April 1965, Volume 13 Issue 4

 

          Research Articles
The Artificial Germination and Growth of Pollen Tube of Maize Pollen
Author: Chien Ying-chien
Journal of Integrative Plant Biology 1965 13(4)
      
    
Abstract (Browse 1929)  |  Full Text PDF       
Site of Oxygen Absorption for Downward Transport in Seedlings of Rice and Other Plants
Author: Sung M. S., Bai K. Z., Cui Y. Y. and Lou C. H.
Journal of Integrative Plant Biology 1965 13(4)
      
    Our earlier reports have shown that appreciable portions (ranging from 20% to 70%) of the total amount of oxygen absorbed by the aerial part can be transported downwards to roots in water cultured intact seedlings of rice, barnyard grass, wheat, pea, etc. By interrupting the alternative paths of transport, it has been demonstrated that oxygen moves downwards mainly through gaseous diffusion along the intercellularspaces in the cortex. The aim of the present investigation is to ascertain the site of oxygen absorption for downward transport in the aerial part and to show that such a transport does not necessarily involve active participation of the absorbing organ. The results are summarized below: 1. Provided that a small upper portion of the leaf is left exposed in air, flooding of the aerial part of the rice seedling does not reduce the amount of total oxygen absorption to any appreciable extent (Fig. 1). In agreement with field observation, the unflooded tip is capable of furnishing the submerged part with enough oxygen to keep it alive. 2. Nor does the complete or partial removal of leaves by cutting in seedlings of rice and pea affect downward oxygen transport appreciably, provided that the stem segment or a leaf sheath is left exposed in air. 3. The following common notion has been confirmed by actual measurement: The abnormal excessive elongation of the coleoptile in rice seedling germinated under water, which may easily extend itself above the water surface, is an adaptive device to furnish the seedling with the oxygen required for root development. 4. The "floating" roots developed at the later stage in rice culture have been demonstrated to be a possible site of oxygen absorption for downward transport. 5. When a rice seedling is held up side down, with its roots exposed in air and the shoot submerged, downward oxygen transport still takes place, although to a lesser extent than in its normal position.
Abstract (Browse 1957)  |  Full Text PDF       
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Author: اѧ ٧ڧ -ѧ ѧ - ݧڧߧ
Journal of Integrative Plant Biology 1965 13(4)
      
    
Abstract (Browse 2022)  |  Full Text PDF       
Comparative Anatomy of Phloem Fibers in Different-aged Branches of Pteroceltis tatarinowii Maxim.
Author: C. L. Lee, Y. S. Hu and S. J. Liu
Journal of Integrative Plant Biology 1965 13(4)
      
    A comparative study in the distribution and morphological characteristics of the phloem fibers in a number of branches of 1, 2, 4 and 6 years of age of Pteroceltis tatari- nowii Maxim. were undertaken. The relative amount of the phloem fibers in the 2C4 years old branches was much greater than that in any other aged branches. The length as well as the length/width ratio of the phloem fibers was also the greatest in the 2C4 years group. Such characters together with the fact that the periderm and the dilated meristem in the bark were yet underdeveloped, all indicated that the 2C4 years old branches were most suitable for the Suan-paper manufacture. By the same token, one explained why the first year or more than 6 years old branches were not usable for paper manufacture. The results of this anatomical analysis were foundamentally pertinent to the technical data of Suan-paper fabrication. Furthermore, they were available as references to the use of bark from other plants for paper production or textile.
Abstract (Browse 2158)  |  Full Text PDF       
On the Fertilization of Oryza sativa L. Sorghum vulgare Pets.
Author: S. H. Wu, C. C. Wang, C. S. Sun and C. K. Tsai
Journal of Integrative Plant Biology 1965 13(4)
      
    1.The pollen germination of Sorghum vulgate appeared normal on the stigma of the Oryza sativa, but the pollen tubes grew slowly in the style. Some of the pollen tubes may become enlarged in their tips or sometimes bursting, while others have continued to grow and entered the embryo sacs. 2. The growth rate of the pollen tubes varied widely. A few pollen tubes were observed in the embryo sacs of the materials 2 hours after pollination, but most of them entered the embryo sacs much later. 3. The zygote associated with a paucity of endosperm nuclei was observed in the materials 1 day after pollination. The double fertilization and 8C12-celled proembryo associated with a number of the free nuclei of the endosperm appeared with a rather high frequency (10.3%) in the materials 3 days after pollination. Some of them are normal in appearance and others may show more or less abnormalities. 4. No division figure was found except in one single case in which mitoses have occurred in both the proembryo and the endosperm. It is most likely that in such case the proembryo and the endosperm if left intact might develop further. 5. A 80-celled embryo was the biggest one which appeared in the materials 5 days after pollination. In general, no cells were ever formed in the endosperm, except in one instance among the 7 days materials the endosperm became cellular in micropylar end. In all other cases the endosperm either ceased to develop early or disorganized. The disorganized endosperm materials are considered to be utilized by the embryo. 6. In certain instances the free nuclei of the endosperm were not distributed at random. They were not equal in size and might fuse into giant nuclelei. 7. The most striking feature is that in the embryo sacs, in which double fertilization or proembryo and endosperm have occurred, a dark stained pollen tube was commonly present. This fact leads us to the conviction that in general only if a healthy pollen tube entered the embryo sac, double fertilization can take place and further development can proceed. 8. In certain cases the protoplasm of the embryo cells appeared scanty. It is apparently that the normal metabolism of the embryo was disturbed owing to the lack of nutrient, and the death of the embryo ensued. 9. No differentiated embryo was observed and no mature seeds were produced. The materials fixed 12 days after pollination showed a variety of abnormalities and collapses. The authors believe that the failure of seed production of rice X kaoliang was primarily due to the fact that the pollen tubes in the style grew too slowly to reach the embryo sacs in time. The consequence is that the double fertilization took place only in a late stage while the male and female gametes may have already become unhealthy. In addition, in this late stage the stored starch in the maternal tissues having gradually disappeared, the nutrient supply to the embryo sac was therefore limited and the young embryo and endosperm were finally in starvation.
Abstract (Browse 2142)  |  Full Text PDF       
Investigation of Sexual Process in Interspecific Crosses Between Gossipium hirsutum and G. arboreum
Author: S. Y. Hu and Z. C. Chu
Journal of Integrative Plant Biology 1965 13(4)
      
    The present investigation is the first of a series of cytological researches on inter-specific hybridization of cottons. The present report deals with the cytological behavior of sex and related cells revealed in crossing Gossipium hirsutum (female parent) with G. arboreum. Self-pollenated G. hirsutum served as control. The germination of pollen grains on the stigma and the growth of pollen tubes in the style and the entry of pollen tubes into the micropyles in crosses are in a fairly normal' manner when compared with controls. The percentages of pollen tubes entering ovules of the crossed and controls have no significant difference, being 48.2% in crosses and 54.7% in controls. Fertilization proceeds also normal in cross pollinated ovules. About 92.7% of pollinated ovules are found to have completed the fusion of sexual elements. It is thus: shown that the growth of foreign pollen tubes and fusion of female elements with foreign sperms are not the factors which cause failure in hybridization. The development of endosperm in crosses is abnormal. The number of free nuclei of hybrid endosperm is much smaller than that of controls; the formation of hybrid cellular endosperm is 6 or 7 days earlier than that of controls. The hybrid endosperm cells start to abort soon after their formation. About 14 days after pollination they become completely disintegrated. The hybrid embryo which thus far developed normally becomes arrested in its development and aborts also after that time. It may be concluded that the sterility of crosses between G. hirsutum and G. arboreum is primarily attributed to the abortion of hybrid endosperm. The sound development of the hybrids should be sought in the improvement nutrition of the hybrid embryo from resource other than their own endosperm.
Abstract (Browse 2047)  |  Full Text PDF       
 

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