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While increasing numbers of studies report wide variations of leaf silicon (Si) accumulation among plant species, within-species variations of leaf Si accumulation have scarcely been examined for tree species. As in crop plants, environmental factors that affect transpiration rates may influence passive transpiration-dependent transport of Si uptake in trees. Here, we tested a hypothesis that leaf Si accumulation rate should be higher in shoots that receive more light and thus achieve faster growth, using Broussonetia papyrifera, a pioneer tree species with successive leaf production and Si accumulation with leaf age. We marked individual leaves weekly throughout the growing season (June-September), and measured Si concentration and light availability in relation to the chronosequence of leaf age in September. In shoots that continued growing and successively produced leaves throughout the growing season, leaf Si content increased linearly with leaf age. In support of our hypothesis, leaf Si accumulation rate varied widely among shoots with positive correlations with shoot growth and light availability. In conclusion, both leaf age and microenvironment affect within-species variations in leaf Si concentration of this species, a moderate Si accumulator.

Research Highlights: Long-term exposure of paper birch to elevated carbon dioxide (CO2) and ozone (O3) modified metabolite content of over-wintering buds, but no evidence of reduced freezing tolerance was found. Background and Objectives: Atmospheric change may affect the metabolite composition of over-wintering buds and, in turn, impact growth onset and stress tolerance of perennial plant species in spring. Materials and Methods: Low molecular weight compounds of paper birch (Betula papyrifera) buds, including lipophilic, polar and phenolic compounds were analyzed, and freezing tolerance (FT) of the buds was determined prior to bud break after 11 growing seasons exposure of saplings to elevated concentrations of CO2 (target concentration 560 µL L−1) and O3 (target concentration 1.5 × ambient) at the Aspen FACE (Free-Air CO2 and O3 Enrichment) facility. Results: The contents of lipophilic and phenolic compounds (but not polar compounds) were affected by elevated CO2 and elevated O3 in an interactive manner. Elevated O3 reduced the content of lipids and increased that of phenolic compounds under ambient CO2 by reallocating carbon from biosynthesis of terpenoids to that of phenolic acids. In comparison, elevated CO2 had only a minor effect on lipophilic and polar compounds, but it increased the content of phenolic compounds under ambient O3 by increasing the content of phenolic acids, while the content of flavonols was reduced. Conclusions: Based on the freezing test and metabolite data, there was no evidence of altered FT in the over-wintering buds. The impacts of the alterations of bud metabolite contents on the growth and defense responses of birches during early growth in spring need to be uncovered in future experiments.

Field studies of biodegradable polymerized vegetable oil-coated paper mulches were conducted to determine if these could replace non-degradable polyethylene mulches for stopping weeds and promoting growth of cottonwood trees. Tests were conducted over two growing seasons in two adjacent field sites in southeastern Missouri. At the end of the 2001 season, eastern cottonwood trees grown on the coated paper mulches had average heights (4.57–4.66 m, 15.0–15.3 ft), which were not significantly different from the control black polyethylene mulch (4.75 m, 15.6 ft). Tree heights were significantly less for uncoated paper mulch (4.45 m, 14.6 ft) or no mulch (3.90 m, 12.8 ft), presumably due to heavy weed growth around the trees. Uncoated paper mulch was extensively degraded after only about 4 weeks, while the coated paper persisted until the fall. Addition of ZnO to the oil coating delayed the onset of visible degradation, such as the formation of holes and tears, especially near the buried edge and above the drip tube. Similar results were seen for the 2002 study except that weed growth was not extensive so that tree heights for the mulched and bare plots were not significantly different. These results suggest that polymerized vegetable oil-coated paper mulches can function as effective mulches during the first year of tree growth, and thus, eliminate the need to use non-degradable polyethylene mulches.

The effect of different paper mulches and two different biodegradable plastic mulches on the yield of field-grown cucumber (Cucumis sativus L.) was examined. The studies were conducted during two climatically different growing seasons 2011 and 2012 in Southern Finland. All the mulches increased the yield as compared to bare ground. In 2011, cucumbers on all the mulches with a dark upper surface produced higher yields than those on kraft paper alone. In 2012, when the average temperatures were lower than in 2011, there were no differences in yield between different types of mulches. Soil temperatures of the experimental plots were monitored throughout the growing seasons. The mulches with a dark-colored upper surface increased the soil temperature more than the ones with a light-colored upper surface. The soil warming effect of the mulches was greater during early season and diminished when the plants grew larger and their leaves covered most of the mulch surface. There was no need for weed control except in uncovered plots. In conclusion, during both years dark-colored paper mulch was comparable to biodegradable film in yield production and could replace it as a mulch material in cucumber production.

Biodegradable mulches made from kraft paper coated with polymerized (cured) vegetable oils were compared to black polyethylene mulches for promoting the growth of watermelon in northern Florida. Data from three spring growing seasons have been collected. Yields of watermelon planted on paper-soy oil and paper-linseed oil mulches were similar to those obtained for the control polyethylene mulches. This was the case where the paper-oil was cured before field application as well as when the paper-oil was applied to the field wet and curing took place in situ. Paper-oil mulches containing carbon black effectively blocked nutsedge growth, while nutsedge pierced and grew through the black polyethylene mulch. Degradation of the buried tucks were more rapid initially for paper-soy oil than paper-linseed oil mulch, but both lasted long enough to hold the mulch in place until spring harvests (approximately equal to 2.5 months). In conclusion, paper coated with polymerized vegetable oil appears to be an effective substitute for polyethylene mulch for growing watermelon in Florida, although drawbacks include messiness in handling oily paper, slower application speeds, higher initial costs than polyethylene, and variability in rates of curing and degradation depending on soil and weather conditions.

Variations in leaf morphological characteristics have been extensively studied at both interand intraspecific levels although not explicitly on paper birch (Betula papyrifera Marsh). Paper birch populations might have considerable genotypic and leaf morphological variations that have allowed them to inhabit wide environmental gradients. In this study, we analyzed variations in leaf morphological characteristics in 23 paper birch populations collected across Canada and grown in a greenhouse. Furthermore, we examined whether the variations in leaf morphological characteristics observed were related to the climate of the population’s origin. We found significant genotypic differences in all leaf morphological characteristics (p five principal components (PC) explaining 84.74% of the total variance in the original data. PCs accumulated with specific leaf area, petiole and leaf width were positively related to latitudinal, longitudinal, and elevational gradients at the population’s origin. Unpredictably, these PCs were significantly negatively correlated to precipitation and aridity index at the origin. Thus, we analyzed if correlations within leaf morphological characteristics had supported the birch populations to acclimate and produce unpredictable relations with the environment of origin. Our results showed that the populations originated in limited precipitation (during growing season) had large leaf width and petiole size but low leaf hairs on adaxial surface. Thus, all these leaf morphological features provide a basis for the birch to reduce water loss from leaves and balance water use efficiency in reduced precipitation. Furthermore, the leaf characteristics measured may also include phenotypic plasticity of the birch as an acclimation to the environment as in the greenhouse.

In order to identify herbaceous species utilizable for pulp and paper production three perennial species ( Miscanthus sinensis Anderss, Spartium junceum L. and Boehmeria nivea (L.) Gaudich) were tested in the Department of Agronomy of University of Pisa. Screening of these species for biomass and stem production was carried out from 1993 to 1995 in the second, third and fourth growing season. Concurrently, these species were also tested for suitability as pulp materials on a laboratory scale with a `high yield process'. The main physical–mechanical and optical properties of the paper produced from these species were evaluated on 80 g m −2 test sheets as functions of the following parameters: Schopper–Riegler freeness, tensile strength, tearing strength, bursting strength, brightness, opacity, permeability and beating time. All the species demonstrated good agronomic traits making them potentially suitable for cultivation in the Mediterranean area. As far as paper-making characteristics are concerned, the most promising results were obtained with M. sinensis pulps. Pulps from this species, when bleached, could already be used for paper making. Their good properties make these pulps suitable for printing or writing paper production up to 20% besides the possibility of using them for low weight coated papers.

Land application of organic wastes to short rotation woody crops (SRWC) can reduce the environmental impacts associated with waste disposal and enhance the productivity of biomass production systems. Understanding the potential impacts of organic amendments however, requires the examination of changes in soil characteristics and plant productivity. This study was conducted to evaluate the effect of paper sludge and dairy manure on biomass production of shrub willow (Salix dasyclados SV1) and to determine the impacts of these amendments on soil chemical properties. Treatments included urea, dairy manure and paper sludge separately and in combination, and a control. These materials were applied in the summer of 2005 to two fields of SV1 at different stages of growth: An old field with one year old shoots on a 10 year old root system and a young field which was beginning regrowth after being coppiced at the end of its first growing season. Foliar nutrient concentrations and soil chemical properties were analyzed at the end of the second growing season after treatment application to determine plant response to the fertilization regimes and to determine the effects of fertilization on soil characteristics. Fertilization did not increase biomass production in either field. However, application of the N-poor paper sludge did not reduce yield either. In general, fertilization did not influence soil or foliar chemistry, although there were some exceptions. The lack of response observed in this study is probably related to the nutrient status of the site or losses of applied nutrients.

In order to maximize food intake per harvesting effort and minimize energy expenditures required to move between feeding patches in nature, herbivores such as moose (Alces alces L.) generally select large plant shoots when browsing in winter. To determine moose preferences for shoots of different morphologies, an experiment was conducted in northern British Columbia in which shoots from birches cut at different times of the growing season were fed in 2 consecutive years to eight human-habituated moose in cafeteria-style feeding trials. The results indicate that moose preferred smaller winter shoots of birches regardless of when the parent plant was cut and also appeared to reject larger shoots containing sylleptic branches. It is argued that the preferences for smaller shoots by moose detected in these trials should be observable under natural conditions, but are generally only supported by literature from some parts of Scandinavia. The findings underscore the importance that factors such as mout...

The environmental benefits of water table management (WTM), as a method to reduce nitrate pollution, are well known. However, there are few published studies on the effects of WTM on water use efficiency (WUE). This paper highlights the agronomic interest of WTM for increasing WUE of irrigated grain corn production. A field study was conducted in 2001 and 2002 at a large scale WTM research facility in Quebec, Canada. The region experienced periods of drought during the two growing seasons. This study shows that, by keeping the water table at 0.80 m below the soil surface, there were on average 35% increases in grain corn yields, compared to conventional free drainage. The WUEs obtained with WTM (5.1 kg m−3 in 2001 and 7.1 kg m−3 in 2002) indicate that the method is generally more water efficient than conventional sprinkler and furrow irrigation. The WUE of WTM also compares well with that of water conservation methods such as alternate furrow irrigation and deficit sprinkler irrigation. Moreover, WTM requires low inputs in terms of equipment, energy, and labour, because it makes use of existing subsurface drainage systems, which are widespread in Eastern Canada due to the region's soils and climate, and because of its design, which does not necessitate high-pressure pumps and allows for automated management. Hence, WTM appears to be an interesting alternative to conventional irrigation methods due to its combined environmental and agronomical benefits.

We examined height growth patterns of paper birch and Douglas-fir in two different biogeoclimatic zones (the Coast Western Hemlock and the Interior Cedar and Hemlock) in British Columbia. Stem analysis data from 20 paper birch and 20 Douglas-fir showed that height of Douglas-fir exceeded height of paper birch at about 50 years after stand establishment at the interior site. In comparison, Douglas-fir exceeded paper birch in height at about 25 years at the coastal site. Difference in height growth patterns of the two species at the two sites contributed to the explanation of differences in the distribution and persistence of paper birch between these two biogeoclimatic zones. This means that the interspecies competitive relationships are different in the two biogeoclimatic zones. However, other differences between the two different biogeoclimatic zones, such as differences in growing degree day, length of growing season, frequencies of natural fire, insect outbreak and forest diseases, may also be important in determining why paper birch is more abundant in the Interior Cedar-Hemlock zone but not in the Coastal Western Hemlock zone.

A critical component of assessing the impacts of climate change on forest ecosystems involves understanding associated changes in the biogeochemical cycling of elements. Evidence from research on northeastern North American forests shows that direct effects of climate change will evoke changes in biogeochemical cycling by altering plant physiology, forest productivity, and soil physical, chemical, and biological processes. Indirect effects, largely mediated by changes in species composition, length of growing season, and hydrology, will also be important. The case study presented here uses the quantitative biogeochemical model PnET-BGC to test assumptions about the direct and indirect effects of climate change on a northern hardwood forest ecosystem. Modeling results indicate an overall increase in net primary production due to a longer growing season, an increase in NO3–leaching due to large increases in net mineralization and nitrification, and slight declines in mineral weathering due to a reduction in soil moisture. Future research should focus on uncertainties, including the effects of (1) multiple simultaneous interactions of stressors (e.g., climate change, ozone, acidic deposition); (2) long-term atmospheric CO2enrichment on vegetation; (3) changes in forest species composition; (4) extreme climatic events and other disturbances (e.g., ice storms, fire, invasive species); and (5) feedback mechanisms that increase or decrease change.

1. In minesoil reclamation, the establishment of a sustainable plant cover requires the improvement of limiting conditions and the re-initiation of carbon (C) and nutrient cycling. 2. The approach used in this study for reclaiming an abandoned sandpit in Quebec, Canada, was based on a heavy organic amendment as an attempt to accelerate the reconstruction of a functional ecosystem. 3. The one-time intervention consisted of incorporating paper de-inking sludge into soil at two rates (0 and 105 dry t ha–1), supplemented with nitrogen (N) at three rates (3, 6 and 9 g kg–1 sludge) and phosphorus (P) at two rates (0·5 and 1·0 g kg–1 sludge) followed by seeding (mid-summer) of Agropyron elongatum (Host) Beauv. (tall wheatgrass). 4. Standing biomass increased in the presence of sludge after both the first and second full growing seasons. High N application rates further increased yield, more importantly in the second season. The high P rate improved grass establishment in all cases. Ground cover increased with time and doubled in the presence of sludge whereas it declined in the absence of sludge. Phosphorus and N uptake was improved consistently in the presence of sludge. 5. Sludge application resulted in improved water retention and cation exchange capacities, and an increase in pH and bulk density of sandpit minesoil, all of which may have accounted for the significant improvement in plant responses. Levels of soil C and N suggest that this reconstructed system is approaching sustainability. 6. Adequate N and P supplements will accentuate the positive influence of sludge on revegetation.

Five container substrates—3 pine bark (PB) : 1 peat (PT) : 1 sand (SD), 3 PB : 1 recycled paper (RP) : 1 SD, 2 PB : 2 RP : 1 SD, 3 vermiculite (VM) : 1 RP : 1 SD, and 2VM : 2 RP : 1 SD—were used to grow rose-of-sharon (Hibiscus syracus L. `Double Purple') and forsythia (Forsythia ×intermedia Zab. `Lynwood Gold') for 4.5 months. The control substrate (3 PB:1 PT:1 SD) had higher concentrations of NH4* in leachate than other substrates at each of four sample times during the growing season except 4 Aug. Leaf number and leaf area per plant and height of rose-of-sharon were greater and the leaf area per leaf was smaller in all substrates containing recycled paper than in substrates without recycled paper. Forsythia plants had greater stem and root dry weights and were taller in substrata without recycled paper than plants in substrates with recycled paper. Processed recycled paper is a possible component for container nursery plant production, but further testing on a large number of species is needed before widespread implementation.

Predicting ozone-induced reduction of carbon sequestration of forests under elevated tropospheric ozone concentrations requires robust mechanistic leaf-level models, scaled up to whole tree and stand level. As ozone effects depend on genotype, the ability to predict these effects on forest carbon cycling via competitive response between genotypes will also be required. This study tests a process-based model that predicts the relative effects of ozone on the photosynthetic rate and growth of an ozone-sensitive aspen clone, as a first step in simulating the competitive response of genotypes to atmospheric and climate change. The resulting composite model simulated the relative above ground growth response of ozone-sensitive aspen clone 259 exposed to square wave variation in ozone concentration. This included a greater effect on stem diameter than on stem height, earlier leaf abscission, and reduced stem and leaf dry matter production at the end of the growing season. Further development of the model to reduce predictive uncertainty is discussed.

Combined primary and secondary papermill sludge (PS) is a good source of C and other nutrients for soils devoted to intensive horticultural production. A field study was conducted to evaluate the effect of PS, spring-applied alone or in combination with ammonium nitrate (AN), on the enzymatic activity of a Bedford clay (Humic Gleysol) in the province of Québec, Canada. The experiment was started in 1996 with winter cabbage (Brassica oleracea var. capitata L.) and continued in 1997 and 1998 on the same plots with sweet corn (Zea mays L.). The PS was applied at 0 (control), 8, 16, 32 and 65 Mg ha−1 in 1996 and at 44% of these rates in 1997. No sludge was applied in 1998. Additional treatments consisted of AN applied yearly at 100% of the plant N requirements and a PS and AN combination. Soil arylsulfatase and acid and alkaline phosphatase activities were measured at three different times in each growing season. The PS rate linearly increased the soil acid phosphatase activity in all 3 yr. In contrast, the alkaline phosphatase and arylsulfatase activities were enhanced in 1997 by the 8–16 Mg PS ha−1 treatments, whereas larger amounts of PS showed activity comparable to the control. The second PS application promoted phosphatase activities mostly in fall, but did not sustain arylsulfatase activity. The AN gave lower phosphatase activities than PS, and depressed arylsulfatase. Addition of AN to PS increased only acid phosphatase activity as compared with PS alone or the control. This study indicated that addition of PS improved enzyme activity of this horticultural soil but rates in excess to 32 Mg ha−1 may be detrimental. Key words: Papermill sludge, soil enzyme, cabbage, corn

Widespread paper birch (Betulapapyrifera Marsh.) mortality associated with the activity of the bronze birch borer (Agrilusanxius Gory) was observed across northern Michigan in 1991. This mortality occurred at two study sites on which paper birch growth has been intensively monitored since 1985. Recent warmer than normal growing seasons and lower than normal moisture availability are statistically associated with a reduction in annual diameter growth. On one study site 62% of the paper birch study trees were dead and 13% were visibly declining; on the other study site, although no trees were dead, 25% of the paper birch study trees were visibly declining. Growth reductions since 1985 suggest that the species was under climatic stress, making it more vulnerable to pest–pathogen activity. The evidence of the role of climatic conditions acting as a precursor to decline and mortality on these sites is of serious concern given recent projections of warmer temperatures and lower precipitation for this region by several global-climate models.

The influence of thinning on the net photosynthetic rate (A), specific leaf area (SLA), photosynthetically active radiation (PAR), water use efficiency (WUE) and nitrogen use efficiency (NUE) of 9 to 13-year-old paper birch (Betula papyrifera Marsh.) stands was studied during the 1992 and 1993 growing seasons. Study sites were located in the Interior Cedar Hemlock (ICH) zone within the moist, warm subzone (ICHmw) in the Kamloops Forest Region, British Columbia, Canada. The birch stands were thinned in June 1991, from initial densities which ranged between 11 000 and 31 000 stems ha−1, to control (unthinned), 400, 1000 and 3000 stems ha−1. Significant physiological responses to thinning were observed during the subsequent two growing seasons. Photosynthetic rate of trees in the thinned stands increased significantly compared with that in unthinned trees. Photosynthetic rates between 11:00 and 14:00 h on cloudless days in the second growing season were 2.2, 7.9, 10.6 and 16.4 μmol CO2 m−2 s−1 for unthinned, 3000, 1000 and 400 stems ha−1, respectively. This increase was attributed to increases in PAR and foliage nitrogen concentration and a decrease in SLA. Among the three thinning densities, the 400 stems ha−1 treatment had the best physiological responses to thinning. Thinning these stands to 1000 stems ha−1 appears more appropriate, however, when timber management objectives, such as improvement of stem quality, are considered.

A study was established to evaluate several management practices for improving American sycamore (Platanus occidentalis L.) establishment on land subjected to daily paper-mill sludge spray irrigation, and where a dense herbaceous cover dominated by pokeweed (Phytolacca americana L.) was nearly 2 m tall. Treatments studied included: two sludge application treatments (spray vs no spray), five weed control treatments (control, hand-release, oxyfluorfen, glyphosate and atrazine, and sulfometuron methyl), and two tree shelter treatments (control vs tree shelter). Survival and growth of sycamore seedlings were evaluated after one growing season. Sludge application treatment had the greatest effect on tree survival; survival was greatest on plots that were not sprayed during the year of tree growth. Among the weed control treatments, the hand-release treatment resulted in best survival; survival was 100% when hand release was used on unsprayed plots. Tree shelters provided no benefit to tree establishment.

This paper is a report of 1) comparative fluoride levels accumulated by lime-treated filter papers exposed in duplicate shelters, 2) the statistical relationship at each of 20 exposure sites between the average monthly filter paper fluoride level for the growing season and the total fluoride level accumulated in heterogeneous ground cover vegetation at each site during the growing season, and 3) the reliability of the lime-treated filter paper technique in measuring the relative intensity of fluoric pollution from one year to another.

A group of five papers has been assembled from presentations at the 10th International Conference on Precision Agriculture (ICPA) held in Denver, Colorado, USA in July 2010. These papers represent an array of studies that were applied to maize, sugar beets, sugar cane, wheat, and grain sorghum. In terms of field applications, the studies covered (1) using aircraft imagery to make adaptive nitrogen (N) management decisions during the growing season; (2) remote sensing for disease detection; (3) biomass production and N management using active crop sensors; (4) implications of spatial variability and past management on crop response, even within relatively small fields; and (5) using remote sensing to estimate crop yields. Technologies employed in these projects included soil testing for nutrient status and several aspects of remote sensing including imagery, spectroscopy, and active crop canopy sensors to better understand and manage spatial and temporal variability. Geographically, the papers emanate from many parts of the globe, including Brazil, China, Germany, and the United States. Sincere appreciation is extended to the authors for their efforts in hopes that readers of Precision Agriculture will find these publications interesting and that each makes a meaningful contribution to science.

An experiment was conducted to evaluate the effect of leaf smothering upon establishment of white spruce in Alaska. Treatment consisted of protecting seed-spots from leaf litter of an overstory paper birch stand with hardware cloth screens for varying periods. Protection significantly improved survival through the first four growing seasons following germination of the spruce seed. After the fourth growing season, most seedlings were large enough to avoid being smothered or crushed by fallen leaves; additional protection through the fifth growing season was not significantly beneficial. It appears unlikely that more than an occasional white spruce can become naturally established beneath birch stands in this region.

The concept of fitness is central to evolutionary biology, yet it is difficult to define and to measure. In plant biology, fitness is often measured as seed count. However, under an array of circumstances, seed count may be a biased proxy of fitness, for example when individuals vary in allocation to sexual versus asexual reproduction. A more subtle example, but also likely to be important in natural populations, is when interindividual variation in conditions during development results in variation in offspring quality among seed parents. In monocarpic (semelparous) plants, this is expected to result from variation in effective season length experienced among individuals that reach reproductive maturity at different times. Here, we manipulate growing season length to ask whether seed count is an accurate representation of parental fitness in the monocarpic herb Lobelia inflata. Simple seed count suggests a paradoxical fitness advantage under constrained‐season length. However, we find that the apparent fitness advantage of a constrained‐season length is overridden by low relative per‐seed fitness. Furthermore, the fitness deficit in the constrained environment is associated primarily with an accelerating decrease in viability and seedling survival in seeds derived from fruits produced progressively later in the season. In this study, the overall fitness value of a seed under a constrained season is 0.774 of that observed under a long season., The number of offspring produced is often used as an individual fitness proxy. This may be problematic, for example, if the quality of environment experienced differs among individuals. We find that Lobelia inflata produces more seeds under an experimentally constrained than long season, but these seeds have low germination success and low seedling survival. Overall, the true fitness value of a single seed under a constrained season is only 77% of that under a long season.

Through sampling reed in Shuangtai estuary wetland in April, 2009 and simulation test in Shenyang Agricultural University, we analyze the removal efficiency of Cu, Zn, Pb and Cd during different growth period of reed and distribution of them in various parts of reed. The results show that the removal efficiency is best in jointing stage, the removal of Pb largest with 21% increase and 30% in sprout and exhibition leaf period, the removal of Zn largest with 53% and 29% increase in jointing stage and the maturity period, the removal of Cd largest with 40% increase in the different growing season. The absorption amount of Cu, Zn, Pb and Cd in roots of reed reaches maximum during the growth, followed by in stems and in leaves. Absorptive capacity in the whole plant for Cu, Zn, Pb and Cd exists extremely significant difference (pZn>Cu>Cd. The absorption in root is higher than in stems and in leaves (p0.05).

Relevance. The study of the collection is one of the main sources of replenishing the source material for the breeding process. The presence of the necessary genetic traits can speed up the breeding process. Therefore, at the Bykovskaya melon breeding experimental station, the genetic diversity of melon plants is assessed and promising samples are selected for use in breeding.Materials and methods. The object of research was samples of table watermelon with an unconventional color of the pulp. The aim of the work is to study and isolate the source material of watermelon for use in the breeding process to create new varieties and hybrids of melon crops. In the course of the study, 12 varieties of table watermelon were identified from 33 varieties of the collection nursery, which are sources of economically valuable traits. The selection was carried out according to the yield, the rate of entry into fruiting, taste, color of the pulp.Results. In the course of the research, the obtained samples of table watermelon with an unconventional color of the pulp were evaluated according to a set of economic characteristics in comparison with the standards: Zenith and Sinchevsky. The analysis of the tested samples made it possible to identify 12 samples by economically valuable traits: 3 samples by early maturity and taste: White sugar lump, White wonder, Golden revenge F1; 7 samples with a high dry matter content, in terms of yield and large fruit: Moon and stars yellowflesh, Sweet Siberian, Orangeglo, Daisy, Clay county yellow meat, Mountain sweet yellow, Tendergold; 2 samples for color and pulp consistency: Early moon beane Bakerlneek, Tenderweet orange. The selected samples meet the modern requirements of the industrial melon growing industry, resistant to stress factors of the environment, good taste and consumer properties.Findings. The obtained experimental data will be used to create a genetic collection of watermelon according to the traits that determine the economic value of the gene pool for further use in the breeding process.

Research Highlights: This research provides a firm basis for understanding the improved aspen hybrid performance that aims at facilitating optimal clone selection for industrial application. Background and Objectives: Rapid growth and wood properties make aspen (Populus tremula L.) suitable for the production of pulp and paper. We assessed the potential of tree improvement through hybridization to enhance aspen productivity in northern Poland, and investigated the effects of Populus tremula hybridization with Populus tremuloides Michaux and Populus alba L. on the growth and cellulosic pulp properties for papermaking purposes. Materials and Methods: A common garden trial was utilized that included 15 hybrid aspen clones of P. tremula &times, P. tremuloides, four of P. tremula &times, P. alba, and one, previously tested P. tremula clone. Clones of P. tremula, plus trees from wild populations, were used as a reference. Tree height and diameter at breast height (DBH) were measured after growing seasons four through seven. At seven years of age, the three clones representing all species combinations were harvested, and their cellulosic pulp properties and paper sheet characteristics were assessed. Results: The clones from wild populations exhibited the poorest growth. In contrast, the clone &lsquo, W&auml, 13&prime, (P. tremula &times, P. tremuloides) demonstrated the highest DBH, height, volume production, and mean annual increment (MAI) (25.4 m3 ha&minus, 1 yr&minus, 1). The MAI ratio calculated for interspecific crosses ranged from 1.35- to 1.42-fold, higher than that for the P. tremula. Chemical properties of pulp, fiber morphology, and the physical properties of paper sheets were more desirable for interspecific hybrid clones than those for the pure P. tremula clone. Conclusions: The results indicated that plantations of hybrid aspen may constitute an important additional source of wood for pulp and paper products in Poland. Our findings further suggested that the standard rotation of these trees may be reduced from 40 to 20 years, increasing overall biomass yield and enhancing atmospheric carbon sequestration.

Canopy structure and physiology of paper birch are examined in the field during two growing seasons. Leaves are found to be steeply inclined in the upper canopy levels and foliage mass is located higher in the canopy than frequently observed in more shade tolerant species. Functional relationships between the controlling environmental factors and the physiological processes of leaf resistance to water vapor diffusion and gross photosynthesis are used in a computer simulation model to examine production and water use aspects of paper birch.

The high sink strength of cassava storage roots prevented the down-regulation of photosynthesis under elevated CO2 concentrations, leading to higher yields., Cassava has the potential to alleviate food insecurity in many tropical regions, yet few breeding efforts to increase yield have been made. Improved photosynthetic efficiency in cassava has the potential to increase yields, but cassava roots must have sufficient sink strength to prevent carbohydrates from accumulating in leaf tissue and suppressing photosynthesis. Here, we grew eight farmer-preferred African cassava cultivars under free-air CO2 enrichment (FACE) to evaluate the sink strength of cassava roots when photosynthesis increases due to elevated CO2 concentrations ([CO2]). Relative to the ambient treatments, elevated [CO2] treatments increased fresh (+27%) and dry (+37%) root biomass, which was driven by an increase in photosynthesis (+31%) and the absence of photosynthetic down-regulation over the growing season. Moreover, intrinsic water use efficiency improved under elevated [CO2] conditions, while leaf protein content and leaf and root cyanide concentrations were not affected. Overall, these results suggest that higher cassava yields can be expected as atmospheric [CO2] increases over the coming decades. However, there were cultivar differences in the partitioning of resources to roots versus above-grown biomass; thus, the particular responses of each cultivar must be considered when selecting candidates for improvement.

Japanese larch (Larix kaempferi (Lamb.) Carr.) and its hybrid are economically important coniferous trees widely grown in the Northern Hemisphere. Ground-level ozone (O3) concentrations have increased since the pre-industrial era, and research projects showed that Japanese larch is susceptible to elevated O3 exposures. Therefore, methodologies are needed to (1) protect Japanese larch against O3 damage and (2) conduct biomonitoring of O3 in Japanese larch forests and, thus, monitor O3 risks to Japanese larch. For the first time, this study evaluates whether the synthetic chemical ethylenediurea (EDU) can protect Japanese larch against O3 damage, in two independent experiments. In the first experiment, seedling communities, simulating natural regeneration, were treated with EDU (0, 100, 200, and 400 mg L−1) and exposed to either ambient or elevated O3 in a growing season. In the second experiment, individually-grown saplings were treated with EDU (0, 200 and 400 mg L−1) and exposed to ambient O3 in two growing seasons and to elevated O3 in the succeeding two growing seasons. The two experiments revealed that EDU concentrations of 200–400 mg L−1 could protect Japanese larch seedling communities and individual saplings against O3-induced inhibition of growth and productivity. However, EDU concentrations ≤ 200 mg L−1 did offer only partial protection when seedling communities were coping with higher level of O3-induced stress, and only 400 mg EDU L−1 fully protected communities under higher stress. Therefore, we conclude that among the concentrations tested the concentration offering maximum protection to Japanese larch plants under high competition and O3-induced stress is that of 400 mg EDU L−1. The results of this study can provide a valuable resource of information for applied forestry in an O3-polluted world.

Relevance and methods. Methodological approaches to assessing the residual amounts of copper-containing pesticides in plant products against the background of natural copper content are presented. The conditions for obtaining reliable results when conducting a hygienic assessment of the content of residual amounts of the active substance are determined. The developed scheme for determining the residual amounts of copper-containing pesticides includes the homogenization of the analyzed material by shredding with dry ice and microwave mineralization of samples with subsequent flameless atomic absorption determination of copper.Results. Data on the levels of natural copper content in samples of potatoes, onions, cucumbers, tomatoes and grapes of various varieties and growing areas are presented. The possibility of applying the developed approaches to study the dynamics of accumulation of active substances during the growing season is shown.

Wild plants with a wide distribution, including those exposed to a wide variety of environmental conditions, may have variations in key functional traits relevant for agricultural applications. The East Asian wild radish (Raphanus sativus var. raphanistroides) is an appropriate model plant because it is widely distributed and has outstanding sink capacity as well as two cultivars within the species. Multiple common garden trials with 14 populations and three testing sites were conducted across the Japanese archipelago to quantify variations in yield and allocation. Significant inter-population variations and interaction effects with testing sites were detected for the root and shoot mass and the root mass fraction (RMF). While the rank order of the population changed drastically among sites and the variance components of genetic effects were small in yield traits (2.4%-4.7%), RMF displayed a large genetic variance (23.2%) and was consistently higher in the northern populations at all sites. Analyses revealed that the mean temperature of growing season of the seed origin was the most prominent factor explaining variation in RMF, irrespective of the sites. We concluded that the trait of resource allocation had a temperature-related cline and plants in cooler climates could invest more resources into their roots.

Summary Despite the importance of nonstructural carbohydrates (NSC) for growth and survival in woody plants, we know little about whole‐tree NSC storage. The conventional theory suggests that NSC reserves will increase over the growing season and decrease over the dormant season. Here, we compare storage in five temperate tree species to determine the size and seasonal fluctuation of whole‐tree total NSC pools as well as the contribution of individual organs. NSC concentrations in the branches, stemwood, and roots of 24 trees were measured across 12 months. We then scaled up concentrations to the whole‐tree and ecosystem levels using allometric equations and forest stand inventory data.While whole‐tree total NSC pools followed the conventional theory, sugar pools peaked in the dormant season and starch pools in the growing season. Seasonal depletion of total NSCs was minimal at the whole‐tree level, but substantial at the organ level, particularly in branches. Surprisingly, roots were not the major storage organ as branches stored comparable amounts of starch throughout the year, and root reserves were not used to support springtime growth.Scaling up NSC concentrations to the ecosystem level, we find that commonly used, process‐based ecosystem and land surface models all overpredict NSC storage.

The purpose of this short paper is to examine the vintage charts from 1949 to 2014 for Bordeaux and Burgundy regions and apply Ashenfelter’s models to estimate the relationship between vintage and weather and compare the results between Bordeaux and Burgundy. The results show that the impact of temperature during the growing season and rain during the harvest season is similar in Bordeaux and Burgundy but also for red and white wines.