Brassica Pekinensis Rupr Research Articles

Floating row covers affect Pb and Cd accumulation and antioxidant status in Chinese cabbage

In 1993 and 1994, crop covering treatments [perforated polyethylene (PO, 500 holes/m 2) and a polypropylene (AO, Agryl-P17)] were used to produce different environmental conditions for the growth of Brassica pekinensis (Lour) Rupr cv. Nagaoka 50. Plant material was sampled five times from transplanting to harvest, and the amounts of chlorophylls, peroxidase activity, biomass, and Pb and Cd accumulation in the above-ground plant material were measured. Uncovered control plants, received lower air and root temperatures as well as lower relative humidity, and showed the highest chlorophyll a, chlorophyll b, carotene and peroxidase activity values. Under floating row covers (PO and AO) the improved thermal conditions resulted in increased fresh and dry mass and accumulation of Pb and Cd. It is also important to consider that because of this accumulation these plants may pose a risk for human health through Pb and Cd contamination of food supplies.

Production And Composition Of Chinese Cabbage Under Plastic Rowcovers In Southern Spain

SummaryThe effects of plastic rowcovers on the growth and quality of Chinese cabbage (Brassica pekinensis (Lour) Rupr. `Nagaoka 50') were investigated in Granada, southern Spain (latitude: 378. 10 9.21 99 N; longitude: 38.38 9 E; .10 99 elevation: 600.m), for three years. Polyethylene (T1) and polypropylene (T2) covers increased air temperature by 7K and 5K, and soil temperature (5- and 15.cm depth) by 3±4K and 2K, respectively, compared with plots in the open (T0). In contrast, radiation levels in T1 and T2 were reduced by 12% to 16%, respectively. Thus, total shoot fresh weight was 111% (T1) and 108% (T2) greater under rowcovers, and the commercial head weights were 105% (T1) and 96% (T2) greater, and dry weights 21% (T1) and 13% (T2) greater than T0. These differences in plant production were reflected in higher yields under plastic, and a higher proportion of marketable heads (23% in open air compared with 68% and 65% under T1 and T2, respectively). The concentration of soluble sugars and pigments were also lower in the shoot under rowcovers than in plants in the open air. There were only small differences between the two plastic covers. Slightly warmer conditions and less shade under polyethylene compared with polypropylene provided greater plant production, yields and sugar concentrations, but lower pigment concentrations. Growing Chinese cabbage plants under plastic rowcovers in southern Spain increased production without significantly affecting composition.

Monitoring of matrix flow and bypass flow through the subsoil in a volcanic ash soil

Daily matrix flow at 1-m depth in a volcanic ash soil was calculated during a period of one year using Darcy's law. Unsaturated hydraulic conductivity of undisturbed core samples could be expressed as a unique function of the soil water content. Hydraulic gradient obtained from soil water suction by a tensiometer installed at 90- and 110-cm depths, and hydraulic conductivity converted from the soil water content by time domain reflectometry (TDR) were monitored every 30 min throughout a year in a maize (Zea mays L.) Chinese cabbage (Brassica pekinensis Rupr.) field. The matrix flow obtained by this method was substituted for the water balance equation to estimate the bypass flow, and monthly and annual evapotranspiration. Annual rainfall in 1997 was 989 mm and evapotranspiration was estimated to be 730 mm. Net matrix flow at 1-m depth was 164 mm downward even though upward matrix flow occurred during half of the year. Downward flow determined by the water balance method exceeded the downward matrix flow during two heavy rain events in the year and the difference between the two flows was 63 mm, which was considered to correspond to a bypass flow. The bypass flow accounted for only 6.4% of the annual rainfall. Matrix flow was well monitored by the application of unsaturated Darcy's law in a field, and monthly evapotranspiration and bypass flow could be quantified by the introduction of the water balance equation.

Temperature in relation to phosphorus nutrition in Chinese cabbage

Chinese cabbage plants [Brassica pekinensis (Lour) Rupr. cv. Nagaoka 50] were cultivated experimentally for two years (1993 and 1994) using a semi‐forcing technique of floating rowcovers, polyethylene (T1), polypropylene (T2), versus no floating row‐covers, control (T0). Five samplings were made, taking four plants per each replication and total phosphorus (P) (Ptotal), inorganic P (Pi), and calculated organic P (Porg) were determined as well as foliar acid phosphatase activity (FAPA). The aerial and root temperatures of the treatments T1 and T2 exceeded those of T0. The Ptotal concentration showed no significant variations with treatment, whereas the Pi concentrations increased in Ti and T2 and Porg decreased in both treatments with respect to T0. The FAPA was influenced a similar way as Pi, raising with temperature. The contents (mg plant‐1) of Ptolal, Pi, and Porg were greater in T1 and T2 than in T0, and this could be due to the fact that the highest temperatures (root and aerial zone) generated by the plastic rowcovers favored the absorption of P, thereby boosting FAPA and the fresh and dry weights, and yield.

Improved method for easy and rapid determination of root length of vegetables

We developed an improved method for the determination of the root length of crisphead lettuce (Lactuca sativa L.) and Chinese cabbage (Brassica pekinensis Rupr.). Boiling of soil containing roots and stirring to collect the roots in water reduced the contamination with debris. The time required for removing the debris was shortened by 30% as compared to washing of roots with water. Boiling had no effect on the nitrogen concentration, but resulted in changes of the phosphate, potassium and calcium concentrations of roots. Use of a crosscounter plate shortened by 30% the time required for the line intersect method. The total time required for root length determination from a 1 kg soil sample was only 15.9 min.

フィルムマルチ施用畑の雨水と土壌水分の挙動

Film mulch is being used in many farm lands because it improves the environment for cultivation by suppressing water evaporation from soil surface, maintaining a mild soil moisture condition, and maintaining the soil temperature higher than the bare soil surface, in addition to protecting against pests and diseases. Crop cultivation in cool high lands (such as the Shinshu Plateau) can be made possible with the introduction of film mulch. However, as the direct infiltration in the root zone are lower in fields where film mulch is used than in bare soil fields, and this raises fears that droughts would be exacerbated.Experimental comparisons of the soil moisture condition and flow between mulched bed and furrow space using the soil moisture measurement technique at many positions and many depths were carried out in the fall of 1995 in field planted with Chinese cabbage (Brassica pekinensis Rupr.), and in the spring of 1996 in field planted with cabbage (Brassica oleracea L.). The results are summarized as follows;(1) The shallow topsoil of the mulched beds had less soil moisture than furrow space and bare soil even after light rains at low soil moisture condition. The sowed areas (hold of the mulch film) in mulched beds, however, were moisture than the surrouding of sowed area. But one or two days after rainfall, soil moisture condition in mulched bed and furrow space were almost same.(2) As the crops grew, the soil moisture became lower than furrow space due to the water uptake by the crops' root system. In the soil layer below the root zone, i.e. at a depth of more than 0.3m, soil moisture is moved from the furrow space to the mulched bed by the gradient of soil moisture potential caused by the soil moisture uptake by the root system.These results propose that occasional plowing in the furrow space causes an increase in the infiltration rate of rain water, and facilitates the movement of moisture from the furrow space to root zone of the mulched beds.

Cadmium concentration in vegetable crops grown in a sandy soil as affected by Cd levels in fertilizer and soil pH

Field trials were conducted over a three-year period with chinese cabbage (Brassica pekinensis Rupr.) and carrots (Daucus carota L.) grown in a sandy soil with pH adjusted to 5.5 and 6.5. The NPK fertilizers containing 1, 30, 90, and 400 mg Cd kg−1 P were applied at the rate of 0.07, 2.1, 6.3 and 28 g Cd ha−1 yr−1. The amounts of Cd added through phosphate rock also ranged between 0.1 and 28 g ha−1 yr−1. The increased Cd application rates through NPK fertilizers increased the Cd concentration in both vegetables but the differences among treatments were not found to be significant. The Cd uptake by both crops was significantly (p<0.01) higher at pH 5.5 than at pH 6.5. Chinese cabbage exhibited lower Cd concentration than carrots. Carrot leaves contained higher Cd than its roots. Cadmium removals by chinese cabbage and carrot were about 0.7 and 1.3 g ha−1 yr−1, respectively. At pH 5.5, Cd concentrations in the two crops, based on a three-year average, were 23 and 46% higher than at pH 6.5. Cadmium uptake by chinese cabbage from different sources of phosphate rock was affected to a very limited extent. Cadmium concentration generally increased over the years. Cadmium extracted by ammonium nitrate after harvest of the crops was closely related with soil pH and Cd concentration in the plants.

BIOGENIC AMINE CONTENT AND MICROBIAL CONTAMINATION OF LEAFY VEGETABLES DURING STORAGE AT 5C

Biogenic amine content and microbial contamination of prepacked salad mixtures and the fresh leafy vegetables Chinese cabbage (Brassica pekinensis Rupr.), endive (Cichorium endivia L.), iceberg lettuce (Lactuca sativa var. capitata) and radicchio (Cichorium intybus var. foliosum) were examined during storage at 5C for 6 days. Putrescine, histamine, spermidine, spermine and tyramine were detected in concentrations ranging from 0.1 to 17 μg/g fresh weight. Only putrescine showed a progressive increase during storage, depending on the type of leafy vegetable; its level of increase ranged from 3- to 8-fold, with the most pronounced for Chinese cabbage. A relationship seems to exist between the Enterobacteriaceae population (representing up to 90% of the total microbial numbers determined by plate count methods) and the putrescine concentration.

Survival of embryo irradiated with gamma rays by embryo culture in Brassica pekinensis rupr.

前報でカンランのガンマー線照射胚の培養により生存率を向上することが明らかにされたので，ハクサイにおいてもカンランの場合と同様の目的で高線量照射された胚を培養した。材料はハクサイの品種，花心，交配65日，改良千歳を用い，受粉後11日と13日目の球形胚と早期のハート形胚に60Coガンマー線10kR/日または20kR/日の線量率で20kRを照射した。胚培養は，受粉後16～23日目(照射後4～1O日目)に行ない，培養後34日目に調査した。照射当代の種子稔性および発芽率も調べた。種子稔性および発芽率は，10kR/日照射区のほうが20kR/日照射区より高かった。培養による胚の茎葉形成率および根形成率は，種子稔性および発芽率と同様に低線量率区(10kR/日照射)で高かった。照射胚の茎葉形成および根形成率に品種間差が認められ，改良千歳が最も率が高かった。照射区の胚は高い率で生存可能であるが，大部分はカルスで生き残った。結論として，ハクサイにおいてはカンランの場合に比較して培養による生存率向上の効果は小さかった。

Effects of TYMV infection on leaf pigments in Brassica pekinensis Rupr

The effects are described of turnip yellow mosaic virus (TYMV) infection on the production of photosynthetic pigments in Chinese cabbage plants. Chlorophylls a and b and the four carotenoid pigments were analysed in plants following their infection with three strains of TYMV. The results support the view that infection reduces the amount of pigments in the plant mainly by inhibition of synthesis rather than by destruction of pre-existing pigments. In inoculated leaves, pale green and yellow green strains of the virus reduced the concentration of chlorophylls more than the carotenoids. A severe white strain of the virus reduced the concentration of all six pigments to a similar extent in all tissues tested.

Metabolism of S-methylcysteine and its sulfoxide in Chinese cabbage, Brassica pekinensis Rupr.

The metabolism of sulfur of S-methyl-L-cysteine and ($)S-methyI-L-cysteine sulfoxide in Chinese cabbage was studied. Results showed that these sulfur-bearing amino acids are metabolized to cysteine by demethylation. This conclusion is based on; 1) the relatively high recovery of radioactivity in the cysteine of the insoluble fraction a short time after the administration of 35S-labeled S-methyl-L-cysteine or ($)S-methyl- L-cysteine sulfoxide; 2) the similarity in the ratios of 3H to 35S in the cysteine of the insoluble fraction and in the double-labeled cysteine part of S-methyl-L-cysteine and its sulfoxide fed to detached leaves and 3) the obvious structural relationship between cysteine and its methyl derivative, S-methyl-L-cysteine. Moreover, we ascertained that the sulfur of S-methyl-L-cysteine was also utilized when supplied to plants; i.e. tomato, tobacco and cucumber, in which this sulfur amino acid has not been found.

Fate of ($ ) S-methyl-L-cysteine sulfoxide in Chinese cabbage, Brassica pekinensis RUPR.

($) S-methyl-L-cysteine sulfoxide (MCS) was scarcely found in seeds of Chinese cabbage, but was present in relatively large amounts in all plant parts after germination. Changes in MCS content paralleled those for soluble sulfur content of tissue. When Na235SO4 was fed to plants, the 35S was predominantly incorporated into MCS in the free amino acid fraction in both sulfur-sufficient and deficient plants, but it was incorporated to a greater extent in the former. 35S-MCS was metabolized more readily in deficient than in sufficient plants, and its sulfur was found not only in various soluble compounds but in the insoluble fractions from plants as well. These results indicate that MCS is a conspicuous constituent in the free amino acid pool of Chinese cabbage and may play an important role in sulfur metabolism by acting as a soluble pool for organic sulfur.

Morphological and Physiological Distinction between Two Populations of the Peach–Potato Aphid

INDIVIDUAL Myzus persicae (Sulz.) which had survived repeated spraying with organophosphorus insecticides were collected from plants grown in glasshouses in 1963 and 1964 and were allowed to multiply on Brassica pekinensis Rupr. Several populations, derived from aphids collected in different glasshouses and from different species of host plant, were reared on B. pekinensis in separate insect proof cages for more than 2 yr. Experiments showed that these populations were much more resistant to organophosphates than another designated NC (normal colony), which had not been exposed to these insecticides1. During 1965 and 1966 experiments were carried out to investigate whether aphids from one of these populations resistant to insecticides (RR3) differed from NC aphids in morphology as well as in physiology.

Selective fertilization in plants in relation to plant breeding. I. Chinese cabbage (Brassica pekinensis RUPR.) 5. Some Schemes of F&lt;SUB&gt;1&lt;/SUB&gt; seed production utilizing selective fertilization.

( 1 ) Size of seed resulting from inter-varietal hybridization (F1 seed) tended to be larger than that of intra-varietal hybridization (seed of female plant), but this tendency was not distinct (Table 1). Therefore, seed size seems to be not always effective in screening F1 seeds. However, since germination of F1 seeds was apparently faster (Table 2) and growth of F1 seedlings was more vigorous than those of intra-varietal ones, F1 Plants may remain in a field only through thinning out weak seedlings. ( 2 ) It was found that F1 plants were distinctly more resistant to virus and Bacillus aroidae than those of female parent (Table 3). ( 3 ) Frequency (%) of F1 seeds in the case of mixpollination was higher in crosses utilizing selfcompatible plants than in self-incompatible ones as female parent (Table 4).

Selective fertilization in relation to plant breeding. I. Chinese cabbage (Brassica pekinensis RUPR.). 4. Competitive compatibility relationships among pollen with different genotypes.

Competitive cornpatibility relationships among pollen with different genotypes (previously determined by MURAKAMI, 1965, vide Fig. 1) were studied. A pollen mixture of two different genotypes, one originating from a plant in the variety Kashin and the other from the variety Matsushimashin No. 2, was pollinated to plants in Kashin and the grades of the compatibility were determined from the frequencies of the inter-varietal hybrids.

BIOCHEMICAL STUDIES ON PTERIDINES IN PLANTS

The main object of this investigation was an attempt to elucidate the steps and intermediates comprising biosynthetic pathway of dihydropteroic acid in a higher plant, Brassica pekinensis Rupr. The inhibition tests with three types of inhibitors specific to affect the respective different processes were projected for this purpose. The results gained as itemized in the followings offered a powereful support for the suggestion that the pathway originating in GMP might proceed through the three steps blocked by the inhibitors, including as intermediary precursors 2-amino-4-hydroxy-6-(D-erythro-trihydroxypropyl) dihydropteridine, 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine and the pyrophosphate ester of the latter pteridine. The cell-free system of the plant was able to catalyze the formation of dihydropteroic acid not only from GMP but also from these pteridine derivatives. These conversions required ATP, Mg2+ and p-aminobenzoic acid, except the case of the pyrophosphate compound that could be immediately transformed to the final product without ATP.1. When 2-amino-4-hydroxy-6-(D-erythro-trihydroxypropyl) dihydropteridine, 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine and the pyrophosphate ester of the latter pteridine were tested as substrates, the formation of dihydropteroic acid from these pteridines was inhibited by p-aminosalicylic acid, sulfanilic acid and sulfanilamide, These findings suggested that the donors are metabolized to dihydropteroic acid by coupling of the phosphate ester with p-aminobenzoic acid.2. The existence of 2-amino-4-hydroxy-6-carboxydihydropteridine, 2-amino-4-hydroxydihydropteridine and dihydrobiopterin caused significant inhibition of dihydropteroic acid formation derived from both 2-amino-4-hydroxy-6-(D-erythro-trihydroxypropyl) dihydropteridine and 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine, but not from the pyrophosphorylated derivative of the latter substance. The most powerful inhibition was shown by the carboxydihydropteridine and reversed by increasing the concentration of the hydroxymethyldihydropteridine supplied in the media. These data indicated a possibility that the inhibitors might affect the pyrophosphorylation of the hydroxymethyldihydropteridine by action of ATP and the transformation of the trihydroxypropyldihydropteridine to the final product might involve this step.3. When 2-amino-4-hydroxy-6-(D-erythro-trihydroxypropyl) dihydropteridine was examined together with one of the corresponding L-erythro, D-threo and L-threo isomers, the yield of dihydropteroic acid was reduced, while no inhibition resulted by the combination of the isomers with either 2-amino-4-hydroxy-6-hydroxymethyldihydropteridine or this pyrophosphorylated pteridine. L-Erythro form was most effective as inhibitor and the inhibition induced by this isomer was partially released by increasing the amount of the D-erythro derivative applied. From these evidence, it was assumed that the isomer could act on the conversion process of the D-erythro compound to the hydroxymethyldihydropteridine.4. Sulfanilic acid, 2-amino-4-hydroxy-6-carboxydihydropteridine and 2-amino-4-hydroxy-6-(L-erythro-trihydroxypropyl) dihydropteridine blocked the production of dihydropteroic acid from GMP. This finding provides a reasonable basis for an assumption that the pathway of GMP metabolized to the final product might involve the three steps suggested above.5. The present findings are discussed in relation to other recent works on pteridine biosynthesis.

Selective fertilization in relation to plant breeding. : I.Chinese cabbage (Brassica pekinensis RUPR.). : 3. Inheritance of self and cross-incompatibility.

In two previous papers, the author reported about the existence of selective fertilization in Chinese cabbage and its mechanism being essentially dependent on two important factors, viz., differences among varieties with regard to the frequencies of compatible pollen grains in given population and existence of various grades of compatibility in compatible pollens (Murakami, 1964 a and b). Since the pollen compatibilities are mainly controlled by genes, genetical aspects of the compatibility systems were also studied later. All the related experiments were conducted under greenhouse conditions. Segregation studies regarding self-incompatibility in the progenies of the selfed plants were conducted during 1956 to 1960. Results for the varieties Kashin and Matsushimashin N0.2 are presented in Figs. I and 2 respectively. During 1958 to 1960, several plants in different groups were crossed in all possible combinations to study their compatibility or otherwise. Results of such studies on three groups in Kashin and two groups in Matsushimashin N0.2 are presented in Tables 1 and 2 respectively.

Isolation and purification of undegraded ribonucleic acids

1. 1. A simple method for purifying phenol prepared RNA is described. It exploits the different solubilities of cetyltrimethylammonium salts of RNA and impurities in recovering pure RNA from the Kirby 4 two phase partition system. 2. 2. [ 32P]RNA prepared by phenol extraction and purified by the standard Kirby procedure is degraded and heavily contaminated by [ 32P]phosphate esters. The procedure described here effectively removes contaminants. 3. 3. RNA isolated from rat liver, Brassica pekinensis Rupr. var. Wong Bok (chinese cabbage) leaves and cultured tobacco pith cells ( Nicotiana tabacum var. Wisconsin 38), and purified by this method appears to be undegraded. RNA isolated from tobacco mosaic virus or a mixture of tobacco mosaic virus and whole rat liver retains biological activity following purification by this procedure.

The effects of salt concentration of culture solution and calcium supplied to the soil on the occurrence of the marginal rot in Chinese cabbage (Brassica pekinensis RUPR.)

In the first experiments reported here, the authors attempted to solve the question whether or not the concentration of soluble salts in culture solution is an accurate index of the occurrence of marginal rot in Chinese cabbage.Plants grown in the solution A containing anions such as chloride and nitrate at high level suffer from leaf marginal rot in the position between 10th and 20th leaves and from the blackening of hydathodal tissue in the position between 20th and 30th leave counted from the bottom up. Therefore, the occurrence of marginal rot may be connected with a disturbance of water-relation due to the cell degeneration. When the heading begins, physiological activity such as mineral absorption becomes higher, but the fullness in tissue decreases. This apparently indicates that there is an unbalanced metabolism in the head of Chinese cabbage during the heading stage.The rate of growth increased in proportion to the concentration of the culture solution. It is therefore difficult to relate the occurrence of marginal rot to high osmotic pressure of culture solution. On the other hand, the solutions of single salt in 0.2 molar concentration led to decrease in the rate of absorption of water, the physiological drought, but did not produce the marginal rot.The second experiment was designed to clear up the effect of calcium supplied to the soil on the CaO content in leaves and on the occurrence of the physiological disorder. The symptom of marginal rot occurred when CaCl2 and Ca(NO3)2 of high rate were applied to the soil. Although the calcium content was high in lower leaves and low in the upper leaves, there was no direct relationship between the occurrence of the marginal rot and the total calcium content.It seems possible that the marginal or heart rot in Chinese cabbage is a symptom of the relative calcium deficiency and not due to the physiological state produced by the failure of calcium absorption. The conclusion, therefore, is that the calciumm content in younger leaves lies between those of the calcium-deficient and normal leaves, and other factors such as osmotic pressure and/or specific ions enhance the occurrence of the marginal rot in the leaves of Chinese cabbage.

Selective fertilization in plants in relation to plant breeding. I. Chinese cabbage (Brassica pekinensis RUPR.). 2. Mechanisms involved in selective fertilization.

Existence of selective fertilization in Chinese cabbage and its dependency essentially on compatibility between varieties were previously reported (Murakami, 1964 ) . With a view to seek, in detail, the mechanisms involving selective fertilization in this crop, another series of experiments were conducted. The methods used for this purpose were different artificial mix-pollinations and the subject materials being Kashin and Matsushimashin No. 2, the two of the flve varieties which were included in the previous trials. When a pollen mixture of the above two varieties was used on Kashin (seed parent), the results of studies in its progeny revealed that inter-varietal hybrids originated predominantly from the basal portion of a pod rather than its upper portion (Table 1). This suggested that the pollen growth of Matsushimashin No. 2 was perhaps faster than that of Kashin. However, in another experiment where styles were cut off at definite intervals after mixpollinations, the results of studies in their subsequent progenies revealed no significant differences among the frequencies of inter-varietal hybrids in the tested cases (Table 2) . In yet another experiment with dual pollinations, the frequncies of intervarietal hydrids in the progenies of some plants of Kashin, contrary to expectations, were found to be almost constant (Fig. 1).