Performance of geophytes on extensive green roofs in the United Kingdom

Dwarf geophytes have great potential for use on extensive green roofs because they often come from arid areas and can survive dry and hot summer in a dormant state. However, there has been little research regarding geophytes on green roofs. This experiment was conducted to study the performance of 26 species of geophytes on a green roof during 2005–2006 in Sheffield, UK. The geophytes were grown at two substrate depths (5 cm and 10 cm) of substrate on a green roof without irrigation. To investigate the susceptibility of geophytes to competition from a covering of permanent plants, the geophytes were grown with or without a surface vegetation layer of Sedum album. Overall, the growth, survival rate, regeneration and flowering of geophytes were more successful at a substrate depth of 10 cm than of 5 cm, probably because of improved moisture retention, fewer temperature fluctuations and the protection from digging by animals. The flowering period was limited to spring, therefore, it is recommended to combine with other plant species such as covering plants. Geophyte species did not compete much with S. album and Sedum cover had no significant effects on the growth, survival rate, regeneration and flowering of geophytes in most species. Iris bucharica, Muscari azureum, Tulipa clusiana var. chrysantha, Tulipa humilis, Tulipa tarda and Tulipa turkestanica had good performance at the substrate depth of 5 cm. In addition, Narcissus cyclamineus ‘February gold’ and Tulipa urumiensis exhibited a successful performance at the substrate depth of 10 cm.     

Rooftop temperature reduction from unirrigated modular green roofs in south-central Texas

Modular green roofs were investigated to better understand surface and membrane level temperature expectations of unirrigated green roofs during hot summer conditions in south-central Texas. We used three succulent monocultures, Sedum kamtschaticum, Delosperma cooperi, Talinum calycinum syn. Phemeranthus calycinus and one unplanted control module, each replicated 3 times. Media surface and below media temperatures were monitored, as well as soil water content and general weather conditions (RH, air temperature). Temperatures at the surface and below the media surface were compared with temperatures of a standard roof surface. We found that diurnal surface temperature reductions were very stable throughout the summer. Much larger temperature reductions were achieved below the modules than at the soil surface. Temperature reductions at the soil surface were predominantly driven by soil volumetric water content (VWC) and, to a lesser degree, air temperature while species and percent cover had small modifying effects through interactions with VWC and air temperature. Temperature reductions below the modules were driven by surface soil temperature, while increasing VWC led to a small decrease in temperature reductions at the membrane level. Mean daily temperature reductions achieved were 18.0 °C at the soil surface and 27.5 °C below the module, thus demonstrating that unirrigated, succulent-based green roofs can provide significant rooftop temperature reductions during hot, dry summer conditions.     

An index to identify suitable species in urban green areas

This paper presents a method that allows sorting of tree and shrub species according to their suitability for planting in urban areas of Madrid (Spain). Suitability was determined from a weighted index for each species according to the severity of damage (biotic, abiotic, and anthropogenic; stem wounds are the main problem in trees, while dead plants are the most important problem in shrubs, seasonal flowers, and vines) and to risk, which was obtained from a new measure, observed Species per Green Area per Year (SAYs). The greater the number of damaged SAYs, the less suitable a species was considered for outdoor planting. For this purpose, 49 green areas corresponding to 141 ha were sampled during 2005–2008. The tree species least recommended for planting include Robinia pseudoacacia, Ulmus sp., Acer negundo, Platanus × hybrid, Populus Boolleana. The shrubs least recommended for planting are Nerium oleander, Cotoneaster sp., Euonymus europaeus, Pyracantha coccinea, and Pittosporum tobira. Statistical analysis reveals that native species have a lower percentage of damaged SAYs than non-native species.     

Relationships between bole and crown size for young urban trees in the northeastern USA

Knowledge of allometric equations can enable urban forest managers to meet desired economic, social, and ecological goals. However, there remains limited regional data on young tree growth within the urban landscape. The objective of this study is to address this research gap and examine interactions between age, bole size and crown dimensions of young urban trees in New Haven, CT, USA to identify allometric relationships and generate predictive growth equations useful for the region. This study examines the 10 most common species from a census of 1474 community planted trees (ages 4–16). Regressions were applied to relate diameter at breast height (dbh), age (years since transplanting), tree height, crown diameter and crown volume. Across all ten species each allometric relationship was statistically (p < 0.001) significant at an α-level of 0.05. Consistently, shade trees demonstrated stronger relationships than ornamental trees. Crown diameter and dbh displayed the strongest fit with eight of the ten species having an R² > 0.70. Crown volume exhibited a good fit for each of the shade tree species (R² > 0.85), while the coefficients of determination for the ornamentals varied (0.38 < R² < 0.73). In the model predicting height from dbh, ornamentals displayed the lowest R² (0.33 < R² < 0.55) while shade trees represented a much better fit (R² > 0.66). Allometric relationships can be used to develop spacing guidelines for commonly planted urban trees. These correlations will better equip forest managers to predict the growth of urban trees, thereby improving the management and maintenance of New England's urban forests.     

The temperature and photoperiod regulation of flowering and runnering in the strawberries,Fragaria chiloensis,F. virginiana,and F. x ananassa

The temperature and photoperiod interactions of a number of elite genotypes of Fragaria virginiana, F. x ananassa, and F. chiloensis were studied in a series of growth chamber experiments. Several parameters were evaluated including: (1) the critical day-length (CDL) for flowering of short day (SD) genotypes under 8, 9, 10, and 11 h days at 18 °C, (2) the floral and runnering response of single and multiple cropping genotypes under 8 and 16 h days at 18 °C, and (3) the effect of temperature on flower bud formation in day-neutral (DN) genotypes held at 18, 22, 26, and 30 °C under 12 h day-lengths. The same number of flowers were initiated under 15 and 30 day induction periods, regardless of photoperiod. Frederick 9, LH 50-4 and RH 30 (F. virginiana), ‘Aromas’ and ‘Tribute’ (F. x ananassa) and CFRA 0368 of F. chiloensis flowered under both long days (LDs) and SDs; while Eagle-14 (F. virginiana), ‘Fort Laramie’ and ‘Quinalt’ (F. x ananassa) flowered only under long days. While those genotypes that flowered under both LD and SD can be considered day-neutral, they varied in the degree of floral response to the two photoperiods. CFRA 0368 and Frederick 9 produced the same number of flowers under both LDs and SDs, while ‘Aromas’ and ‘Tribute’ had more flowers under LDs and RH 30 had more under SDs. Of the DN genotypes, LH 50-4 and RH 30 were the only ones that produced runners under SDs. Flowering in ‘Fort Laramie’ was least affected of any genotype by high temperature, although its dry weight was negatively impacted. Based on these data, several genotypes show promise as breeding parents: CFRA 0368 and Frederick 9 to equalize flower production under LD and SD conditions, LH 50-4 and RH 30 to produce more freely runnering DNs, and ‘Fort Laramie’ for floral heat tolerance.     

Spatial distribution of saplings in heavily worn urban forests: Implications for regeneration and management

We studied the spatial distribution of saplings in the vicinity of other saplings and mature trees in heavily worn urban forests. Our aim was to identify favorable microsites for saplings to regenerate under different levels of wear. We hypothesized that these safe microsites were situated close to tree trunks that might offer shelter from trampling caused by humans and their pet dogs. The distribution of saplings was explored at 0.1–0.6 m to the nearest sapling and 0.1–2 m to the nearest mature tree. Sorbus aucuparia was the most abundant sapling species, followed by Populus tremula, Betula pubescens and Picea abies. These species all tended to cluster with their conspecific saplings and were generally randomly distributed with respect to mature trees. Saplings of S. aucuparia and P. tremula favored growing close to mature P. abies (already at 0.4–0.8 up to 2 m from the trunk base, respectively) and S. aucuparia trees (at 0.2–0.4 m up to 2 m). Betula sp. and Acer platanoides grew close to Pinus sylvestris trees. Furthermore, with increased levels of wear, saplings clustered more likely together and close to tree trunks. The results are contrary to the gap regeneration hypothesis known from rural unworn forests where saplings often grow in canopy gaps. We suggest the idea of a ‘sheltering group’, i.e. tree groups and thickets of densely growing conspecific saplings, for the maintenance of regeneration of saplings and other vegetation in heavily worn recreational forests. Since urban forestry may strongly affect the existence and spatial location of a high variety of microhabitats, small-scale spatial exploration is needed to identify microsites that offer opportunities for natural regeneration under heavy recreational use. To maintain natural regeneration and the survival of saplings in worn urban forests, we recommend microhabitat-level species-specific forest management.     

Shade response of bermudagrass accessions under different management practices

The development of cultivars ‘TifGrand’ and ‘Celebration’ has shown potential increases in shade tolerance compared to previous industry standards of bermudagrass (Cynodon spp.). Based on the literature, further improvements in shade tolerance can be attained through changes in nitrogen fertility rates, mowing heights, and the application of plant growth regulators. In this study, two South African hybrid (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy) bermudagrass accessions (‘WIN10F’ and ‘STIL03’) and three standard cultivars (Celebration, Tifgrand, and ‘Tifway’) were compared for their ability to persist under 63% shade, two mowing heights, two trinexapac-ethyl (TE) treatments, and two nitrogen fertility rates. The experimental design was a strip-strip-split plot and digital image analysis was used to measure percent turfgrass cover, percent turfgrass spread after cup-cutter removal, and percent turfgrass re-growth after divot formation. Turf quality was measured using the normalized difference vegetation index (NDVI). Differences among genotypes, TE treatments, and mowing heights were observed across all response variables in 2014 and 2015. Differences in fertility treatments were observed in NDVI, percent turfgrass growth, and percent turfgrass recovery within and across years. Significant differences were observed for the interactions between entry by plant growth regulator (PGR) treatments, entry by mowing height, and mowing height by PGR. These results suggest shade management recommendations should be dependent on genotype and site-specific considerations. The development and implementation of specific management plans for certain bermudagrass varieties will contribute to the more widespread use of Cynodon spp. in shaded environments.     

Density,diversity and richness of woody plants in urban green spaces: A case study in Chennai metropolitan city

A tree diversity inventory was carried out in urban green spaces (UGSs) of Chennai metropolitan city, India. This inventory aims to study the diversity, density and richness of trees in UGSs of Chennai. A total of one hundred 10 m × 10 m (total 1 ha) plots were laid to reveal tree diversity and richness of UGSs. Trees with ≥10 cm girths at breast height (gbh) were inventoried. We recorded 45 species in 42 genera and 21 families. Caesalpiniaceae and Fabaceae each with 6 species dominated the study area followed by Arecaceae (3). Density and stand basal area of the present study were 500 stems ha^?1 and 64.16 m², respectively. Most of the inventoried trees were native (31 species) and deciduous (28 species). Fabaceae and Caesalpiniaceae dominated the present study area in terms of stand basal area and density. The Shannon diversity index and evenness of study area were 2.79 and 0.73, respectively. The most important species and families based on species important value index (IVI) and family important value index were Albizia saman, Polyalthia longifolia and Azadirachta indica; Fabaceae, Caesalpiniaceae and Annonaceae respectively. We find Chennai's urban forest is relatively superior to many urban forests of the world in terms of stand basal area and species richness. Results emphasize the importance of enhancement of urban green spaces in Chennai metropolitan city.     

Fragmentation and recreational use affect tree regeneration in urban forests

The aim of this study was to test whether fragmentation or recreational use affect tree regeneration in urban forests, and to quantify these effects. We sampled tree saplings at different distances from edges in spruce (Picea abies) dominated forests, and at different distances from paths that represented different levels of wear. Generalized linear mixed models were used to test our hypotheses. We found that fragmentation favours the regeneration of deciduous trees in urban spruce dominated forests: distance from the edge had a pronounced effect on regeneration, at least up to 80 m into the forests. Saplings of Betula pendula, Populus tremula, other deciduous species and Pinus sylvestris benefited from edge conditions. Betula pubescens saplings, however, were most abundant in the interior and small Sorbus aucuparia saplings at 25–30 m from the edge. All species suffered from the direct effects of trampling, while varying responses of species to distance from the paths were observed up to 6 m, and possibly further. As trees essentially define the living conditions for other forest species, we suggest that the spatial extent of edge and trampling effects should be studied for different types of forests. This knowledge should then be used in urban forestry and planning to define the threshold value that will allow for at least some “intact” interior. We suggest a diameter larger than 160 m to support indigenous species in boreal spruce dominated forests.     

Seasonal changes in CO2 assimilation in leaves of five major Greek olive cultivars

Leaf CO₂ assimilation rate, stomatal conductance (g_s), internal CO₂ concentration (C_i), chlorophyll (a + b) content, specific leaf weight (SLW) and stomatal density were measured during the season, under field conditions, for five major Greek olive cultivars, ‘Koroneiki’, ‘Megaritiki’, ‘Konservolia’, ‘Lianolia Kerkiras’, and ‘Kalamon’, with different morphological and agronomic characteristics and diverse genetic background. Measurements were taken from current-season and 1-year-old leaves, and from fruiting and vegetative shoots, throughout the season, from March to November in years 2001 and 2002. CO₂ assimilation rates showed a substantial seasonal variation, similar in all cultivars, with higher values during spring and autumn and lower values during summer and late autumn. Stomatal conductance (g_s) followed similar trends to leaf CO₂ assimilation rates, increasing from March to July, following by a decrease during August and increasing again in autumn. ‘Koroneiki’ had the highest leaf CO₂ assimilation rate and g_s values (21 μmol m⁻² s⁻¹ and 0.45 mol m⁻² s⁻¹, respectively) while ‘Lianolia Kerkiras’ and ‘Kalamon’ showed the lowest leaf CO₂ assimilation rate and g_s values (13–14 μmol m⁻² s⁻¹ and 0.22 mol m⁻² s⁻¹, respectively). One-year-old leaves had significantly higher leaf CO₂ assimilation rate than current-season leaves from April to June, for all cultivars. From August and then, leaf CO₂ assimilation rate in current-season leaves was higher than in 1-year-old leaves. There were no significant differences in leaf CO₂ assimilation rate between fruiting and vegetative shoots. Total chlorophyll (a + b) content increased with leaf age in current-season leaves. In 1-year-old leaves chlorophyll content increased in spring, then started to decrease and increased slightly again late in the season. Chlorophyll content was higher in 1-year-old leaves than in current-season leaves throughout the season. Total specific leaf weight (SLW) increased throughout the season for all cultivars. Stomatal density in lower leaf surface was lowest for ‘Koroneiki’ (399 mm⁻²) and highest for ‘Megaritiki’ (550 mm⁻²). Our results showed differences in leaf CO₂ assimilation rate among the five different olive cultivars, with a diverse genetic background, ranging from 12 to 21 μmol m⁻² s⁻¹. From the five cultivars examined, ‘Koroneiki’, a drought resistant cultivar, performed better and was able to maintain higher leaf CO₂ assimilation rate, even under high air vapor pressure deficit. All cultivars had a pronounced seasonal variation in leaf CO₂ assimilation rate, affected by date of the year, depending on ambient conditions. The high temperatures and high air vapor pressure deficit occurring during summer caused a reduction in leaf CO₂ assimilation rate in all cultivars. Leaf CO₂ assimilation rate was also affected by leaf age for all cultivars, with old leaves having significantly higher leaf CO₂ assimilation rate than young leaves early in the season.     

Quality assessment of three warm-season turfgrasses growing in different substrate depths on shallow green roof systems

In an effort to increase the accessibility and functionality of shallow green roof systems, the ability of warm-season grasses to provide acceptable growth needs to be further investigated. In the current study, which was conducted during 2011 and 2012, three warm-season grasses (hybrid bermudagrass, Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy ‘MiniVerde’; seashore paspalum, Paspalum vaginatum Swartz ‘Platinum TE’ and zoysiagrass, Zoysia japonica Steud. ‘Zenith’) were established in outdoor lysimeters. The lysimeters were equipped with all necessary green roof layers placed below a coarse-textured substrate that comprised pumice, thermally treated attapulgite clay, peat, compost and zeolite. Half of the lysimeters had a substrate depth of 15 cm, while the other half had a substrate depth of 7.5 cm. Irrigation was applied at crop evapotranspiration (ET_c). Measurements included determination of substrate moisture content, green turf cover (GTC) and leaf stomatal resistance. Significant differences were observed in the values of GTC among the three turfgrass species and the two substrate depths. Zoysiagrass exhibited the best adaptation at the lower depths of shallow green roof systems. At 15 cm substrate depth, zoysiagrass managed to sustain green coverage for the two study periods. In addition, it was the only turfgrass species that managed to perform well at the substrate depth of 7.5 cm. Seashore paspalum exhibited limited green cover at both substrate depths, while hybrid bermudagrass could provide acceptable green coverage only at 15 cm substrate depth.     

Differential tolerance to iron deficiency of citrus rootstocks grown in nutrient solution

We studied the effects of Fe deficiency on physiological parameters of citrus rootstocks grown in nutrient solution. Three 4-week old rootstocks (‘Troyer’ citrange – Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf., Citrus taiwanica Tan. and Shim., and ‘Swingle’ citrumelo – Poncirus trifoliata (L.) Raf. × Citrus paradisi Macf.) were grown in nutrient solutions with 0, 5, 10, 15 and 20 μmol Fe dm⁻³. Calcium carbonate (1 g dm⁻³) was added to all solutions to mimic the natural conditions in calcareous soils. For each rootstock, shoot length, number of leaves, and root and shoot dry weights were measured at the end of experiment. Chlorophyll concentration was estimated using a portable SPAD-502 meter calibrated for each rootstock. The amount of nutrients (P, K, Mg, Ca, Fe, Zn, Mn, and Cu) was determined in shoots. Chlorophyll fluorescence parameters (F₀: basal fluorescence; F_m: maximum fluorescence; F_v = F_m − F₀: variable fluorescence) were measured with a portable fluorimeter. ‘Troyer’ citrange rootstock was the most tolerant to Fe deficiency. These plants grew more and accumulated more chlorophyll and nutrients than the others in the presence of low levels of Fe (10 μmol Fe dm⁻³). ‘Swingle’ citrumelo plants needed 20 μmol Fe dm⁻³ in the nutrient solution to secure adequate growth. ‘Taiwanica’ orange rootstock had an intermediate behaviour, but could be distinguished from ‘Troyer’ citrange based on fluorescence parameters, since there was a variation in the basal fluorescence in the former, whereas in ‘Troyer’ citrange the basal fluorescence was not affected by the supply of Fe.     

Improvement of in vitro micropropagation of Lilium oriental hybrid ‘Casablanca’ by the formation of shoots with abnormally swollen basal plates

Bulb scales of Lilium oriental hybrid ‘Casablanca’ were cultured on MS medium supplemented with cytokinins (kinetin, BA (benzyladenine), TDZ (thidiazuron)). The basal part of bulb scales swelled and formed adventitious shoots with foliage small, leafy bulb scales and abnormally swollen basal plates on the media with cytokinins. Shoots were formed rapidly from the basal parts of bulb scales and became shoot clusters. The medium containing 2.2 μM BA was most favorable in the shoot formation from bulb scales. Cutting shoots into small segments (7–8 mm wide × 12–15 mm length) were cultured on media containing BA and IAA (indole acetic acid) and the segments regenerated many new shoots and formed shoot clusters. The shoot section to shoot cluster cycle method improved adventitious shoot proliferation. The media supplemented with 4.4 μM BA and 5.7 μM IAA. or 8.9 μM BA and 0.6–2.9 μM IAA were effective in allowing the proliferation of shoots from shoot segments under light condition. Sucrose and activated charcoal (AC) improved bulblet growth. Bulblet growth was effectively performed on MS medium containing 60 g/L sucrose. Bulblet growth was also improved by the supplement of AC. The medium with 2.0 g/L AC was most effective for bulblet growth. Normal bulblet growth was stimulated more by the culture of shoots than that of bulb scales. Bulblet weight from shoots reached to an average of over 1100 mg of a bulblet after 3 months in culture on MS medium containing 60 g/L sucrose and 2 g/L AC. Most of the bulblets produced by this method generated stems with several leaves in the green house, after cold treatment at 5 °C for 3 months.     

Methyl jasmonate and CMN-pyrazole applied alone and in combination can cause mature orange abscission

Methyl jasmonate (MJ) and CMN-pyrazole alone and in combination were applied to ‘Hamlin’ and ‘Valencia’ orange trees (Citrus sinensis (L.) Osbeck) in seven separate experiments in the 1998/1999 and 1999/2000 growing seasons to induce abscission of mature fruit for mechanical harvesting. MJ alone significantly reduced fruit detachment force (FDF) of ‘Hamlin’ oranges at concentrations of 10 mM and higher. However, MJ at 20 and 100 mM caused significant defoliation. For ‘Hamlin’ oranges, the most effective treatments were those combining 10 mM MJ and 50 mg l⁻¹ CMN-pyrazole, and 20 mM MJ and 25 mg l⁻¹ CMN-pyrazole. ‘Valencia’ oranges did not respond to 10 mM MJ treatments alone or in combination with CMN-pyrazole, and required MJ at 20 mM in combination with CMN-pyrazole to loosen this late-maturing variety to below 50 N, but excessive defoliation occurred.     

The rootstock effects on plant adaptability,production, fruit quality,and nutrition in the peach (cv. ‘Suncrest’)

In clayey and calcareous soils without a stable irrigation and fertilization system, the type of rootstock can particularly affect both the vegetative and productive properties of ‘Suncrest’ peach (Prunus persica L. Batsch) plants, and the qualitative and nutritional attributes of their fruit. The GF677 rootstock (P. persica × Prunus amygdalus) promoted the highest vegetative development, followed by Julior (Prunus insistitia). The ‘Suncrest’ on Ishtara [(Prunus cerasifera × P. persica) × (P. cerasifera × Prunus salicina)] and Barrier1 (P. persica × Prunus davidiana) had lower, but similar, plant vigour, but the latter rootstock differed in its higher production of pruned wood. The lowest adaptability to these cultivation conditions was observed for ‘Suncrest’ grafted onto Citation (P. persica × P. salicina), which showed the lowest plant development and production. For the plant yield, the ‘Suncrest’ grafted onto GF677, Julior, Ishtara, and Barrier1 were all similar. The fruit yield and both the canopy volume and pruned wood of ‘Suncrest’ grafted onto Ishtara showed a particular relationship, giving the best indices of yield efficiency and plant physiological equilibrium. Moreover, the same rootstock promoted the largest fruit size, while the smallest fruit were found on GF677 rootstock. The fruit from the Citation ‘Suncrest’ ripened 3 days early, while those from Barrier1 had a late fruit ripening. Firmness, soluble solids and the soluble solids to total acidity ratio were only affected slightly by the different rootstocks, while the total acidity of the fruit varied significantly according to rootstock; the fruit from ‘Suncrest’ grafted onto Barrier1, Julior, and Citation had the highest total acidities. The rootstock effects on the nutritional attributes of the fruit were relevant. The ‘Suncrest’ on Julior and GF677, followed by Ishtara, produced fruit with the greatest antioxidant activities and total phenolic contents. The ‘Suncrest’ on Citation and, especially, Barrier1 had reduced nutritional values of the fruit. The variations in antioxidant activities and total phenolic contents showed a positive correlation.     

Analysis of rhythmic growth in holly (Ilex × meserveae) grown in controlled conditions

The influence of 24 h mean air temperature (18.3, 20.6, 23.9 and 25.8 °C) and photosynthetic photon flux (PPF; 0.6, 2.1, 3.7 and 4.7 mol m⁻² d⁻¹) on the growth cycles of vegetative growth in Ilex × meserveae (‘Blue Princess’ S.Y. Hu) was investigated. Plants propagated from top cuttings were grown in greenhouse compartments. The number of unfolded leaves was recorded continuously throughout the experiment. A modified sine function was fitted to collected data and the values for the amplitude and frequency of the growth curves were analysed. The sine function was tested as a method to evaluate the influence of climate on periodically flushing species. Both amplitude and frequency were significantly influenced by air temperature and PPF. The highest frequency of flushing was found at 23.9 °C and 3.7 mol m⁻² d⁻¹. The function resulted generally in a good fit to collected data with R² values above 0.9. Growth curves of all individual plants were categorised with respect to their growth pattern as poor synchronisation within the treatments did not allow analysis of the mean values of the growth curves.     

Urban green spaces for children: A cross-sectional study of associations with distance,physical activity,screen time,general health,and overweight

This study investigates the associations between: (i) urban green spaces (UGSs), children‘s frequency and duration of physical activity (PA), and screen time (TV viewing and computer use) and (ii) children‘s frequency and duration of PA and their general health and overweight. In this study, ‘children’ includes both younger children and adolescents, ages 1–18. Parent-reported data (n = 422) collected though face-to-face personal interviews between April 1 and May 31, 2015 in the city of Aydin, Turkey were used in the study. Multivariate regression analyses were conducted to examine the associations controlling for children’s sex, age, and parents’ monthly income. Stratified analyses were also conducted to determine differences between sex (boys and girls) and age (1–6, 7–12, and 13–18 years old) groups of children. The findings showed that UGS closeness to home was positively associated with higher frequency of children’s PA (b = −.22, p ≤.001) and less screen time (b = .18, p ≤.001). Results also revealed that children‘s frequency of PA positively correlated with children‘s general health (b = .08, p ≤.05), whereas overweight was associated with only age. In stratified analyses, nearest distance to UGSs was positively associated with both boys‘ and girls‘ frequency of PA. On the other hand, longer distance to UGS was associated with longer screen time for only girls. In regard to age groups, nearest distance to UGSs was related to higher frequency of PA for 1–6 and 7–12 years old, while nearest distance to UGS was associated with longer duration of PA and less screen time for only children ages 7–12. In age groups 13–18, no significant differences between variables of UGSs, PA and health were documented. No sex and age groups showed any significant associations with general health and overweight. The findings of this study suggest that distance to UGSs is important for children‘s PA, screen time, and general health. This study implies that UGSs do not seem to be associated with PA and general health in older age groups and needs further investigations.     

Microtuberization of Andean potato species (Solanum spp.) as affected by salinity

The effects of NaCl stress on in vitro tuberization of potato species were studied. Three species of potato (Solanum tuberosum L., S. curtilobum Juz. and Bukasov, and S. juzepczuckii Bukasov) differing in frost resistance were subjected to 0, 25, 50, 75, and 100 mmol l⁻¹ NaCl. Stolon growth and microtuberization were evaluated. The in vitro induced microtubers were characterized with respect to their carbohydrate composition by measuring reducing, non-reducing, total soluble sugars and starch contents. Tuberization and stolon growth, expressed by stolon height or fresh mass, were significantly affected by salinity. The highest saline level (100 mmol l⁻¹ NaCl) completely inhibited tuber development in all species, but not stolon growth. Stolon growth for sensitive species (S. tuberosum) had a significant decrease, whereas both frost tolerant species (S. juzepczuckii and S. curtilobum) tended to increase stolon length with increasing saline levels. Salinity differentially influenced sugar accumulation among potato genotypes. The starch levels in both, S. curtilobum and S. juzepczuckii, remained constant under all salt levels, whereas starch increased in S. tuberosum microtubers.     

The impact of photoperiod and irradiance on flowering of several herbaceous ornamentals

Forty-one herbaceous species were grown under short-days (8 h photoperiod, ambient irradiance averaged 12–13.2 and 6.4–8.3 mol m⁻² day⁻¹ for Experiments I and II, respectively) with or without supplemental high-pressure sodium lighting (+50, 100, or 150 μmol m⁻² s⁻¹); or under long-days delivered using natural day lengths and irradiance with night interruption lighting (2200–0200 h at 2 μmol m⁻² s⁻¹ from incandescent lamps) or under ambient daylight plus supplemental irradiance during the day and as a day extension to 18 h (0800–0200 h) with supplemental high pressure sodium lighting (+50, 100, or 150 μmol m⁻² s⁻¹) to identify the impact of photoperiod and irradiance on flowering of each species. Days to first open flower, leaf number below first flower, and mean dry weight gain per day (MDWG) were measured when the first flower opened. Twenty-seven species were photoperiodic with examples of five photoperiodic response groups represented: obligate short-day (2), facultative short-day (5), obligate long-day (16), facultative long-day (4); 13 were day neutral (no photoperiod response in flowering). One species, Salvia sclarea L., did not flower. A facultative irradiance response was observed with 10 species; 28 species were irradiance indifferent; 2 had delayed flowering as irradiance increased. Photoperiod affected MDWG of 30 species. Increasing irradiance affected MDWG with 14 species. Photoperiod interacted with irradiance to affect MDWG of 11 species. Cobaea scandens had the greatest MDWG (0.40 g day⁻¹) while Amaranthus hybridus had the least MDWG (0.01 g day⁻¹) across photoperiod and irradiance levels.     

Wood hydraulic and mechanical properties induced by low water availability on two ornamental species Photinia × fraseri var. Red Robin and Viburnum opulus L.

Deficit irrigation at the nursery stage induces drought acclimation through the establishment of avoiding mechanisms and hardening processes. In this experiment, we hypothesized that water deficit would affect wood hydraulic conductivity and mechanical properties with effects on the leaf water potentials of two ornamental species, Photinia × fraseri var. Red Robin and Viburnum opulus L.The experiment was conducted in a nursery (Pistoia, Italy) during summer 2011. Individuals were arranged in three plots under three watering regimes. The control plot (C) received an amount of water replacing that lost via evapotranspiration, while two plots were maintained under severe water deficit (SWD = 33% C) and moderate water deficit (MWD = 66% C).Water deficits reduced stem diameter in both species without changing wood density (D). Concerning mechanical properties, stiffness (E) and strength (YS) of Photinia resulted higher in Photinia than in Viburnum, which did not show differences between treatments in either E or YS, whereas in Photinia, E was lower in SWD (P < 0.05) than in C. Photinia was also characterized by higher k without significant differences between treatments while Viburnum showed a lower conductivity and a significant reduction of k_h under SWD (P < 0.05). Despite this, in field conditions the two species had similar behaviour concerning the leaf water status, showing a reduction of Ψ under SWD.A longer acclimation period would probably be necessary to induce major changes in wood mechanical properties, but the similarity of responses on leaf water status in MWD and C might indicate that a reduction to 66% of water need might be sufficient to maintain the level of turgor necessary for plant physiological functioning.