January 1966, Volume 14 Issue 1

 

          Research Articles
Histochemical Observations on the Distribution of Adenosine Triphosphatase in Phloem and Motor Organs in Higher Plants
Author: Kuo Chi-fang and Lou Cheng-hou
Journal of Integrative Plant Biology 1966 14(1)
      
    In a previous communication (Kuo 1964), it was shown by histochemical means that the phloem of cucurbit, as compared with the ground parenchyma, is particularly rich in adenosine triphosphatase (ATPase). A concurrent research by Yen et al. (1965) has succeeded in actually extracting from the vascular bundle of tobacco a crude protein fraction which not only possesses high ATPase activity, but also exhibits viscosity changes on addition of ATP or AMP. Such properties have been known to be characteristic of the contractile proteins constituting the muscle in animals. Although little is known about the actual role played in food transport by the living tissues in phloem, evidence has been accumulating that the active participation of the protoplasm in the phloem is necessary to facilitate sap movement. All these results have tempted us to think that higher plants, just like animals, also derive the energy required for performing mechanical work directly from ATP through the mediation of the contractile protein which is the ATPase itself. Accordingly, the present investigation is engaged in further histochemical observations to locate more precisely ATPase in the sieve element and to map out the distribution of the enzyme in various motor organs of higher plants, with the purpose in mind to see whether the map of enzyme distribution in the tissue has anything to do with its peculiar way of movement. 1. Presence of ATPase in the slime body of the functioning sieve element. In the functioning sieve element, high ATPase activity is displayed at the slime body and the connecting strands traversing the pores of the sieve plate (Plate i, figs. 2, 3 & 4). However, as the pores of the sieve plate are partially blocked by the callose, the enzyme reaction becomes lessened. If the plate is completely covered by the callose pad, none could be detected. Since the slime body has been claimed by many workers to be pro- teinaceous in nature (cf. Esau 1950), there should be no surprise that it also possesses enzyme activity and contractile action. This seems to indicate that the slime body and the connecting strands are not mere hindrance to the sap flow but may actively participate in propelling the translocation stream. The fact that the intense ATPase reaction is given in the companion cell (Plate I, figs. 1 & 3) is in conformity with the common notion that the cell is actively involved in the normal functioning of phloem. 2. Enzyme distribution in various motor organs of different sensitivity. The ATPase content in the various motor organs (pulvinus, stamen, tendril, etc.) of different sensitivity has been compared histochemically, ranging from. 1) the highly sensitive organs; e.g. the pulvinus of Mimosa pudica (Plate j, fig. 5) and of Oxalis piota (Plate j, fig. 6), the stamen of Berberis Watsonae (Plate k, fig. 10), the young tendril of Cucurbita maxima Duchesne and Vitis vinifera (Plate k, figs. 11 & 12); 2) the moderately sensitive organs; e.g. the pulvinus of Sesbania cannabina (Plate j, fig. 8); 3) the feebly sensitive or insensitive organs, e.g. the pulvinus of Robinia pseudoacacia (Plate j, fig. 7), the stamen of Brassica campestris var. oleifera (Plate k, fig. 9). From the results, it can be seen that the higher the sensitivity of the organ, the greater its enzyme activity. In addition to the morphological assymetry which is typical of plant motor organs, there also exists a physiological gradient, as evidenced by the uneven distribution of ATPase, usually being more intense on the more irritable side. The claim made recently by Aimi (1963) and others that the sudden collapse of the pulvinus of Mimosa on stimulation is not a direct result of the loss of turgidity as is generally assumed, but an immediate manifestation of the active vacuolar contraction in the motor cells is supported by the high ATPase content in the motor cells in our investigation.
Abstract (Browse 2195)  |  Full Text PDF       
The Effects of Cyanide on the Rate of Oxygen-Consumption and P32 Uptake by Cyanogenic Tissues of the Cassava (Manihot esculenta) Tuber
Author: P. S. Tang, Y. L. Tai and Y. S. Liang
Journal of Integrative Plant Biology 1966 14(1)
      
    The effects of cyanide on the rate of respiration (oxygen-consumption) and p32 up-take were studied in rind tissue discs from root tubers of the cyanogenic plant, Manihot esculenta (cassava). The following results were obtained. 1. Cyanide (M/1000, buffered at pH 7), instead of inhibiting the rate of respiration, evoked a marked stimulation (ca 168% of control rate) of the process. Within the range of concentration tested (10-5 to 10-2 M, pH 7) Qo2 increases with cyanide concentration in a manner indicative of rate/substrate relationship. This stimulation as well as the ground rate are abolished in dead (boiled) tissues. 2. Tissue extracts made with S6rensen phosphate buffer gave an easily measurable rate of oxygen-consumption which was stimulated by cyanide to the same extent (ca. 180% of control rate) as in tissue discs. The stimulated rate as well as the ground rate of oxygen-consumption are heat labile. It appears therefore, that at least the bulk of the cyanide stimulated oxygen-consumption is located in the extractable parts of the cassava tissue and is therefore extramitochondrial. Azide (M/1000, pH 7) also stimulates tissue respiration but to a slightly lower extent than cyanide. 3. Contrary to its stimulatory effect on the rate of respiration cyanide (M/1000, pH 7) inhibits p32 uptake by cassava rind tissue discs to 70% of the control rate. This inhibition is significantly weaker than that for the same process in wheat seedlings (ca. 10% of the control rate). On the other hand p32 uptake by cassava and wheat seedlings are strongly inhibited to about the same degree (29% and 18%) by DNP the un-coupling agent for phosphorylation. It was concluded from these results that the respiration-dependent process of p32 up-take in the tissues of a cyanogenic plant (cassava), like that in other commonly investigated plant tissues, is also mediated largely through the process of oxidative phosphorylation. The bulk of the cyanide-stimulated oxygen-consumption is extra-mitochondrial. The physiological significance of this enzyme mediated stimulatory effect by cyanide was considered in the light of a detoxication mechanism.
Abstract (Browse 2851)  |  Full Text PDF       
Relationship Between Downward Oxygen Transport and Intercellular Spaces in Root Cortex in Water Cultured and Moist Cultured Seedlings
Author: Yin, W. Y., Cui, Y. Y. and Lou, C. H.
Journal of Integrative Plant Biology 1966 14(1)
      
    In the present investigation, seedlings of rice, pea, sorghum, and maize are raised both in water culture and moist culture. The former culture is to provide the roots with an oxygen deficient condition; while the latter, a direct access to air. The amount of oxygen transported downwards in the seedlings varies not only with the nature of plants but also with the way how they are raised: More oxygen is transported downwards in marsh plant (rice) than in land plants (pea, sorghum, maize); and, in case the same plant is concerned, more in water cultured seedlings than in moist cultured ones. Downward oxygen transport in the various seedlings is intimately correlated with the relative volume of the intercellular spaces in the root: the more the downward transport, the larger the air spaces in the cortex. The fractional volume of the intercellular spaces in a small plant segment can be conveniently estimated by determining the specific gravities of the fresh turgescent segment before and after it is filled with water by vaccum infiltration. The difference between the two consecutive measurements in specific gravity times 100 gives directly the percentage of the volume occupied by air spaces. When large root segments are used, the relative volume can also be determined by weighing before and after vaccum infiltration. To test whether oxygen diffusion in the intercellular spaces of roots could actually account for its downward transport, a model is built of capillary tubings with dimensions and oxygen pressure gradients similar to those found in roots. The amount of oxygen diffused in such a model is measured with a respiratory hydrometer (see Fig. 1) and fits closely that measured in roots. By comparing the amount of oxygen transported downwards in a seedling with that consumed by its excised roots in air, it can be shown that, in case of rice, it could meet (and at times may even exceed) 100% of that consumed by roots in water cultured seedlings, but is less in moist cultured ones. In land plants (pea, sorghum, and maize), however, the downward oxygen supply is far below its requirement, being 80%每100% in water cultured seedlings and 30%每60% in moist cultured ones. The above results, together with those obtained in previous communications, support the view that adaptation of a plant to flooded condition is primarily achieved by its capacity of providing adequate intercellular spaces for downward oxygen diffusion. The capacity depends not only upon the phylogeny of the plant concerned but also upon its ontogenic development.
Abstract (Browse 2076)  |  Full Text PDF       
Comparative Anatomy of Resin Canals of the Needles of Picea Grown in China
Author: C. L. Lee and Mu Sih-kin
Journal of Integrative Plant Biology 1966 14(1)
      
    The comparative anatomy of the leaves of 21 species and 5 varieties of the genus Picea has been investigated with special reference to their resin canals. Resin canals are found in the needles of all Picea species under study. They are always arranged in longitudinal series, mostly being interrupted by transverse partitions of mesophyll except in a few species where they exhibit two disinterrupted canals. The number of the canal segments in a needle is quite variable in different species, and even in different needles of the same species. Their arrangement, according to the frequency of the occurrence of two-canals, one-canal and no canal in the middle transection of the needles and from the observation of the clearing specimens, can be classified into four groups (fig. 1). It would seem preferable that the characteristic difference of the resin canals, which might be of texonomic importance, lie in their discrepancy in the relative distribution of the resin canals rather than in the number or the relative length of the canals in each needle. This study also suggests that those with two canals lying along the lateral angles of the needles might be considered as the primitive types, from which other forms have been derived. Long canals may be broken into short cystic segments or subsequently degenerated into residue canals located only on one side of the needles.
Abstract (Browse 2337)  |  Full Text PDF       
The Differentiation of the Leaf Cells of Wheat and the Development of Its Chloroplasts in the Mesophyll Cells
Author: H. C. Tuan, W. L. Hung, L. C. Hsu and P. Y. Tso
Journal of Integrative Plant Biology 1966 14(1)
      
    1. By means of cell separation method, we studied the differentiation of the leaf cells of wheat, Nongda 183 and the development of the chloroplasts in the mesophyll. cells. 2. The differentiation of the cells of the first leaf can be divided into 3 stages. Beginning from the leaf primordium to the fully expanded leaf, the cells are in the stage of division and expansion. When the fully expanded leaf becomes deep green in color, the leaf cells are in the prime of life. When the leaf begins to show yellowish colored spots to its complete withering, the cells are in the stage of senescence. Accompanying these stages, the external form and the internal structure of the cells change also. 3. In the early stage of cell division and expansion, one can observe many 0.5米 ℅ 3.4米 mitochondria-like protoplastids which go through various morphological changes to become chloroplasts. 4. The mesophyll cells of the leaf begin to show the signs of senescence sooner than the epidermal cells and the cells of the vascular bundle. The latter last the longest in the life span of the leaf.
Abstract (Browse 1811)  |  Full Text PDF       
On Plant-Remains from the Devonian of Yunnan and their Significance in the Identification of the Stratigraphical Sequence of this Region
Author: Hs邦 Jen(J. Hs邦)
Journal of Integrative Plant Biology 1966 14(1)
      
    The present paper treats of three plant-remains recently collected in the district Chu-tsing, East Yunnan. They are Zosterophyllum yunnanicum sp. nov., Protopteridium minuturn Halle and Sporogonites yunnanense sp. nov., and their distinctions from the related species from the other parts of the world are rather fully discussed. In addition, the paper further discusses the geological age of the region wherefrom these and other plant-remains have been collected. Zosterophyllum yunnanicum is preserved in a bed of dark greyish sandy clay in the locality Hsu-Chia-Chong in the district Chuitsing, East Yunnan. It is associated with Drepanophycus spinaeformis Goeppert. This bed belongs to the uppermost layer of the Tsuifengshan Series. The diagnosis of Zosterophyllum yunnanicumsp, nov. is given as follows: A small plant with slender erect axes, about 1-1.3 mm across and sparingly dicho- tomous branches, axis possessing a slender central vascular strand. Sporangia are short-stalked, closely and radially arranged on the upper part of the erect axis to form a compact strobilus, up to 5 cm long. Each strobilus consists of about 40每50 sporangia which are roundish to reniform, about 1.9每2.7 mm across, and about 9.4 mm thick; dehiscence by a slit running along the convex upper edge. Epidermal cells of the axis and the sporangium are elongate-fusiform, about 360 米 long and 45-90米 wide. Zosterophyllum yunnanicum agrees with Z. myretonianum Penh. and Z. australianum in general morphology, but smaller in size. The genus Zosterophyllum has so far been recorded only from the Late Silurian of Australia and England and the Early Devonian of England, Scotland, France, Germany, West Siberia and North America. Remains of axes with H-shaped branching (cf. Zostero- phyllum) have previously been recorded by the present author from the district Chutsing (Hsu 1947, 354-355. Pl. V, Fig. 52 and text-figs. 5 a-c), but the actual locality and horizon were then unknown. So the present discovery of Z. yunnanicum helps to settle the question of the Tsuifengshan Series which is definitely not younger than the Late Devonian in age. Protopteridium minutum and Sporogonites yunnanense were found in a bed of light grey sandstone in the locality Lunghuashan of the same district, from where the type of Protopteridium minutum Halle was collected. From the same bed some fragments of Protolepidodendron scharyanum Krejci were observed. This bed belongs to the uppermost layer of the Lunghuashan Series. From the lower part of the same series fragments of Drepanophycus spinaeformis Goeppert were also collected. It is interesting to note that under a critical investigation by the present author, it conclusively proves that Proto-pteridium minutum is not a small plant, as Halle first described. It attains a height of at least 1 meter. The main axis measures about 1.8 cm in diameter. Both the larger and the smaller specimens show sympodial development. Unequally dichotomous branching has been found only in some primary and secondary lateral branches. Most of the lateral branches are pinnulelike and subdivide 4每6 times, each possessing a slender central vascular strand. If the terminology of Zimmermann is adopted, the type of branching may be described as "Oscillating overtopping". However, some slender branches have been observed. These branches are sparingly unequally dichotomous, forking 6每7 times, and appear to be thinner than those just mentioned. Young branches are circinately coiled. Sporangia are arranged in clusters, 2-4-8 in number, attached to the terminal branches. These sporangia are 0.9 mm long, fusiform or sometimes almost cylindrical. Some larger obovate ones are about 2.5 mm long and borne singly, or in 2 (rarely in 4) in each tassel on the top of the flattened lateral branches. Epidermal cells of the axes are elongate, about 136 Ft long and 45.5 米 wide, while those of the smaller sporangia are oblong-fusiform, about 100每150 米 long and 25 米 wide and those of the larger, about 130每230米 long and 40每70米 wide. No annulus is observed. Sometimes mineral grains, occupying the interior of the sporangia, are observable through a longitudinal slit in the wall and thus give false markings of cells. Evidently, the plant-body of Protopteridium minutum is much more complex than Halle thought. A new reconstruction of it is drawn here to replace that given by Halle in 1936. It is considered that Protopteridium minutum is more closely related to P. hostimense Krejci than to others. The former is also complex in the vegetative branches, but simpler in the fertile ones. Sporogonites yunnanense is represented only by some detached capsules, hich are elongate-obovate, measuring about 3.2每4.5 mm long and 1.4每1.8 mm wide. These capsules are borne on the top of a slender stalk, measuring about 0.4每0.8 mm across. The younger ones look rather smooth, but the mature ones exhibit 12 longitudinal ridges, separated by shallow grooves, 6 ridges being visible on the surface exposed. Epidermal cells of the wall of the capsules are elongate, 150米 long and 50 米 wide. No stomata could be made out among them. Sporogonites yunnanense closely resembles S. exaberans Halle of the Early Devonian, but the capsules of the former exhibit variable forms and the upper end of the capsules is rather more pointed than those of the latter. Owing to the occurrence of Drepanophycus spinaeformis and the general aspect of the flora so far known, the author suggests that the geological age of the Lunghuashan Series is of the Middle Devonian or probably the Early Eifelian. The flora of the Tsuifengshan Series is predominated by Drepanophycus spinaeformis and Zosterophyllum yunnanicum, thus indicating that its geological age is no doubt of the Early Devonian.
Abstract (Browse 2587)  |  Full Text PDF       
 

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