Vegetative Phase Of Development Research Articles

ЭВОЛЮЦИЯ ОЗЕРА ХАНКА И ОКРУЖАЮЩИХ ЛАНДШАФТОВ В МАКСИМУМ ПОХОЛОДАНИЯ ПОЗДНЕГО ПЛЕЙСТОЦЕНА

The problems of the environmental development in the western part of the Khanka lowland and the evolution of Khanka Lake during the last glaciation maximum and the maximum lacustrine transgression in the Late Pleistocene are considered. Lithology and diatom data on lacustrine sediments indicate two depositional environments in the lake during the period 24.0–19.0 cal ka BP: 1) an oligotrophic-mesotrophic, moderately swamped shallow basin with variable water level; and 2) a relatively deep lake. The beginning of the maximum transgression (about 19.6 cal ka BP) was established. For the first time in the Late Pleistocene the lake level was 1.5–2.0 m higher than the present one. Four phases of vegetation development in the western part of the Khanka lowland were recognized: birch and larch mari with alder and frigid shrubs (23.8–22.8 cal ka BP); II – dark coniferous taiga with dwarf pine and an admixture of broad-leaved trees (22.8–20.6 cal ka BP); III – spruce forests with dwarf pine, fir, larch and a rare admixture of oak (20.6-20.1 cal ka BP); and IV – light birch forests with alder and larch mari with frigid shrubs (20.1–19.0 cal ka BP). Two phases of cooling were reconstructed in the Khanka lowland: about 24.0 cal ka BP (maximum cooling) and 20.6 cal ka BP, and one phase of warming (about 22.8 cal ka BP). These events correlate well with the global records of the Greenland glaciers. The longest dry periods were established during 21.7–21.2 cal ka BP. The quantitative characteristics of climatic events were reconstructed based on the present-day vegetation analogues.

Genome-wide identification of miR156 and SPL family genes and phenotypic analysis of vegetative phase change in pepper (Capsicum annuum L.)

After germination, plants go through two phases of vegetative development - juvenile and adult - before entering the reproductive phase. These phases have varying characteristics and timing across plant species, making it challenging to determine if different vegetative traits correspond to the same or distinct developmental processes. miR156 has been identified as the primary regulator of vegetative phase change in plants, with the miR156-SPLs (SQUAMOSA Promoter Binding Protein-Likes) module playing a crucial role in regulating age-related agronomic traits in various crops. Such traits include disease resistance, optimal plant breeding, and secondary metabolism regulation. However, it is unknown whether miR156-SPLs contribute to the critical agronomic traits of pepper (Capsicum annuum L.). Thus, this study seeks to identify miR156 and SPLs genes in pepper, analyze their evolutionary links with model plants, and confirm their expression patterns using gene expression assays. The study also examines the relationship between miR156 expression levels in two cultivars of pepper and specific traits associated with the juvenile-to-adult transition. The results indicate that leaf shape and the number of leaf veins are correlated to the timing expression of miR156. Our study represents an important resource for identifying age-dependent agronomic traits in pepper and lays the foundation for future systematic regulation of miR156-SPLs to advance pepper development.

THE IMPACT OF AGRO-CLIMATIC FACTORS ON THE PRODUCTIVITY OF AGRICULTURAL LANDS OF ORENBURG REGION

Currently, the shortage of fresh water is an important abiotic factor limiting the survival, growth and distribution of plants in semi-arid areas. The productivity of natural forage lands is influenced by seasonal fluctuations in temperature and precipitation, especially characteristic of the steppe Orenburg region. The uneven intra-annual distribution of precipitation does not meet the water needs of the phytocenosis in the vegetative phase of development. The aim of the study was to analyze the effect of atmospheric precipitation on agricultural forage lands of Orenburg region. An important and necessary task is to assess the interaction of agro-climatic factors on the development of agricultural land is an important and necessary task. The research area is located in a zone with a semiarid (semi-arid) climate of temperate latitudes of the Orenburg Urals of the Orenburg region (Orenburg region, Russia). Studies of agricultural land were carried out on 4 plots in the vicinity of the village of Nezhinka, Orenburg district, Orenburg region. For this purpose, various facies of agricultural lands located on the supports of watershed surfaces are identified and analyzed. To study local geosystems of various facies, we used camera methods, aerospace images and in-kind observations. Statistical and mathematical processing of digital data was carried out according to the StatsoftStatisticav 6.1 RUS program. Elements of descriptive statistics of average annual indicators (total precipitation per year, precipitation during the growing season, productivity of natural lands) revealed that the theory of normality was not rejected. The analysis of the average long-term data on the amount of precipitation and their relationship with the productivity of natural forage lands shows a reliable positive correlation between these parameters, at r2 = 0.95. In the conditions of the semi-arid zone during the growing season, plants use the moisture of atmospheric precipitation most effectively

Beyond the Genetic Pathways, Flowering Regulation Complexity in Arabidopsis thaliana

Flowering is one of the most critical developmental transitions in plants’ life. The irreversible change from the vegetative to the reproductive stage is strictly controlled to ensure the progeny’s success. In Arabidopsis thaliana, seven flowering genetic pathways have been described under specific growth conditions. However, the evidence condensed here suggest that these pathways are tightly interconnected in a complex multilevel regulatory network. In this review, we pursue an integrative approach emphasizing the molecular interactions among the flowering regulatory network components. We also consider that the same regulatory network prevents or induces flowering phase change in response to internal cues modulated by environmental signals. In this sense, we describe how during the vegetative phase of development it is essential to prevent the expression of flowering promoting genes until they are required. Then, we mention flowering regulation under suboptimal growing temperatures, such as those in autumn and winter. We next expose the requirement of endogenous signals in flowering, and finally, the acceleration of this transition by long-day photoperiod and temperature rise signals allowing A. thaliana to bloom in spring and summer seasons. With this approach, we aim to provide an initial systemic view to help the reader integrate this complex developmental process.

Оцінка потенціалу урожайності мутантних ліній салату посівного листкового за різних кліматичних умов вирощування

Оцінка потенціалу урожайності мутантних ліній салату посівного листкового за різних кліматичних умов вирощування

Regulatory cis-elements are located in accessible promoter regions of the CAT2 promoter and affect activating histone modifications in Arabidopsis thaliana.

Catalase 2 (CAT2) plays an important role in the detoxification of hydrogen peroxide released either during photorespiration or as a consequence of biotic and abiotic stress as well as in the initiation of senescence. To date, our understanding of the regulation of CAT2 gene expression is rather poor. Chromatin immunoprecipitation experiments revealed that a wide region of the CAT2 promoter is nucleosome depleted, reflecting the ability to rapidly respond to changing environmental and stress conditions and, thus, adjusting the transcript levels of CAT2. The lowest nucleosome density was found in the region of -900bp relative to the transcription initiation start (TIS) where two regulatory elements are located. The distance of the nucleosome depleted region to the TIS is quite unusual because the majority of nucleosome free regions are generally located in close vicinity to the 5' untranslated region. The analysis of transgenic 5' upstream deletion::gusA Arabidopsis lines showed that this region is important for the regulation of CAT2 promoter activity. To evaluate the function of the two motifs, the contribution of each element to CAT2 promoter activity was analyzed by site directed mutagenesis. The data revealed that the CAT2 promoter is regulated by the ACGT motif (Box2) rather than by the G-Box binding motif (Box1) in the vegetative phase of development. Furthermore, the presence of both Box1 and Box2 positively affected the abundance of activating histone modifications.

Intraspecific variation of phyllotaxis stability in Anagallis arvensis

Qualitative transformations of phyllotaxis in <em>Anagallis arvensis</em> occur typically during the generative phase of development. In the vegetative phase phyllotaxis usually does not change. An exception to this rule is one peculiar population of <em>Anagallis arvensis</em>, belonging to a pink-flowered form carnea, in which phyllotaxis often transforms in both the generative and vegetative phase of development. The presence of a relatively large number of vegetative transitions, virtually absent in two control red-flowered populations of form arvensis, is accompanied also by the higher frequency of generative transitions. This might be a result of a genetically determined instability of shoot apex geometry. It has been proved experimentally that changing conditions of growth affect the transition frequencies and the time lapse from the beginning of either the vegetative or generative phase to the transition (measured in plastochrons). A comparison of two types of transitions shows that divergence changes are less abrupt in vegetative transitions. The differences between the two types also pertain to the vertical spacing of leaves and to the pattern formed by leaf bases and wings on the stem surface in the transition zone.

Growth and development of shoot apex in barley I. Morphology and histology of shoot apex in vegetative phase

The vegetative phase of development of the main shoot apex lasts over 5 plastochrons after germination. The endosperm has a sufficient store of nutrition for this period. At the beginning of this phase the apex has a one-layer tunica. The cells of the latter divide above the level of bulge formation for leaf primordia, exclusively anticlinally, although somewhat lower within the leaf bulge periclinal divisions may occur. The cells immediately under the first tunica layer in the apical part grow tangentially to the surface. These cells divide only anticlinally forming gradually the second tunica layer. In the course of the entire phase the shape of the meristeanatic caulis from the tip to the 4th frustum remains unchanged.

Model of wetland development of the Amapá coast during the late Holocene

The modern vegetation types, sedimentary sequences, pollen records and radiocarbon dating obtained from three sediment cores from Calçoene Coastal Plain were used to provide a palaeoecological history during the late Holocene of Amapá coastal wetland according to flood regime, sea-level and climatic changes. Based on these records, four phases of vegetation development are presented and they probably reflect the interaction between the flow energy to the sediment accumulation and the brackish/freshwater influence in the vegetation. This work suggests interchanges among time periods characterized by marine and fluvial influence. The longitudinal profile did not reveal the occurrence of mangrove in the sediment deposited around 2100 yr B.P. During the second phase, the mud progressively filled the depressions and tidal channels. The mangrove probably started its development on the channel edge, and the herbaceous field on the elevated sectors. The third phase is characterized by the interruption of mangrove development and the increase of "várzea" vegetation that may be due to the decrease in porewater salinity related to a decrease in marine water influence. The last phase is represented by the mangrove and "várzea" increase. The correlation between current patterns of geobotanical unit distribution and palaeovegetation indicates that mangrove and "várzea" forests are migrating over the herbaceous field on the topographically highest part of the studied coast, which can be related to a relative sea-level rise.

Vegetation and climate changes during the Eemian interglacial in Central and Eastern Europe: comparative analysis of pollen data

Velichko, A. A., Novenko, E. Y., Pisareva, V. V., Zelikson, E. M., Boettger, T. & Junge, F. W. 2005 (May): Vegetation and climate changes during the Eemian interglacial in Central and Eastern Europe: comparative analysis of pollen data. Boreas, Vol. 34, pp. 207–219. Oslo. ISSN 0300–9483. The article discusses pollen data from Central and Eastern Europe and provides insight into the climate and vegetation dynamics throughout the Eemian interglacial (including preceding and succeeding transitional phases). Three sections with high resolution pollen records are presented. Comparison of the data indicates that the range of climatic and environmental changes increased from west to east, whereas the main phases of vegetation development appear to have been similar throughout the latitudinal belt. At the interglacial optimum, the vegetation in both Central and Eastern Europe was essentially homogeneous. An abrupt change marks the Saalian/Eemian boundary (transition from OIS 6 to OIS 5e), where environmental fluctuations were similar to those detected at the transition from the Weichselian to the Holocene (Allerod and Dryas 3). Transition from the Eemian to the Weichselian was gradual in the western part of the transect, with forest persisting. In the east, fluctuations of climate and vegetation were more dramatic; forest deteriorated and was replaced by cold open landscapes.

Genetic variability of nitrogen accumulation during vegetative development and remobilization during the forcing process in witloof chicory tuberized root ( Cichorium intybus L.)

A better knowledge of genetic variability of traits related to nitrogen use efficiency (NUE) is a potential strategy to optimize N fertilization and to reduce environmental pollution without decreasing marketable yield and quality. To this aim, in this study, 13 cultivars of witloof chicory were compared with three reference cultivars known for their adaptation to low, intermediate and high N availability in the field during the vegetative phase of development. Pertinent criteria used for this study were determined by a thorough comparison of nitrogen reserve accumulation in tuberized roots during vegetative development and mobilization during the forcing process in the three reference cultivars. Cluster analysis allowed us to sort the cultivars into four main groups we named G1, G2, G3 and G4. Cultivars of group G4, better adapted to soils with high nitrogen contents (N-demanding cultivars), showed higher total N, nitrate, total amino acids (AA), glutamine contents and lower total N and AA mobilization for chicon growth than did cultivars of group G1, adapted to soils with low nitrogen content (N-sensitive cultivars). An intermediate behavior was exhibited by cultivars of groups G2 and G3, characterized as N tolerant. It is proposed that either chicory growers or breeders may take advantage of the genetic variability revealed in the present study to gain flexibility in choosing the right cultivar for the type of soil available (N-rich soil vs N-poor soil) or to adapt the level of N fertilization to the type of cultivar (N-demanding vs N-sensitive) in order to target the highest NUE for the best chicon yield and trade quality.

Activities of antioxidative enzymes during Chenopodium rubrum L. Ontogenesis in vitro

For the short-day plant Chenopodium rubrum, a 14 h/10 h photoperiod is inductive for flowering, while continuous light (CL) is noninductive. Plants of one group were grown continuously under an inductive photoperiod, while in the other group flowering induction was delayed by 17 days of CL in order to separate on the time scale different developmental phases in plants of the same age. Regardless of the photoperiodic conditions the plants were exposed to, seed maturation occurred in 10 weeks. Activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) were determined in different phases of development (vegetative growth, flowering, seed development, and maturation). The activities of antioxidative enzymes depended on both the phase of development and the photoperiod. In plants grown continuously under an inductive photoperiod, high CAT and POD activities were detected at the time of flowering and decreased during seed development and maturation. In plants in which flowering induction was delayed by 17 days of CL, the activities of POD and SOD were lowest in the vegetative phase of development and attained maximum values in the phase of seed maturation. In both groups of plants, the highest CAT activity was measured at the time of flowering.

Histone H4 gene expression and morphological changes on shoot apices of strawberry (Fragaria×ananassa Duch.) during floral induction

To investigate flower induction in June-bearing strawberry plants, morphological changes in shoot apices and Histone H4 expression in the central zone during flower initiation were observed. Strawberry plants were placed under flower inducible, short-day conditions (23 °C/17 °C, 10 h day length) for differing number of days (8, 16, 20, 24 or 32 days) and then these plants were transferred to non-inducible, long-day conditions (25 °C/20 °C, 14 h day length). The shoot apices of plants placed under short-day conditions for 8 days were flat, similar to shoot apices of plants in the vegetative phase of development, and Histone H4 was not expressed in the central zone during the experimental period. On the other hand, the shoot apices of plants placed under short-day conditions for 16 days remained flat, similar to shoot apices of plants placed under short-day conditions for 8 days, but Histone H4 was expressed in the central zone at the end of the short-day treatment. Morphological changes in the shoot apices of these plants were observed 8 days after the change in day-length. These plants developed differentiated flower organs after they were grown for another 30 days under long-day conditions. These results indicate that changes in the expression pattern of the Histone H4 gene occur before morphological changes during flower induction and that the expression of the gene in the central zone can be used as one of the indicators of the flowering process in strawberries.

Late Pliocene vegetation and climate in Namibia (southern Africa) derived from palynology of ODP Site 1082

The present‐day condition of bipolar glaciation characterized by rapid and large climate fluctuations began at the end of the Pliocene with the intensification of the Northern Hemisphere continental glaciations. The global cooling steps of the late Pliocene have been documented in numerous studies of Ocean Drilling Program (ODP) sites from the Northern Hemisphere. However, the interactions between oceans and between land and ocean during these cooling steps are poorly known. In particular, data from the Southern Hemisphere are lacking. Therefore I investigated the pollen of ODP Site 1082 in the southeast Atlantic Ocean in order to obtain a high‐resolution record of vegetation change in Namibia between 3.4 and 1.8 Ma. Four phases of vegetation development are inferred that are connected to global climate change. (1) Before 3 Ma, extensive, rather open grass‐rich savannahs with mopane trees existed in Namibia, but the extension of desert and semidesert vegetation was still restricted. (2) Increase of winter rainfall dependent Renosterveld‐like vegetation occurred between 3.1 and 2.2 Ma connected to strong advection of polar waters along the Namibian coast and a northward shift of the Polar Front Zone in the Southern Ocean. (3) Climatically induced fluctuations became stronger between 2.7 and 2.2 Ma and semiarid areas extended during glacial periods probably as the result of an increased pole‐equator thermal gradient and consequently globally enhanced atmospheric circulation. (4) Aridification and climatic variability further increased after 2.2 Ma, when the Polar Front Zone migrated southward and the influence of Atlantic moisture brought by the westerlies to southern Africa declined. It is concluded that the positions of the frontal systems in the Southern Ocean which determine the locations of the high‐pressure cells over the South Atlantic and the southern Indian Ocean have a strong influence on the climate of southern Africa in contrast to the climate of northwest and central Africa, which is dominated by the Saharan low‐pressure cell.

Cretaceous and Cenozoic vegetation of Antarctica integrating the fossil wood record

AbstractA compilation of data for Cretaceous and Cenozoic Antarctic fossil wood floras, predominantly from the James Ross Island Basin, provides a different perspective on floristic and vegetation change when compared with previous studies that have focused on leaf macrofossils or palynology. The wood record provides a filtered view of tree-forming elements within the vegetation, something that cannot be achieved from studies focusing on regional palynology or leaf floras. Four phases of vegetation development in the over-storey are recognized in the Cretaceous and Cenozoic of the Antarctic Peninsula based on the distribution and taxonomic composition of wood floras: Aptian-Albian coniferous forests; ?Cenomanian-Santonian mixed angiosperm forests; Campanian-Maastrichtian southern temperate forests; and Palaeocene-Eocene reduced diversity Nothofagus forests. Comparisons between the wood record and information derived from palynological and leaf floras have important implications for our understanding of the spatial composition of the vegetation. There is no doubt that climate change during the Cretaceous and Tertiary influenced the vegetational composition, but evolving palaeoenvironments in the Antarctic Peninsula region were probably of equal, if not greater, importance.

Bioconversion of Plant Raw Materials in Value-Added Products by Lentinus edodes (Berk.) Singer and Pleurotus spp.

Lentinus edodes and Pleurotus spp. were compared for their ability to produce extracellular hydrolytic and oxidative enzymes in solid-state fermentation (SSF) and submerged fermentation (SF) of different lignocellulosic agroindustrial wastes. From received data the following conclusions were drawn.First, fungi cultivation in identical culture conditions reveals wide differences among both species and strains of the same species. For example, in SSF of tree leaves by fungi of genus Pleurotus, endoglucanase activity varied from 0.5 U mL−1 (P. ostreatus IBB 8) to 26.0 U mL−1 (P. ostreatus (Jacq.: Fr.)P. Kumm. IBB 2191), whereas xylanase activity varied from 3.1 U mL−1 (P. tuberregium (Rumph.: Fr.) Singer IBB 624) to 43.7 U mL−1 (P. ostreatus 2175).Second, the nature and chemical composition of lignocellulosic material is one of the main factors determining the expression of fungi lignocellulolytic potential as well as the ratio of individual enzymes in lignocellulolytic system. For example, P. dryinus (Pers.: Fr.) P.Kumm. IBB 903 maximal laccase activity was equal to 119,195, 794, and 4103 U/L−1 in SF of milled tree leaves, banana, apple, and mandarin peels, respectively.Third, the effect of lignocellulosic substrate concentration on enzyme synthesis varies in dependence on fungi peculiarities. Whereas P. dryinus IBB 903 hydrolytic and oxidative enzyme activity increased by 3−8 times with the elevation of mandarin peels or tree leaves concentration from 1 to 4−6%, in the case of P. tuberregium IBB 624 the lowest substrate concentration was sufficient to ensure the maximal production of laccase, cellulase, and xylanase by this mushroom.Fourth, the data proved that most plant raw materials tested contained sufficient nitrogen concentrations to ensure both mushroom growth and enzyme synthesis. However, depending on fungi and lignocellulosic substrate, supplementation of additional nitrogen sources in the medium effects the yield of lignocellulolytic enzymes. It is worth noting that in most cases only increased fungi growth and biomass in the presence of additional nitrogen accounts for the higher level of laccase activity.Fifth, supplementing the culture medium by stimulators (xylidine, copper, or manganese) increased the yield of P. dryinus IBB 903 ligninolytic enzymes or caused their early and rapid accumulation in culture liquid.The investigation of fruiting body yield and hydrolytic and oxidative enzyme accumulation during bioconversion of different lignocellulosic wastes by Pleurotus spp. and Lentinus edodes showed that biological efficiency reached 86−118% and 81−116%, depending on growth substrate and medium used to soak the substrate.Cultivation of two strains of P. ostreatus on wheat straw and tree leaves as growth substrates clearly showed physiological and biochemical changes taking place during mushroom growth and development on plant raw materials. Mushroom cellulases and xylanase activity appeared to be very low during the vegetative phase of substrate colonization by mycelia. Their activity sharply rose with the appearance of primordia and reached their maximum at a stage of matured fruiting bodies. After fruit bodies were harvested, when the culture was in vegetative phase of development, the activity of these enzymes decreased again. In contrast, mushroom cultures were distinguished by high laccase and MnP activity during substrate colonization. The activity of both enzymes decreased at stages of primordia appearance and fruiting bodies maturation. However, when the culture enters the second vegetative phase (5 days after the fruit bodies were harvested), laccase and MnP activities increased again.The study of lignocellulolytic enzyme activity of L. edodes in mushroom cultivation on wheat straw and tree leaves showed the same regularities that were revealed in cultivation of Pleurotus spp. with insignificant variations. The vegetative growth of these edible mushrooms is characterized by comparatively low activity of polysaccharases and high activity of ligninolytic enzymes. During the period of fruiting body formation, when the mushroom growth requires large quantities of plastic materials and energy, the secretion of cellulases and xylanase sharply increases to accelerate polysaccharide hydrolysis. In contrast, ligninolytic enzyme production appears, to some extent, is repressed to prevent the expenditure of constructive materials and energy.Finally, the data on mushroom enzyme activity show that residual spent substrate may become a cheap source of lignocellulolytic enzymes for several biotechnological applications.

Taxonomic turnover and abundance in Cretaceous to Tertiary wood floras of Antarctica: implications for changes in forest ecology

Based on the temporal distribution, abundance, and taxonomic composition of wood floras, four phases of vegetation development are recognized through the Cretaceous to Early Tertiary of the Antarctic Peninsula: (1) Aptian to Albian communities dominated by podocarpaceous, araucarian, and minor taxodiaceous/cupressaceous conifers with rare extinct gymnosperms ( Sahnioxylon). (2) Progressive replacement of these communities in ?Cenomanian to Santonian times by angiosperms, most without modern analogues. (3) Increasing dominance of angiosperms becoming important both in terms of diversity and abundance towards the mid-Late Cretaceous. (4) Modernization of the flora during the Campanian to Maastrichtian with the extinction of earlier forms, appearance of the Nothofagaceae and diversification of associated elements. These patterns broadly follow trends seen in the leaf and palynological record but with some important differences. During the Cretaceous, conifer composition undergoes a change whereby Phyllocladoxylon-type woods increase relative to the older Podocarpoxylon forms. During the Paleocene to Eocene period, a marked extinction in wood types occurs associated with an increase in the abundance of nothofagaceous wood. Detailed examination of wood abundance and distributions from sections within Maastrichtian and Paleocene formations points to strong environmental control on taxonomic compositions. Similar differences are encountered when comparing coeval floras from different geographic regions and palaeoenvironments.

Remoção de polifenóis da farinha de folhas de mandioca

A farinha de folhas de mandioca apresenta baixa digestibilidade, mesmo possuindo um teor relativamente elevado em proteínas, principalmente, devido à presença de substâncias como os polifenóis. Visando melhorar o aproveitamento protéico desta farinha, empregaram-se três solventes (água, etanol 50mL/100mL e hidróxido de amônio 1mol/L) para remover os polifenóis. Folhas maduras de mandioca foram coletadas na fase vegetativa, em três repetições, colocadas em bandejas de papel e secas à sombra sobre bancadas de madeira, em recinto fechado e arejado, em temperatura ambiente. Após secagem, retiraram-se os pecíolos e as folhas foram moídas e passadas em peneira de 40mesh. A farinha foi submetida, antes e após a remoção dos polifenóis, às análises de umidade, fibra detergente neutra (FDN), fibra detergente ácida (FDA), açúcares totais, proteína bruta, vitamina C total, beta-caroteno, cianeto, inibidor de tripsina, polifenóis e digestibilidade protéica in vitro. Após remoção dos polifenóis, houve diminuição dos teores de açúcares totais, vitamina C total, inibidor de tripsina e polifenóis e aumento de FDN, FDA, proteína bruta, beta-caroteno e digestibilidade protéica in vitro. Dos solventes empregados para remover polifenóis, o hidróxido de amônio foi o mais eficaz, com índice de remoção de 94%, seguido pelo etanol (83%) e água (65%). A digestibilidade da proteína in vitro aumentou em 74%, quando o solvente empregado na remoção dos polifenóis foi o hidróxido de amônio.

Module-specific regulation of the beta-phaseolin promoter during embryogenesis.

The phas promoter displays stringent spatial regulation, being very highly expressed during embryogenesis and completely silent during all phases of vegetative development in bean, Phaseolus vulgaris. This pattern is maintained in transgenic tobacco and, as shown here, Arabidopsis. Dimethyl sulphate in vivo footprinting analyses revealed that over 20 cis-elements within the proximal 295 bp of the phas promoter are protected by factor binding in seed tissues whereas none are bound in leaves. The hypothesis that this complex profile represents a summation of several module (cotyledon, hypocotyl, and radicle)-specific factor-DNA interactions has been explored by the incorporation of site-directed substitution mutations into 10 locations within the -295phas promoter. Only 2.6% of -295phas promoter activity remained after mutation of the G-box; the CCAAAT box, the E-box and the RY elements were also found to mediate high levels of expression in embryos. Whereas the CACA element has dual positive and negative regulatory roles, the vicilin box was identified as a strong negative regulatory element. The proximal (-70 to -64) RY motif was found to bestow expression in the hypocotyl while all the RY elements contribute to expression in cotyledons but not to vascular tissue expression during embryogenesis. RY elements at positions -277 to -271, -260 to -254, and -237 to -231 were found to orchestrate radicle-specific repression. The G-box appears to be the functional abscisic acid responsive element and the E-site may be a coupling element. The results substantiate the concept that autarkical cis-element functions generate modular patterning during embryogenesis. They also reflect the existence of both redundancy and hierarchy in cis-element interactions. Importantly, the virtually identical expression patterns observed for the two distantly related plants studied argue strongly for the generality of function for the observed factor-element interactions.

The changing peroxidase polymorphism in Lupinus albus during vegetative development

Analyses of 14 samples representing organs in different stages of skotomorphogenic and photomorphogenic development, and the iterative growth from both root and shoot apical meristems, showed preliminary evidence for the operation of at least six different peroxidase groups showing differential patterns of activity during vegetative development. These included two acidic forms, a neutral-basic form and three highly basic forms. While no peroxidase group was organ specific or restricted to either the skotomorphogenic or photomorphogenic developmental pathways, clear and similar qualitative changes in peroxidase polymorphism occurred during the maturation of several different organs. This suggested that a developmental program regulating the changing isoperoxidase content in vegetative development was common to several organs in Lupinus albus. The subcellular locations, tissue specificity and spatial distribution of individual peroxidase groups in etiolated hypocotyls were related to the spatial location of active elongation and a marker of lignification, the isoperoxidase A2. Individual isoperoxidases could be associated with the developmental phases of either (a) pre-elongation, (b) active elongation, (c) restricted elongation and (d) active lignification. The possible functions of these peroxidases are discussed, and we present our selection of the peroxidase groups associated with the early phases of vegetative development for further studies and purification. Those selected include a highly soluble basic peroxidase (B5, pI 9.3) which appears to be largely restricted to the apoplast of juvenile tissues prior to the onset of active cellular elongation, and an ionically bound, basic peroxidase (B6, pI 9.7) of the epidermal apoplast which has a distribution strongly correlated to the reduction in cellular elongation along the hypocotyl axis.