April 1963, Volume 11 Issue 4

 

          Research Articles
Studies on Plant Respiration VI.
Author: L. F. Yen, F. C. Wang, K. L. Kuan and P. S. Tang
Journal of Integrative Plant Biology 1963 11(4)
      
    (2-C14)-acetate was fed to etiolated rice seedlings and the respiratory pathways of the acetate in them were studied. The following results were obtained from feeding experiments: 1. 5-day old etiolated rice seedlings were extracted with 80% alcohol. The extract was passed through the anion exchange resin Amberlite IRA-400 and the eluant was collected for chromatography on Sin Hua no. 1 filter paper. The paper chromatogram showed that citric, isocitric, 汐-ketoglutaric, succinic, fumaric and malic acids were present in the rice tissues. It demonstrates that the intermediates of the tricarboxylic acid cycle exist in the intact rice seedling. 2. The rice seedlings were fed with (2-C14)-acetate, incubated in various time intervals from 2 to 40 or 60 minutes and then extracted with 80% hot alcohol. The extracts were passed through cation exchange resin Zerolite 225 and anion exchange resin Amberlite IRA-400 to separate them into organic acids, amino acids and sugars. The estimation of the three kinds of compounds indicates that radio activity appeared first in the organic acids, followed by amino acids and rarely appeared in the sugars. 3. The above organic acids were fractionated with ion exchange chromatography of Zerolite FF. The fractions were collected and concentrated for radioactivity determination. The results showed that citric, isocitric, succinic, fumaric and malic acids are labelled with Cl4. When malonate was added to the substrate solution, the incorporation of acetate into the organic acids was reduced to below 50%, while the radioactivity of the labelled succinate increased correspondingly. The radiochromatogram indicates the accumulation of succinate in the rice seedlings fed with labelled acetate and malonate. 4. The radioactivities of the organic acids isolated from the rice seedlings showed that succinate appeared in the initial 2 minutes in quite measurable quantity, and ma- late and citrate increased in amount until 10 minutes later. Radiochromatogram con- firmed this result. 5. When arsenite and 汐,汐∩-dipyridyl were added to the media, the incorporation of acetate into organic acid was inhibited to 68 % and 44% respectively, but the amount in- corporated into succinate was depressed 46% and 29% respectively. It means that some labelled succinate accumulates even as the inhibitors are operative. 6. The radiochromatogram of the amino acids extracted from the seedlings fed with (2-C14)-acetate shows that the radioactivities of aspartate and glutamate approach 17% and 20% of the total radioactivity of amino acids respectively. If malonate was added, the incorporation of C14 into amino acids was reduced to 50%. It means that the labelled acetate incorporates into those amino acids which are assiociated with the tricarboxylic acid cycle. 7. The following conclusion may be drawn from the above experimental results. Tricarboxylic acid cycle is present in the intact rice seedlings. From the facts that large amounts of succinate was labelled during the first moment of feedings and that some amount of succinate was still accumulated even after inhibition by arsenite and 汐,汐∩- dipyridyl, it is suggested that besides the tricarboxylic acid cycle as the main route for the utilization of acetate, it is probable that glyoxylate cycle and dicarboxylic acid cycle may be operative in these rice seedlings.
Abstract (Browse 2087)  |  Full Text PDF       
Studies on Plant Respiration V.
Author: Y. L. Tai, Y. G. Liang, Y. P. Tsou and P. S. Tang
Journal of Integrative Plant Biology 1963 11(4)
      
    The pathways of pyruvate oxidation in subc'ellular particles (mitochondria) prepared from shoots of 4-day old etiolated rice seedlings were studied. The operation of the tricarboxylic acid (TCA) pathway was established by the following results: 1. Succinate and 汐-ketoglutarate were oxidised rapidly by the panicles followed by citrate, malate and fumarate in decreasing order of rapidity. 2. Pyruvate oxidation was accelerated by catalytic amount of succinate. The operation of condensing enzyme is thus indicated. 3. Succinate oxidation was inhibited by malonate, 汐-Ketoglutarate oxidation was inhibited by arsenite. The latter inhibition was reversed by addition of succinate. 4. When reaction mixtures were examined for products on paper chromatograms, succinate was found to be converted to fumarate, malate and isocitrate, 汐-ketoglutarate was found to be converted to succinate, fumarate and malate. The presence of glyoxylate pathway along with the TCA route of pyruvate oxidation in these rice seedling particulate preparations is indicated by results obtained when homogenates and supernatant fractions were assayed for isocitratase and malate synthetase.
Abstract (Browse 1876)  |  Full Text PDF       
The Effect of Temperature on the Physiological Changes of Wheat during Grain Development
Author: Hsia Chen-au, Waon Shin-shan and Wang Fu-te
Journal of Integrative Plant Biology 1963 11(4)
      
    Experiments were made to study the physiological changes of wheat plants during grain development in different temperatures. The results obtained are summarized as follows: 1. When wheat plants were cultured at the same day temperature (25⊥) and different night temperatures (10⊥, 20⊥) from flowering to ripening, the period of grain-filling was prolonged for 10 days by low night temperature treatment. 2. Under low night temperature condition, the area of green leaves increased, the senescence of the lower leaves was retarded, the respiratory activities of leaves were lower in the night. All the responses mentioned above favored the accumulation of dry weight of the plant. Although stems, leaf sheaths, spikes and grains increased on dry weight respectively, yet the accumulation of dry matters was mainly due to the growth of stem from the beginning of flowering to 17th day after flowering. In ripening stage the difference of the dry weight of grains between high and low night temperature treatments increased significantly. 3. Since the photosynthetic products were rich in the low night temperature treatment, it favoured the growth of late flowered grains. Therefore, low night temperature treatment not only increased the weight of the 1st and 2nd grains, the fertility and the weight of 3rd grains also increased. 4. The soluble sugar content of leaf sheaths, leaves, especially the stem was higher in low night temperature treatment than in high night temperature treatment. During early stage of grain development, the alcohol soluble sugar content of grains was high and the starch content low in the low night temperature treatment. The difference between the two treatments became insignificant as plant grew to ripening. 5. In the milk ripe stage the translocation and distribution of C14-assimilated products were changed by local temperature variation (from 5每8 ⊥ to 20每25 ⊥) around the spike, the internode below spike or the feeding leaf. The photosynthetic products translocated to grains was inhibited by low temperature treatment. The effect of inhibition was greater when the low temperature treatment was around the spike than when the treatment was around the feeding leaf. Treatment of low temperature around the node below spike gave weak effect. 6. The increase of alcohol soluble substances of either supplying, conductive or receiving organ was reduced by low temperature treatment, and the spikes was most sensitive to low temperature. The radiactive activity of alcohol soluble part in the grains was about 65% in the low temperature treatment around the spike, but in the untreated plant about 63% of radiactive activity in the grains was in the dilute acid part. It was indicated that the processes of the transformation of sugars to high molecular substances in the grains was inhibited. 7. The physiological considerations of high thousand grain weight in Chinhai province, the effects of night temperature on the growth of grains, and the possibility to increase grain weight per spike are discussed.
Abstract (Browse 1983)  |  Full Text PDF       
A Study of Polyphenol Oxidase in Litchi Pericarp
Author: Li Ming-chih and Yan Jun-ling
Journal of Integrative Plant Biology 1963 11(4)
      
    Litchi is a famous fruit indigenous to southern China. When the fruit is fully ripe it is beautifully bright red, but the color fades rapidly and turns dull brown a few days after being kept at room temperature. In order to find out what is the active agent responsible for the rapid browning of the fruit, a study was made of the oxidizing enzymes present in the fruit shell. Crude enzyme preparation was made by grinding fruit shells with water or with phosphate-citric acid buffer (pH 6.8) and then filtering. Enzyme activity was measured by manometric method with the Warburg apparatus. An enzyme was found which can oxidize catechol and hydroquinone at pH 6.8, but it cannot oxidize monophenols such as p-cresol and tyrosine. The enzyme in litchi pericarp was thus found to resemble laccase with respect to substrate specificity. Enzyme activity was much reduced at pH values below 6.8, being about one-half at pH 6.2 and about one-fourth at pH 5.0 as that at pH 6.8. Boiled fruit shell extract still had some oxidizing activity toward hydroquine, presumably due to the presence of some thermostable factors capable of oxidizing polyphenols in the crude extract. Copper chelating agents such as thiourea and sodium diethyldithiocarbamate (dieca) had peculiar effects on this enzyme. The enzyme from fruit shells of the variety "Bailazi" (啞嶸赽)was inhibited by thiourea in only a short period. The inhibition gradually diminished and totally disappeared within 20每80 minutes. The degree and duration of inhibition varied with the concentration of thiourea, the higher the concentration, the greater the degree and the shorter the time of inhibition would be. After the inhibition has disappeared, absorption of oxygen continued to increase to an amount higher than that of the control, resulting in a stimulation effect. No inhibition was shown by thiourea to the enzyme from fruit shells Of the variety ※Huai-zhi§ (輕皉), which was stimulated by thiourea at the very beginning of oxidation reactions. Dieca inhibited the enzyme at low concentration (0.2 mM). At higher concentrations (2 or 4 mM) dieca gave a stimulation effect; the absorption of oxygen was markedly enhanced in the presence of dieca (2 or 4mM) as compared with that of the control. The increase of oxygen uptake in the presence of thiourea or dieca was not due to the direct oxidation of these reagents by the enzyme. Further studies are being carried out to make clear the nature of these effects.
Abstract (Browse 2383)  |  Full Text PDF       
尿技忌把我抉抖抉忍我折快扼抗抉快 我扼扼抖快忱抉志忘扶我快 扼抉我 Glycine soja (L.) Sieb. Et Zucc. i.
Author: 朱改 妙抑扶抆 - 攻忘扶抆
Journal of Integrative Plant Biology 1963 11(4)
      
    
Abstract (Browse 1983)  |  Full Text PDF       
A Quantitative Investigation on the Arrangement of the Mechanical Tissue in Bamboo Culm
Author: C. H. Yu and J. W. Chang
Journal of Integrative Plant Biology 1963 11(4)
      
    The present paper contributes a knowledge of the quantitative arrangement of the mechanical tissue in the culm of Phyllostachys pubescens Mazel. Materials are taken from the middle portion of the selected internodes of 12 culm-specimens collected from Hunan province. All are 4 years of age and 4每14 cm. in D. B. H. The measurements of the area of fiber strands on transverse sections of the culm are done directly on the photomicrographs by lineal method (5), and the sq. cm. is used as the basic unit to denote the amount of the mechanical elements in per unit area or in per ※counting area§, a term originally used by Penskoy (4) to show an area of 1 cm. in length and the width is just the same as the thickness of the culm wall on its trans- verse section. The so-called layer is an arbitrary unit for indicating the horizontal position of the culm. It is taken by tangentially dividing the wall into 10 equal parts, each of them is called a ※layer§. Thence the dimension of a ※layer-counting area§ is just one tenth as large as that of the corresponding counting area. After an examination of our results, the variability of the quantitative arrangement of the mechanical tissue in bamboo culm can be concluded as follows: 1. In different internodes of the same culm, the quantity of the fiber in counting area is decreased from the bottom upwards, whereas in the unit area, it is, however, increased. 2. In any internode of the same culm, the quantity of the fiber either in layer- counting area or in the unit area, is always decreased from the outermost layer inwards. 3. The range of variability of the fiber amount tends to be greater in different internodes of a single culm than that in the homologous internode of different culms either in counting area or in unit area. 4. In the same culm, the range of variability of the fiber shows to be greater in horizontal direction than in vertical one. 5. As for the quantitative variations of fiber in separate layers, they are more distinctive in the first to third layer and more prominent in the basal internodes.
Abstract (Browse 1836)  |  Full Text PDF       
孛我找抉抒我技我折快扼抗抉快 我扼扼抖快忱抉志忘扶我快 技我抗把抉扼扭抉把抉忍快扶快戒忘 我 技我抗把抉忍忘技快找抉忍快扶快戒忘 扶快抗抉找抉把抑抒 扭抉抗把抑找抉扼快技快扶扶抑抒
Author: 妣我 妤忘抉 - 忱快扶抆
Journal of Integrative Plant Biology 1963 11(4)
Abstract (Browse 1830)  |  Full Text PDF       
Cytological Studies on the Intergeneric Fl Hybrid between Oryza sativa L. ℅ Pennisetum sp.
Author: Wu Su-hsuen and Tsai Chi-kuei
Journal of Integrative Plant Biology 1963 11(4)
      
    The Fl hybrid plant between Oryza sativa L. and Pennisetum sp. was obtained by Teng Yen Tang in 1958. In many morphological characters the hybrid appears to be superior to the parental plants, such as the culms are taller, the leaves are comparatively longer and broader, and the spikes are apparently much larger. However, the form of the spikes of the hybrid plant is spreading type which resembles that of the mother plant. In general, the hybrid plant bears a close resemblance to the female parent, though its spikelets produce conspicuous long awns which must be inherited from the pollen plant. The Fl hybrid is almost completely sterile, for it only occasionally produces one or two grains in open condition. Owing to the high regenerating feature, the hybrid plant has been successfully cultivated by vegetative propagation. In a majority of cases, megaspores have been observed to degenerate in rather early stages. More than half of the ovaries examined thus lack embryo-sac formation, they seem to grow parthenocarpically to some extent before degeneration sets in. Embryo- sacs have also been observed to degenerate sooner or later after their formation. In a well formed embryo-sac, when it does occur, the normal three successive mitoses of the nucleus of the embryosac mother cell do not occur regularly, and the matured embryo- sac which results, lacks some of its apparatuses. In. some cases, the apparatuses differentiate in abnormal way. The number of the polar nuclei may be more than two, that of the antipodals is, sometimes, less than three, and the egg apparatus may be composed of four cells instead of three. It is apparently that the apparatuses of the embryo-sac produced in such abnormal manner are functionless. In other cases, the sac loculus of an enlarged ovary has been found to contain nothing but liquid. Only in very rare cases, the formation of the embryo-sac and the differentiation of the apparatuses have been carried through in the proper manner. The chromosome number of Oryza sativa L. is n = 12 and that of Pennisetum sp. is n=9. Both the somatic and the gametic chromosome numbers of the Fx hybrid are variable and they generally do not correspond to the sum of the reduced chromosome numbers of the parents, unlike what they usually do in the intergeneric hybrids raised from other cereals as reported by many investigators. In meiosis of the hybrid, the chromosome behavior is very irregular, different numbers of uivilents and bivalents have been counted in different pollen mother cells, and one or two trivalents may also be present in some of the pollen mother cells. The trivalents are often V-shaped, but some- times they are chain-shaped. A number of lagging chromosomes have been met with at metaphases and anaphases of both first and second meiotic divisions. During the formation of the restitution nuclei the laggards are often excluded, but they do not form micronuclei. In both heterotypic and homotypic meiotic divisions the spindle formation is regular. There is no unequal division of the pollen mother cell. Multipolar spindle and multispindle are not present, and finally normal tetrads result. However, the tetrads do not develop further and most of them soon degenerate. There is only a small number of floulets in the anthers of which a few fertile pollens have been observed. It is evident that all the irregularities occurred in the course of embryo-sac formation and differentiation together with the breakdown of the meiotic cycle in the pollen mother cells are the causes of the sterility of the Ft hybrid plant.
Abstract (Browse 2196)  |  Full Text PDF       
Effect of Food Materials Supply on the Development of Wheat Grains and Interrelationship of Main Stem and Tiller in Wheats
Author: Yu Shu-weng, Wang Huai-chi, Kung Tsan-hsia, Sung Ting-sheng and Chien Ren
Journal of Integrative Plant Biology 1963 11(4)
      
    The removal of ear from the main stem or the tiller of wheat plant at earing stage induces its assimilate to go to the ear of another stalk on the same plant, so that the later is nourished supplementarily. By means of this method an investigation on the effect of food materials supply on the weight of grains was carried out. Even at favorable ripening condition, to enrich the supply of food materials to the developing ear results in a considerable increase of the weight of wheat grains. This result does not agree with the conclusion of Tumanov. The mean 1000-grain weight of the tested wheat variety ※Nang-dae 2419§ has increased to 59.8 g., a record about 50% heavier than its normal level (40 g). The differences of the average weight of grains between upper and middle and lower parts of the ear are not due entirely to the insufficient supply of food materials. There is little or no movement of assimilates from ear-bearing tiller to main stem or vice verse after earing stage. Under conditions of ear removal or severe defoliation of either main stem or tiller, net translocation takes place from the stalk of high to low carbohydrate production. This indicates that there exists a readjusting mechanism of translocation between stalks on the same wheat plant.
Abstract (Browse 1911)  |  Full Text PDF       
 

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