Orthotropic Shoots Research Articles

Adaptation of two woody plant species – Betula pubescens and Salix udensis to the high Arctic conditions (Tiksi settlement, Russia)

The positive trends in climate change that have become apparent in recent decades are accompanied by a shift in the range boundaries of many boreal plant species further north, to the shores of the Arctic Ocean. Monitoring the displacement of these boundaries, the introduction of plants unusual to the Arctic, as well as monitoring their adaptation to new conditions, is an important component of botanical research. In 2016, in the village Tiksi identified 2 species of woody plants – Betula pubescens and Salix udensis, known from the forest zone and not previously observed in this area. Obviously, both species appeared here due to the unintentional introduction of seeds by humans. Repeated observations of the condition of these species, conducted in 2023, showed that they exhibit stable vitality, withstood 7 winter periods and gave some increase in phytomass. Measurements of the area of the leaf blade of Betula pubescens and the size of 10 leaves of Salix udensis showed that these indicators are within the normal biological parameters of these species. Both species do not form generative structures yet. Salix udensis has grown significantly during the observation period, reaching a height of about 2.5 m. Perhaps this is the result of the protective influence of the building behind which it develops. Betula pubescens grows more slowly, hardly retains orthotropic shoots exceeding the average snow cover levels, which reach a height of 54 cm, but at the same time partially drained and deprived of foliage. Nevertheless, the lower part of the plant has fully leafy branches. Both species are valuable objects for further observations of their adaptation to Arctic conditions. Since Betula pubescens grows near the slope of the highway, it is recommended to move it to a safe place less susceptible to anthropogenic influence. Tiksi village, located in high latitudes, could serve as a good reference base for a wide range of scientific observations of plant adaptation to Arctic conditions. The optimal solution for this would be the creation of the Arctic Botanical Garden in Tiksi.

Some Features of the Shoot Systems in Representatives of the Tribe Sequoiae, Cultivated in Russia

The article focuses on the growth rates of three extant species belonging to the tribe Sequoiaceae: Metasequoia glyptostroboides, Sequoia sempervirens and Sequoiadendron giganteum. The material was collected from botanical garden collections on the Black Sea coast of the Caucasus and Crimea. During a long growing season, all three species form shoot systems of varying complexity: from unbranched shoots consisting of a single elementary shoot to sylleptically branched multi-axial systems. In S. giganteum, the shoot systems formed during an extra-bud growth period are similar to those of other Cupressaceae species and partly to those of Pinaceae. In Metasequoia glyptostroboides and Sequoia sempervirens, sylleptically branched shoot systems are differentiated into several variants: on orthotropic shoots in the upper part of the growth, plagiotropic branches are sylleptic and continue to grow after the orthotropic part of the shoot system has stopped growing. Plagiotropic sylleptic lateral shoots continue to branch into second-order lateral shoots. Similar structures are found in Araucaria and archaic fossil conifers. M. glyptostroboides and S. sempervirens have phyllomorphic branches of the same appearance as those described for Tsuga canadensis. Plagiotropic lateral sylleptic shoots continue to branch into second-order lateral shoots. Similar structures are known in Araucaria and fossil archaic conifers. M. glyptostroboides and S. sempervirens have phyllomorphic branches of the same appearance as described for Tsuga canadensis. These species are also characterized by buds formed serially below the sylleptically growing shoot. In M. glyptostroboides, the phyllomorphic branches fall off annually, and their perennial bases form a growing, basisympodially shortened shoot. The renewal bud is not located under the bark, as in Taxodium distichum.

Novo modelo de jardim clonal para a produção de mudas de café robusta

Abstract The objective of this work was to evaluate the production of cuttings of Coffea canephora genotypes, in a new system for training mother plants called “vertical clonal garden”. The proposed new system consists of training coffee plants with only one shoot and without bending the main shoot, so that the secondary orthotropic shoots, from which the clonal cuttings will be taken, are formed across the length of the stem in the vertical direction. The capacity for the production of cuttings of ten hybrid genotypes of coffee plants was evaluated over ten production cycles. The 'BRS 2314', 'BRS 3213', and 'BRS 3210' genotypes showed cutting production per cut of 425,000 cuttings per hectare, considered above the obtained average. The 'BRS 3193', 'BRS 2336', 'BRS 3220', and 'BRS 3137' genotypes were the least productive. Coffee plants trained in the “vertical clonal garden” system can produce about 425,000 cuttings per hectare per harvest period or about 1.275 million cuttings per hectare per year, over three harvest periods, with a greater ease in crop management and treatments.

Studying Althaea officinalis L. by an introduction experiment in the Kuzbass Botanical Garden (KuzBS)

Althaea officinalis L. was studied in the Kuzbass Botanical Garden. It’s a perennial herbaceous plant, that is included in the Red Book of the Kemerovo Region with the status 2 - declining. During the first year of life, the following ontogenetic stages are recognized under introduction conditions: seedling, juvenile, immature, virginile, and young generative. A semi-rosette orthotropic monocarpic shoot, branching in a sylleptic way, and a caudex emerge in the first year. In pregenerative plants, there is an increase in ascorbic acid but a decrease in the activity of phenolic compounds and malonic dialdehyde; in generative plants, there is an inverse link.

Early induction of orthotropic shoots in Coffea canephora

ABSTRACT In Coffea canephora, the number of orthotropic shoots is directly related to plant yield. The objective of this study was to evaluate the vegetative and yield performance of Coffea canephora, from the botanical variety Conilon, under different management systems for early emission of orthotropic shoots. The experiment was carried out in Ouro Preto do Oeste, Rondonia, between November 2011 and May 2014. Three types of management techniques were tested for early induction of orthotropic shoots in coffee trees (T1 = bending of the orthotropic shoot; T2 = apical pruning of the orthotropic shoot, T3 = free growing). The experiment was conducted in a randomized block design with 20 replicates. Each block consisted of a clonal genotype (clone) from the Embrapa Coffee Breeding Program. The techniques pruning and apical pruning were efficient to induce early growth of orthotropic shoots in Coffea canephora, resulting in higher yield in the first commercial bean production.

EFFECT OF PRUNING HEIGHT ON THE PRODUCTION OF ORTOTROPIC BUDS OR BRANCHES IN VIVERO CONDITIONS

Introduction: reforestation constitutes an imperative need for current generations; this guarantees the sustainability of wood for different purposes, while promoting healthy conditions for the environment; The scientific community redouble efforts to investigate techniques that make reforestation increasingly feasible and viable. Objective: To determine the effect of pruning height according to the number of buds in the production of orthotropic shoots or branches under nursery conditions. Methodology: experimental, descriptive and longitudinal study in which young plants of Juglans neotrópica were subjected to clonal forestry techniques by means of training prunings in mother plants Different statistics were used to identify the statistical significance of the changes in the appearance of shoots according to the pruning height and number of buds; These include the use of Pearson's chi-square, the correlation for continuity, the likelihood ratio and the linear association for linear. Results: the plants submitted to the A2S2 combination were the ones that showed the best yield in relation to the appearance of shoots. The plants subjected to the A1S1 and A2S2 combinations were the ones with the greatest delay in the appearance of shoots. Conclusions: there is no significant relationship between the appearance of shoots and the height of pruning according to the number of buds; therefore, it can be determined that the buds will appear interchangeably whether the pruning is performed at three or five buds.

PENGARUH UMUR TUNAS PANGKASAN TERHADAP PERTUMBUHAN SETEK Hopea odorata Roxb.

Propagation of Hopea odorata Roxb. could be carried out through the vegetative methods by cutting s . Material cuttings with a high juvenility are obtained by pruning a stock plant. Information on shoot age after pruning as material cuttings were still limited. The purpose of this study was to determine the effect of shoot age after pruning on the successful propagation of H . odorata cuttings. The study design was a randomized block design with shoot age treatments of 3, 4, 5 and 6 months. Each treatment was placed in 5 blocks and each treatment consisted of 20 cuttings. Growth response of cuttings observed was cutting survival percentage, shoot height, root length, root dry weight, shoot dry weight, carbon, and nitrogen content. The results showed that the age of pruning shoots had a significant effect on all measured growth response of cuttings. H . odorata cuttings from orthotropic shoots aged 4 and 5 months after pruning showed cutting survival percentage, shoot height, root length, shoot and root dry weight were higher than shoots aged 3 and 6 months after pruning. The age of 6 months pruning shoots showed the highest C/N ratio (18.14) and carbon content (47.48 percent), but but the lowest nitrogen content (2.62 percent). The percentage of woody on shoots aged 4 and 5 months after pruning was 50%, while almost all of the cuttings on shoots of the age of 6 months were woody. The best propagation material for H. odorata cuttings was orthotropic shoots aged 5 months after pruning, because of the high cuttings survival percentage (94.18 percent). In addition C/N ratio from shoot aged 5 months (15,11) was higher than from shoot aged 4 months (13,14).

Cloning by cuttings in Nordmann fir, Abies nordmanniana: hormonal characteristics in relation crown position, rooting competence, and orthotropism as ramets

Conifer tree species belonging to Abies are notoriously difficult to propagate vegetatively due to aging of material, slow rooting, and persistent plagiotropism in rooted cuttings. We produced orthotropic shoots by reiteration from strongly pruned trees (5–6 years and 12–14 years, respectively), and harvested cuttings in summer. By HPLC–MS we analyzed the stem base of each cutting for initial hormonal status, and used state-of-the art techniques for a lengthy rooting procedure. Rooting efficiency and orthotropism of the resulting ramets were recorded. Hormonal content varied significantly among cuttings types with differing positional origins on the mother tree. High rooting percentages were obtained in all types; a low original position on the main stem gave slightly better rooting but orthotropism in the ramets was slightly less frequent. Striking differences were found in cytokinin profiles between cuttings from young and mature trees. This might explain a generally lower rooting success in the latter; neither auxin levels nor the auxin: active cytokinin ratio showed any correlation with rooting capacity. Cuttings from mature trees were also less likely to remain orthotropic after rooting. Cuttings that eventually developed into orthotropic ramets were characterized by low ABA, and high levels in a range of cytokinins. The study suggests that active: conjugated cytokinins may be related to the maturation process in trees and that cytokinin content may also relate to shoot dimorphism. These results contribute to a protocol for propagation of orthotropic ramets in a Massart model tree species with strong plagiotropism.

Optimal pheromone trap density for mass trapping cacao mirids

AbstractSahlbergella singularis Haglund and Distantiella theobroma (Distant) (Heteroptera: Miridae) are the key insect pests of cacao in Ghana and elsewhere in West Africa. Since 1954, spraying with synthetic insecticides has been the principal means of controlling these pests. In West Africa, environmental concerns, economic stimuli, and unreliable access to insecticides have stimulated interest in ecologically more benign mirid control strategies as an alternative to a total reliance on insecticides. Males of both mirid species, and those of the less damaging Bryocoropsis laticollis Schumacher, respond to the same synthetic sex pheromone blend, so pheromone‐based strategies may provide control as well as monitoring opportunities. Pheromone traps were deployed for 3 months at nine densities between two and 30 traps per 0.1 ha plot (20–300 traps ha−1) plus an untreated control treatment in a replicated large‐scale field experiment on mature mixed Upper Amazon hybrid cacao in Ghana, in order to determine the optimal dispenser density for mass trapping, lure‐and‐kill, and/or lure‐and‐infect. At the end of the trapping period, mirid populations in the various treatments were assessed by insecticide knockdown on 400 trees and by searches to hand height on 1 200 trees, together with an assessment of mirid damage. In total 781 S. singularis and 235 D. theobroma were captured in the pheromone traps. The optimal dispenser density for S. singularis was 150 traps ha−1. Over 300 traps ha−1 was probably optimal for D. theobroma as a smaller proportion of the population was captured, and numbers caught per trap displayed no decline with increasing trap density. From insecticide knockdowns, mirid population density was estimated at 220–230 ha−1, 63% of which were D. theobroma. Too few pods and orthotropic shoots were damaged by mirids to establish the efficacy of pheromone trapping for mirid control.

Effect of Growth Regulators in Production and Rooting of <i>Coffea arabica</i> L. Minicuttings

The plants of C. arabica do not naturally produce a large number of orthotropic sprouts, hindering clonal multiplication by cutting, which would be the simplest technique with a lower cost of production compared to other methods of vegetative propagation. An alternative form, used successfully in the propagation of eucalyptus, is propagation by minicutting, which consists of pruning the shoot apex of the plant, forming the ministumps, which in variable time interval emits the shoots that will be used to make minicutting. In C. arabica plants the number of shoots can be increased with the application of growth regulators and fertilizers. So, the purpose of this work was to verify the effect of growth regulators and foliar fertilizers on the emission and development of orthotropic shoots of C. arabica. The experiment was installed in a randomized complete block design, with ten treatments composed by growth regulators and fertilizers: T1 (Control); T2 (Stimulate + Sturdy + Enervig); T3 (Stimulate + Vitakelp + Biozyme); T4 (Tiba + Sturdy + Enervig); T5 (Tiba + Vitakelp + Biozyme); T6 (Brs + Sturdy + Enervig) T7 (Brs + Vitakelp + Biozyme); T8 (Stimulate); T9 (TIBA); T10 (Brs-Brassinoesteroid), each plot consisting of two plants. Biometric and physiological parameters were evaluated for the ministumps, as well as the biometric parameters of the shoots and plant survival. The results showed that there was no influence of the treatments on the biometric parameters of the ministumps. A greater number of orthotopic sprouts were obtained in treatments with the TIBA growth regulator, as well as a greater plant survival of the minicuttings, after 25 days of transplanting in a greenhouse. It was concluded that TIBA treatments influenced the production and quality of clonal minicuttings of C. arabica.

Architecture of Mabea fistulifera Mart. (Euphorbiaceae), a Neotropical semideciduous tree: development and variations in crown allometry between environments

Tree crown growth reflects many aspects of the species’ life history. It was postulated that the potential for a pioneer species to invade a deforested area, or maintain a viable population in a forest under intermediate disturbance regime, is related to the tree trunk growth rates, patterns of crown construction, as well as the ability to regenerate broken branches. We investigated if Mabea fistulifera Mart. (Euphorbiaceae) crown architecture and tree allometry varies in two contrasted environments in a secondary fragment of Atlantic rainforest: forest edge and interior. First, we described the development of crown architecture by following the growth of the crown in 15 young individuals, with special attention to growth and branching models and to the morphologic differentiation of axes. Secondly, allometric differences in crown construction patterns between environments were studied by quantifying 10 traits in 20 individuals from each environment. Nozeran architectural model was found, a process of parenchymatization of the terminal meristem and a tier of branches form distally followed by an orthotropic shoot forming the next relay axis. This results in modular sympodial branching and polyaxial morphology of branches, allowing this tree species to occupy different environments by quick expansion wherever light availability is higher, towards the upper canopy (forest interior) or towards one side (forest edge). Crown asymmetry occurred towards border sunlit spaces or in response to inner canopy openings caused by hilly topography. Crown structure and growth patterns here found are suitable for a pioneer species adapted to intermediate disturbance regime.

The relationships between structural and functional diversity within and among macrophyte communities in lakes

We studied the relationships between structural and functional diversity within and among macrophyte communities of softwater lakes. Diversity was assessed based on Simpson’s diversity index (SD), species richness (S), Rao’s functional diversity (FDQ) and shared plant traits along a gradient of pH. A total of 10,800 cover-plant samples (area=0.1 m2) were analysed, collected from 241 sections of the bottom (with a depth resolution of 1.0 m) of 38 lakes in Poland. We identified 59 species of macrophytes and recognized four communities. Along a gradient of increasing pH we found i) an increase of species richness; ii) a uniformity of abundance in communities; and iii) an increase in the quantitative contribution of life history traits such as perennials, submerged anchoring, leaf placement along an orthotropic shoot and generative reproduction. On the other hand, there was a decrease in unanchored and evergreen perennials. In our study, we found that the variety of these traits within communities is greater than that between them. Within lakes, structural diversity was low, whereas it was high between lakes. Functional diversity exhibited an opposite pattern: it was high at lake scale, and low between lakes. A combination of partitioning diversity and utilizing environmental variables significantly improves the prediction of community structure and the conservation of lakes.

ROOTING OF Araucaria angustifolia: TYPES OF CUTTINGS AND STOCK PLANTS SEX

ABSTRACT Araucaria angustifolia is native to Brazil and has always raised economic interest for the qualities of its timber and as a supplier of pine nuts for human consumption. The scarce germination viability of the stored seeds and the possibility to produce rooted cuttings all year round make cuttings propagation a good alternative for the production of plants, giving also the possibility to obtain genetically superior clones. On this basis, we assessed the influence of stock plants sex and type of cuttings (apical and intermediate) on the percentage of survival, rooting and vigor of the cuttings, together with the efficiency of this technique in the production of rooted cuttings of this species. So, cuttings from orthotropic shoots, collected in a clonal garden composed by feminine and masculine plants, had their survival percentages assessed at 60, 90, 120 and 150 days after installation of the experiment (DAI). Rooting in full sunlight area after 180 days, together with vigor characteristics of roots and aerial portion at 120 and 180 DAI were also evaluated. At 180 DAI, apical female cuttings presented the greatest rooting percentage (53.7%), number of roots (1.2) and average length of roots at the bottom of the rooting tray (4.4 cm). On the other hand, the applied cuttings procedures showed to be adequate to increase the rooting percentages of the species, which, supported by the fact that this technique is important for the formation of rooted cuttings to be used in the mini-cuttings technique, indicates that it can be considered efficient.

Allomorphic growth of Epipremnum aureum (Araceae) as characterized by changes in leaf morphophysiology during the transition from ground to canopy

The aroid vine Epipremnum aureum (L.) Engler has an allomorphic growth throughout its ascent into the forest. In the literature, the allomorphic increase in leaf area of aroid vines was hypothesized to improve its light foraging capacity. This study aims to test this hypothesis by characterizing nitrogen allocation, chlorophyll fluorescence, and morphophysiological and anatomical changes at leaf level along a vertical ascension of E. aureum toward the canopy. Leaf samples were chosen to represent the transition from ground (individuals with ageotropic shoot near to soil surface) to crown (individuals with orthotropic shoot living at canopy). Leaf allomorphic development was accompanied by a simultaneous increase of leaf area, maximum ETR, leaf succulence, and mass per area, as well as mesophyll thickness and stomatal pore height. Stomatal conductance differed only slightly between growth habits. Since nitrogen content (% of dry mass) did not differ, total nitrogen allocated per individual leaf increased only with lamina area. Multivariate analysis indicates that the increases of fluorescence parameters, as well as chlorophyll and total nitrogen contents, are positively related to leaf area, supporting the hypothesis that an increase in the leaf area of aroid vines improves its light foraging capacity. With such increased light foraging capacity in E. aureum leaves, the survival and productivity of larger plants of this vine in the canopy is potentially improved.

The diagnostic method ARCHI applied on declining pedunculate oaks

When evaluating tree architecture, condition and vitality, often, the prevalence and morphology of epicormic shoots are ignored or misinterpreted. However, epicormic shoots can play a fundamental role in tree survival and need to be taken into account when they occur. The presence and abundance of three morphologically different types of epicormic shoots can be used to distinguish between trees which are healthy, stressed, resilient (i.e. likely to recover after being stressed), undergoing natural crown retrenchment, or in a state of irreversible decline. Orthotropic and plagiotropic epicormic shoots, which respectively replicate the architecture of young trees and branches, act as the tree's “life insurance” against future catastrophe. On the other hand, ageotropic epicormic shoots, which have the characteristics of old age, indicate irreversible decline. Analysis of annual growth-ring width has shown that the architectural characters assessed for pedunculate oak (Quercus robur L.) are good indicators of the physiological state of the trees.

VEGETATIVE RESCUE AND CUTTINGS PROPAGATION OF Araucaria angustifolia (Bertol.) Kuntze

Brazilian pine or araucaria (Araucaria angustifolia) is a coniferous tree with great economic, social and environmental importance in southern Brazil, being exploited for both wood production and for its edible pine nuts. However, no efficient cloning techniques are available and, therefore, the purpose of this study was to evaluate the effectiveness of vegetative rescue methods for cuttings propagation of the species. Shoots/cuttings were generated in two ways: 26 years old trees underwent coppicing and 20 years old trees had the primary branches on the upper third of crown pruned at 2, 20 and 50 cm from the main trunk. Orthotropic shoots were rooted after application of indole-3-butyric acid (IBA) at 0, 2, 4 and 6 g.L-1. Coppicing produced 47 cuttings per plant with 90% orthotropic shoots, while pruning resulted in 182 cuttings per plant with 44% orthotropic shoots. Rooting success indexes were low with no influence of IBA, although they are slightly superior to the ones available in the literature for the species, ranging from 12 to 30% for the coppice shoots and from 0 to 28% for the branches shoots. We conclude that both vegetative rescue techniques are viable and have potentially important applications. Coppicing is recommended for the propagation aiming the production of wood, while shoots derived from the side branches of the crown are more appropriate for seeds orchards formation.

Relationships between crown architecture and available irradiance in two cerrado species with different leaf phenologies

Structural differences between cerrado species with different leaf phenologies are linked to crown architecture, leaf production, and biomass allocation to shoots and leaves. The present study characterized crown structures and the patterns of biomass allocation to leaves and shoots in two woody cerrado species with contrasting leaf phenologies and quantified the irradiance reaching their leaves to determine the best period during the day for photosynthetic activity. The shoots and leaves of five individuals of both Annona coriacea (deciduous) and Hymenaea stigonocarpa (evergreen) were collected along a 50 m transect in a cerrado fragment within the urban perimeter of Catalao - GO, to determine their patterns of biomass allocation in their crowns. The evergreen H. stigonocarpa had significantly higher mean values of shoot inclination (SI), petiole length (PL), leaf area (LA), leaf display index (LDI), and individual leaf area per shoot (ILA), while the deciduous species A. coriacea had significantly higher leaf numbers (LN). The more complex crown of H. stigonocarpa had shoots in more erect positions (orthotropic), with intense self-shading within shoots; A. coriacea, on the other hand, had slanting (plagiotropic) shoots in the crown, allowing similar irradiance levels to all leaf surfaces. The production of plagiotropic shoots by the deciduous species (A. coriacea) is a strategy that enables its use of incident sunlight early in the morning and preventing excessive water loss or excessive irradiance. Hymenaea stigonocarpa (an evergreen), by contrast, had orthotropic shoots and uses intense self-shading as a strategy to avoid excessive irradiance, especially at midday. Differences in crown architectures between evergreen and deciduous species of cerrado sensu stricto can therefore be viewed as adaptations to the environmental light regime.

Morphophysiological characteristics of (Coffea arabica L.) in different arrangements: lessons from a 3d virtual plant approach

3D vegetative structural and functional models are useful in simulations of ecophysiological and biophysical processes. The main objective of this study was to model a 3D Coffea arabica L. structure. The specific aim was to use 3D mock-ups for analysis of vertical leaf and berry distribution and light interception in coffee crops cultivated in different planting densities and arrangements. The mock-ups were built after abstraction and codification by VPlants, based on morphological measurements (orthotropic shoot height and its number of internodes; positions of second to fourth branching order plagiotropics; internode number on first to fourth branching order plagiotropics number of leaf pairs), and several hypotheses. Mock-ups were visualized in PlantGLViewer, while Silhouette to Total Area Ratio (STAR), leaf area (LA) and berry distribution were processed in VegeSTAR. Planting arrangements influenced STAR when the plants were grown in a low density (6,000 plants ha-1). Plant density had a significant effect on the number of berries in square arrangements. The higher layers were occupied by first order foliage and few berries, allowing more light to pass to the lower canopy layers. Berries were abundant in the first and second order plagiotropic branches, in the highest and middle layers. Light distribution was more uniform than leaf area distribution, indicative of a disperse foliage and efficient space occupation. STAR correlated strongly with berry number, especially in the upper, less shaded canopy layers, where flower induction was the most intense.

Alterations of the structure of <em>Posidonia oceanica</em> beds due to the introduced alga <em>Caulerpa taxifolia</em>

The impact of Caulerpa taxifolia on the structure of shallow Posidonia oceanica beds was studied in permanent quadrats from 1995 to 2005 at the invaded site of Cap Martin and the control site of Cap d’Antibes (French Riviera, France). The cover of C. taxifolia , shoot density, number of orthotropic and plagiotropic shoots and proportion of ramifications of P. oceanica were measured yearly. The cover of C. taxifolia in the invaded zone rapidly reached a maximum of infestation in 2000 with 93% of the quadrats covered by the alga. In 2001 an unexplained phenomenon led to a sharp decrease in the infestation and in the following years the colonisation remained low. Within the 10 years of the study, P. oceanica did not disappear from the permanent quadrats, but we observed a drastic change in the structure of the meadow invaded by C. taxifolia . Between 1999 and 2000 a decrease in the shoot density observed at both sites was probably related to the warm temperature event recorded in 1999 (from 636 to 143 shoots m -2 at the invaded site and from 488 to 277 at the control site). At the invaded site, the seagrass never recovered its initial density even after a sharp decrease in C. taxifolia . The orthotropic/plagiotropic shoot ratio was strongly modified at the invaded site, where plagiotropic shoots became dominant because of an increase in their ramification.

Influence of shoot inclination on irradiance and morphophysiological leaf traits along shoots in cerrado trees with distinct leaf deciduousness

This study investigated the relationship among shoot inclination, irradiance and morphophysiological traits of basal (BL) and distal (DL) leaves in six cerrado trees with distinct leaf deciduousness. Deciduous species showed plagiotropic shoots (44º) and larger leaf area than semideciduous and evergreen species, which showed orthotropic shoots (56º and 63º, respectively). Despite larger leaf area, irradiance at shoot base in deciduous was around 85% in relation to full irradiance, while in semideciduous and evergreen only 23% of irradiance reached on BL. Likewise, maximum net photosynthesis (Pnmax) was similar between BL and DL in deciduous. Contrastingly, semideciduous and evergreen showed significant decreasing of Pnmax in BL. Plagiotropic shoots of deciduous allow similar irradiance along shoots, resulting in similar Pnmax along shoot. On the other hand, orthotropic shoots of semideciduous and evergreen resulted in shading and decreasing of Pnmax on BL. However, considering BL and DL together, there was not significant difference of leaf-life-span or Pnmax among deciduous, semideciduous and evergreen. Therefore, shoot inclination and shading among leaves on same shoot should be significant influencing leaf morphophysiological traits along shoots in cerrado trees. On the other hand, similar leaf-life-span among phenological groups resulted in absence of Pnmax differences when BL and DL were considered together.