Abstract: Due to the fragile pressure gradients present in the xylem and phloem, methods to study sap flow must be minimally invasive. Magnetic resonance imaging (MRI) meets this condition. A dedicated MRI method to study sap flow has been applied to quantify long-distance xylem flow and hydraulics in an intact cucumber (Cucumis sativus) plant. The accuracy of this MRI method to quantify sap flow and effective flow-conducting area is demonstrated by measuring the flow characteristics of the water in a virtual slice through the stem and comparing the results with water uptake data and microscopy. The in-plane image resolution of 120 x 120 microm was high enough to distinguish large individual xylem vessels. Cooling the roots of the plant severely inhibited water uptake by the roots and increased the hydraulic resistance of the plant stem. This increase is at least partially due to the formation of embolisms in the xylem vessels. Refilling the larger vessels seems to be a lengthy process. Refilling started in the night after root cooling and continued while neighboring vessels at a distance of not more than 0.4 mm transported an equal amount of water as before root cooling. Relative differences in volume flow in different vascular bundles suggest differences in xylem tension for different vascular bundles. The amount of data and detail that are presented for this single plant demonstrates new possibilities for using MRI in studying the dynamics of long-distance transport in plants.

Abstract: We studied ice propagation in stems and leaves of various angiosperm deciduous and evergreen trees and shrubs and gymnosperms by differential thermal analysis (DTA) of thermal images captured with a digital infrared camera. This so-called infrared DTA (IDTA) technique should elucidate the smallest freezing exotherms in plant tissues. After intrinsic ice nucleation in the stem, ice spread into the leaves. On the leaf lamina, it was possible to differentiate between initial freezing in the veins and subsequent freezing in the mesophyll. The spread of ice followed the venation and could usually be tracked to third-order lateral veins. The exception was in mature leaves of Buxus sempervirens L., where large ice lenses formed in the central mesophyll lacunas. Longitudinal ice propagation within veins was faster (0.3-4.7 cm s(-1)) than measured in earlier studies (0.25-2.7 cm s(-1)). Peculiar leaf freezing patterns indicated that lateral ice propagation in the vascular bundles may take significantly longer than longitudinal ice propagation. Within the vascular bundle, the exact sites of initial vein freezing could not be resolved. However, the observed freezing patterns combined with chemical theory and anatomical structures suggest that initial freezing most probably occurs within the xylem vessels and tracheids. Ice barriers appeared to be present in leaf laminas of Cinnamomum camphora (L.) J. Presl., resulting in freezing of small mesophyll compartments produced by sclerenchymatic bundle sheath extensions. The IDTA was demonstrated to be a highly efficient method for resolving peculiarities of ice propagation at the plant tissue level.

Abstract: The effects of salinity (400 mM NaCl) on growth, biomass partitioning, photosynthesis, and leaf ultrastructure were studied in hydroponically grown plants of Aeluropus littoralis (Willd) Parl. NaCl produced a significant inhibition of the main growth parameters and a reduction in leaf gas exchange (e.g. decreased rates of photosynthesis and stomatal conductance). However, NaCl salinity affected neither the composition of photosynthesis pigments nor leaf water content. The reduction in leaf gas exchange seemed to correlate with a decrease in mesophyll thickness as well as a severe disorganisation of chloroplast structure, with misshapen chloroplasts and dilated thylakoid membranes. Conspicuously, mesophyll chloroplasts were more sensitive to salt treatment than those of bundle sheath cells. The effects of NaCl toxicity on leaf structure and ultrastructure and the associated physiological implications are discussed in relation to the degree of salt resistance of A. littoralis.

Abstract: Vascular tissue differentiation is essential to enable plant growth and follows well-structured and complex developmental patterns. Based on recent data obtained from Arabidopsis and Populus, advances in the understanding of the molecular basis of vascular system development are reviewed. As identified by forward and/or reverse genetics, several gene families have been shown to be involved in the proliferation and identity of vascular tissues and in vascular bundle patterning. Although the functioning of primary meristems, for example the shoot apical meristem (SAM), is well documented in the literature, the genetic network that regulates (pro)cambium is still largely not deciphered. However, recent genome-wide expression analyses have identified candidate genes for secondary vascular tissue development. Of particular interest, several genes known to regulate the SAM have also been found to be expressed in the vascular cambium, highlighting possible overlapping regulatory mechanisms between these two meristems.

Abstract: The regeneration patterns of shoot apices derived from in vitro plants of four varieties of sugar cane in response to different growth regulators and light were evaluated. The cellular origin of the regeneration processes was also investigated. Explants cultivated on medium supplemented with NAA and incubated under light showed direct bud regeneration from cells of external layers of the ground parenchyma of the stem. Explants cultivated in the dark on medium supplemented with low concentrations of picloram (PIC) or 2,4D (4.0 and 4.5 μM, respectively) showed callus formation derived from the ground parenchyma of stem and development of preembryogenic masses derived from bundle sheath cells facing the phloem tissue of immature leaves. Somatic embryos at further developmental stages were visible following transfer to medium devoid of growth regulators and incubation under light. When incubated under light since the begining of the experiment, explants cultivated in the presence of higher PIC or 2,4D concentrations (40 and 22.6 μM, respectively) first displayed direct organogenesis from external layers of the ground parenchyma of the stem, followed by the development of organogenic calluses. Preembryogenic masses were also observed from bundle sheath cells of immature leaves. However, in contrast to the cultures pre-incubated in darkness for 30 days, the subsequent stages of embryo development were not detected. The regeneration efficiency of calluses induced by 2,4D and PIC was generally increased following desiccation in laminar flow or incubation on medium solidified with phytagel.

Abstract: Susceptibility of photosystem II complex (PSII) to photoinhibition and degradation of D1 protein has been described in the chloroplasts of C3 plants but so far, the PSII turnover has not been characterised in any C4 plant, which contains two types of chloroplasts differing biochemically and structurally. In maize (Zea mays L. Olenka), chloroplasts located in mesophyll (M) develop grana, while bundle sheath (BS) chloroplasts are agranal. In this paper, we report the D1 protein phosphorylation, damage and proteolysis in mesophyll as well as in agranal bundle sheath thylakoids of maize plants. Photoinhibitory treatment (1800 μmol photons m–2 s–1) of isolated thylakoids led to donor side inhibition of PSII electron transport and then to damage of reaction centre in both M and BS thylakoids. Rate of D1 degradation rate was faster in BS than in M thylakoids, and the addition of ATP to incubation medium delayed D1 degradation in both types of thylakoids. Furthermore, we demonstrated that the proteases belonging to FtsH and Deg families were present but their amounts significantly differed in M and BS thylakoids. Protease inhibitor studies revealed that serine- and metallo-proteases were involved in degradation of D1 protein. Apparent existence of D1 degradation cycle and the presence of proteolytic enzymes responsible for this process in BS thylakoids confirm that PSII plays an important role in agranal membranes, and when damaged, D1 can be rapidly degraded to enable PSII repair and restoration in these membranes.

Abstract: The plant vascular system is a complicated network of conducting tissues that interconnects all organs and transports water, minerals, organic compounds, and various signaling molecules throughout the entire organism. This system is composed of two major tissue types - xylem and phloem - that originate from the vascular meristem, i.e., the procambium. Recently, combined applications of molecular genetics and genomics tools have provided significant insights into the underlying mechanisms by which specification of these two types are regulated. They include 1) the asymmetric patterning of xylem and phloem in the vascular bundle that arises through antagonistic functioning between the HD-ZIP III and KANADI transcription factors, 2) control of vascular cell proliferation by brassinosteroids (BRs) and the HD-ZIP III transcription factors, and 3) regulation of vascular tissue identity by the MYB transcription factor APL and the NAC transcription factors VND6 and VND7. These findings define an emerging developmental framework for the control of vascular tissue specification.

Abstract: This work is a comparative pharmacobotanical study between the leaves of Turnera chamaedrifolia Cambess. and Turnera subulata Sm. (Turneraceae), which are used in folk medicine. The botanical identifications and macroscopical morphodiagnosis were done after morphological studies. The microscopical morphodiagnosis was carried out by paradermic and transversal cuts of the leaves (blade and petiole), clarified and coloured with safranin and astrablue. The leaves of T. chamaedrifolia have hypostomatics epidermis, with wavy cells walls; the mesophyll is dorsiventral; and the vascular system of the peciole has three vascular bundles in the distal and medium portions, and only one, in the proximal portion. T. subulata has amphihypostomatic epidermis, with sinuous cells walls; the mesophyll is isobilateral; and the vascular system of the petiole has only one vascular bundle in the distal portion and three in the medium and proximal portions. The vegetative and reproductive morphologies associated to the leaf anatomy constitute a set of distinctive characters for these species.

Abstract: It is generally accepted that viral systemic infection follows the source-to-sink symplastic pathway of sugar translocation. In plants that are classified as apoplastic loaders, the boundary between the companion cell-sieve element (CC-SE) complex and neighboring cells is symplastically restricted, and the potential passage of macromolecules between the two domains has yet to be explored. Transgenic tobacco plants expressing green fluorescence protein (GFP) and cucumber mosaic virus (CMV)-encoded proteins fused to GFP under the control of the fructose-1,6-bisphosphatase (FBPase) promoter were produced in order to localize the encoded proteins in mesophyll and bundle sheath cells and to explore the influence of viral infection on the functioning of plasmodesmata interconnecting the two domains. GFP produced outside the vascular tissue could overcome the symplastic barrier between the CC-SE complex and the surrounding cells to enter the vasculature in CMV-infected plants. Grafting of control (non-transgenic) tobacco scions to CMV-infected FBPase-GFP-expressing root stocks confirmed that GFP could move long distances in the phloem. No movement of the gfp mRNA was noticeable in this set of experiments. The ability of GFP to enter the vasculature and move long distances was also evident upon infection of the grafting plants with other viruses. These results provide experimental evidence for alteration of the functioning of plasmodesmata interconnecting the CC-SE complex and neighboring cells by viral infection to enable non-selective trafficking of macromolecules from the mesophyll into the sieve tube.

Abstract: The vascular supply of the proximal, middle, and distal parts of the petiole were studied in 11 caesalpinioid species with the aim of documenting any changes in vascular anatomy that occurred within and between the petioles. The characters that proved to be taxonomically useful include vascular trace shape, pericyclic fibre forms, number of abaxial and adaxial vascular bundles, number and relative position of secondary vascular bundles, accessory vascular bundle status, the tendency of abaxial vascular bundles to divide, distribution of sclerenchyma, distribution of cluster crystals, and type of petiole trichomes. There is variation between studied species in the number of abaxial, adaxial, and secondary bundles, as seen in transection of the petiole. There are also differences between leaf trace structure of the proximal, middle, and distal regions of the petioles within each examined species. Senna italica Mill. and Bauhinia variegata L. show an abnormality in their leaf trace structure, having accessory bundles (concentric bundles) in the core of the trace. This study supports the moving of Ceratonia L. from the tribe Cassieae to the tribe Detarieae. Most of the characters give valuable taxonomic evidence reliable for delimiting the species investigated (especially between Cassia L. and Senna (Cav.) H.S.Irwin & Barneby) at the generic and specific levels, as well as their phylogenetic relationships.

Abstract: The location and structure of ferritin in the parenchyma of leaf minor veins of the common ice plant (Mesembryanthemum crystallinum L.) treated with exogenous putrescine under salinity conditions were investigated by electron microscopy. Considerable aggregates of ferritin were detected in the chloroplasts of bundle sheath cells, in companion phloem cells, and other parenchyma cells of leaf minor veins. The structure of ferritin in the vascular parenchyma chloroplasts suggests that it was partially degraded and converted to phytosiderin. This point of view is based on indistinct structure of Fe-containing cores of ferritin molecules, break of distance between the cores, and their pronounced ability to aggregate and produce larger structures. Aggregation of Fe-containing cores apparently pointed to the destruction of ferritin protein envelope or its partial degradation. In a certain stage of ferritin destruction, electron-dense material and the structures resembling small vesicles appeared between the Fe-containing cores. Electron-dense inclusions, whose structure was similar to that of phytosiderin, were also detected in the vacuoles. Examination of the cross sections done without additional staining showed that the same as ferritin, phytosiderin in the chloroplasts and vacuoles was dark-colored against weakly colored cellular structures. In the vascular parenchyma of control plant leaves, the level of ferritin and phytosiderin was greater than in the mesophyll and much lower than in the plants simultaneously treated with NaCl and putrescine. In control material, iron cores of ferritin and phytosiderin were more light-colored and 2–3 times smaller in size than in the experimental treatment. Destruction of ferritin essentially did not occur in the mesophyll but was observed in the chloroplasts of bundle sheath cells on the border between the mesophyll and vascular bundle. The presence of much ferritin and phytosiderin on the border between the mesophyll and the vessels is accounted for by the fact that the vascular parenchyma is a buffer area that maintains a specific concentration of iron in the mesophyll of leaves and other parts of the plant. Within the cell, the role of such a buffer is performed by ferritin and vacuoles. Transformation of ferritin to insoluble hydrophobic phytosiderin is supposed to be an efficient way of withdrawing the excess of active iron from the cellular metabolism and therefore of relaxing oxidative stress. Ferritin and phytosiderin were detected not only in parenchyma cells of leaf minor veins but in sieve tubes as well. This suggests that iron may be transported within the plant as a component of protein complex.

Abstract: The Glycine max sucrose binding protein (GmSBP2) promoter directs vascular tissue-specific expression of reporter genes in transgenic tobacco. Here we showed that an SBP2-GFP fusion protein under the control of the GmSBP2 promoter accumulates in the vascular tissues of vegetative organs, which is consistent with the proposed involvement of SBP in sucrose transport-dependent physiological processes. Through gain-of-function experiments we confirmed that the tissue-specific determinants of the SBP2 promoter reside in the distal cis-regulatory domain A, CRD-A (position −2000 to −700) that is organized into a modular configuration to suppress promoter activity in tissues other than vascular tissues. The four analyzed CRD-A sub-modules, designates Frag II (−1785/−1508), Frag III (−1507/−1237), Frag IV (−1236/−971) and Frag V (−970/−700), act independently to alter the constitutive pattern of −92pSBP2-mediated GUS expression in different organs. Frag V fused to −92pSBP2-GUS restored the tissue-specific pattern of the full-length promoter in the shoot apex, but not in other organs. Likewise, Frag IV confined GUS expression to the vascular bundle of leaves, whereas Frag II mediated vascular specific expression in roots. Strong stem expression-repressing elements were located at positions −1485 to −1212, as Frag III limited GUS expression to the inner phloem. We have also mapped a procambium silencer to the consensus sequence CAGTTnCaAccACATTcCT which is located in both distal and proximal upstream modules. Fusion of either repressing element-containing module to the constitutive −92pSBP2 promoter suppresses GUS expression in the elongation zone of roots. Together our results demonstrate the unusual aspect of distal sequences negatively controlling tissue-specificity of a plant promoter.

Abstract: The formation of adaptive response to salt stress in mesophyll and bundle sheath cells of maize (Zea mays L.) leaves was studied at the level of operation of enzyme systems that participate in oxidation of malate. Functioning of four malate dehydrogenases (MDH), the components of this system, was studied and found to maintain malate and pyruvate pools, which are required for operation of the Hatch-Slack cycle and actively used for neutralization of salt treatment. The increase in activity of NAD-MDH was related to salt-induced synthesis of the additional isoform of MDH in mesophyll cells. Such changes in the isozyme pattern were not found in bundle sheath cells.

Abstract: Maize (Zea mays L.) seedlings of two cultivars (cv. Bastion adapted to W. Europe, and cv. Batan 8686 adapted to the highlands of Mexico), raised in a glasshouse (19–25 °C), were transferred to 4.5 or 9 °C at photon flux density (PPFD) of 950 µmol m−2 s−1 with 10-h photoperiod for 58 h and then allowed to recover at 22 °C for 16 h (14 h dark and 2 h at PPFD of 180 µmol m−2 s−1). The ultrastructural responses after 4 h or 26 h at 4.5 °C were the disappearance of starch grains in the bundle sheath chloroplasts and the contraction of intrathylakoid spaces in stromal thylakoids of the mesophyll chloroplasts. At this time, bundle sheath chloroplasts of cv. Batan 8686 formed peripheral reticulum. Prolonged stress at 4.5 °C (50 h) caused plastid swelling and the dilation of intrathylakoid spaces, mainly in mesophyll chloroplasts. Bundle sheath chloroplasts of cv. Batan 8686 seedlings appeared well preserved in shape and structure. Batan 8686 had also higher net photosynthetic rates during chilling and recovery than Bastion. Extended leaf photobleaching developed during the recovery period after chilling at 4.5 °C. This was associated with collapsed chloroplast envelopes, disintegrated chloroplasts and very poor staining.

Abstract: In this work, we analyzed the developmental anatomy of cotyledons and leaves in the has mutant of Arabidopsis thaliana. It is a recessive T-DNA insertion mutation that causes changes in the size, shape, and tissue organization of the cotyledons and leaves of has plants. Analysis of has cotyledons revealed a prominent decrease in the cell number and an increase in the area of cotyledon cells and intercellular spaces of has plants. At early stages of development, has leaves are fingerlike structures, but later they develop small, lobed blades with rare trichomes. An important characteristic of the mutant leaf anatomy is the absence of mesophyll tissue differentiation. In addition, both cotyledons and leaves display a disrupted pattern of vascular bundles. Furthermore, mutant plants are defective in root and shoot morphology, indicating that the has mutation affects a number of aspects in plant development.

Abstract: The structural and functional characterization of the blade-sheath boundary region of a rice cultivar T65 and its near-isogenic line T65lg were examined by light and electron microscopy and in situ hybridization. Starch accumulation in bundle sheath cells was compared between the lamina joint of T65 and the corresponding region of T65lg and also between the lamina joint and the leaf blade. In the lamina joint of T65, starch grains were predominantly accumulated in bundle sheath cells, and the starch-containing chloroplasts within these cells were spherical in shape. On the other hand, in the blade-sheath transition region of T65lg, little starch accumulation was observed and the chloroplasts were oval in both mesophyll and bundle sheath cells. Furthermore, photosynthesis-related genes, rbcS and cab, were expressed in mesophyll cells within the blade-sheath transition region of T65lg as in the leaf blade and sheath, while no expression of these genes was found within the lamina joint of T65. These ...

Abstract: In order to reveal the relations between the characters of vascular bundle and panicle in rice,An F6 population from a cross between a japonica variety Zhongyouzao 8 and an indica variety Fengjin was used as materialsThere was a significantly positive correlations between the number of the large and small vascular bundle of the neck-panicle,the number of the large and small vascular bundle of the second internode,the efficiency of large vascular bundles and primary rachis branches and the number of the first and second branches and their grains and filled grains,the length of the first and second branches,secondary rachis branches grains rate,panicle neck width,the length and weight of panicle,grains density,the number of grains and filled grains per panicle,and the yield of per panicle,respectivelyBut the number of panicle was oppositeThe relations between the characters of vascular bundle and secondary rachis branches was closer than primary rachis branchesThe relation between the ratio of large vascular bundles to small vascular bundles of the second internode,the ratio of large vascular bundles between the second top stem and neck-panicle,that of the small one and panicle traits is negativeThere was not correlation between the characters of vascular bundle and seed setting rate,1 000-grain weight,panicle type index,the first node length of panicleRegression and path analysis for the characters of vascular bundle and panicle showed the efficiency of primary rachis branches had a greatly direct effect on the grains per panicle,the number of the first and second branches and their grains,and yield per panicleThe effect of primary rachis branches efficiency for yield per panicle was the mostThe efficiency of large vascular bundles had a greatly indirect effect on those charactersThe efficiency of large vascular bundles exceeded 05 in japonica and pre-japonica rice,but the rice of indica and pre-indica was oppositeThe efficiency of primary rachis branches was nearly 10 in indica and pre-indica rice,but the rice of japonica and pre-japonica was about 05There was a close correlation between the efficiency of large vascular bundles and primary rachis branches and the panicle characters,and yield per panicleThe vary degree of the efficiency of large vascular bundles and primary rachis branches was notably different in parents and its hybrid descendantsBecause it reflected the good configuration and function of panicle characters,it could be thought of a reference standard as the choice of good panicle characters

Abstract: We investigated the role of the “sieve tube-companion cell complex” lining the tube periphery, particularly the microfilament and microtubule, in assisting the pushing of phloem sap flow. We made a simple phloem transport system with a living radish plant, in which the conducting channel was exposed for local treatment with chemicals that are effective in modulating protoplasmic movement (acetylcholine, (ACh) a neurotransmitter in animals and insects; cytochalasin B, (CB) a specific inhibitor of many cellular responses that are mediated by microfilament systems and amiprophos-methyl, (APM) a specific inhibitor of many cellular responses that are mediated by microtubule systems). Their effects on phloem transport were estimated by two experimental devices: (i) a comparison of changes in the amount of assimilates in terms of carbohydrates and 14C-labeled photosynthetic production that is left in the leaf blade of treated plants; and (ii) distribution patterns of 14C-labeled leaf assimilates in the phloem transport system. The results indicate that CB and APM markedly inhibited the transfer of photosynthetic product from leaf to root via the leaf vein, while ACh enhanced the transfer of photosynthetic product in low concentrations (5.0×10-4 mol/L) but inhibited it in higher concentrations (2.0×10-3 mol/L) from leaf to root via the leaf vein. Autoradiograph imaging clearly reveals that ACh treatment is more effective than the control, and both CB and APM treatments effectively inhibit the passage of radioactive assimilates. All of the results support the postulation that the peripheral protoplasm in the sieve tube serves not only as a passive semi-permeable membrane, but is also directly involved in phloem transport.

Abstract: The quantitative changes of chloroplast ultrastructure and dimensions in mesophyll (MC) and bundle sheath (BSC) cells, associated with the onset of leaf senescence, were followed along the developmental leaf blade gradient of the third leaf of maize (Zea mays L.). To ascertain whether the rapidity of structural changes associated with the transition of chloroplasts from mature to senescent state is a heritable trait, the parental and the first filial generations of plants were used. The heterogeneity of leaf blade, associated with the development of maize leaf (with the oldest regions at the apex and the youngest ones at the base) was clearly discernible in the ultrastructure and dimensions of chloroplasts; however, there were differences in the actual pattern of chloroplast development between both genotypes as well as between both cell types examined. While the course of MC chloroplasts' development at the onset of leaf senescence in maize hybrid followed that of its parent rather well, this did not apply for the BSC chloroplasts. In this case, each genotype was characterized by its own distinguishable developmental pattern, particularly as regards the accumulation of starch inclusions and the associated changes of the size and shape of BSC chloroplasts.

Abstract: Changes in ultra-structure of starch granules in the middle scales of Lilium davidii var.unicolor bulb were studied with the scanning electron microscope(SEM) during the bulb development and storage at low temperature.The results indicated that a few separate starch granules coexisted with floccules in the cell beside the big vascular bundle at planting stage.With the development of bulb,the amount of starch granules increased significantly and reached the maximum at the half withered stage.Furthermore,the shape changes were observed from spindle to almost rotundity.For the cells between the big and small vascular bundle,the amount of starch granules were smaller than that in the cells beside the big vascular bundle.And there are some cracks on the surface of the starch granule at the vegetative growth stage and bud autumn stage.During the storage at low temperature,the amount of starch granules tended to decline.By contrast with the process of bulb development,the amount of starch granules in the cells between the big and small vascular bundle were much more than that in the cells beside the big vascular bundle.

Abstract: The recombinant inbred lines (RILs) population derived from the cross between “Zhongyouzao8” (hsien or indica) and “Fengjin” (keng or japonica) was grown in Liaoning and Sichuan Provinces to compare the subspecies characteristics under different environments. The results showed that the distribution of Cheng’s index was japonicalinous. The population was more japonicalinous in Sichuan than that in Liaoning as a whole. Further analysis indicated that indica and indica-cline in Sichuan were more indicalinous than those in Liaoning, japonica and japonica-cline in Sichuan were more japonicalinous than those in Liaoning. The effects of environment on six characteristics of Cheng’s index were different because of different characters, as well as on the correlations between the six characters, the Cheng’s index and the vascular bundle traits. For example, the length of the first and second rachis and leaf pubescence were more japonicalinous in Sichuan than in Liaoning, while the length/width ratio of spikelets and glume color at heading time were more indicalinous in Sichuan than in Liaoning. The vascular bundle characteristics of RILs in different environments changed remarkably. The number of large vascular bundles in panicle neck was less in Sichuan than in Liaoning, while the number of small vascular bundles in panicle neck and second top stem was greater in Sichuan than in Liaoning. The ratio of large to small vascular bundles in panicle neck decreased and the ratio of large vascular bundles between the second top stem and panicle neck increased in Sichuan. Though total trend was the vascular bundle ratio of large to small in indica was greater than that in japonica and the ratio of large vascular bundles in indica was less than that in japonica, it is not appropriate that the vascular bundle ratio of large to small and the ratio of large vascular bundles are regarded as the parameters for subspecies classification in rice. The vascular bundles characteristics from typical indica or japonica were recombined in the population derived from indica and japonica crossing.

Abstract: A recombinant inbred line(RIL)population derived from a cross between Qishanzhan(typical indica)and Akihikari(typical japonica)was used as materialsThe result of subspecies discrimination in F6 and F8 generations based on the Cheng's index and vascular bundle characteristics showed that intermediate type lines were dominant and both populations were japonicalinousThe vascular bundle characteristics which were significantly different between indica and japonica were recombined in the RIL populationThe discrimination results based on the ratio of large to small vascular bundles in panicle neck(RLSVB)and the ratio of large vascular bundles between the second internode from the top and panicle neck(RLVB)were consisted with those by the Cheng's index,so they could be regarded as the parameters for subspecies classificationMoreover,these parameters were more stable than the number of large or small vascular bundles in panicle neck or the second internode from the top among different generationsBecause most lines in the populations were intermediate type without complete indica and japonica differentiation,the discrimination results in a certain line based on RLSVB and RLVB might be different

Abstract: Morphology and anatomy of aerial vegetative axis of Achyrocline alata (Kunth) DC. (Asteraceae). Achyrocline alata occurs in a dense and low vegetation in Mato Grosso do Sul State, Brazil and it has been studied under physical-chemical and yield aspects, being scarce anatomical data. The present work has as objective the study of the aerial vegetative axis. Stem is cylindrical and hairy, having five wings, which are arisen from their leaves. The blade shows the presence of uniseriate epidermis, which is covered by the cuticle of variable thickness; and nonglandular and glandular trichomes. The non-glandular trichomes are uniseriate and multicellular and have their apex cell in whip form, while the glandular trichomes are multicellular, uniseriate or biseriate. The mesophyll is dorsiventral with uni-stratified palisade parenchyma in most of the cases and lacunal parenchyma formed by three to four layers of irregular cells. Only one collateral vascular bundle occurs in the midvein. Stem in transversal section is covered by epidermis with trichomes similar to leaves; the cortex is constituted by a discontinuous area of angular collenchyma, which is followed by chlorophyll parenchyma. Vascular cylinder that is delimited by pericycle shows vascular bundles of collateral type. In the secondary structure, the periderm is originated from epidermal and subepidermal tissues. In vascular region, the fascicular cambium differs into secondary xylem and phloem, while interfascicular cambium produces sclerenchymatous tissue.

Abstract: In order to understand the effect of different water conditions on the development of vascular bundle in the first internode below ear and the relationship between the vascular bundle traits and yield components in wheat,a doubled haploid(DH) population with 150 lines,derived from a cross between two Chinese common wheat varieties Hanxuan10 and Lumai14 was employed.Paraffin sections were made from the middle part of the first internodes,which were sampled on 14th~15th day after flowering.The vascular bundle traits,its genetic characters and the relationship between the vascular bundle traits in the first internode below ear and yield components under drought stress and well-watered conditions were analyzed,respectively.The results showed that,water stress restrained seriously the development of vascular bundle,such as areas of large,small and total vascular bundle,and the numbers of small and total vascular bundle as well.The broad heritability of vascular bundle was high and ranged from 74.16% to 97.51%.Phenotypes of the traits separated in broad ranges,a lot of lines showed traits significantly surpassing their parents.Significant and positive correlations between most vascular bundle traits and total spikelet,fertile spikelet,fertile spikelet rate and spike length were identified under well-watered condition,whereas only significant and negative correlation was detected under water stress.Then we concluded that the numbers and areas of large and small vascular bundle traits in the first internode might keep a straightway "flow" of wheat.Therefore,anatomical characters in the first internode can be considered as the reference criteria for improving the yield in wheat.

Abstract: Whereas the uptake of ions into the xylem roots is well understood, less is known about the uptake from the xylem to the symplast of the leaves. LAMMA experiments using 85Rb+ as a tracer showed that ions move over the cell membrane between xylem and bundlesheath cells of small veins of Zea maize. A new isolation technique was developed that enabled the separation of mesophyll cells and bundle-sheath cells of maize leaves. Whole-cell patch-clamp experiments revealed three types of channel, MB-1 and MB-2 in bundle-sheath cells and MM-2 in mesophyll cells. Stimulation by acidic lumenal medium suggested that MB-1 and MB-2 take care of charge balancing during uptake of anions, whereas stimulation at high pH would provide MM-2 with a fail-safe function by clamping membrane potential to EK, if the H+ pump is inactive. The distinction between MB-1 and MB-2 was based on current density, temporal behaviour and different conductivity with Rb+ at 100 mM KCl at the lumenal side. MB-2 requires ATP for activation. Freshly prepared bundle-sheath cells are either of MB-1- or of MB-2-type. The isolation procedure developed for the patch clamp experiments was employed to separate c-DNA from vascular strands from that of mesophyll cells and of epidermis cells. Physiological behaviour, especially pH-dependence, indicated that KZM1 found in the vascular strands originated from the phloem. Thus the genetic identification of MB-1 and MB-2 is still an open question.

Abstract: A study concerning the relationship of dynamic accumulation of triterpenoid saponins and anatomical characteristics of Achyranthes bidentata Bl roots was undertaken by anatomical, histochemical and phytochemical method respectively. Results revealed that the primary and secondary structures of the root resembled those of usual dicots. The continual thickening growth of root principally resulted from the differentiation and development of the tertiary structure. The first ring of supernumerary cambium originated from the parenchyma and vascular ray cells of secondary phloem and each of the followed rings initiated in the outmost foundamental parenchyma cells which were derived from the immediate preceding ring. In the supernumerary cambiums, there had not distinction between the fusiform initial and the ray initial. Its cells present stratifide arranged from a longitudinal section through root. Regular and concentric rings of tertiary vascular bundles who differentiate centrifugally were enclosed by the connective parenchyma. The number of the rings continually increase with the development of the root itself. Triterpenoid saponins accumulated mainly in pericycle, primary phloem and parenchyma between primary phloem and xylem in the primary structure of root but came into existence in cells of secondary phloem and phelloderm with secondary structure development of root, and as well as in supernumerary cambium and phloem of tertiary vascular bundle after the tertiary structure maturated gradually in the roots. The investigation provides indications that the tertiary structure were not only main parts in the roots of Achyranthes bidentata Bl, but also important storage region of triterpenoid saponins in its growth and development. In addition, the analysis of using the HPLC showed that dynamic increasing trend oleanolic acid was as "S" curve during the roots growth and development and up to the highest content of triterpenoid saponins after plants grew 120 days. Meanwhile, the number of the rings of tertiary vascular bundles, length and diameter of the roots were the same as the triterpenoid saponins increasing trend. It should be optimal season for harvest.