How does Striga hermonthica Bewitch its hosts?

The common name witchweed synonymous with the Latin name Striga befits the bewitching effects, viz wilting and chlorosis, the parasite inflicts on its hosts long before it emerges and becomes visible above the ground. However, interactions in the rhizosphere between host roots and Striga seedlings are concealed and inscrutable. In vitro experiments revealed that abscisic acid was produced by S. hermonthica seedlings and a considerable portion of the phytohormone was exuded. The phytohormone in the rhizosphere could, at least in part, contribute to the bewitching effects, disrupt host immunity and promote commencement of parasitism.

Bio-priming mitigates detrimental effects of salinity on maize improving antioxidant defense and preserving photosynthetic efficiency.

Salinity is an abiotic stress which seriously affects crop production over the world, particularly in arid and semi-arid regions, with harmful effects on germination, growth and yield. Maize (Zea mays L.), cultivated in a wide spectrum of soil and climatic conditions, is the third most important cereal crop after rice and wheat, moderately sensitive to salt stress. A saline level more than 250 mM NaCl damages maize plants, causing severe wilting. In this study, the effects of hydro-priming (distilled water) and bio-priming (Rosmarinus officinalis L. and Artemisia L. leaf extracts) on seed germination and seedling growth of maize, under 100 mM NaCl salinity were investigated. The factorial experiments were carried out in greenhouse under controlled condition (25 °C in 12/12 h day/night) based on a completely randomized design with three replicates. Results showed that both hydro- and bio-priming increased germination percentage and germination indexes in maize seeds. Rosmarinus extract was the most effective in inducing salt resistance in 30 days old seedlings, with beneficial effects in the strengthening of the antioxidant system and in the maintenance of a higher photosynthetic efficiency under salt stress condition.

Metabolomic profiling delineate taste qualities of tea leaf pubescence.

The amount of pubescence on leaf epidermis is an important morphological marker for the quality of green tea, and the tea with plenty of pubescence is generally recognized as having a better taste. However, there is no systematic study on chemical compositions of tea leaf pubescence. The contributions of pubescence to taste properties are far from clear. In this research, 114 components were identified from the tea leaf pubescence of yunkang 10, a broad-leaf tea cultivar with plenty leaf pubescence, for the first time with a non-targeted metabolomics approach using ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Compared to the tea leaf with the pubescence removed (non-pubescent leaf), the pubescence obtained from the same shoots had relatively higher contents of amino acids and lower contents of polyphenols. It was also found that the umami of pubescence was elevated, while the bitterness and astringency were significantly declined. Partial least-squares (PLS) analysis suggested that the polyphenols and amino acids accounted for the taste quality. To the best of our knowledge, this is the first time that the metabolites in tea leaf pubescence were profiled. The results offer the direct concrete evidence on the contributions of pubescence to the tea taste properties.

[SCREENING OF WILD SPREAD AND CULTIVATED OF BUXUS SPECIES GROWING IN GEORGIA ON THE CONTENT OF ALKALOIDS AND BIOLOGICAL ACTIVITY].

Georgian flora is represented by about 4150 plant species. Many important alkaloid-containing plant species and among of them are species Buxus L. of genus in Adjara. The aims of the research were: sequential screening of the plants for the consistence of alkaloids; Study of anatomical characteristics of Buxus colchica Pojark. and revealing of specific pharmacological activity of steroidal alkaloids. The objects of research were B. colchica, B. balearika and B. sempervirens, growing in Adjara (Georgia), collected in active phase of flowering of the plants. There were revealed 370 species of alkaloid containing plants. Sum of alkaloids and crude aqueous extract have spasmolitic and antihistaminic activity. Experimental anatomical research of diagnostic characteristics of the bines showed the existence of monocyclic transient system with fiber like tracheids, dorsoventral mesophyll of the leaves; the structure for the upper part of epidermis is linear and the lower part is curved, type of stomata is paracitic.

A novel Brassica-rhizotron system to unravel the dynamic changes in root system architecture of oilseed rape under phosphorus deficiency.

BACKGROUND AND AIMS: An important adaptation of plants to phosphorus (P) deficiency is to alter root system architecture (RSA) to increase P acquisition from the soil, but soil-based observations of RSA are technically challenging, especially in mature plants. The aim of this study was to investigate the root development and RSA of oilseed rape (Brassica napus L.) under low and high soil P conditions during an entire growth cycle. METHODS: A new large Brassica-rhizotron system (approx. 118-litre volume) was developed to study the RSA dynamics of B. napus 'Zhongshuang11' in soils, using top-soils supplemented with low P (LP) or high P (HP) for a full plant growth period. Total root length (TRL), root tip number (RTN), root length density (RLD), biomass and seed yield traits were measured. KEY RESULTS: TRL and RTN increased more rapidly in HP than LP plants from seedling to flowering stages. Both traits declined from flowering to silique stages, and then increased slightly in HP plants; in contrast, root senescence was observed in LP plants. RSA parameters measured from the polycarbonate plates were empirically consistent with analyses of excavated roots. Seed yield and shoot dry weights were closely associated positively with root dry weights, TRL, RLD and RTN at both HP and LP. CONCLUSIONS: The Brassica-rhizotron system is an effective method for soil-based root phenotyping across an entire growth cycle. Given that root senescence is likely to occur earlier under low P conditions, crop P deficiency is likely to affect late water and nitrogen uptake, which is critical for efficient resource use and optimal crop yields.

Sexual dimorphism in floral longevity and flowering synchrony in relation to pollination and mating success in three dioecious Ilex species.

UNLABELLED: • PREMISE OF THE STUDY: Sexual floral dimorphism may have evolved under pollinator-mediated natural selection by which female and male functions are differently influenced. We hypothesized that mating success is differently influenced by display size between sexes, under which sexual dimorphism in flowering schedule has evolved in dioecious species.• METHODS: We examined sexual dimorphism in the total number of flowers per shoot, maximum daily display size, longevity of individual flowers, and flowering synchrony (maximum proportion of open flowers) in three dioecious Ilex species (I. pedunculosa, I. serrata, and I. crenata) whose female flowers are not smaller than male flowers. We compared pollinator response to natural variation of daily display size between sexes. We also examined the effect of display size on female and male success (fruit set and pollen deposition and removal).• KEY RESULTS: In the three species, male shoots produced significantly more flowers than female shoots did. Although female flowers lasted longer and opened more synchronously than male flowers, maximum daily display size was larger on male shoots than on female shoots. Fruit set was significantly pollen-limited in the field in all species. Pollen deposition and/or fruit set increased with female display size, whereas pollen removal decreased or was approximately constant with male display size in the three species.• CONCLUSIONS: We suggest that sexual dimorphism in floral longevity and flowering synchrony might enhance both female and male success in relation to the display size-mating success (pollinator attraction) association irrespective of flower size dimorphism.

Aluminium alleviates manganese toxicity to rice by decreasing root symplastic Mn uptake and reducing availability to shoots of Mn stored in roots.

BACKGROUND AND AIMS: Manganese (Mn) and aluminium (Al) phytotoxicities occur mainly in acid soils. In some plant species, Al alleviates Mn toxicity, but the mechanisms underlying this effect are obscure. METHODS: Rice (Oryza sativa) seedlings (11 d old) were grown in nutrient solution containing different concentrations of Mn(2+) and Al(3+) in short-term (24 h) and long-term (3 weeks) treatments. Measurements were taken of root symplastic sap, root Mn plaques, cell membrane electrical surface potential and Mn activity, root morphology and plant growth. KEY RESULTS: In the 3-week treatment, addition of Al resulted in increased root and shoot dry weight for plants under toxic levels of Mn. This was associated with decreased Mn concentration in the shoots and increased Mn concentration in the roots. In the 24-h treatment, addition of Al resulted in decreased Mn accumulation in the root symplasts and in the shoots. This was attributed to higher cell membrane surface electrical potential and lower Mn(2+) activity at the cell membrane surface. The increased Mn accumulation in roots from the 3-week treatment was attributed to the formation of Mn plaques, which were probably related to the Al-induced increase in root aerenchyma. CONCLUSIONS: The results show that Al alleviated Mn toxicity in rice, and this could be attributed to decreased shoot Mn accumulation resulting from an Al-induced decrease in root symplastic Mn uptake. The decrease in root symplastic Mn uptake resulted from an Al-induced change in cell membrane potential. In addition, Al increased Mn plaques in the roots and changed the binding properties of the cell wall, resulting in accumulation of non-available Mn in roots.

Life cycle stage and water depth affect flooding-induced adventitious root formation in the terrestrial species Solanum dulcamara.

BACKGROUND AND AIMS: Flooding can occur at any stage of the life cycle of a plant, but often adaptive responses of plants are only studied at a single developmental stage. It may be anticipated that juvenile plants may respond differently from mature plants, as the amount of stored resources may differ and morphological changes can be constrained. Moreover, different water depths may require different strategies to cope with the flooding stress, the expression of which may also depend on developmental stage. This study investigated whether flooding-induced adventitious root formation and plant growth were affected by flooding depth in Solanum dulcamara plants at different developmental stages. METHODS: Juvenile plants without pre-formed adventitious root primordia and mature plants with primordia were subjected to shallow flooding or deep flooding for 5 weeks. Plant growth and the timing of adventitious root formation were monitored during the flooding treatments. KEY RESULTS: Adventitious root formation in response to shallow flooding was significantly constrained in juvenile S. dulcamara plants compared with mature plants, and was delayed by deep flooding compared with shallow flooding. Complete submergence suppressed adventitious root formation until up to 2 weeks after shoots restored contact with the atmosphere. Independent of developmental stage, a strong positive correlation was found between adventitious root formation and total biomass accumulation during shallow flooding. CONCLUSIONS: The potential to deploy an escape strategy (i.e. adventitious root formation) may change throughout a plant's life cycle, and is largely dependent on flooding depth. Adaptive responses at a given stage of the life cycle thus do not necessarily predict how the plant responds to flooding in another growth stage. As variation in adventitious root formation also correlates with finally attained biomass, this variation may form the basis for variation in resistance to shallow flooding among plants.

Maize varieties released in different eras have similar root length density distributions in the soil, which are negatively correlated with local concentrations of soil mineral nitrogen.

Larger, and deeper, root systems of new maize varieties, compared to older varieties, are thought to have enabled improved acquisition of soil resources and, consequently, greater grain yields. To compare the spatial distributions of the root systems of new and old maize varieties and their relationships with spatial variations in soil concentrations of available nitrogen (N), phosphorus (P) and potassium (K), two years of field experiments were performed using six Chinese maize varieties released in different eras. Vertical distributions of roots, and available N, P and K in the 0-60 cm soil profile were determined in excavated soil monoliths at silking and maturity. The results demonstrated that new maize varieties had larger root dry weight, higher grain yield and greater nutrient accumulation than older varieties. All varieties had similar total root length and vertical root distribution at silking, but newer varieties maintained greater total root length and had more roots in the 30-60 cm soil layers at maturity. The spatial variation of soil mineral N (Nmin) in each soil horizon was larger than that of Olsen-P and ammonium-acetate-extractable K, and was inversely correlated with root length density (RLD), especially in the 0-20 cm soil layer. It was concluded that greater acquisition of mineral nutrients and higher yields of newer varieties were associated with greater total root length at maturity. The negative relationship between RLD and soil Nmin at harvest for all varieties suggests the importance of the spatial distribution of the root system for N uptake by maize.

Phene synergism between root hair length and basal root growth angle for phosphorus acquisition.

Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for phosphorus acquisition, meaning that their combined effect is greater than the sum of their individual effects. To evaluate this hypothesis, phosphorus acquisition in the field in Mozambique was compared among recombinant inbred lines of common bean (Phaseolus vulgaris) having four distinct root phenotypes: long root hairs and shallow basal roots, long root hairs and deep basal roots, short root hairs and shallow basal roots, and short root hairs and deep basal roots. The results revealed substantial synergism between BRGA and RHL/D. Compared with short-haired, deep-rooted phenotypes, long root hairs increased shoot biomass under phosphorus stress by 89%, while shallow roots increased shoot biomass by 58%. Genotypes with both long root hairs and shallow roots had 298% greater biomass accumulation than short-haired, deep-rooted phenotypes. Therefore, the utility of shallow basal roots and long root hairs for phosphorus acquisition in combination is twice as large as their additive effects. We conclude that the anatomical phene of long, dense root hairs and the architectural phene of shallower basal root growth are synergetic for phosphorus acquisition. Phene synergism may be common in plant biology and can have substantial importance for plant fitness, as shown here.

Effect of crude oil contamination on the chlorophyll content and morpho-anatomy of Cyperus brevifolius (Rottb.) Hassk.

Chlorophyll plays a pivotal role in the plant physiology and its productivity. Cultivation of plants in crude oil contaminated soil has a great impact on the synthesis of chlorophyll pigment. Morpho-anatomy of the experimental plant also shows structural deformation in higher concentrations. Keeping this in mind, a laboratory investigation has been carried out to study the effect of crude oil on chlorophyll content and morpho-anatomy of Cyperus brevifolius plant. Fifteen-day-old seedling of the plant was planted in different concentrations of the crude oil mixed soil (i.e., 10,000, 20,000, 30,000, 40,000, and 50,000 ppm). A control setup was also maintained without adding crude oil. Results were recorded after 6 months of plantation. Investigation revealed that there is a great impact of crude oil contamination on chlorophyll content of the leaves of the experimental plant. It also showed that chlorophyll a, chlorophyll b, and total chlorophyll content of leaves grown in different concentrations of crude oil were found to be lower than those of the control plant. Further, results also demonstrated that chlorophyll content was lowest in the treatment that received maximum dose of crude oil. It also showed that chlorophyll content was decreased with increased concentration of crude oil. Results also demonstrated that there was a reduction in plant shoot and root biomass with the increase of crude oil concentration. Results also revealed that the shoot biomass is higher than root biomass. Morphology and anatomy of the experimental plant also show structural deformation in higher concentrations. Accumulation of crude oil on the cuticle of the transverse section of the leaves and shoot forms a thick dark layer. Estimation of the level of pollution in an environment due to oil spill is possible by the in-depth study of the harmful effects of oil on the morphology and anatomy and chlorophyll content of the plants grown in that particular environment.

New evidence of the reproductive organs of Glossopteris based on permineralized fossils from Queensland, Australia. II: pollen-bearing organ Ediea gen. nov.

Ediea homevalensis H. Nishida, Kudo, Pigg & Rigby gen. et sp. nov. is proposed for permineralized pollen-bearing structures from the Late Permian Homevale Station locality of the Bowen Basin, Queensland, Australia. The taxon represents unisexual fertile shoots bearing helically arranged leaves on a central axis. The more apical leaves are fertile microsporophylls bearing a pair of multi-branched stalks on their adaxial surfaces that each supports a cluster of terminally borne pollen sacs. Proximal to the fertile leaves there are several rows of sterile scale-like leaves. The pollen sacs (microsporangia) have thickened and dark, striate walls that are typical of the Arberiella type found in most pollen organs presumed to be of glossopterid affinity. An examination of pollen organs at several developmental stages, including those containing in situ pollen of the Protohaploxypinus type, provides the basis for a detailed analysis of these types of structures, which bear similarities to both compression/impression Eretmonia-type glossopterid microsporangiate organs and permineralized Eretmonia macloughlinii from Antarctica. These fossils demonstrate that at least some Late Permian pollen organs were simple microsporophyll-bearing shoot systems and not borne directly on Glossopteris leaves.

Virtual medical plant modeling based on L-system.

BACKGROUND: Searching the drug molecules from the medicinal plants become more and more popular given that herbal components have been widely considered to be safe. In medical virtual plant studies, development rules are difficult to be extracted, the construction of plant organs is highly dependent on equipment and the process is complicated. AIM: To establish three-dimensional structural virtual plant growth model. METHODS: The quasi-binary tree structure and its properties were obtained through the research of theory on binary tree, then the relationship between quasi-binary tree structure and plant three-dimensional branching structure model was analyzed, and the three-dimensional morphology of plants was described. RESULTS: A three-dimensional plant branch structure pattern extracting algorithm based on quasi-binary tree structure. By using 3-D L-system method, the extracted rules were systematized, and standardized. Further more, we built a comprehensive L-model system. With the aid of graphics and PlantVR, we implemented the plant shape and 3-D structure's reconstruction. CONCLUSION: Three-dimensional structure virtual plant growth model based on time-controlled L-system has been successfully established.

Cytogenetic and anatomic behavior of cytochimeras and total polyploids in cassava.

Cassava periclinal cytochimeras, cultivars, and interspecific hybrid and polyploid types were studied in relation to embryonic, cytogenetic, and anatomical behavior. Their apical shoots, pollen grains, male and female buds, roots, stomata, and flowering period were analyzed. Chimeras exhibited increased size of L1 and L2 cells. Polyploidy led to enlargement of stomata in chimeras whereas L2 gave tetraploid chromosome configurations, tetrad irregularity, decrease of pollen viability, and increase in frequency of polyembryo sacs. The chimeric composition of tetraploids L1 and L2 and diploid L3 expressed a notable epigenetic effect seen in a marked enlargement of edible roots compared to total diploid. One of the chimeric types was accompanied by complete flowering inhibition. Pollen viability and diameter appeared to be reliable markers to determine ploidy levels.

Regeneration capacity of small clonal fragments of the invasive Mikania micrantha H.B.K.: effects of burial depth and stolon internode length.

The perennial stoloniferous herbaceous vine Mikania micrantha H.B.K. is among the most noxious exotic invaders in China and the world. Disturbance can fragment stolons of M. micrantha and disperse these fragments over long distances or bury them in soils at different depths. To test their regeneration capacity, single-node stolon fragments with stolon internode lengths of 0, 3, 6 and 12 cm were buried in soil at 0, 2, 5 and 8 cm depths, respectively. The fragments were growing for nine weeks, and their emergence status, growth and morphological traits were measured. The results indicated that increasing burial depth significantly decreased survival rate and increased the emergence time of the M. micrantha plants. At an 8-cm burial depth, very few fragments (2.19%) emerged and survived. Burial did not affect the total biomass and root to shoot ratio of the surviving M. micrantha plants that emerged from the 0- and 2-cm burial depths. Increasing internode length significantly increased survival rate and growth measures, but there was no interaction effect with burial depth for any traits measured. These results suggest that M. micrantha can regenerate from buried stolon fragments, and thus, disturbance may contribute to the spread of this exotic invader. Any human activities producing stolon fragments or facilitating dispersal should be avoided.

Basal root whorl number: a modulator of phosphorus acquisition in common bean (Phaseolus vulgaris).

BACKGROUND AND AIMS: Root architectural phenes enhancing topsoil foraging are important for phosphorus acquisition. In this study, the utility of a novel phene is described, basal root whorl number (BRWN), that has significant effects on topsoil foraging in common bean (Phaseolus vulgaris). METHODS: Whorls are defined as distinct tiers of basal roots that emerge in a tetrarch fashion along the base of the hypocotyl. Wild and domesticated bean taxa as well as two recombinant inbred line (RIL) populations were screened for BRWN and basal root number (BRN). A set of six RILs contrasting for BRWN was evaluated for performance under low phosphorus availability in the greenhouse and in the field. In the greenhouse, plants were grown in a sand-soil media with low or high phosphorus availability. In the field, plants were grown in an Oxisol in Mozambique under low and moderate phosphorus availability. KEY RESULTS: Wild bean accessions tended to have a BRWN of one or two, whereas cultivated accessions had BRWN reaching four and sometimes five. BRWN and BRN did not vary with phosphorus availability, i.e. BRWN was not a plastic trait in these genotypes. Greater BRWN was beneficial for phosphorus acquisition in low phosphorus soil. Genotypes with three whorls had almost twice the shoot biomass, greater root length and greater leaf area than related genotypes with two whorls. In low phosphorus soil, shoot phosphorus content was strongly correlated with BRWN (R(2) = 0.64 in the greenhouse and R(2) = 0.88 in the field). Genotypes with three whorls had shallower root systems with a greater range of basal root growth angles (from 10 to 45 ° from horizontal) than genotypes with two whorls (angles ranged from 60 to 85 ° from horizontal). CONCLUSIONS: The results indicate that BRWN is associated with increased phosphorus acquisition and that this trait may have value for selection of genotypes with better performance in low phosphorus soils.

High-throughput root phenotyping screens identify genetic loci associated with root architectural traits in Brassica napus under contrasting phosphate availabilities.

BACKGROUND AND AIMS: Phosphate (Pi) deficiency in soils is a major limiting factor for crop growth worldwide. Plant growth under low Pi conditions correlates with root architectural traits and it may therefore be possible to select these traits for crop improvement. The aim of this study was to characterize root architectural traits, and to test quantitative trait loci (QTL) associated with these traits, under low Pi (LP) and high Pi (HP) availability in Brassica napus. METHODS: Root architectural traits were characterized in seedlings of a double haploid (DH) mapping population (n = 190) of B. napus ['Tapidor' × 'Ningyou 7' (TNDH)] using high-throughput phenotyping methods. Primary root length (PRL), lateral root length (LRL), lateral root number (LRN), lateral root density (LRD) and biomass traits were measured 12 d post-germination in agar at LP and HP. KEY RESULTS: In general, root and biomass traits were highly correlated under LP and HP conditions. 'Ningyou 7' had greater LRL, LRN and LRD than 'Tapidor', at both LP and HP availability, but smaller PRL. A cluster of highly significant QTL for LRN, LRD and biomass traits at LP availability were identified on chromosome A03; QTL for PRL were identified on chromosomes A07 and C06. CONCLUSIONS: High-throughput phenotyping of Brassica can be used to identify root architectural traits which correlate with shoot biomass. It is feasible that these traits could be used in crop improvement strategies. The identification of QTL linked to root traits under LP and HP conditions provides further insights on the genetic basis of plant tolerance to P deficiency, and these QTL warrant further dissection.

Effects of supplemental UV-A on the development, anatomy and metabolite production of Phyllanthus tenellus cultured in vitro.

Phyllanthus tenellus is widely used for its antiviral, analgesic and hepatoprotective properties. Although the production of several chemical classes of secondary metabolites is influenced by UV radiation, particularly phenolic compounds, we also know that UV radiation can result in anatomical and developmental damage. However, the morphological, anatomical and phytochemical changes in response to UV-A exposure are generally understudied in the Phyllanthaceae. Therefore, we evaluated the effects of UV-A radiation on plant development and leaf anatomy, as well as the production of secondary metabolites and the contents of carotenoids and chlorophylls a and b, in P. tenellus. To accomplish this, in vitro cultures of P. tenellus were maintained for 60 days under white light (WL) and WL plus UV-A radiation. Results showed different phenotypic responses under additional UV-A, such as high phenolic metabolite production, increasing dimensions of abaxial epidermis and thickness of palisade parenchyma. Compared to plants cultured under WL, UV-A radiation caused damage to plant morphogenesis, including a reduced number of branches and shoots, consequently reducing the rate of proliferation. On the other hand, geraniin, ellagic acid and carotenoid contents increased after UV-A exposure, indicating that this light source is an important resource for inducing phenolic compounds.

Capacidade de enraizamento de estacas de Maytenus muelleri Schwacke com a aplicação de ácido indol butírico relacionada aos aspectos anatômicos / Rooting capacity of Maytenus muelleri Schwacke cuttings with indolebutyric acid application related to anatomical aspects

A espinheira-santa (Maytenus muelleri - Celastraceae) é a planta medicinal nativa do Sul do Brasil, cujas folhas são tradicionalmente utilizadas pela medicina popular para o tratamento de úlceras e outros problemas gástricos. Existem poucos trabalhos publicados sobre a produção de mudas e técnicas de propagação vegetativa da espécie. A propagação de espinheira-santa por estaquia poderia ser um método eficiente para obtenção de material homogêneo, com características genéticas desejáveis, produzido a partir de plantas matrizes selecionadas. O presente trabalho teve por objetivo estudar os efeitos da aplicação de ácido indol butírico (AIB), em solução e em pó, no enraizamento de estacas de espinheira-santa coletadas nas quatro estações do ano (abril/2005 a janeiro/2006), bem como averiguar, por meio de análises anatômicas e histoquímicas das estacas, a presença de possíveis impedimentos à iniciação do enraizamento adventício. Estacas provenientes de ramos de plantas matrizes de seis anos cultivadas da Estação Experimental do Canguiri, Pinhais, PR, foram coletadas e tratadas com AIB (0, 1500, 3000 mg L-1 ou mg kg-1), em solução alcoólica (50 por cento v/v) e em talco. Aos 365 dias foram avaliadas as porcentagens de estacas enraizadas e mortas, número e comprimento médio de raízes formadas por estaca. Análises anatômicas e histoquímicas com lugol e cloreto férrico foram realizadas. A estação mais promissora para o enraizamento foi o verão/2006 com 62,50 por cento para o tratamento controle, devido à menor lignficação dos ramos no período de intenso crescimento vegetativo. O número médio de raízes formadas por estaca foi de 6,94 (solução) e o comprimento médio de raízes formadas/estaca chegou a 4,82 cm nesta mesma estação. As concentrações de AIB aplicadas não foram eficientes na indução radicial, independentemente do modo de aplicação. Foi detectada a presença de uma camada quase contínua de fibras e braquiesclereídes, a qual constitui barreira anatômica à indução radicial. Os testes histoquímicos revelaram a presença de amido e de compostos fenólicos nas estacas, em todas as estações do ano. A dificuldade ou demora no enraizamento não pode ser justificada pela falta de reservas de amido nos tecidos das estacas, mas pode ser justificada pela presença de compostos fenólicos, possivelmente do grupo dos monofenóis, que causam a degradação do AIA, interferindo negativamente na indução do enraizamento.

"Espinheira-santa" (Maytenus muelleri - Celastraceae) is a medicinal plant native to Southern Brazil, the leaves of which are traditionally used in popular medicine for the treatment of stomach ulcers and other gastric problems. There are few published studies about seedling production and vegetative propagation techniques for this species. The propagation of "espinheira-santa" by cuttings could be an efficient method to obtain homogeneous material, with desirable genetic characteristics, produced from selected mother plants. This paper aimed to study the effects of indolebutyric acid (IBA) application, in solution and in powder, on the rooting of "espinheira-santa" cuttings, collected in four seasons (April/2005 to January/2006), as well as to investigate, by means of cutting anatomical and histochemical analyses, the presence of possible impediments to adventitious rooting initiation. Cuttings from branches of six-year mother plants grown at "Estação Experimental do Canguiri", Pinhais, Paraná State, Brazil, were collected and treated with IBA (0, 1500, 3000 mg L-1 or mg kg-1) in alcoholic solution (50 percent v/v) and in powder. After 365 days, the percentages of rooted and dead cuttings, the number and mean length of roots/cutting were evaluated. Anatomical and histochemical analyses were performed with lugol and ferric chloride. The most promising season for rooting was Summer/2006, with 62.50 percent of rooting for the control treatment, due to the lesser lignification degree of branches in intense vegetative growth period. The mean number of roots/cutting was 6.94 (solution) and the mean length of roots/cutting was 4.82 cm in that same season. The applied IBA concentrations were not efficient in inducing root growth, regardless of the application method. An almost continuous layer of fibers and stone cells was detected, constituting an anatomical barrier for rooting induction. The histochemical tests revealed the presence of starch and phenolic compounds in cuttings, in all seasons. The difficulty or delay in rooting cannot be justified by the absence of starch reserve in the cutting tissues but by the presence of phenolic compounds, possibly of the group of monophenols, which cause IAA degradation, negatively affecting rooting induction.

Produção de mudas de dois genótipos de alecrim-de-tabuleiro (Lippia gracilis Schauer) em função de fertilizante mineral, calcário, substratos e recipientes / Seedling production of two "alecrim-de-tabuleiro" (Lippia gracilis Schauer) genotypes under mineral fertilizer, limestone, substrates and containers

Lippia gracilis Schauer popularmente conhecida como alecrim-de-tabuleiro possui moderada atividade antibacteriana, antimicrobiana e antiséptica. Objetivando avaliar o efeito de doses de fertilizante mineral, calcário, substratos e recipientes na produção de mudas de dois genótipos de alecrim-de-tabuleiro realizou-se experimentos com estacas de dois genótipos de L. gracilis. No experimento 1, foram utilizadas estacas apicais distribuídas em bandejas de poliestireno expandido de 128 células com o substrato pó-de-coco + areia (1:1), três repetições e oito estacas por repetição. O delineamento experimental foi em blocos ao acaso, em esquema fatorial 4x2x2, sendo quatro doses do fertilizante (6-24-12+micronutrientes) (1, 2, 3 e 4 g L-1), duas doses de calcário (0 e 1 g L-1) e dois genótipos (LGRA106 e LGRA201). Aos 35 após plantio, foram avaliadas a sobrevivência ( por cento), enraizamento ( por cento), comprimento de raiz (cm) e massa seca de raiz (mg). No experimento 2, foram utilizadas três repetições com oito estacas por repetição. O delineamento experimental foi em blocos ao acaso, em esquema de parcelas subdivididas onde foram testados nas parcelas dois recipientes (bandeja de poliestireno expandido de 128 alvéolos e tubetes de 110 cm³, na sub parcela foram testadas as combinações de quatro substratos (PC - pó de coco; PCA (1:1) - pó de coco + areia (1:1); PCA (2:1) - pó de coco + areia (2:1) e PCA (3:1) - pó de coco + areia (3:1) e dois genótipos (LGRA106 e LGRA201). Aos 35 dias após o plantio foram analisadas as mesmas variáveis do experimento 1, além de altura de parte aérea (cm) e massa seca de parte aérea (mg). A utilização de 1 g L-1 do fertilizante na ausência de calcário foi efetivo para sobrevivência de plantas e enraizamento de estacas de alecrim-de-tabuleiro. Com base nesses experimentos, concluiu-se que o genótipo LGRA106 é superior ao LGRA201 nas variáveis analisadas e recomenda-se a bandeja de poliestireno expandido para produção de mudas de L. gracilis via estaquia.

Commonly known as "alecrim-de-tabuleiro", Lippia gracilis Schauer (Verbenaceae) has moderate antibacterial, antimicrobial and antiseptic activity. This study aimed to evaluate the effect of doses of mineral fertilizer, limestone, substrates and containers on seedling production of two "alecrim-de-tabuleiro" genotypes, using cuttings. In experiment 1, apical cuttings were distributed on expanded polystyrene trays of 128 cells containing coir + sand (1:1), using three replicates of eight cuttings each. Experimental design was in randomized blocks, in a 4x2x2 factorial arrangement, i.e. four doses of fertilizer (6-24-12 + micronutrients) (1, 2, 3 and 4 g L-1), two doses of limestone (0 and 1 g L-1) and two genotypes (LGRA106 and LGRA201). At 35 days after planting, we evaluated survival ( percent), rooting ( percent), root length (cm) and root dry matter (mg). In experiment 2, three replicates of eight cuttings each were used. Experimental design was in randomized blocks, in a split-plot scheme. In the plots, we tested two containers (expanded polystyrene tray of 128 cells and 110 cm³ tubets). In the subplots, we tested four substrate combinations [coir, coir + sand (1:1), coir + sand (2:1) and coir + sand (3:1)] and two genotypes (LGRA106 and LGRA201). At 35 days after planting, the same variables of experiment 1 were evaluated, besides shoot length (cm) and shoot dry matter (mg). The use of 1 g L-1 fertilizer without limestone was effective for plant survival and cutting rooting. Based on these experiments, the genotype LGRA106 is superior to LGRA201 as to the evaluated variables and the expanded polystyrene tray is recommended for the production of L. gracilis seedlings through cuttings.