Growth of lulo (Solanum quitoense Lam.) plants affected by salinity and substrate

The effects of 0, 30 and 60 mM NaCl and substrates (red peat, sand or 3:1:1 [w/w] mixture of peat, sand, or soil) on vegetative growth of lulo, an Andean fruit species, during 12 weeks were studied. The experiment was carried out by using 2000 cm³ of polypropylene plastic pots under greenhouse conditions. Plant height, number of leaves and nodes, leaf area, total plant dry matter (DM), and shoot/root ratio were evaluated. With the increase of salt concentration, the plant height, the number of leaves and nodes, the leaf areas and plant dry mass DM decreased, whereas shoot/root ratio increased. Sand grown lulo plants were most affected by salinity and presented total mortality at 60 mM NaCl. On the other hand, plants held either in peat or in substrate mixture developed larger height, greater leaf and node numbers, higher leaf area and dry matter content. Shoot/root ratio in control (soil) and sand-grown plants (30 mM NaCl) was lower.

Correlated genetic effects on reproduction define a domestication syndrome in a forest tree.

Compared to natural selection, domestication implies a dramatic change in traits linked to fitness. A number of traits conferring fitness in the wild might be detrimental under domestication, and domesticated species typically differ from their ancestors in a set of traits known as the domestication syndrome. Specifically, trade-offs between growth and reproduction are well established across the tree of life. According to allocation theory, selection for growth rate is expected to indirectly alter life-history reproductive traits, diverting resources from reproduction to growth. Here we tested this hypothesis by examining the genetic change and correlated responses of reproductive traits as a result of selection for timber yield in the tree Pinus pinaster. Phenotypic selection was carried out in a natural population, and progenies from selected trees were compared with those of control trees in a common garden experiment. According to expectations, we detected a genetic change in important life-history traits due to selection. Specifically, threshold sizes for reproduction were much higher and reproductive investment relative to size significantly lower in the selected progenies just after a single artificial selection event. Our study helps to define the domestication syndrome in exploited forest trees and shows that changes affecting developmental pathways are relevant in domestication processes of long-lived plants.

Growth variability of Scots pine (Pinus sylvestris) along a West-East gradient across northern Fennoscandia: a dendroclimatic approach

We performed a spatiotemporal analysis of a network of 21 Scots pine (Pinus sylvestris) ring-width chronologies in northern Fennoscandia by means of chronology statistics and multivariate analyses. Chronologies are located on both sides (western and eastern) of the Scandes Mountains (67°N-70°N, 15°E-29°E). Growth relationships with temperature, precipitation, and North Atlantic Oscillation (NAO) indices were calculated for the period 1880-1991. We also assessed their temporal stability. Current July temperature and, to a lesser degree, May precipitation are the main growth limiting factors in the whole area of study. However, Principal Component Analysis (PCA) and mean interseries correlation revealed differences in radial growth between both sides of the Scandes Mountains, attributed to the Oceanic-Continental climatic gradient in the area. The gradient signal is temporally variable and has strengthened during the second half of the 20th century. Northern Fennoscandia Scots pine growth is positively related to early winter NAO indices previous to the growth season and to late spring NAO. NAO/growth relationships are unstable and have dropped in the second half of the 20th century. Moreover, they are noncontinuous through the range of NAO values: for early winter, only positive NAO indices enhance tree growth in the next growing season, while negative NAO does not. For spring, only negative NAO is correlated with radial growth.

Residual effect of growth regulators in etiolation and regeneration of in vitro pineapple plants

This work aimed to evaluate the influence of naphthaleneacetic acid (NAA) and gibberellic acid (GA3) plant regulators in in vitro etiolation and subsequent regeneration of the PE x SC-60 pineapple hybrid. Nodal segments of in vitro plants with approximately 5-7 cm height were incubated in basic MS culture medium supplemented with 0.0; 0.5 and 1.0 mg L-1 of naphthaleneacetic acid (NAA) in combination with gibberellic acid (GA3) in concentrations of 0.0; 0.5 and 1.0 mg L-1, and maintained at 27 ºC under dark condition. Evaluations were carried out at 90 and 180 days after incubation period. The best results for length of etiolated stems were obtained with 1.0 mg L-1 of NAA. In the experiment followed by the regeneration, stems with 3 cm from the etiolation treatment, were cultivated in proliferation medium and the number of regenerated plants per treatment was evaluated at 60 days of cultivation. The treatment that promoted the best etiolation of plants also promoted the worst regeneration rates, demonstrating the residual effect of the auxin used in the previous step in the regeneration of plants of the pineapple hybrid evaluated.

Germplasm characterization of three jabuticaba tree species

The purpose of this study was to characterize cultivated genotypes of three jabuticaba species (Plinia cauliflora, P. trunciflora, and P. jaboticaba). Phenology and fruit growth, as well as leaf, flower and fruit traits were evaluated. Variability in all traits was observed among genotypes of the three jabuticaba species. The trait peduncle size is indicated for differentiation of the three species under study. The leaf and fruit sizes of the genotypes P. trunciflora 3, P. trunciflora 4, P. trunciflora 5 and P. jaboticaba 1 differ from those described in the literature for these species, indicating the formation of ecotypes. Jabuticaba fruit skin contains high anthocyanin and flavonoid concentrations, with potential use in food and pharmaceutical industries.

Natural history of growth hormone deficiency in a pediatric cohort.

BACKGROUND/AIMS: Controversies still exist regarding the evaluation of growth hormone deficiency (GHD) in childhood at the end of growth. The aim of this study was to describe the natural history of GHD in a pediatric cohort. METHODS: This is a retrospective study of a cohort of pediatric patients with GHD. Cases of acquired GHD were excluded. Univariate logistic regression was used to identify predictors of GHD persisting into adulthood. RESULTS: Among 63 identified patients, 47 (75%) had partial GHD at diagnosis, while 16 (25%) had complete GHD, including 5 with multiple pituitary hormone deficiencies. At final height, 50 patients underwent repeat stimulation testing; 28 (56%) recovered and 22 (44%) remained growth hormone (GH) deficient. Predictors of persisting GHD were: complete GHD at diagnosis (OR 10.1, 95% CI 2.4-42.1), pituitary stalk defect or ectopic pituitary gland on magnetic resonance imaging (OR 6.5, 95% CI 1.1-37.1), greater height gain during GH treatment (OR 1.8, 95% CI 1.0-3.3), and IGF-1 level <-2 standard deviation scores (SDS) following treatment cessation (OR 19.3, 95% CI 3.6-103.1). In the multivariate analysis, only IGF-1 level <-2 SDS (OR 13.3, 95% CI 2.3-77.3) and complete GHD (OR 6.3, 95% CI 1.2-32.8) were associated with the outcome. CONCLUSION: At final height, 56% of adolescents with GHD had recovered. Complete GHD at diagnosis, low IGF-1 levels following retesting, and pituitary malformation were strong predictors of persistence of GHD. © 2015 S. Karger AG, Basel.

Effect of gibberellic acid and the biostimulant stimulate® on the initial growth of tamarind

Plant growth regulators and biostimulants have been used as an agronomic technique to optimize the production of seedlings in various crops. This study aimed to evaluate the influence of gibberellic acid and the biostimulant Stimulate® on the initial growth of tamarind (Tamarindus indica L.). The experiments were conducted in a nursery with 50% shading, in a randomized block design with five replications and five plants per plot. Thirty eight days after sowing, the leaves were sprayed seven times a day with 0.0 (control), 0.8, 1.6, 2.4 and 3.2 mL of gibberellic acid L-1 aqueous solution and with 0.0 (control), 6.0,12.0, 18.0, and 24.0 mL Stimulate® L-1 aqueous solution. Stem diameter (SD), plant height (PH), longest root length (LRL), shoot dry mass (SDM), root dry mass (RDM) and RDM:SDM ratio were evaluated ninety days after sowing. Variance and regression analysis showed that GA3 at 4% promoted plant growth (height), but had no significant effect on stem diameter, longest root length, shoot and root dry mass and the RDM:SDM ratio. On the other hand, all concentrations of Stimulate® significantly increased plant height and shoot and root dry mass of tamarind seedlings.

Spatiotemporal variability in radial growth of trees in the Central Pyrenees: climatic and site influences.

To understand how tree growth has responded to recent climate warming, an understanding of the tree-climate-site complex is necessary. To achieve this, radial growth variability among 204 trees established before 1850 was studied in relation to both climatic and site factors. Seventeen forest stands were sampled in the Spanish Central Pyrenees. Three species were studied: Pinus uncinata, Abies alba, and Pinus sylvestris. For each tree, a ring-width residual chronology was built. All trees cross-dated well, indicating a common influence of the regional climate. For the 1952-1993 period, the radial growth of all species, especially P. uncinata, was positively correlated with warm Novembers during the year before ring formation and warm Mays of the year the annual ring formed. Differences in species-stand elevation modulated the growth-climate associations. Radial growth in P. uncinata at high elevation sites was reduced when May temperatures were colder and May precipitation more abundant. In the 20th century, two contrasting periods in radial growth were observed: one (1900-1949) with low frequency of narrow and wide rings, low mean annual sensitivity, and low common growth variation; and another (1950-1994) with the reverse characteristics. The increased variability in radial growth since the 1950s was observed for all species and sites, which suggests a climatic cause. The low shared variance among tree chronologies during the first half of the 20th century may result from a"relaxation" of the elevation gradient, allowing local site conditions to dominate macroclimatic influence. These temporal trends may be related to the recently reported increase of climatic variability and warmer conditions. This study emphasizes the need to carefully assess the relationships between radial growth and site conditions along ecological gradients to improve dendroclimatic reconstructions.

Papaya seedlings growth using a low-cost, automatic watering controller

The study assessed growth and physiological parameters of 'Sunrise Golden' and 'Tainung 01' papaya seedlings grown in 280mL plastic tubes and watered using a low-cost automatic irrigation system adjusted to operate at substrate water tension for starting irrigation (STI) of 3.0, 6.0 or 9.0 kPa. The water depths applied by the dripping system and drainage were monitored during germination and seedling growth. Germination, emergence velocity index (EVI), leaf area, plant height, shoot and root dry weight, stomatal conductance, relative water content (RWC) and relative chlorophyll content (RCC) were evaluated. Soil nutrient levels were determined by electrical conductivity (EC). Water use efficiency (WUE) corresponded to the ratio of plant dry mass to depth of water applied. STI settings did not affect papaya germination or EVI. System configuration to 3.0 and 6.0 kPa STI exhibited the highest drainage and lowest EC and RCC, indicating soil nutrient loss and plant nutrient deficiency. Drainage was greater in tubes planted with the 'Tainung 01' variety, which developed smaller root systems and lower stomatal conductance than 'Sunrise Golden' seedlings. The highest values for shoot dry weight and WEU were obtained at 6.0 kPa STI for 'Sunrise Golden' (0.62 g and 0.69 g L-1) and at 9.0 kPa in 'Tainung 01' (0.35 g and 0.82 g L-1). RWC at 9.0 kPa STI was lower than at 3.0 kPa in both varieties. The results indicate that the low-cost technology developed for irrigation automation is promising. Even so, new studies are needed to evaluate low-flow irrigation systems as well as the nutrient and water needs of different papaya varieties.

Growth and production of irrigated vitória pineapple grown in semi-arid conditions

This study aimed to evaluate the growth characteristics of irrigated Vitória pineapple plants grown in semi-arid conditions and determine its developmental stages based on those characteristics. It was used a randomized block design with four replicates. The experimental treatments were: plant harvest at 270, 330, 390, 450, 510, 570, 690, 750, and 810 days after planting (DAP). The following variables were determined: plant height, stem diameter, D-leaf length, D-leaf fresh and dry mass, biomass production of plants and plant parts (organs), and vegetative biomass. Five phenological stages are proposed based on vegetative biomass production: < 20% biomass production (V1); 21-40% (V2); 41-60% (V3); 61-80% (V4); and > 80% (V5). The maximum growth rate for plant height, D-leaf length, and stem diameter was observed at the end of the phenological stage V1 (390-411 DAP), and at the end of stage V5 these plant traits had average values of 106, 82, and 7 cm, respectively. The maximum biomass accumulation rates were observed at stages V4 and V5, resulting in a final fruit yield and total fresh biomass of 72 t ha-1 and 326 t ha-1, respectively. Finally, we estimated that 80% of the accumulated biomass may remain in the field after fruit and slip harvest, and could be incorporated as plant residue into the soil.

Disentangling the formation of contrasting tree line physiognomies combining model selection and Bayesian parameterization for simulation models.

Alpine tree-line ecotones are characterized by marked changes at small spatial scales that may result in a variety of physiognomies. A set of alternative individual-based models was tested with data from four contrasting Pinus uncinata ecotones in the central Spanish Pyrenees to reveal the minimal subset of processes required for tree-line formation. A Bayesian approach combined with Markov chain Monte Carlo methods was employed to obtain the posterior distribution of model parameters, allowing the use of model selection procedures. The main features of real tree lines emerged only in models considering nonlinear responses in individual rates of growth or mortality with respect to the altitudinal gradient. Variation in tree-line physiognomy reflected mainly changes in the relative importance of these nonlinear responses, while other processes, such as dispersal limitation and facilitation, played a secondary role. Different nonlinear responses also determined the presence or absence of krummholz, in agreement with recent findings highlighting a different response of diffuse and abrupt or krummholz tree lines to climate change. The method presented here can be widely applied in individual-based simulation models and will turn model selection and evaluation in this type of models into a more transparent, effective, and efficient exercise.

GROWTH AND NUTRITION OF CACAO SEEDLINGS INFLUENCED BY ZINC APLICATION IN SOIL

ABSTRACT Levels of Zn in tropical soils profoundly influences growth and nutrition of tree crops. Research was undertaken to assess the effect of soil Zn on growth and nutrition of clonal cacao tree seedlings of PH 16. Three acidic Oxisol soils differing in texture were used with nine doses of Zn (0, 1, 2, 4, 8, 16, 32, 48, and 64 mg dm-3). Rooted clonal seedlings were grown in plastic pot with 11 dm-3 of the soils at varying Zn levels for 240 days. At harvest growth (dry matter mass of leaves, stems, shoots, roots, and total) and nutrient concentrations were determined. The clonal cacao seedlings showed differences for production of dry matter mass and foliar nutrient concentrations for P, K, Ca, Mg, Mn, Fe, Zn, and Cu. There was Zn toxicity in all soils.

Health-Related Quality of Life of Young Adults Treated with Recombinant Human Growth Hormone during Childhood.

BACKGROUND: Since recombinant human growth hormone (rhGH) became available in 1985, the spectrum of indications has broadened and the number of treated patients increased. However, long-term health-related quality of life (HRQoL) after childhood rhGH treatment has rarely been documented. We assessed HRQoL and its determinants in young adults treated with rhGH during childhood. METHODOLOGY/PRINCIPAL FINDINGS: For this study, we retrospectively identified former rhGH patients in 11 centers of paediatric endocrinology, including university hospitals and private practices. We sent a questionnaire to all patients treated with rhGH for any diagnosis, who were older than 18 years, and who resided in Switzerland at time of the survey. Three hundred participants (58% of 514 eligible) returned the questionnaire. Mean age was 23 years; 56% were women; 43% had isolated growth hormone deficiency, or idiopathic short stature; 43% had associated diseases or syndromes, and 14% had growth hormone deficiency after childhood cancer. Swiss siblings of childhood cancer survivors and the German norm population served as comparison groups. HRQoL was assessed using the Short Form-36. We found that the Physical Component Summary of healthy patients with isolated growth hormone deficiency or idiopathic short stature resembled that of the control group (53.8 vs. 54.9). Patients with associated diseases or syndromes scored slightly lower (52.5), and former cancer patients scored lowest (42.6). The Mental Component Summary was similar for all groups. Lower Physical Component Summary was associated with lower educational level (coeff. -1.9). Final height was not associated with HRQoL. CONCLUSIONS/SIGNIFICANCE: In conclusion, HRQoL after treatment with rhGH in childhood depended mainly on the underlying indication for rhGH treatment. Patients with isolated growth hormone deficiency/idiopathic short stature or patients with associated diseases or syndromes had HRQoL comparable to peers. Patients with growth hormone deficiency after childhood cancer were at high risk for lower HRQoL. This reflects the general impaired health of this vulnerable group, which needs long-term follow-up.

Evolutionary Ecology of Mountain Birch in Subarctic Stress Gradients: Interplay of Biotic and Abiotic Factors in Plant-Plant Interactions and Evolutionary Processes

In nature, variation for example in herbivory, wind exposure, moisture and pollution impact often creates variation in physiological stress and plant productivity. This variation is seldom clear-cut, but rather results in clines of decreasing growth and productivity towards the high-stress end. These clines of unidirectionally changing stress are generally known as ‘stress gradients’. Through its effect on plant performance, stress has the capacity to fundamentally alter the ecological relationships between individuals, and through variation in survival and reproduction it also causes evolutionary change, i.e. local adaptations to stress and eventually speciation. In certain conditions local adaptations to environmental stress have been documented in a matter of just a few generations. In plant-plant interactions, intensities of both negative interactions (competition) and positive ones (facilitation) are expected to vary along stress gradients. The stress-gradient hypothesis (SGH) suggests that net facilitation will be strongest in conditions of high biotic and abiotic stress, while a more recent ‘humpback’ model predicts strongest net facilitation at intermediate levels of stress. Plant interactions on stress gradients, however, are affected by a multitude of confounding factors, making studies of facilitation-related theories challenging. Among these factors are plant ontogeny, spatial scale, and local adaptation to stress. The last of these has very rarely been included in facilitation studies, despite the potential co-occurrence of local adaptations and changes in net facilitation in stress gradients. Current theory would predict both competitive effects and facilitative responses to be weakest in populations locally adapted to withstand high abiotic stress. This thesis is based on six experiments, conducted both in greenhouses and in the field in Russia, Norway and Finland, with mountain birch (Betula pubescens subsp. czerepanovii) as the model species. The aims were to study potential local adaptations in multiple stress gradients (both natural and anthropogenic), changes in plant-plant interactions under conditions of varying stress (as predicted by SGH), potential mechanisms behind intraspecific facilitation, and factors confounding plant-plant facilitation, such as spatiotemporal, ontogenetic, and genetic differences. I found rapid evolutionary adaptations (occurring within a time-span of 60 to 70 years) towards heavy-metal resistance around two copper-nickel smelters, a phenomenon that has resulted in a trade-off of decreased performance in pristine conditions. Heavy-metal-adapted individuals had lowered nickel uptake, indicating a possible mechanism behind the detected resistance. Seedlings adapted to heavy-metal toxicity were not co-resistant to others forms of abiotic stress, but showed co-resistance to biotic stress by being consumed to a lesser extent by insect herbivores. Conversely, populations from conditions of high natural stress (wind, drought etc.) showed no local adaptations, despite much longer evolutionary time scales. Due to decreasing emissions, I was unable to test SGH in the pollution gradients. In natural stress gradients, however, plant performance was in accordance with SGH, with the strongest host-seedling facilitation found at the high-stress sites in two different stress gradients. Factors confounding this pattern included (1) plant size / ontogenetic status, with seedling-seedling interactions being competition dominated and host-seedling interactions potentially switching towards competition with seedling growth, and (2) spatial distance, with competition dominating at very short planting distances, and facilitation being strongest at a distance of circa ¼ benefactor height. I found no evidence for changes in facilitation with respect to the evolutionary histories of plant populations. Despite the support for SGH, it may be that the ‘humpback’ model is more relevant when the main stressor is resource-related, while what I studied were the effects of ‘non-resource’ stressors (i.e. heavy-metal pollution and wind). The results have potential practical applications: the utilisation of locally adapted seedlings and plant facilitation may increase the success of future restoration efforts in industrial barrens as well as in other wind-exposed sites. The findings also have implications with regard to the effects of global change in subarctic environments: the documented potential by mountain birch for rapid evolutionary change, together with the general lack of evolutionary ‘dead ends’, due to not (over)specialising to current natural conditions, increase the chances of this crucial forest-forming tree persisting even under the anticipated climate change.