January 1957, Volume 6 Issue 1

 

          Research Articles
Dormancy of Wheat Grains Harvested at Different Stages of Maturity and Treated with Various Methods
Author: Chao Tung-fang
Journal of Integrative Plant Biology 1957 6(1)
      
    Fifteen varieties of wheat (Triticum vulgare) were sown in the experimental farm of the Institute of Plant Physiology, Academia Sinica in November 1955. From May to the first part of June 1956, three red and three white varieties were harvested at four stages of maturity (milk-ripe, dough-ripe, waxy-ripe, and yellow-ripe), while the other varieties (3 white and 6 red varieties) were harvested at the yellow-ripe stage only. Germination tests either immediately after harvest or after treatment with various methods were made at given temperature on moist paper in large petri-dishes. The results are summarized as follows. 1. The grains harvested at milk-ripe stage did not germinate at all , but a high percentage of germination was obtained after a two-month storage . Those harvested at dough-ripe, waxy-ripe and yellow-ripe stages showed an increase in the percentage of germination. Higher percentages were found in the white varieties. 2. The effect of desiccation with CaCl2 at room temperature (to moisture content of around 10%) on the germination of grains varied greatly with the varieties and the stages of maturity. Desiccation of grain at the milk-ripe stage showed very little effect , but with grains of other stages, a great increase in germination percentage was achieved. Grains desiccated at 25每30⊥ had a shorter dormant period than those desiccated at 4每8⊥ . 3. Pre-chilling at 4⊥ for 2 days before drying had no effect on the germination percentage of grains harvested at the milk-ripe stage, but a great increase resulted from the same treatment when the grains had been first desiccated. The response to the pre-chilling treatment varied also with varieties. The white varieties showed a higher percentage of germination as the result of she treatment, which, however could bring about no effect on the grains without soaking . 4. All the red varieties except one had a longer dormant period than the white varieties . 5. There was no correlation to have been found between the length of dormancy and the vernalization characteristics in the white varieties, but with the red wheat, the varieties with a longer dormant period belonged to the semi-winter type. 6. An increase in percentage of germination was achieved from the grains stored: at high temperatures (40, 44, 47 ⊥) for one week. The grains of the white wheat varieties lost their viability to some extent after bring stored for three weeks at 47 ⊥, whereas those of the red varieties remained sound . 7. Fumigation with chloropicrin (80 g per cubic metre) resulted in a loss of viability in the white varieties, but no effect was observed on the red varieties. 8. When separated from the endosperm, the embryo of dormant grain would germinate promptly. The mechanism of dormancy of wheat grain and the sprouting in the ear before harvest are discussed according to the results of the present paper and earlier literature.
Abstract (Browse 2153)  |  Full Text PDF       
The Effect of Copper on the Growth and Drought Resistance of Cotton Seedlings
Author: Kuei Mei-hsiang and Tsui Cheng
Journal of Integrative Plant Biology 1957 6(1)
Abstract (Browse 1834)  |  Full Text PDF       
Explanatory Notes on the Wood Anatomical Features Used in the Softwoods Descriptions
Author: T. C. Cheng and K. Y. Wei
Journal of Integrative Plant Biology 1957 6(1)
      
    In 1041, Phillips developed a ※multiple entry§ key for the anatomical descriptions of softwoods. The anatomical features selected as being, of value for the purpose of identification were defined, and their significance was discussed. 岐戒快扶抗抉-孚技快抖快志扼抗我抄 (1954) gave more details for the definition and explanation. Their opinions in some parts are different. Having finished our studies on ※The Anatomical Features and Uses of the Gymnosper mous Woods of China§, we found that some anatomists have been wrong in their views of the anatomical features of some species. According to the anatomists* papers and the writers* findings, 25 main features and 18 minor features were selected for identification purposes. Based on some anatomists* and the writers* opinions, the selected features were defined and explained respectively. The Chinese coniferous species are used here in illustrating most of the features. The anatomical features of coniferous woods may be indicated below: i. Growth Rings: 1. Distinctness of growth rings; 2. Conspicuousness of latewood; 3. Dimpled grain. j. Tracheids: 4. Distribution of bordered pits on R-walls of earlywood tracheids; 5. Arrangement of bordered pits on R-walls of earlywood tracheids; 6. Distribution of bordered pits on R-walls of latewood tracheids; 7. Bordered pits on T-walls of latewood tracheids: 8. Contour of bordered .pits on R-walls of earlywood tracheids; 9. Spiral thickenings; 10. Callitroid thickenings. k. Wood Parenchyma: 11. Wood parenchyma present: 12. Distribution of wood paten chyma; 13. Transverse walls (Endwalls) nodular. l. Wood Rays: 14. Ray tracheids present; 15. Ray tracheids dentate or non-dentate: 16. Horizontal walls thin or thick; 17. Horizontal walls pitted or unpitted; 18. Indenture: 10. End wails (Tangential, Terminal or Vertical walls) nodular: 20. Cross-field pitting; 21. Height of wood rays. m. Resin Canals: 22. Vertical resin canals; 23. Horizontal resin canals: 24. Epithelial cells thick- or thin-walled; 25. Number of epithelial cells per canal. VI. Minor Features: (1) Tracheids: 1. Thickness of tracheid walls; 2. Intercellular spaces; 3. Crassulae; 4. Trabeculae; 5. Torus; 6. Barlikc thickenings on close membrane. (2) Wood Rays: 7. Width of wood rays; 8. Biseriate rays or biseriate in part; 9. Shape and size of ray cells; 10. Thickness of end walls of ray cells; 11. Contents of ray cells; 12. Height of the uniseriate wings of fusiform rays. (3) Resin Canals: 13. Size of resin canals; 14. Tylosoids. (4) Crystals: 15. Crystals present. (5) Maceration: 16. Shape of ends of earlywood tracheids; 17. Distribution of bordered pits on R-walls of tracheids; 18. Length of tracheids.
Abstract (Browse 2087)  |  Full Text PDF       
On the Development of thc Endosperm in Cotton Plants
Author: F. H. Wang and N. F. Chien
Journal of Integrative Plant Biology 1957 6(1)
      
    The present report was chiefly based upon the study of the endosperm slides prepared by the dissection method under the binocular microscope. The macrospore membrane of the endosperm sac has been carefully removed and the endosperm was spread out on the slide. Since the endosperm in early stages (3每10 days old) is only a film of protoplasm with embedded free nuclei, it is much better to examine the behavior of the free nuclei from the surface than from the section. Three strains of the cotton (Gossypium hirsutum L.) were used, they are: Deltapine 14, Stoneville 2B and Delfos 531. So far as the development of the endosperm is concerned, there is no difference among them. The mitoses of the endosperm free nuclei and cells were met at the different stages of the endosperm development. The mitotic figures occur usually in strips and form gradations along the longitudinal axis of the embryo sac. Amitosis was found for tile first time in the endosperm 5 days following pollination. At this time the number of the free nuclei amounts to a little over 1000, though the endosperm is still in the period of rapid growth. Three kinds of amitoses were found in cotton endosperm, they are: direct division, building and amitosis of the amoeboid nucleus. The direct division is more frequently met with, while the other two methods of amitoses are met with infrequently. As a result of the amitoses, particularly the last two named variations, very small nuclei or the small nuclei with the irregular shapes are found among the normal-sized free nuclei, especially at the chalaza end. The mitosis undoubtfully plays an important role in the development of the cotton endosperm. Amitosis appears much less frequently and occurs rather sporadically. However, it is considered to be the regular means of the free nuclear division along with the mitosis. Amitosis surely plays a definite role in the development of the endosperm. Besides, nuclear fusion also occurs in the developing endosperm. Polyploid nucleus (since the endosperm is triploid, polyploid here means more than triploid) is formed due to the fusion of the free nuclei. The polyploid nucki may also undergo mitotically. They are usually formed in the endosperm near the chalaza end. The result of the mitosis and tile nuclear fusion makes the difference in nuclear size to be very considerable. Cell wall may appear among the free nuclei at the resting stage and it also may be formed between the two free nuclei at mitosis. Two modes of wall formation may progress at the same time. The first formed endosperm cells may be uninucleate or multinucleate, but later they all become uninucleate.
Abstract (Browse 2290)  |  Full Text PDF       
Effects of Vernalization and PhotoPeriod on the Development of Chinese Cabbage and Mustards
Author: Lee Shu-hsien and Sheo Chen-hsioh
Journal of Integrative Plant Biology 1957 6(1)
      
    The present study was carried out both in the greenhouse and in the field of the experiment farm of this institute in Hangchow during the years 1954每1956. An attempt was made to investigate the effect of various treatments of vernalization and photoperiod on the flowering and vegetative growth of Chinese cabbage and mustards, and on the interaction of photoperiod and temperature. Chinese cabbage herein studied included both the headed varieties (Brassica pekinensis Rupr.), and non-headed varieties (B. chinensis L.). The varieties of mustards (B. juncea Coss.) included those grown for their abundant radical leaves, and those for their swollen fleshy roots or stems. They were collected from many geographic regions of China. The common cabbage (B. olcracea var. capitata L.) and Chinese kale (B. o. var. acephala subvar, alboglabra Burkill) were also used in this study. From the result of the present experiment, it was found that almost all the varieties herein studied of both Chinese cabbage and mustards may complete their stage of varnalization by lowtemperature treatment of sprouted seeds. The varieties of each species, cabbage or mustard, may further be generally separated into winter type and spring type according to their responses to vernalization and photoperiod. The ※spring§ varieties may flower in the same season after seed sowing, without a definite period of low temperature treatment; while the ※winter§ varieties have to pass through a definite period, generally 20每30 days, of vernalization treatment. The common cabbage did not produce flowers in the same growing season even if it bad been exposed for a certain period to low temperature treatment either of the sprouted seeds or of the plants being too young to be affected by the treatment. The Chinese kale which taxonomically belongs to the same species of common cabbage, may produce flowers without exposure to a low-temperature treatment under Hangchow condition. Obviousely, the plants which may complete their vernalization stage by the sprouted seeds, may also complete this stage by growing plants, but the reverse was not the case. The temperature favourable for the completion of vernalization of both Chinese cabbage and mustards was not very low. No appreciable differences were found in the number of days required to flower between the lots vernalized at 0每3⊥, and those at 6每8⊥. The duration of vernalization of the ※winter§ varieties of both Chinese cabbage and mustards lay between 20 and 40 days at 0每3⊥. They would produce no flowers as the unvernalized seeds were sown on April 9,1956, under Hangchow climatic and soil conditions. But the ※spring§ varieties of non-headed Chinese cabbage and mustard*s collected from South China, produced flowers in the same season after sowing, without any low-temperature treatment. The number of days required from seeding to flowering decreased with increasing the duration of vernalization from 5 to 60 days. But the influence by the duration of vernalization on the ※spring§ varieties was not so pronounced as on the ※winter§ varieties. Some varieties of Chinese cabbage was able to complete the stage of vernalization in 5 days at 0每3⊥, while others were in need, of 20 to 30 days at least. All the varieties of Chinese cabbage and mustard were found to be of long day plants. Flowering may be accelerated by increasing the day length, but there, were great differences of photoperiodic responces among different varieties. In one experiment carried out on 1956, the vernalized seeds of Tzu Tsai Tai (B.chinensis) and Hsueh Li Hung (B. juncea) sown on July 11, required much more days to flower than that sown on April 9. Apparently too high a temperature (30⊥ or more) during the photoperiodic exposure may retard the flower development of both Chinese cabbage and mustard after vernalization treatment. Moderate cold nights (15每20⊥) may accelerate the photostage. Not only did the photoperiod and temperature influence the flower development of a given variety, but also influence the height of the plants, the size and shape of the leaves and even the structure of the flower organs. Chinese cabbages were found to be generally more pronouncedly affected , by these factors than mustards.
Abstract (Browse 3151)  |  Full Text PDF       
Education Orient谷e des Levures II. Sur deux souches de levure adapt谷es aux fluorures
Author: Fang Hsin-fang, Tsai Chin-ko and Kuan Suan-min
Journal of Integrative Plant Biology 1957 6(1)
Abstract (Browse 1801)  |  Full Text PDF       
A Cytological Study on the Endosperm Development of Wheat
Author: Yang Miao-hsien
Journal of Integrative Plant Biology 1957 6(1)
      
    The present report embodies a part of the investigation of the endosperm of wheat. It was conducted at the Department of Biology, University of Peking. -. The material used was Triticum vulgate var. erythrospermum. Collections were made in the springs of 1955 and 1956. Paraffin sections were cut serially. For the early stages endosperms were also dissected out and either mounted in toto, or split open, spread out and then mounted. Smear prepardations were also made. In addition, material freshly dissected out were examined in the living condition under a phase contrast microscope. In the present paper material is presented in 3 sections: 1. Formation and development of the endosperm, 2. Multiplication of the endosperm nuclei by mitosis and non-mitotic methods* and 3. Behavior of the antipodal tissue and nuclear migration. 1. Formation and development of the endosperm. The endosperm of wheat is of the nuclear type. The primary endosperm nucleus divides mitotically (Pl. j, fig. 4). A free nuclear stage follows. At this time the endosperm is a protoplasmic bag containing a large central vacuole. It is in the shape of a pear in external appearance. At the micropylar end the endosperm protrudes into the nucellar tissue to form a sort of haustorium. In this the proembryo resides (Pl. i, fig 2). Nuclei of the endosperm are ellipsoid or spherical in shape, measuring 40每45 米 in the large diameter. A few are many times larger or smaller (Pl. i, figs. 3每4). It contains one to 10 nucleoli or even more. Nucleoli multiply by fission or budding. in the fixed material, there appears a hyaline shell around each nucleolus which is not stainable. In the living material, however, no such shell exists. The living nucleolus is larger than in fixed material. It is, therefore, believed that the ※shell§ is an artifact produced by differential shrinkage of the nucleolus and the surrounding nucleoplasm. In the vicinity of the antipodal tissue fusion between free nuclei were observed (PI. i, Figs. 5每6). Cell wall formation of the endosperm is initiated about 2 days after fertilization. It starts around the proembryo and progresses toward the chalazal end. Endosperm nuclei are more numerous at the region of the antipodal tissue but here the cell formation tags. Phragmoplast and subsequently cell plate and cell wall appear between 2 young sister nuclei resulting from a mitosis, but they also arise elsewhere between 2 nuclei which are not sisters (Pl. i, figs. 7每8). A noteworthy feature in young cells of the endosperm is that neighboring cells are connected by thick plasmic strands (Pl. j, fig. 2). 2. Multiplication of the endosperm nuclei. In the early stage of endosperm development, nuclei multiply solely by means of mitoses. Frequently all free nuclei of an endosperm were undergoing division at the time of fixation. Mitoses follow an orderly sequence. When nuclei in the vicinity of the antipodal tissue are in the metaphase, those farther away are in anaphase and those still farther removed are in telophase (Pl. j, fig. 3). It appears that the antipodal tissue exerts some influence over cell division. It may be due to some enzyme secreted by that tissue. Among the dividing nuclei, polyploid ones were observed. They posses 2每5 times as many chromosomes as the normal triploid nuclei (Pl. k figs. 3每4; PI. V fig. 33). These giant nuclei are also in the neighborhood of the antipodal tissue and probably had their origin in nuclear fusions. In the later stage of endosperm development, mitotic divisions presist, but now the are sporadic occurrences. About 2 days after fertilization cases of non-mitotic multiplication of nuclei appear in addition to the mitotic method. Non-mitotic divisions are not frequent but their occurrence is regular and they are found in every specimen at this stage of development. They occur most often in the region lying between the proembryo and the antipodal tissue. Non-mitotic divsions assume various forms: (1) by transverse constriction of the nucleus, (Pl. l, figs. 5每6), (2) by longitudinal split (Pl. l, figs. 7每11), (3) by budding (Pl. l. figs. 11每16) and (4) by quartering. In this last mentioned manner 4 arms arc sent out from a nucleus and from this cross-shaped figure, 4 daughter nuclei result (Pl. m, figs. I每2). There is also a problematical form of nuclear multiplication. from an amoeboid nucleus, bits are possibly shed, which grow into new nuclei. Observed facts tend to show that mitotic and non-mitotic methods of nuclear multiplication are closely associated and may be interconvertible. Nuclei are generally in the prophase condition, when they start to divide non-mitotically by constriction (Pl. l, figs. 3每4). Cases were also observed when 2 newly formed daughter nuclei plainly arisen from mitotic division divided again this time non-mitotically (Pl.l, figs. 1每2). 3. Behavior of the antipodal tissue and migration of nuclei. The antipodal tissue occupies a lateral position in the embryo sac (Pi. m, fig. 7). After fertilization antipodal cells increase in size and number. They multiply both by mitotic and non-mitotic division (Pl. m, figs. 5每6). Nucleoli in the nucleus also multipy. 5 or 6 days after fertilization, when starch grains begin to be formed in the endosperm cells, the antipodal tissue starts to disorganize. Their nuclei lose their normal structure, nucleoli disappear and the disintegrated nuclear matter forms irregular lumps or long strips. Next, cellwalls break down. Nucleoplasm streams into the endosperm tissue through intercellular spaces (PI. n, figs. 1每2). Some penetrates the wall and enters the endosperm ceil. Evidently the disorganized antipodal tissue furnishes nutritive material for the endosperm, at the time when the latter is actively building starch. At the time when the antipodal tissue becomes disorganized, nuclei of some endosperm cells also migrate into adjacent ones (Pl. n, figs. 4每6). Migration of nuclear material occurs most frequently in the neighborhood of tile disorganized antipodal tissue. Observations of the various cytological events that take place in the course of the endosperm growth and development leads to the view that these events are associated with the physiology of the development of the endosperm.
Abstract (Browse 2430)  |  Full Text PDF       
 

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