This study identified 70 anthocyanins, 19 of which have never been described before and 32 of which are reported here in R. sativus for the first time. Sango radish sprouts are exceptional dietary sources of heath-promoting micronutrients.

Earthworm-induced N2O emissions in a sandy soil with surface-applied crop residues

Abstract Earlier research with endogeic and epigeic earthworm species in loamy arable soil has shown that both earthworm groups can increase nitrous oxide (N 2 O) emissions, provided that crop residue placement matches the feeding strategy of the earthworm ecological group(s). However, it is not yet clear whether these effects also occur in sandy soils which typically contain less soil organic matter and have low soil aggregation levels. Here, we aimed to quantify N 2 O emissions as affected by endogeic and/or epigeic earthworm species, and to relate changes in N 2 O emissions to earthworm-induced changes in soil properties in a sandy soil. A 90 day mesocosm study was conducted with sandy soil and 15 N-labeled radish ( Raphanus sativus cv. Adagio L.) residue applied on top. Treatments included: (i) no earthworm addition, (ii) addition of the endogeic species Aporrectodea caliginosa (Savigny), (iii) addition of the epigeic species Lumbricus rubellus (Hoffmeister), and (iv) both species combined. An additional treatment was included without earthworms and with residue manually incorporated into the soil. L. rubellus significantly increased cumulative N 2 O emissions from 228 to 859 μg N 2 O–N kg −1 ( F 1,12 = 83.12, P A. caliginosa did not affect N 2 O emissions. In contrast to earlier studies in loamy soil, no positive interaction between both species with regard to N 2 O emissions was found. This was probably related to high competition for organic resources in the relatively poor soil and a low potential for stable soil aggregate formation (and associated anaerobic microsites) by endogeic worms in sandy soil. 15 N isotope analysis revealed that the activity of L. rubellus significantly increased ( F 1,12 = 6.20, P = 0.028) the recovery of 15 N in the 250–8000 μm size fraction, indicating incorporation of crop residues into the mineral soil. When residues were manually incorporated, N 2 O emissions were significantly ( P 2 O–N kg −1 ) than when incorporated by L. rubellus . The high N 2 O emissions in the presence of L. rubellus , when compared to manual mixing, suggest a stimulation of microbial activity and/or changes in the microbial community composition. Insights on the earthworm effects on N 2 O emission from such soils are discussed.

First Report of Bacterial Blight of Crucifers Caused by Pseudomonas cannabina pv. alisalensis in Australia.

In 1978 and 1979, Pseudomonas syringae pv. maculicola strains DAR 33362, DAR 33363, and DAR 33406 were isolated from diseased Brassica hirta, B. nigra, and B. napus var. napus, respectively, in Wagga Wagga and Armatree, NSW, Australia (2). Peters et al. (2) demonstrated that these strains were similar to P. syringae pv. maculicola ICMP 4326 (CFBP 1637), which was recently transferred to Pseudomonas cannabina pv. alisalensis (1). We evaluated these Australian strains to determine if they might also be P. cannabina pv. alisalensis. Amplification of DNA using the BOXA1R primer and PCR resulted in identical DNA fragment banding patterns for Australian strains DAR 33362 and DAR 33363 and P. cannabina pv. alisalensis ICMP 4326 and CFBP 6875. The third Australian strain, DAR 33406, was 90% similar to P. cannabina pv. alisalensis; in contrast, it was only 77% similar to P. syringae pv. maculicola. All strains of P. cannabina pv. alisalensis, including the pathotype strain (CFBP 6866) and all three Australian strains, were lysed by bacteriophage PBS1, which is specific for P. cannabina pv. alisalensis strains (1). To complete Koch's postulates, pathogenicity was evaluated on B. hirta, B. nigra, and B. napus var. napus. In two independent experiments, two plants of each species were inoculated with each Australian strain or a phosphate buffer control treatment. In separate experiments, pathogenicity was evaluated on the differential hosts radish (Raphanus sativus cv. Comet) and broccoli raab (Brassica rapa cv. Sorrento), and plants inoculated with the pathotypes of P. cannabina pv. alisalensis and P. syringae pv. maculicola served as additional control treatments. Inoculum was prepared by growing the bacteria on nutrient agar for 48 h (27°C), suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), and adjusting each suspension to 0.6 OD at 600 nm (approximately 108 CFU/ml). Treatments were applied by spraying until runoff. DAR 33362, DAR 33363, and DAR 33406 caused typical bacterial blight symptoms on B. hirta, B. nigra, and B. napus var. napus. Infected leaves became yellow, followed by the development of small (<2 mm in diameter), angular, water-soaked, and eventually, shot-holed spots. Bacteria isolated from symptomatic tissue following surface disinfestation of tissue with sodium hypochlorite (0.525%) had identical characteristics (rep-PCR DNA fragment banding patterns and phage sensitivity) to the strains used to inoculate the plants. Additionally, DAR 33362, DAR 33363, and DAR 33406, as well as P. cannabina pv. alisalensis, caused symptoms on radish and broccoli raab while P. syringae pv. maculicola and the buffer control did not. These data support the transfer of the Australian crucifer strains, originally identified as P. syringae pv. maculicola, to P. cannabina pv. alisalensis. To our knowledge, this is the first report of a bacterial disease of crucifers caused by P. cannabina pv. alisalensis in Australia. Differentiation of these pathogens will inform crop rotation strategies for disease management.

Interactions between residue placement and earthworm ecological strategy affect aggregate turnover and N 2O dynamics in agricultural soil

Previous laboratory studies using epigeic and anecic earthworms have shown that earthworm activity can considerably increase nitrous oxide (N 2O) emissions from crop residues in soils. However, the universality of this effect across earthworm functional groups and its underlying mechanisms remain unclear. The aims of this study were (i) to determine whether earthworms with an endogeic strategy also affect N 2O emissions; (ii) to quantify possible interactions with epigeic earthworms; and (iii) to link these effects to earthworm-induced differences in selected soil properties. We initiated a 90-day 15N-tracer mesocosm study with the endogeic earthworm species Aporrectodea caliginosa (Savigny) and the epigeic species Lumbricus rubellus (Hoffmeister). 15N-labeled radish ( Raphanus sativus cv. Adagio L.) residue was placed on top or incorporated into the loamy (Fluvaquent) soil. When residue was incorporated, only A. caliginosa significantly ( p < 0.01) increased cumulative N 2O emissions from 1350 to 2223 μg N 2O–N kg −1 soil, with a corresponding increase in the turnover rate of macroaggregates. When residue was applied on top, L. rubellus significantly ( p < 0.001) increased emissions from 524 to 929 μg N 2O–N kg −1, and a significant ( p < 0.05) interaction between the two earthworm species increased emissions to 1397 μg N 2O–N kg −1. These effects coincided with an 84% increase in incorporation of residue 15N into the microaggregate fraction by A. caliginosa ( p = 0.003) and an 85% increase in incorporation into the macroaggregate fraction by L. rubellus ( p = 0.018). Cumulative CO 2 fluxes were only significantly increased by earthworm activity (from 473.9 to 593.6 mg CO 2–C kg −1 soil; p = 0.037) in the presence of L. rubellus when residue was applied on top. We conclude that earthworm-induced N 2O emissions reflect earthworm feeding strategies: epigeic earthworms can increase N 2O emissions when residue is applied on top; endogeic earthworms when residue is incorporated into the soil by humans (tillage) or by other earthworm species. The effects of residue placement and earthworm addition are accompanied by changes in aggregate and SOM turnover, possibly controlling carbon, nitrogen and oxygen availability and therefore denitrification. Our results contribute to understanding the important but intricate relations between (functional) soil biodiversity and the soil greenhouse gas balance. Further research should focus on elucidating the links between the observed changes in soil aggregation and controls on denitrification, including the microbial community.

The influence of nickel sulphate on some physiological aspects of two cultivars of Raphanus sativus L.

In this study two cultivars of radish Raphanus sativus cv. longipinnatus (white radish) and Raphanus sativus cv. Cherry Belle (red radish) were treated with different concentrations of nickel sulphate (0.0-50-100-150-200 ppm). The fresh and dry weight of shoots and roots, photosynthetic pigments, some antioxidant enzymes, total carbohydrates, total proteins and the SDS-PAGE protein profile of both cultivars were determined after 32 days. The results showed that increasing nickel sulphate concentrations decreased the fresh and dry weights of the shoots and roots, photosynthetic pigments, total carbohydrates and total protein in both cultivars. Higher concentrations of nickel sulphate increased the activity of catalase, peroxidase and polypenol oxidase. Electrophoresis banding profiles of proteins revealed qualitative and quantitative changes, and also the appearance or disappearance of some bands of the two cultivars. .

Time dependence of bioactive compounds and antioxidant capacity during germination of different cultivars of broccoli and radish seeds

Optimisation of the germination process of different cultivars of broccoli (Brassica oleracea var. italica cv. Lucky, cv. Tiburon and cv. Belstar) and radish (Raphanus sativus cv. Rebel and cv. Bolide) seeds in relation to the content of glucosinolates (GLS), vitamin C and total antioxidant capacity was carried out in order to maximise the health-promoting properties of Brassica sprouts. The content of total and individual GLS varied between species, among cultivars, and germination time. Glucoraphanin in broccoli and glucoraphenin in radish were the predominant GLS in raw seeds (61–77 and 63–129 μmol/g DM, respectively) and, although their content decreased during germination, they were maintained in rather large proportions in sprouts. Vitamin C was not detected in raw seeds and its content increased sharply in broccoli and radish sprouts (162–350 and 84–113 mg/100 g DM, respectively). Raw brassica seeds are an excellent source of antioxidant capacity (64–90 and 103–162 μmol Trolox/g DM in broccoli and radish, respectively) and germination led to a sharp increase. Germination of broccoli cv. Belstar and radish cv. Rebel for 4 days provided the largest glucoraphanin and glucoraphenin content, respectively, and also brought about large amounts of vitamin C and antioxidant capacity.

Excess lead alters growth, metabolism and translocation of certain nutrients in radish

To elucidate the deleterious effects of excess lead on radish ( Raphanus sativus) cv. Jaunpuri plants were grown in refined sand in complete nutrient solution for 30 days. On the 31st day lead nitrate was superimposed at 0.1 and 0.5 mM to radish for 65 days. A set of plants in complete nutrient solution was maintained as control for the same period without lead. Excess Pb at 0.5 mM showed growth depression with interveinal chlorosis on young leaves at apex. Excess Pb reduced the fresh and dry weight pronouncedly at d 65. Lead accumulation reduced the concentration of chlorophyll, iron, sulphur (in tops), Hill reaction activity and catalase activity whereas increased the concentration of phosphorus, sulphur (in roots) and activity of peroxidase, acid phosphatase and ribonuclease in leaves of radish.

Characterization of fertile amphidiploid between Raphanus sativus and Brassica alboglabra and the crossability with Brassica species

A fertile amphidiploid × Brassicoraphanus (RRCC, 2n = 36) between Raphanus sativus cv. HQ-04 (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) was synthesized and successive selections for seed fertility were made from F4 to F10. F10 plants exhibited good fertility with 14.9 seeds per siliqua and 32.3 g seeds per plant. Cytological observation revealed that frequent secondary pairing occurred among 3 chromosome pairs in pollen mother cells of plants (F4) with lower fertility, but not of plants with high fertility (F10). GISH analysis indicated that these F10 plants included the expected 18 chromosomes from R. sativus and B. alboglabra, respectively, but they lost approximately 27.6% R. sativus and 35.6% B. alboglabra AFLP (amplified fragment length polymorphism) bands. The crossability of the Raphanobrassica with R. sativus and 5 Brassica species (13 cultivars) were investigated. Seeds or F1 seedlings were easy to be produced from crosses × Brassicoraphanus × R. sativus, and B. napus, B. juncea and B. carinata × Brassicoraphanus. Fewer seeds or seedlings were obtained from crosses × Brassicoraphanus × B. napus, B. juncea and B. carinata. However, few seeds were harvested in the reciprocals of × Brassicoraphanus with B. rapa and B. oleracea. The possible cause of fertility improvements and the potential of the present × Brassicoraphanus for breeding were discussed.

Excess Copper‐Induced Oxidative Damages and Changes in Radish Physiology

To identify the detrimental effects of excess copper in radish (Raphanus sativus) cv. Jaunpuri, plants were grown in refined sand at control (0.001) and 0.1 and 0.2 mM (excess) copper (Cu) supplied as Cu sulphate. Previously plants were maintained for 24 days in complete nutrient solution and on the 25th day, excess Cu was superimposed. After 6 days of metal supply, the visible effects of excess Cu appeared as retardation in growth and interveinal chlorosis of young leaves; chlorosis intensified later with the development of irregular brown spots on lamina. Excess Cu not only reduced the size of leaves but also affected adversely the root development. In radish, Cu toxicity decreased the fresh weight, biomass, root weight, concentrations of total and active iron, chlorophyll, activities of antioxidative enzymes catalase (CAT), and peroxidase (POX), starch phosphorylase (ST) and acid phosphatase (AP) with concomitant increase in Cu accumulation in different parts. These effects were more pronounced at 0.2 than 0.1 mM Cu.

Anthocyanins from the Rhizome of Raphanus sativus, and Change in the Composition during Maturation

Four new acylated anthocyanins with three known pigments were isolated from the rhizome of the Chinese red radish (Raphanus sativus cv. Beijing hong xin), and their structures were determined. All of them possessed pelargonidin 3-sophoroside-5-glucoside as a common structure, and each was substituted with one to two aromatic acyl residues, with/without a malonyl residue and with/without a sugar residue. The major aromatic acyl moiety was feruloyl. Most of the pigments were malonylated. The cambium part was richer in polyacylated anthocyanins than the parenchyma part.

First Report of Alternaria raphani Causing Black Patches on Chinese Radish During Postharvest Storage in Canada.

During November of 2003, Chinese radishes (Raphanus sativus cv. Taibai) harvested in St. Catharines, Ontario and stored in less than 1°C with 98% relative humidity (RH) and 5°C with 96% RH showed symptoms of black and dark brown, irregular patches, with or without decay. The symptoms were closely associated with skin wounds and damaged root hairs. Fungal DNA was extracted from discolored skin samples peeled from a radish, and 18S rRNA genes were amplified with fungal-specific PCR primers (1) EF4f (5'-ggaagggrtgtatttattag-3') and EF3r (5'-tcctctaaatgaccagtttg-3'). The cloned genes were sequenced using the primer EF4f and compared directly with nonredundant nucleotides in GenBank with BLAST. The results indicated that more than 75% of the fungal microflora on the diseased radish were Alternaria spp. Alternaria sp. was successfully isolated from discolored and decayed radish tissues. Morphological and molecular identification indicated that the isolated Alternaria sp. cultures belong to A. raphani, which was previously reported to cause leaf and pod blight on radish (2). For pathogenicity studies, a spore suspension (1 × 105 conidia/ml) obtained from a 4-week-old A. raphani culture was used to inoculate 'Taibai' Chinese radish tissues, including inner tissues and wounded and nonwounded skin. All tests were carried out at room temperature (22 to 24°C). On inner tissue and wounded skin, symptoms of dark brown-to-black patches appeared 2 days after inoculation and progressed with time. No symptoms developed on the noninoculated control or the nonwounded, inoculated treatment. A. raphani was reisolated from symptomatic tissue. Further evidence of pathogenicity was obtained by an additional inoculation and observation of symptoms. The results indicated that A. raphani was the causal agent of the black patches observed on Chinese radish, and to our knowledge, this is the first report that A. raphani could cause a postharvest disease on Chinese radish in storage.

Life cycle duration of Meloidogyne incognita and host status of Brassicaceae and Capparaceae selected for glucosinate content

AbstractDifferent plant species in the families Brassicaceae and Capparaceae were evaluated for their potential use in management of the root-knot nematode, Meloidogyne incognita. Preliminary tests on host suitability were carried out for toxic effects on the nematode in small field plots of soil naturally infested with M. incognita. Afterwards, the best accessions and a susceptible tomato cultivar (UC82) were tested in pots to collect more complete observations of the nematode life cycle on the selected plant roots. Plants were cultivated in the glasshouse for 14–15 weeks and evaluated every 2 weeks. Root gall rating, population reproduction factor and life cycle duration showed wide differences amongst the different accessions and indicated two distinct approaches for control of M. incognita: catch crops or green manure. At 14–15 weeks after sowing, Rapistrum rugosum sel. ISCI 15, Eruca sativa cv. Nemat, Barbarea verna sel. ISCI 50 and Raphanus sativus cv. Boss were considered 'poor to nonhost' species; Brassica juncea sel. ISCI 99 was classified as 'maintenance host'; Lepidium campestre sel. ISCI 103 and Erucastrum gallicum were 'good hosts'. At 10 weeks after sowing, B. juncea sel. ISCI 20 was classified as a good host, so it could be grown for fewer than 8–10 weeks in a cropping system. The presence of galls and the identification of juveniles, females and egg masses, confirmed that second-stage juveniles had penetrated into the root of the tested accessions and completed their life cycle. However, in R. rugosum sel. ISCI 15, M. incognita did not complete its life cycle, even after 15 weeks.

Uptake and translocation of phytochemical 2-benzoxazolinone (BOA) in radish seeds and seedlings.

The molecular aspects of phytochemical interactions between plants, especially the process of phytochemical translocation by the target plant, remain challenging for those studying allelopathy. 2-Benzoxazolinone (BOA) is a natural chemical produced by rye (Secale cereale) and is known to have phytotoxic effects on weed seeds and seedlings. The translocation of BOA into target plants has been poorly investigated. Therefore, the total absorption of [ring U 14C] BOA was estimated by oxidizing whole seedlings of Raphanus sativus cv. for 8 days and quantifying the radioactivity. Non-radiolabelled BOA in seedlings was also estimated by HPLC. BOA applied at 10(-3) M was readily taken up by germinated radish at a rate of 1556 nmol g(-1) FW. At these same concentrations, BOA reduced radish germination by 50% and caused a delay in radicle elongation. Exogenous BOA was responsible for the observed germination inhibition. At a concentration of 10(-5) M, BOA was taken up by germinated seeds (31 nmol g(-1) FW), but this quantity did not affect radish germination. Labelled BOA was not mineralized in the culture medium during seedling growth as no 14CO2 was recovered. Both 10(-3) and 10(-5) M BOA were translocated into radish organs, mainly into roots and cotyledons. These organs were then identified as potential physiological target sites. Cotyledons remained the target sink (44% of the total radioactivity). The kinetics of BOA uptake at 10(-3) and 10(-5) M in radish seedlings was identical: BOA accumulation was proportional to its initial concentration. A comparison between radioactivity and HPLC quantification for 10(-3) M BOA indicated that BOA (along with some metabolites) could effectively be recovered in radish organs using chromatography.

Uptake and Translocation of Copper in Brassicaceae

Ten cvs. of four Brassicaceae species were tested to evaluate their copper (Cu) uptake and translocation. Germination and root length tests indicated that Brassica juncea cv. Aurea and Raphanus sativus cvs. Rimbo and Saxa were the species with the highest germinability and longest roots at Cu concentrations ranging from 25 up to 200 µM. Raphanus sativus cv. Rimbo grown in hydroponic culture at increasing Cu concentrations (from 0.12 up to 40 µM) for 10 days produced a relatively high biomass (17.2 mg plant−1) at the highest concentration and had a more efficient Cu translocation (17.8%) in comparison with cvs. Aurea and Saxa. The potential of cv. Rimbo for Cu uptake was then followed for 28 days at 5, 10, and 15 µM Cu. In comparison with the control, after 28 days of growth the 15 µM Cu‐treated plants showed a reduction in the tolerance index (−40%) and in the above‐ground dry biomass (−19%). On the contrary, an increase in the below‐ground dry weight was observed (+35%). Copper accumulated during the growth period both in the below‐ and above‐ground parts (about 14 and 4 µg plant−1 at 10 and 15 µM Cu, respectively), but the translocation decreased from 50 to 30% in the last week at all the concentrations used. In addition, cv. Rimbo grown in a multiple element [cadmium (Cd), chromium (Cr), Cu, lead (Pb), and zinc (Zn)] naturally‐contaminated site accumulated all elements in the above‐ground part in a range from 5 to 62 µg plant−1.

Heat shock protein synthesis is induced by diethyl phthalate but not by di(2-ethylhexyl) phthalate in radish ( Raphanus sativus)

The toxicity and effects on protein synthesis of the phthalate esters diethyl phthalate (DEP) and di(2-ethylhexyl) phthalate (DEHP) was studied in radish seedings (Raphanus sativus cv. Kööpenhaminan tori). Phthalate esters are a class of commercially important compounds used mainly as plasticizers in high molecular-weight polymers such as many plastics. They can enter soil through various routes and can affect plant growth and development. First the effect of DEP and DEHP on the growth of radish seedings was determined in an aqueous medium. It was found that DEP, but not DEHP, caused retardation of growth in radish. A further investigation on protein synthesis during DEP-stress was executed by in vivo protein labeling combined with two-dimensional gel electrophoresis (2D-PAGE). For comparisons with known stress-induced proteins a similar experiment was done with heat shock, and the induced heat shock proteins (HSPs) were compared with those of DEP-stress. The results showed that certain HSPs can be used as an indicator of DEP-stress, although the synthesis of most HSPs was not affected by DEP. DEP also elicited the synthesis of numerous proteins found only in DEP-treated roots. The toxic effect of phthalate esters and the roles of the induced proteins are discussed.

Effect of drying and salting on the flavour compound of Asian white radish

Asian white radish ( Raphanus sativus cv. Hoshiriso) was dried to <10% moisture using a hot air drier at 40, 50 60 and 70 °C, a heat pump drier at 35, 40, 45 and 50 °C and a freeze-drier, and was salted under pressure with concentrations of 0, 5, 15 and 25% sodium chloride. The primary compound responsible for the flavour of white radish, 4-methylthio-3-trans-butenyl isothiocyanate (MTBITC), was found to be substantially decreased by the hot air and heat pump driers, the loss increasing with increasing drier temperature, but the loss was lower in the heat pump drier than the hot air drier at equivalent temperatures. Osmotic dehydration with salt also caused a substantial loss of MTBITC with the loss increasing with increasing salt concentration. MTBITC loss of about 50% occurred with a heat pump drier at 50 °C, hot air drier at 40 °C and 25% salt. Freeze-dried white radish showed a relatively low loss (15% MTBITC).

The effect of fertilizer additions on the solubility and plant-availability of Cd, Ni and Zn in soil

We conducted a pot experiment to investigate the effect of fertilizer additions on the solubility of Cd, Ni and Zn in soil solution and their uptake by plants. Radish (Raphanus sativus cv. Crystal Ball), oat (Avena sativa cv. Thule) and water spinach (Ipomoea aquatica cv. Kangkon) were grown in a naturally metal-rich soil. From day 7 after planting, fertilizers were added daily to each pot. Additions of fertilizer nutrients affected the pH of soil and soil solution, soluble and tissue concentrations of Ca, Mg, K, Cd, Ni and Zn differently in three plant species. The trend of soil and solution pH was in the order: water spinach < radish < oats, that resulted highest soluble and plant tissue concentrations of Cd and Zn in the water spinach followed by radish and then oats. However, Ni concentration in the soil solution increased in all pots and was not affected by pH changes. Soil solution pH increased by more than 1unit in the pots with radish and oats, indicating that mechanisms other than acidification, such as ion exchange and root exudation, may be responsible for the increased heavy metal uptake in these two plant species. Paired t-test showed significantly higher uptake of Cd and Zn in the radish plants resulting in lower concentrations of these elements in the solution. The contribution of mass flow to the supply of major cations and heavy metals varied among elements and plant species. Cadmium, Zn and K were taken up rapidly by all plant species in response to the amount supplied by mass flow. In contrast, the supply of Ni was in excess of its uptake by radish and water spinach. The uptake of all elements was positively correlated (p<0.0001) with mass flow and the transpiration rate in individual plant species. The study suggests that fertilizer cations increased the uptake of metals by improving growth conditions, but the magnitude of increase depended on plant species.

Breeding of Moricandia arvensis Monosomic Chromosome Addition Lines (2n=19) of Alloplasmic (M. arvensis) Raphanus sativus.

By backcrossing to Raphanus sativus cv. 'Pink ball', 55 BC 2 plants were obtained from two sesquidiploidal BC 1 plants (MaRR, 2n = 32) between Moricandia arvensis (MaMa, 2n = 28) and R. sativus (RR, 2n = 18). Their somatic chromosome numbers ranged from 2n = 18 to 2n =23, except for one hyperploid plant with 2n=44. In the BC 3 generation, 64 plants (2n = 19) were generated from 16 BC 2 plants with 2n = 19∼23. Each plant with 2n=19 exhibited both morphological and physiological characteristics diagnostic for the presence of an added chromosome of M. arvensis genome, and showed predominantly the chromosome pairing type of 9II + 1I at metaphase I of PMCs. They were classified into twelve (a∼l) types of monosomic chromosome addition lines (MALs) of alloplasmic (M. arvensis) R. sativus carrying M. arvensis cytoplasm by their morphological, physiological and cytogenetical characteristics. The mean of seed setting in the twelve types of MALs ranged from 2.88 grains (f-type) to 0.51 grains (j-type) per pollinated flower when they were backcrossed to R. sativus cv. 'Pink ball'. The transmission rates to the next generation through female gametes ranged from 32.5% (f- and j-types) to 5.5% (h-type) when smaller seeds were selectively grown. The specific characteristics of each type of MALs were transmitted from the BC 3 generation to the BC 4 and BC 5 ones without any modification. The MALs of the distinctive twelve types were also identified using RAPD markers in the BC 5 generation. Pollen fertility of the twelve types of MALs ranged from 85.6% (c-type) to 3.4% (l-type), although four types (g-, h-, i- and j-types) exhibited complete male sterility. Furthermore, alloplasmic (M. arvensis) R. sativus plants (2n = 18) which were derived from male fertile MALs showed complete male sterility. The twelve types of MALs produced in this study should be useful materials to determine the localization of genes for agronomic traits on the individual chromosome of M. arvensis and the alloplasmic (M. arvensis) R. sativus should also be a useful material for the development of a new cytoplasmic male sterility system in R. sativus.

A chilling-insensitive stage in germination of a low-temperature-adapted radish, rat’s tail radish ( Raphanus sativus L.) cv. “Pakki-hood”

The rat’s tail radish ( Raphanus sativus cv. “Pakki-hood”), cultivated in the northern part of Thailand, does not require low temperature for flower-bud initiation and shows high germinability even at low temperature. To analyze its characteristic temperature response, seedlings were subjected to a 3 day-chilling treatment at 0°C after a series of incubations for germination at 26°C which ranged from 3 h to 4 days. The chilling treatment after an initial stage (3 h to less than 2 days) of incubation at 26°C did not significantly affect the hypocotyl regrowth, but the same treatment after a more than 2-day incubation at 26°C reduced subsequent hypocotyl growth of plants. 1-aminocyclopropane-1-carboxylic acid (ACC)-dependent ethylene-forming activity was also reduced by the chilling treatment after 2–4-day incubation at 26°C. Electrolyte leakage from tissues of seedlings in the chilling treatment was increased in proportion to the length of the incubation at 26°C, indicating severe damage of chilling to plasma membranes after a longer incubation. We found a transition of chilling-sensitivity at 2 days in the incubation period for germinating seeds of Pakki-hood. Seedlings of Pakki-hood chilled earlier than the transition are relatively unaffected in their subsequent growth, but the seedlings become sensitive to chilling after the transition.