Abstract: Transverse sections of immature and mature sugarcane internodes were investigated anatomically with white and fluorescence light microscopy The pattern of lignification and suberization was tested histo-chemically Lignification began in the xylem of vascular bundles and progressed through the sclerenchymatic bundle sheath into the storage parenchyma Suberization began in parenchyma cells adjacent to vascular bundle sheaths and spread to the storage parenchyma and outer sheath cells In mature internodes most of the storage parenchyma was lignified and suberized to a significant degree, except in portions of walls of isolated cells The pattern of increasing lignification and suberization in maturing internodes more or less paralleled an increase of sucrose in stem tissue In mature internodes having a high sucrose concentration, the vascular tissue was surrounded by thick-walled, lignified and suberized sclerenchyma cells The apoplastic tracer dyes triso-dium 3-hydroxy-5,8,10-pyrenetrisulfonate (PTS) and amido black 10 B, fed into cut ends of the stalk, wereconfined to the vascular bundles in all internodes above the one that was cut — with no dye apparently in storage parenchyma tissue Thus both structural and experimental evidence is consistent with vascular tissue being increasingly isolated from the storage parenchyma as maturation of the tissue proceeds We conclude that in mature internodes the pathway for sugars from the phloem to the storage parenchyma is symplastic The data suggest that an increasingly greater role for a symplastic pathway of sugar transfer occurs as the tissue undergoes lignification/suberization

Abstract: The stoloniferous clonal herb Glechoma hederacea (Labiatae) has a decussate phyllotaxy. Each node bears two leaves which emerge from the opposite faces of a quadrangular stolon. Anatomical studies showed that the vascular tissue of the stolon is concentrated into four major bundles, and leaf traces connect each leaf of a ramet to the proximal pair of vascular bundles. These two vascular bundles also provide the vascularization for the secondary stolon developing from the axial of that leaf. Transport of resources in the vascular system was analysed using acid fuchsion dye and 14 C-labelled photoassimilate. All transport of dye in the xylem was acropetal (...)

Abstract: Immunofluorescence microscopy and in situ hybridization were used to examine the expression of genes encoding C4 photosynthetic enzymes during early leaf development in the C4 dicotyledonous grain plant amaranth During early developmental stages, the chloroplast-encoded large subunit and nuclear-encoded small subunit genes of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) were expressed in both bundle sheath and mesophyll cells in a C3-type pattern The RuBPCase proteins and mRNAs became specifically localized to bundle sheath cells in the characteristic C4-type pattern as the leaves continued to expand and develop Changes in the localization of the RuBPCase proteins corresponded closely with changes in the localization of their mRNAs, indicating that the cell-specific expression of genes encoding RuBPCase is controlled, at least in part, at the level of transcript accumulation Genes encoding pyruvate orthophosphate dikinase were expressed specifically in mesophyll cells at all developmental stages examined Immunolocalization with antibodies raised against phosphoenolpyruvate carboxylase (PEPCase) showed that this enzyme is present only in leaf mesophyll cells, even though RNA sequences with homology to PEPCase gene sequences were present in both bundle sheath and mesophyll cells These results suggest that the regulation of genes encoding PEPCase in amaranth is complex and could involve the differential expression of divergent PEPCase genes or possibly regulation at the post-transcriptional level

Abstract: In a previous study we found that the apoplast of mature sugarcane stalk tissue contains up to 700 mM sucrose. In the current study, we found that xylem sap, exuded under root pressure from decapitated stalks, was virtually free of sucrose. This suggested that the apoplast of sugarcane stalk tissue contains at least two separate compartments: one within the free space of the vascular bundles, which is nearly free of sucrose, and another in the free space of the surrounding storage tissue. Anatomical observations indicated that these putative compartments were separated by the sclerenchymatous bundle sheath cell walls that were suberised and lignified early in development, constituting a barrier to the movement of relatively large molecular weight solutes but not water. It was hypothesised that this semipermeability would enable sucrose and other solutes in the apoplast of the storage tissue to provide a gradient for osmotic water flow from the xylem, generating a hydrostatic pressure in the apoplast. Additional lines of evidence were obtained to support this hypothesis: (i) apoplastic dyes were restricted to the xylem and did not accumulate in the apoplast of storage tissue when water-stressed plants were rehydrated, (ii) water potential measured with in situ psychrometers decreased when sections of intact stalks were cut, (iii) mature internode tissue of well-watered plants often cracks after maximum fresh and dry weight accumulation, and (iv) internode sections typically shrink in diameter immediately upon excision. The existence of a semipermeable barrier separating the vascular bundles from the storage parenchyma apoplast would require that phloem unloading involve a symplastic step in order to traverse the barrier. The presence of plasmodesmatal connections between companion, sclerenchyrna, and storage parenchyma cells supported this conclusion.

Abstract: The differential expression of PSII genes was investigated in mesophyll and bundle-sheath cells of Flaveria trinervia, a dicotyledonous C4 plant of the NADP-malic enzyme type. A comprehensive immunoblot analysis showed that three extrinsic proteins of the water-splitting complex (10, 16 and 23 kDa) are selectively depleted in mature bundle-sheath chloroplasts. In contrast, the reaction-centre core remained virtually unaffected as inferred from the abundance of the 47-kDa chlorophyll-a-binding protein, the D1 and D2 polypeptides, cytochrome b559 and the 34-kDa polypeptide. The selective depletion of the 10-, 16- and 23-kDa polypeptides in bundle-sheath chloroplasts was paralleled by a diminished PSII capacity. On the basis of oxygen evolution in the presence of the artifical electron acceptor 2,5-dimethyl-p-benzoquinone, bundle-sheath chloroplasts maintained up to 23 % of the PSII capacity shown by mesophyll chloroplasts. However, the levels of the 10-, 16- and 23-kDa proteins and, concomitantly, PSII activity varied to some degree and appeared to be correlated with environmental factors caused by seasonal changes. The selective depletion of the three members of the water-splitting complex was not reflected at the transcript level. The corresponding mRNAs were detectable in considerable amounts in bundle-sheath cells, indicating that the depletion of these proteins is regulated by post-transcriptional events. These findings reinforce the view that the peripheral proteins of the water-splitting complex are a focal point for controlling PSII activity in bundle-sheath chloroplasts of both mono- and dicotyledonous C4 plants of the NADP-malic enzyme subtype.

Abstract: C4 phosphoenolpyruvate carboxylase (PEPC) is post-translationally regulated by reversible phosphorylation of a specific N-terminal seryl residue in response to light/dark transitions of the parent leaf tissue. The protein-serine kinase (PEPC-PK) that phosphorylates/activates this mesophyll-cytoplasm target enzyme is slowly, but strikingly, activated by high light and inactivated in darkness in vivo by a mechanism involving cytoplasmic protein synthesis/degradation as a primary component. In this report, evidence is presented indicating that the inhibition of Calvin cycle activity by a variety of mesophyll (3-(3,4-dichlorophenyl)-1,1-dimethylurea, isocil, methyl viologen) and bundle sheath (dl-glyceraldehyde)-directed photosynthesis inhibitors blocks the light activation of maize (Zea mays L.) PEPC-PK and the ensuing regulatory phosphorylation of its target enzyme in vivo. Based on these and related observations, we propose that the Calvin cycle supplies the C4 mesophyll cell with (a) a putative signal (e.g. phosphorylated metabolite, amino acid) that interacts with the cytoplasmic protein synthesis event to effect the light activation of PEPC-PK and the concomitant phosphorylation of PEPC, and (b) high levels of known positive effectors (e.g. triose-phosphate, glucose-6-phosphate) that interact directly with the carboxylase. The combined result of this complex regulatory cascade is to effectively desensitize PEPC to feedback inhibition by the millimolar levels of l-malate required for rapid diffusive transport to the bundle sheath during high rates of C4 photosynthesis.

Abstract: The degree of polylamellation in the fibre cell walls of the bamboo Phyllostachys virideglaucescens has been investigated. The extent of polylamellation was found to be influenced by position of the vascular bundle in the culm wall, in certain positions by age of the culm and, most strikingly, with position within the vascular bundle. The number of wall lamellae was variable but tended to be greatest in fibres adjacent to either vascular elements or ground tissue at the periphery of the fibre bundles. A similar pattern of variation in fibre wall lamellation was also observed in two other species of bamboo. The characteristic pattern of fibre wall lamellation probably influences mechanical properties and warrants further investigation.

Abstract: In a survey of over 300 nonevergreen dicots in 69 families, many species were found to have translucent patterns attributed to the presence of bundle-sheath extensions (BSE) on the small and ultimate veinlets. The BSE have been shown by others to inhibit transverse air movement within leaves, and it has been suggested that they are important passageways between vascular tissue and the palisade. The only characteristic found to be associated with prominent BSE is that more trees have such features than herbaceous plants. However, many important herbs have them also, including soybeans and sunflowers.

Abstract: The long-term effects of white light (WL) on epidermal cell elongation and the mechanical properties and ultrastructure of cell walls were investigated in the subapical regions of hypocotyls of sunflower seedlings (Helianthus annuus L.) that were grown in darkness. Upon transition to WL a drastic inhibition of epidermal cell elongation was observed. However, the mechanical properties of the inner tissues (cortex, vascular bundles, and pith) were unaffected by WL. Thus, the light-induced decrease in cell wall plasticity measured on entire stems occurs exclusively in the peripheral tissues (epidermis and 2 to 3 subepidermal cell layers).

Abstract: The mechanism of hormone-enhanced solute accumulation was investigated in crown galls of Kalanchoe diagremontiana, induced by Agrobacterium tumefaciens (C58). Electrophysiological, cytological staining, and 14CO2-tracer techniques were used. Intracellular auxin and zeatinriboside concentration increased in tumours by three and five times, respectively, compared with the mesophyll. In contrast, the electrical membrane potential difference, in particular the energy-dependent component across the plasma membrane of tumours was at least 60 mV smaller than that of mesophyll cells. The detection of functional sieve tubes, metabolically active companion cells and also developed xylem vessels correlated well with evidence for reversed, long-distance, 14C-labelled assimilate flow from CAM–performing mesophyll to sugar and potassium-accumulating tumours. The change in hormone production, encoded by the iaaM, iaaH and ipt T-DNA genes, apparently induced functioning vascular bundles and established a strong sink. From a comparison with tobacco suspension cells (SR1 and SR1-C58), the changes in the amino acid pattern in the mesophyll/tumour complex can be attributed to the enzymatic activities incited by the nos encoding gene. Differences in sugar and inorganic ion content were not apparent in the transformed suspension cells, indicating that the increase in extracellular concentration by enhanced phloem unloading may be the crucial factor for the pathological solute accumulation in the tumours.

Abstract: The cell walls of parenchyma, rind and vascular bundle fractions of pearl millet (Pennisetum glaucum (L) R Br) were isolated from two brown midrib mutants (bmr) 5753 and 5778 and from their normal (N) near-isogenic line. The cell wall content of parenchyma was lower than that of vascular bundle which, in turn, was lower than that of rind. The amounts of ferulic and p-coumaric acids released by NaOH treatment of the cell walls were in the ranges 3-7 mg g−1 and 2-26 mg g−1, respectively. Parenchyma cell walls of the N line had the highest content of p-coumaric acid (26 mg g−1). This content of p-coumaric acid in the N line contrasts with that of bmr 5753 parenchyma (2 mg acid g−1 walls) and bmr 5778 (7 mg acid g−1 walls). The concentration of p-coumaric acid was highest in parenchyma cell walls that had been found to be the least digested. Parenchyma, rind and vascular bundle cells walls of the N line had much higher ratios of p-coumaric acid to ferulic acid than the mutants; rind and vascular bundle walls were less digestible than parenchyma. Small amounts of truxillic acid dimers were released by NaOH from the parenchyma walls of bmr 5778. Treatment of parenchyma, rind and vascular bundle cells walls with purified ‘driselase’ (containing xylanases and cellulases) released p-coumaroyl and feruloyl trisaccharides. Between 25 and 53% of the ferulic acid that was released by the NaOH treatment could be accounted for as feruloyl trisaccharide, but only 1-19% of the p-coumaric acid was accounted for as p-coumaroyl trisaccharide.

Abstract: no fibers. The 0. subterraneum portion of the tuber consists of a mass (up to 933 grams fr. wt.) of starch-filled parenchyma penetrated by vascular bundles containing both xylem and phloem. All cells in the 0. subterraneum portion of the tuber are 0. subterraneum cells-host cells were not mixed with parasite cells and there are no chimeral meristems as reported for Balanophora. The interface between host and parasite is sinuous but generally smooth, not a mixture of host and parasite cells. The tuber has no apical meristem; no leaves or axillary buds; no eustele; no epidermis. It produces long (up to 20 cm), slender (4 mm diam) runners that have an apical meristem with no root cap; no leaf primordia; a protoderm and epidermis but no stomata, no trichomes and no root hairs. In some places the runners' stele is rootlike (a protostele), in other places it is stemlike (with pith and collateral bundles).

Abstract: Mannose/glucose- and galactose-binding lectins (ML and GL respectively, were located by immunogold labelling in tissues of a peanut (Arachis hypogaea) nodule induced by an effectiveBradyrhizobium sp. strain. Light and electron microscopic examination of silver-enhanced semithin and ultrathin sections, respectively, revealed that both lectins were widely distributed throughout the cortex and bacteroidal zones although ML was more abundant. The lectins were predominantly in the vacuoles of cortical cells but GL was absent from, or at low concentration in, a two-cell-thick layer of cortical cells surrounding the bacteroidal region. Only ML was detected in cells of the vascular bundle endodermis and in central vascular bundle cells; neither lectin was found in pericycle cells. Bacteroidal cells contained abundant ML in the nuclei and cytoplasm surrounding bacteroids while GL was mainly located in the central vacuoles of these cells. Neither lectin was associated with bacteroid surfaces, peribacteroid membranes, plant cell walls or cell organelles and membranes. The above observations indicate that the nodule lectins are not symbiotic cell recognition determinants and suggest that they have protein storage functions.

Abstract: We have determined the levels of photosystem II activity and polypeptide abundance in whole leaves and isolated bundle sheath and mesophyll cells of C 4 , “C 4 -like,” and C 3 species of the genus Flaveria (Asteraceae). On a chlorophyll basis, the whole leaf levels of the D1, D2, and 34-kilodalton photosystem II polypeptides were similar for each Flaveria species. Photosystem II activity varied twofold, but was not correlated with photosynthetic type (C 3 or C 4 ). The bundle sheath cell levels of photosystem II activity and associated polypeptides in C 4 -like and C 4 Flaveria species were approximately one-half those observed in mesophyll cells but equivalent to those in bundle sheath cells of the C 3 species, Flaveria cronquistii. Analyses of the steady-state levels of transcripts encoding photosystem II polypeptides indicated that there were no differences in transcript abundance between mesophyll and bundle sheath cells of the C 4 Flaveria species. This pattern was in contrast to the three- to tenfold higher levels of transcripts encoding photosystem II polypeptides in mesophyll versus bundle sheath cells of maize. It is apparent that the higher mesophyll cell to bundle sheath ratio of photosystem II polypeptides in C 4 - and C 4 -like species of Flaveria is the result of higher levels of photosystem II expression in mesophyll cells rather than lower levels of expression in bundle sheath cells.

Abstract: Quantitative histochemistry was used to investigate the tissue-specific compartmentation of soluble carbohydrates (sucrose, glucose, fructose), starch and malate in the laminar pulvinus, leaf blade and petiole of Phaselous coccineus L. at day and night positions of diurnal leaf movement. Total carbohydrate levels measured in a series of cross sections along individual pulvini of 24-d-old plants showed only small differences between the day and night positions of the respective leaf. In contrast, the level of malate changed during diurnal leaf movement, especially in the central part of a pulvinus. The levels of glucose and fructose in the pulvinus increased towards the transition zones between the pulvinus and lamina, and pulvinus and petiole, and this trend was even more pronounced for starch. By contrast, sucrose levels were highest in the pulvinus proper. The transverse compartmentation of metabolites was studied in distinct, approx. 0.5-mm-thick tissue slices from the central part of a pulvinus. These were dissected further into up to 14 distinct subsamples (bundle, bundle sheath, motor tissues, flanks). Irrespective of the position of the leaf (day or night), the central vascular core and the surrounding bundle sheath had high levels of sucrose (up to 500 mmol-(kg DW)−1) and low levels of glucose and fructose (below 100 mmol-(kg DW)−1), while in the cortex the situation was reversed. In the night position the level of sucrose decreased by approx. 30% in the bundle sheath and the central vascular core but not in the other sections. We thus suggest that because of the relatively small diurnal changes in their cortical pools, soluble sugars are not involved in the osmotic processes resulting in leaf movement. In contrast, pulvini from 14-d-old plants showed an interesting diurnal change in starch and malate pools in the outermost layer of the extensor. Here starch increased at night while the malate pool was lowered nearly stoichiometrically. Inverse pool sizes were found in the day position of the respective leaves. Although less significant, the opposite diurnal variation occurred in samples taken from the flexor region. We thus were able to locate areas of different carbohydrate activities in the laminar pulvinus of P. coccineus. The central vascular core, including the bundle sheath, is involved in temporary storage of photoassimilates, and the cortical regions are responsible for osmotically driven leaf movement. The results are discussed with respect to guard-cell physiology.

Abstract: Distributions of free water, which is called water in this investigation, in mangrove (Bruguiera gymnorrhiza (L.) Lam.) tissues were examined by using1H-NMR imaging, and accumulation of Na+ in hypocotyls was examined by using high resolution23Na-NMR and23Na-NMR imaging in relation to their morphology. Water located preferentially in the epidermis and the outer layer of cortex adjacent to the epidermis, and around vascular bundles of a root, a branch stem, and hypocotyls. Amount of water detected in the middle parts of cortex and pith was small unlikeAucuba japonica branch tissue. On the other hand, relatively high concentration of Na+ was detected in the pith besides the epidermis and the outer layer of the cortex adjacent to the epidermis, and around vascular bundles of the hypocotyl. The localization of Na+ did not correspond to that of water. Concentrations of Na+ accumulated (up to 22mM) in the hypocotyl were approximately 10 times higher than those observed in tissues of ordinary plants. The characteristic water distribution and accumulation of Na+ in the mangrove are considered to relate to their ecological nature for the adaptation to saline environments.

Abstract: Quantitative histochemistry was used to inves tigate the tissue-specific compartmentation of soluble carbohydrates (sucrose, glucose, fructose), starch and malate in the laminar pulvinus, leaf blade and petiole of Phaselous coccineus L. at day and night positions of diurnal leaf movement. Total carbohydrate levels mea sured in a series of cross sections along individual pulvini of 24-d-old plants showed only small differences between the day and night positions of the respective leaf. In contrast, the level of malate changed during diurnal leaf movement, especially in the central part of a pulvinus. The levels of glucose and fructose in the pulvinus in creased towards the transition zones between the pul vinus and lamina, and pulvinus and petiole, and this trend was even more pronounced for starch. By contrast, sucrose levels were highest in the pulvinus proper. The transverse compartmentation of metabolites was studied in distinct, approx. 0.5-mm-thick tissue slices from the central part of a pulvinus. These were dissected further into up to 14 distinct subsamples (bundle, bundle sheath, motor tissues, flanks). Irrespective of the position of the leaf (day or night), the central vascular core and the surrounding bundle sheath had high levels of sucrose (up to 500 mmol-(kg DW) ~J) and low levels of glucose and fructose (below 100 mmol-(kg DW)-1), while in the cor tex the situation was reversed. In the night position the level of sucrose decreased by approx. 30% in the bundle sheath and the central vascular core but not in the other sections. We thus suggest that because of the relatively small diurnal changes in their cortical pools, soluble sugars are not involved in the osmotic processes resulting in leaf movement. In contrast, pulvini from 14-d-old plants showed an interesting diurnal change in starch and malate pools in the outermost layer of the extensor. Here starch increased at night while the malate pool was low ered nearly stoichiometrically. Inverse pool sizes were found in the day position of the respective leaves. Al though less significant, the opposite diurnal variation occurred in samples taken from the flexor region. We thus were able to locate areas of different carbohydrate activities in the laminar pulvinus of P. coccineus. The central vascular core, including the bundle sheath, is involved in temporary storage of photoassimilates, and the cortical regions are responsible for osmotically driven leaf movement. The results are discussed with respect to guard-cell physiology.

Abstract: Experiments were conducted to determined the development of the vascular bundles in the peduncle of different tillers on its development in order to improve the vascular system and possibly increase grain yield. The development of the vascular bundle in the leaf, stem and panicle is an important aspect of assimilate translocation and differentiation of panicle characters. Two cultivars were used in this study: IR58, an indica type, and Unbong 7, a japonica type. The main culm(M) had more and bigger vascular bundles in the peduncle and those vascular bundle decreased with tiller order and tiller development. In the primary tillers, P1 had more large and small vascular bundles than P5 in both cultivars. IR58 developed more large vascular bundles compared to Unbong 7, but the small vascular bundle in unbong 7 was more than in IR58. The cross sectional area of phloem and xylem in large vascular bundle decreased with tiller order in both cultivar. Larger area of phloem and xylem in the early formed tillers more efficient transport of assimilates. The number of spikelets, the weight of panicle and grain yield per panicle were highest in the main culm followed by the order of their initiation or emergence. The number of primary and secondary branches to be positive associated with the number and area of vascular bundles. Furthermore, the number of vascular bundles in the peduncle was highly correlated with the peduncle thickness which in turn was correlated with the number of primary and secondary branches on the panicle. These results showed tillers that are initiated early and have relatively ation usually have more vascular bundles, larger peduncle, more spikelets spike let filling and ultimately higher yield.

Abstract: Within each internode and about four plastochrons after its formation, an intercalary growth area appears, leading to a continued lengthening due essentially to anticline mitoses. It temporarily looks like a cambium. The blade of the leaf which is directly above the internode is absolutely necessary for the formation of this growth area. Xylem integrity of the cauline vascular bundle connected with this leaf is also required. Within each leaf, the presence of the blade and the integrity of vascular bundles are also indispensable for the lengthening of the petiole, whose mitotic system resembles the internode's. The hypothesis of a blade influence on the mitotic lengthening system through mechanical pressure due to the vascular development is discussed. Key words: internode, petiole, blade, vascular tissues, Manihot esculenta, intercalary growth.

Abstract: Boron deficiency caused the damages of differient tissues of sesame. The observation of sections with electron microscope showed that sesame leaves not only had deformed surface and deformed and closed stomas. but also had abnormal inner struture due to boron deficiency. These changes include following eharactaristics: firstly, boron deficient sesame eaves had small veins and vascular bundles. Secondly. the leaf cells were tightly arranged and the number of chloroplasts which did not develope well reduced, therefore, the photosynthesis of boron deficient leaves would be negatively affected. Then, petiole and stem deformed, such as their vascular bundles were small and secondary structures were weak. the arrangement of the celis was in disorder. Low boron content also affected the mitoehondria as well as pollen.

Abstract: For the histochemical localization of nucleoside triphosphatases at the electron microscopic level, prefixed tissues were incubated with lead nitrate in addition to substrate (GOMORI reaction) While ATP and UTP as substrates gave electron-dense reaction products at the plasmalemma of sieve tubes, companion cells and phloem parenchyma cells, and at plasmodesmata in primary pitfields, AMP gave reaction products only at the tonoplast of parenchyma cells Since electron-dense deposits also occur in cell walls and vacuoles, energy dispersive X-ray microanalysis was used to distinguish between lead deposits and lead-phosphate deposits The latter were restricted to the symplast Among the three plant species used, the leaf bundle phloem ofHordeum distichon showed ATPase activity largely restricted to the phloem cells, except for the thickwalled sieve tubes Some activity also bordered the chloroplasts of the bundle sheath cells In the C4 plantGomphrena globosa, ATPase and UTPase activities appeared to be the greater in phloem parenchyma cells than in sieve tubes In the phloem of youngMonstera deliciosa roots, ATPase occurred not only at the plasmalemma of sieve tubes, but also around sieve-tube plastids When compared with AMP as substrate, it appears that nucleoside triphosphates are the natural substrates of the enzyme(s) in the plasmalemma of sieve tubes and phloem parenchyma cells

Abstract: C 4 species of the genus Aristida (Poaceae) have 3 distinct types of photosynthetic cells in their leaves, the mesophyll (M) cells, the outer bundle sheath (BS) cells, and the inner BS cells, and exhibit a unique Kranz-type leaf anatomy. The cellular localization of C 3 and C 4 photosynthetic enzymes was investigated in leaves of Aristida latifolia Domin by the protein A-gold immunocytochemical technique. The outerBS cells contained centripetally located small chloroplasts, which were structurally similar to those of the M cells