February 1956, Volume 5 Issue 2

 

          Research Articles
Developmental Morphology of the Tubers of Sweet Potatoes
Author: Lee Shu-hsien and Sheo Chen-hsioh
Journal of Integrative Plant Biology 1956 5(2)
      
    The present study was carried cut at the Experiment Station of Chekiang Institute of Agriculture in Hangchow. Three varieties, viz., Sun-li No. l00, Nancy Hall, and Red-skin-white-flesh 6o, were used under ordinary cultural practices. Of all the three varieties herein studied, the growth rate of the tops, including vines and leaves, was found to be much higher than that of the tubers during the first two to three months after planting. From July to August, the top growth reached its maximum stage. After that time, however, the top may decrease in weight gradually associated with the cessation of the top growth, whereas the fleshy roots began to increase rapidly up to the harvest time. In case the vines and leaves grew continually thoughout the growing season, tubers would be slender in shape, and smaller in size, and, in the extreme case, tubers may not be formed at all. It is gound that tubers of the higher yield varieties usually begin to form earlier than that of the lower yield varieties. The percentage of dry matter content in the tubers, no matter what varieties they are, is lower in the early stage of growth, and a little higher in the latter stage, and that in the tubers is by far higher than that in the tops. Morphogically, the tuber is a storage organ developed through secondary and tertiary thickening of a lateral root. It should be pointed out that not all the lateral roots of a plant but only those roots with suitable soil and climatic conditions form fleshy roots or tubers. Besides the function of the primary cambium in the usual manner, the extensive activity of the secondary cambiums has much to do with the tuber formation. These secondary cambiums are first found to occur in the parenchyma of the central portion of the stele, surrounding each of the protoxylem points; later, they occur as cylinders surrounding groups of secondary xylem elements; and still later, they appear in the parenchyma of the roots which are not related spatially to any vascular elements. As a result of the different manners of activities of these secondary cambiums, the storage parenchyma produced from them may differentiate in their properties of internal breakdown and susceptibility of frozen injury. A feeding root of sweet potato is anatomically characterized by the limited development of the secondary cambiums and the lignification of the xylem elements; whereas a fleshy root by the extensive activity of the secondary cambiums and the differentiation of abundant thin-walled storage parenchyma. The continuous increase in cell number by the meristematic activity of the secondary cambiums almost throughout the whole period of tuberization is found to be the main cause for the development of tubers. In Nancy Hall, for example, the diameter of the interstitial parenchyma cells increases very little after the middle of July, while the diameter of tubers increases continually up to the end of October. Since the secondary cambiums first occur around each of the protoxylem points, the roots with more number of protoxylem points will enhance the activity of the secondary cambiums to favour the formation of tubers, The number of protoxylem points of the variety Sun-Li No. l00 (average 5.4每5.8) is greater than that of ※Nancy Hall§ (average 5.0每5.4). And within a single root, the number is more in the base, less in the medium, and still less in the apex part of the root. It should be shown that the number of protoxylem points is one, but not the only one factor effecting the development of the tubers. The activity of the secondary cambiums, the lignification of the xylem elements, and the number of protoxylem points may all be effected by various climatic and soil conditions under which they are grown.
Abstract (Browse 2464)  |  Full Text PDF       
Salt Tolerance of Some Popular Trees in North Kiangsu
Author: Ting Tsing, Fang Yi-hsiung and Wang Wan-li
Journal of Integrative Plant Biology 1956 5(2)
      
    The region of north Kiangsu adjacent to the seashore is an area of saline soil with sodium chloride as the principal soluble salt content. In line with a government project for planting a windbreak and shelter belt in that region, we tested, during 1953每1955, the salt tolerance of 8 species of trees and shrubs, most of which can be frequently found in north Kiangsu. Experiments dealing with seed germination and early growth of seedlings, transplantation and cuttings were made. The investigation was carried out in pots, which had no hole at the bottom and were glazed both inside and outside. The saline soil was artificially made by adding common salt to garden soil. The salt content was expressed in terms of percentage of sodium chloride on air-dry soil basis. Plain garden soil was used as control. The pots were placed in the open field but sheltered from rainfall. The water loss was supplemented with tap water at intervals so as to ensure, roughly, a favourable soil moisture. Seeds of 20 species of trees were sown in various concentrations of salinity, ranging from 0 to 0.6%. Seed germination and the death of seedlings in both experimental and centrol pots were carefully observed. The general growth of seedlings in the course of the first year was also noted. The results of germination experiments indicated that Melia azedarach L., Ailanthus altissima Swingle and Sapium sibiferum Roxb. had the highest tolerance to sainity. M. azedarach was able to germinate and survive in 0.6% saline soil, and its growth in 0.25% saline soil was comparable to that of the control. A. altissima germinated and survived in 0.5% saline soil and grew well in 0.3% saline soil. In the case of S; sebiferum, the tolerable salinity for germination, seedling survival and good growth was 0.6%, 0.4%, and 0.2% respectively. Robinia pseudoacacia, Gleditsia sinensis, Sophora japonica, Amorpha, fruticosa and Thuja orientalis were found to be less resistane than the previously mentioned trees. Still less tolerant to salinity were Juglaus regia, Catalpa ovata and Celtis julianae, while Quercus acutissima and some others showed practically no tolerance at all. In general the increase of soil salinity causes (1) decrease in germination percentage; (2) delay of the date of germination; (3) increase of death rate of seedlings and (4) reduction of the height of seedlings. In planting experiments, nursery stocks (1每2 years old) of 10 species of trees were transplanted in soil of various salt concentrations. Subsequently, their date of foliation, the height of new shoots and the die-back of the terminal axis were observed. Robinia pseudoacacia displayed the strongest resistance to salinity. Amorpha fruticosa, Sophora japonica, Gleditsia sinensis and Ulmus pumila were also found to be tolerant, though to a less degree, than R. pseudoacacia. The effect of salinity on the stem cuttings of Tamarix chinensis Lour. And root cuttings of Ulmus jumila was also investigated. From the examination of the number of suckers produced and their growth in soil of different salt concentrations, it can be concluded that these cuttings are very resistant to soil salinity. The result of some preliminary experiments performed with the seedlings of Sophora japonica and Sapium sebiferum indicates that if a relatively high salt concentration (e.g. 0.4%) reached gradually by stepwise additions of salt, these seedlings would show less damage due to the toxic action of salinity. In the discussion, earlier works on salt tolerance of trees and shrubs were briefly mentioned. Various aspects of the effect of salinity on plant growth, especially the phenomena of the death of seedlings and of the difference in salt tolerance at different growth stages were discussed. Finally, based on the results of the present experiment, some suggestions were made in connection with the practical project of north Kiangsu. The writers wish to express their thanks to professor T. L. Loo for his suggestion and guidance in this work and his help in the preparation of the manuscript.
Abstract (Browse 2171)  |  Full Text PDF       
The Role of Involucre in the Growth of Cotton Boll
Author: C. W. Cheng, S. F. Lui, W. Y. Lui and S. G. Lee
Journal of Integrative Plant Biology 1956 5(2)
      
    Researches on the role of involucre in the growth of cotton boll are yet scarce. This problem has not come to a conclusion although Kearney, Tep-式志忘扶快扼攸扶 and some others already noticed it and pointed it out. For the purpose of acquiring further knowledge, we engaged in a number of experiments in 1954 & 1955 by removing the involucre at different growth periods of bud and observing its effect on the shedding and growing of the boll. Our field experiment proved that at different growth period of bud the influence of involucre varied at different degrees. The removing of involucre at an earlier growth period of bud caused comparatively serious shedding. The effect of involucre was not only seen in shedding but also in the decrease of fresh weight, dry weight and the weight of seed cotton. The effect of involucre on the growth of cotton boll is not invariable; it varies under different environmental factors. For example, when cotton plant comes to prime growth, the branches and leaves are cross-shading together; light intensity of the lower part between rows is weakened which decreases the photosynthesis of vegetative parts and other green parts. Here we see that involucre is incapable of producing of food to meet the growth need of bolls and other parts. Simultaneously, owing to the consumption for its own respiration and other physiological processes, the involucre increases the burden of cotton plant and heightens the shedding of cotton bolls. Furthermore, we carried on a supplementary experiment by partially shading the flower in order to compare the role of involucre with leaves and green bolls. As a conclusion, we found out that the role of involucre is being rather great; the role of the involucre of each flower almost equals to 40 CM2 area of leaf. According to the results of the above experiments we can say that involucre has comparatively significant nutritive value in the growth of cotton bolls.
Abstract (Browse 1944)  |  Full Text PDF       
Induced Adaptation in Yeast Growth, Respiratory and Fermentation Characteristics of Yeast Adapted to High Temperature
Author: Fang Sin-fang, Tang Pei-sung, Tsai Ching-ko and Wu Chiung-fa
Journal of Integrative Plant Biology 1956 5(2)
      
    Based on the principle of Michrin Biology we have successfully induced two strains of yeast which are adapted to withstand a temperature of 40⊥. These strains of yeast are not only that able to survice these higher temperature, but can actually grow better at this adapted condition. Their rates of cell division are increased over the original forms, and what is more important, at this high temperature when the original forms gradually die off and their ability of alcoholic fermentation ceases, the adapted forms actually produced 7% to 11% more alcohol than the original forms; their ability to utilize sugar is increased from 5% to 8% as compared with the original strains. At 42⊥, the fermentative power of the adapted strains is twice that of the original unadapted forms. This change in the genetic character of the yeasts is accompanied by a pronounced change in their metabolic pattern as indicated from their respiratory behavior. The variation of respiratory intensity with pH and with temperature of the adapted strain is significantly different from the original strain. Not only is the QO2 of the adapted strain higher than that of the original strain, the optimum pH and optimum temperatures showed wide differences in the two strains: These changes in metabolic activity accompanying genetic changes in the yeast are of importance both from the theoretical and practical viewpoints.
Abstract (Browse 1991)  |  Full Text PDF       
The Effect of Light Intensity on Bud and Boll Shedding of Cotton Plant
Author: C. C. King, T. S. Ni, Y. W. Tang, C. W. Cheng, C. L. Chang, S. F. Lui, W. Y. Lui and S. G. Lee
Journal of Integrative Plant Biology 1956 5(2)
      
    There are a number of external factors which cause the physiological shedding of buds and bolls of cotton plant. It is, however, suggested that under different environmental conditions, the factors which affect the dropping most are quite different. In a preliminary experiment we found that under the condition of excessive growth of cotton plant, the low light intensity was the principal factor in the heavy shedding of buds and bolls. In an endeavour to investigate the effect of different light intensity on the dropping of buds and bolls at different growth periods and to reveal the physiological mechanism of shedding, a series of experiments were performed. The results are given as follows: First of all, we found that the lower the light intensity was, the higher the percentage of shedding would be. The dropping of buds and bolls was 100 % when the light intensity on the top of cotton plant was reduced to one twentieth of sunlight by means of a shade. Heavy shedding was induced from the beginning of bud formation to the stage of 50% flowering by low light intensity, and the percentage of shedding was found to the 90% even under the intensity of one fourth to one fifth of the sunlight. Low light intensity delayed the formation of buds and altered their characteristic of shedding with regard to their relative positions on the fruit branches. Furthermore, it was found that the lower the light intensity was, the younger the shed buds would be. Although the dropping of bolls was increased by low light intensity, yet the correlation between the age of the boll and its shedding remained unchanged even under the lowest light intensity. In addition, it was found that none of the bolls at the ago of l0 days shed under low light intensity. Dealing with the metabolic changes within plant, we found a change in the proportion of different types of organic food substances because of the reduction of the light intensity and as a result of the overgrowth of the vegetative part a decrease in available organic food for the reproductive organ occurred, hence the heavy shedding of buds and bolls. It frequently happened that the vegetative growth was exuberant when the supply of water and fertilizers was sufficient. As a result of the overlapping of the branches and leaf blades, the light intensity in the cotton field was very low especially under the condition of high density of crop. Low light intensity is, therefore, the principal factor of heavy shedding, and the effect of ventilation is of secondary importance The heavy dropping of valuable buds and bolls at the middle and lower parts of cotton plant occurred under the condition mentioned above. Thus, not only was the period of harvest delayed but also the yield and the quality of fibres were decreased. In order to improve the light condition in the cotton field, the following points of agricultural technique are recommended: (1) to pinch the plants together with proper defoliation; (2) to adopt a rational density of crop; (3) to change the spacing and to plant in square and (4) to breed new types of cotton with short branches.
Abstract (Browse 2489)  |  Full Text PDF       
The Effect of Light Intensity on the Formation of Pollen and on the Shedding of Flower Buds and Bolls of Cotton
Author: Hsia Chen-ao
Journal of Integrative Plant Biology 1956 5(2)
      
    Under shading, the flower buds and bolls of cotton shed seriously either before or after the formation of tetrad of the pollen mother cell. The flower buds, especially the young ones, shed much more than the bolls. Shading to give various light intensities shows different effect on the development of pollens. Very low light intensity (l/20 of sun light) delays the formation of tetrad of PMC which requires twice the time than the unshedded plants. But 1/4每1/10 of sun light has no influences. After shading, the petals and bracts of the flower become small, and the germination percentage of the pollen decreases. In those plants which were ringed and sheded, most of the anthers remained indehiscent, even at 24 hours after blossoming and no pollen tubes could be found at the base of the styles of some flowers.
Abstract (Browse 2090)  |  Full Text PDF       
Accumulation and Redistribution of Dry Matter in Rice after Flowering
Author: Yin Hung-chang, Shen Yun-kang, Chen Yin, Yu Chih-hsin and Li Pin-chang
Journal of Integrative Plant Biology 1956 5(2)
      
    The accumulation and redistribution of dry matter in 11 varieties of rice from the time of flowering to harvest were studied. The dry weights of the ear and the internodes were compared in both normal and treated plants〞partially or wholly defoliated or with half of spikelets removed at the time of flowering. The main results can be summarized as follows. In all the varieties there was a great increase in the dry weight of the ear from flowering to maturation. Generally about 1/4 to 1/3 of the increase was found to come from the reserve substances of leaves and stem. Since translocation from root and between the tillers was probably negligible, the great majority of dry substance (2/3每3/4) of the ear must come from concurrent photosynthesis. The magnitude of the post-flowering photosynthesis differed greatly in the different varieties, as well as under different conditions of cultivation. The loss of dry weight in the stem after flowering was different among the varieties. Some actually showed a net gain. But in general the loss was around 20%每30% of the stem weight. This loss was not equally borne between the internodes. The lowest (oldest) internodes lost the most, amounting sometimes to 1/2 of the original weights. This phenomenon was shown to be coincident with the tendency to lodge. The loss from the stem showed a definite time course. It was most rapid up to the time of milk-ripe stage. The stem weight remains low till wax-ripe when it recovered slightly and gradually went down again. The time sequence fitted well with the changing activities of the ear. Early experiments showed that respiration, enzymic activities and the accumulation of dry matter in the ear were highest in the milk-ripe stage. This correlation indicated an active transport during that period toward the ripening ear. The plants defoliated at the time of flowering yielded a smaller final total weight (ear + stem) than the intact plants (less 22%每36%), showing that the leaves were the chief assimilating organ, and their removal invariably reduced the yield. But as the total weight of the defoliated plants did show in general an increase after flowering, the stem and ear were not completely inactive in photosynthesis. The amount assimilated was, however, small in comparison with the leaves and varied with the different varieties and different conditions. In some instances, the total weight actually decreased, indicating that assimilation here could not balance the loss by respiration. The loss from the stems of the defoliated plants was always larger than that of the intact plants and was the larger the more the leaves were removed. The result showed that there are substances in the stem which are not normally used in seed development but are drawn upon when the formal supply becomes insufficient such as induced by defoliation. The amount drawn, however, could never make up the normal contribution from the leaves. Preliminary analyses were made on one variety to ascertain the nature of the substances drawn from the stem to the ear. It was found that from the time of flowering to full-ripe, about 1/2 of the proteinous material and all of the starch and soluble sugars disappeared from the stem in both intact and defoliated plants. Cellulosic material was usually only slightly used but when the plants were defoliated, the cellulosic materials of the lower internodes decreased greatly. Apparently these substances are not normally called upon for seed development but are drawn when the supply is inadequate. It also explains the weakness of the lower internodes and the tendency to lodge. Removing the lower leaves and the keeping the flag leaf intact resulted in a slight decrease in the final total weight, whereas the removal of the flag leaf alone produced no observable effect. The loss in the final total weight resulted from complete defoliation was larger than the sum of the losses resulting from the separate removals of the upper and of the lower leaves. This finding indicated that there exists a compensatory mechanism between the leaves so that the removal of one leaf will enhance the assimilatory activity of the remaining ones. This interesting phenomenon is being further investigated. Another effect of defoliation was the decrease in the percentage of ※full grains§. Removal of part of the spikelets of the ear resulted in a higher percentage of ※full grains§. Apprently one of the causes of empty and partially filled grains was the insufficient material supply from the leaves. The results were discussed in connection with the compensation of assimilatory activities among the leaves, the dominance of the ear over the material supply of the plant, and the location, time course and nature of the material transported from stem in relation to ear development and lodging.
Abstract (Browse 1899)  |  Full Text PDF       
Morphology of Pollen Grains of Meliaceae
Author: K. T. Chang and F. H. Wang
Journal of Integrative Plant Biology 1956 5(2)
Abstract (Browse 1922)  |  Full Text PDF       
On the Presence of Trabeculae in the Wood of Juglans cathayenis Dode
Author: C. H. Yu
Journal of Integrative Plant Biology 1956 5(2)
Abstract (Browse 1830)  |  Full Text PDF       
The Wood Structure of Tsugo-Keteleeria with Special Reference to its Taxonomy
Author: C. H. Yu
Journal of Integrative Plant Biology 1956 5(2)
Abstract (Browse 1781)  |  Full Text PDF       
妍扭把快忱快抖快扶我快 妥志快把忱抉扼批扶 妥把忘抒快我忱 坏把快志快扼我扶抑 妊抉扼扶抑
Author: 圾.圾.妤忘技扳我抖抉志
Journal of Integrative Plant Biology 1956 5(2)
Abstract (Browse 1882)  |  Full Text PDF       
 

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