Spring Regrowth Research Articles

Fall defoliation affects acquisition of freezing tolerance and spring regrowth in asparagus

Asparagus (Asparagus officinalis L.) acquires freezing tolerance during a period of fall acclimation when both photoperiod and temperature decrease. The above-ground vegetative growth may be important for sensing changing environmental conditions and translocating compounds to the below-ground crown. Defoliation experiments, repeated over 2 yr, were conducted by removing fern in mid-August, -September, and -October and evaluating crown metabolites and LT50, the temperature at which 50% of plants die, at monthly intervals to mid-November. Spring emergence and vigor were also assessed in separate experiments. In the first year, only mid-August defoliation affected LT50 values, decreasing freezing tolerance, which was associated with diminished rhizome proline concentration and storage root low- and high-molecular-weight fructan concentrations. All defoliation treatments in the second year decreased LT50 values, or increased freezing tolerance, possibly resulting from an interaction between defoliation and drought which increased rhizome sucrose concentrations. Defoliation decreased spring vigor in both experiments; the response was proportional to the earliness of the treatment and associated with rhizome and storage root fructan levels. Crowns of plants defoliated in mid-August had increasing proline concentrations during the fall, similar to control plants, suggesting the below-ground organs may have sensed soil temperature to cold acclimate. Autumn defoliation to control disease, harvest seed, or implement other cultural practices can reduce vigor and likely attenuate long-term performance of a plantation.

Эффективность микроудобрений для повышения семенной продуктивности и качества семян родиолы розовой в зависимости от условий сезона вегетации

Изучено влияние абиотических факторов среды на прохождение основных фенологических фаз у растений родиолы розовой 2-го, 3-го и 4-го годов вегетации. На 4-й год вегетации количество растений с пестичными цветками составляло 54 %. Используемые бинарные смеси микроудобрений — Силиплант (1 мл/л), Феровит (1,5 мл/л), ЭкоФус (5 мл/л) — в целом заметно повысили не только семенную продуктивность растений родиолы розовой, но и качество семян. Некорневые обработки проводили двукратно: в фазу весеннего отрастания и в фазу начала бутонизации. Наиболее перспективным вариантом обработки оказалась бинарная смесь Силиплант + Феровит. У растений 3-го года вегетации масса 1000 семян превышала контроль (без обработки микроудобрениями) на 19,6 %, у растений 4-го года вегетации — на 33,5 %. В варианте Силиплант + Феровит у растений 4-го года вегетации доля крупных семян увеличилась на 8 % по сравнению с контролем. В данном варианте у растений 3-го и 4-го годов вегетации доля выполненнных семян превышала контроль на 24,1 – 35,9 %. Всхожесть у крупных семян повысилась по сравнению с контролем на 3 – 5 %, у мелких семян — на 4 – 8 %. Энергия прорастания семян увеличилась соответственно на 2 – 5 и 1 – 5 %.

Sand topdressing and protective covers impact creeping bentgrass crown moisture during winter

AbstractWinter desiccation injury can severely impact golf courses in the northern and central Great Plains. While it is well‐established that turfgrass crown moisture content (CMC) declines during fall cold‐acclimation, little is known about CMC during winter desiccation stress and how management practices influence CMC during desiccation stress. The objectives of this study were to understand how protective covers, sand topdressing, and spray‐applied treatments impact creeping bentgrass (Agrostis stolonifera) CMC and spring green‐up following winter desiccation stress in Nebraska. Spray‐applied treatments included a turf colorant, horticultural oil plus colorant, anti‐transpirant, and a fall applied soil wetting agent. Crown moisture content was measured monthly from December to March at Mead, NE and after winter in Axtell, NE. Visual turfgrass quality ratings were used to monitor survival and spring regrowth. Late‐fall sand topdressing and permeable and impermeable protective covers reduced winter desiccation injury compared to a non‐treated plot. Turfgrass CMC ranged from 0.251 to 0.764 g H2O g−1 fresh weight (FW) depending on treatment and location. Logistic regression indicated that turf plants with a CMC of 0.518 g H2O g−1 FW had a 50% probability of significant winter desiccation injury. Under severe desiccation pressure, the spray‐applied treatments did not prevent winter desiccation injury. Under these circumstances, a majority of plots receiving spray‐applied treatments had a March CMC of less than 0.500 g H2O g−1. Physical protection of turfgrass crowns with covers or sand topdressing in late fall sustained CMC during late‐winter and decreased the potential for winter desiccation injury the following spring.

Biochemical and molecular responses during overwintering of red clover populations recurrently selected for improved freezing tolerance

Low freezing tolerance reduces the persistence of red clover under northern climate. The incidence of winter damages in perennial crops could increase in the future due to the adverse effects of the predicted warmer fall temperature on plant cold acclimation. To accelerate breeding progress, two cultivars of red clover Christie (C-TF0) and Endure (E-TF0) were exposed to a recurrent selection protocol for freezing tolerance performed indoor. New populations were obtained after five (C-TF5 and E-TF5), six (C-TF6 and E-TF6), and seven (C-TF7 and E-TF7) cycles of recurrent selection. These populations were overwintered under natural conditions and monitored for freezing tolerance and cold-induced molecular traits. Freezing tolerance was improved by up to 6 °C in recurrently selected populations when compared to initial cultivars confirming that further progress are achieved with advanced cycles of selection. Monthly analysis of biochemical changes shows that higher starch concentrations at the onset of the fall hardening period are contributing to the acquisition of superior freezing tolerance through its impact on sucrose accumulation. They also contribute to the vigor of spring regrowth by sustaining more pinitol and proline synthesis. Larger concentrations of these metabolites in populations with higher levels of freezing tolerance (TF7) hint at their involvement in winter survival of red clover. Among genes differentially expressed in response to both cold acclimation and recurrent selection, a concomitant cold induction of APPR9 and cold repression of 1-aminocyclopropane-carboxylate synthase suggests a link between the repression of a pathway regulated by ethylene and the improvement of freezing tolerance in red clover.

Influence of snow mold on winter rye productivity in the Kirov region

In the conditions of the Kirov region, the major factor reducing the productivity of winter crops is infestation with snow mold (Microdochium nivale (Fr.) Samuels et. Hallet. - synonym Fusarium nivale (Fr.) Ces.), which annually grows by 80-100%. Therefore, the main direction of breeding is receiving winter rye varieties having maximum resistance to this disease. During the period of 2003-2017 there was carried out the assessment of zoned and perspective cultivars of domestic breeding of various ecological-and-geographical origin for snow mold infestation in natural provocative conditions. Weather conditions differed greatly in all periods of rye development. It has been established that plant resistance to M. nivale pathogen is influenced greatly by the condition of plants before wintering regulated by the sowing time. Well-developed plants of Falenskaya 4 variety formed the optimum density of an agro-phytocenosis, accumulated bigger amount of sugars (more than 7%), regenerated during spring re-growth by more than 90%, and produced stable high yield (more than 4.9 t/ha). In order to realize the biological potential of the variety, there was a need to shift the previously established sowing time to 5-10 days later period. The productivity was influenced greatly by April conditions, namely, by the period of total clearing of sowings from snow, which took only several days (3-6). Warm and dry weather favored an active re-growth of rye and prevented disease development. Cold and damp weather provoked fungus development, which affected quickly the plants weakened after rewintering. It was revealed that winter rye varieties of different ecological-and-geographical groups responded to this disease differently. The variability in productivity of each cultivar by years was high (CV = 25.8…65.4%). The greatest stability was characteristic for varieties bred in FARC North-East. The main methods of breeding for the resistance to snow mold are crossing and selection in the conditions of a provocative background. The efficiency of a selection method is confirmed with creation from Falenskaya 4 a highly winter-hardy variety Flora with active regeneration after snow mold infestation (100%) and stable productivity by years – 4.62 t/ha (addition yield to an initial cultivar was 0.27 t/ha). The distinctive feature of Flora variety is active formation of powerful green mass in spring that is important for the early use for green forage for cattle and poultry. Since 2012 the variety is included in the State Register of breeding achievements in Volga-Vyatka and North-West regions of the Russian Federation.

Влияние погодных условий на химический состав сухого вещества люцерны (Medicago varia Mart.) в фазу цветения

The influence of weather conditions in the autumn-winter period and in the growing season on the content of crude protein, crude fiber and crude fat in the dry matter of alfalfa (Medicago varia Mart.) in the flowering phase has been studied. It was found that if during the formation of alfalfa herbage weather conditions were such to the average annual, the content of crude protein was 17.1–20.6%, crude fiber 24.5–28.6% and crude fat 2.4–3.3 percent. In conditions of sufficient moisture supply, increased heat supply and the predominance of Sunny days, the protein content reached to 18.9–24.8%, fiber was 19.0–23.0%, fat was 1.7–2.4 percent. With high heat and moisture with a predominance of cloudy weather, the protein content decreased to 15.0–17.7%, fiber increased to 35.4–39.3%, fat – to 2.6–3.5 percent. It was found that excessively wet weather in the autumn-winter period of the previous year significantly weakens alfalfa plants. Therefore, the beginning of spring regrowth, even in warm weather in April, was delayed for 
 1–2 weeks. The intensity of growth and development of alfalfa in May–June, even with optimal heat and moisture, was slow. The entry of alfalfa into the flowering phase was late by an average of 2 weeks compared to normal dates. At the same time, the content of crude protein decreases to 12.4–15.0%, the content of crude fiber increases to 32.1–34.4%, and the content of crude fat (2.4–2.9%) was not affected by unfavorable wintering conditions. It was found that the relatively high quality of dry matter in the flowering phase (average for 4 years of use) have varieties Vega 87 and Taisia (protein content of 18.3 and 19.5%, fiber 29.3 and 29.2%, fat 2.7 and 3.0%). Performance of alfalfa varieties to Pastbishchnaya 88 and Selena was a 15.9%, 30.9%, 2.3% and 17.3%, 28.8 %, 2.7%, respectively.

Продуктивна кущистість та клонування інтактних рослин жита озимого

Продуктивна кущистість та клонування інтактних рослин жита озимого

YIELD OF CHAMOMILE MEDICINAL DEPENDING ON SOWING DATE AND FERTILIZING IN TERMS OF CLIMATE CHANGE

On the market of medicinal plants of Ukraine there is a deficiency of chamomile. Increasing its production and obtaining profits from the sale of medicinal raw materials is possible through the use of new breeding practices and adaptive technologies for growing this crop in the context of global climate change. The conducted scientific researches in different regions of our country and abroad show that the yield of chamomile and the content of biologically active substances in it depend on genetic features of a variety, type of soil, climatic factors, dates and methods of sowing, fertilization, etc. The purpose of our research was to establish the regularities of the formation of the Perlyna Lisostepu chamomile variety yield, depending on the elements of the technology of cultivation in the agroecological conditions of Pollyssya, where this question is not sufficiently studied. We have found that the autumn sowing of this culture has significantly higher yields than spring sowing. This is due to the fact that culture has a larger vegetation period, and therefore it is better to assimilate fertilizers in post-sowing period, and at the time of spring regrowth, it is rapidly increasing the weight and gaining superiority over weeds. The yield of raw mass of flowers varies from 0.7 to 1.4 t/ha depending on the fertilizer, and the dry mass, respectively, from 0.3 to 0.7 t/ha. The best weather conditions in the period of sowing and the formation of generative organs of chamomile plants were in 2018. During the autumn sowing season (September) there was more heat. The average monthly air temperature in April, May and June significantly exceeded the average multi-year norm. On average, over two years of research, the maximum yield of crude mass of chamomile flowers was 1.3 t/ha and dry mass of 0.65 t/ha was obtained with the addition of N16P16K16 (to the main fertilizer). Chamomile plants respond well to the N10 foliar feeding which provided 1.2 t/ha and 0.6 t/ha of raw material. During spring sowing, the yield was in the range of 0.5-1.1 t/ha of raw mass and, respectively, 0.2-0.6 t/ha of dry mass of flowers. Fertilized options were not inferior to each other in yield of medicinal raw material. Application of fertilizers according to the experimental scheme increased the yield of finished medicinal raw materials by 0,1-0,3 t/ha

Winter hardiness of Miscanthus (II): Genetic mapping for overwintering ability and adaptation traits in three interconnected Miscanthus populations

AbstractMiscanthus × giganteus (M×g) is the primary species of Miscanthus for bioenergy feedstock production. The current leading biomass cultivar, M×g ‘1993‐1780’, is insufficiently adapted in temperate regions with cold winters such as USDA hardiness zone 5 (average annual minimum temperature of −28.9 to −23.3°C) or lower. Three interconnected Miscanthus F1 populations that shared a common parent were planted in a replicated field trial at Urbana, IL (hardiness zone 5b; average annual minimum temperature of −26.1 to −23.3°C) in spring 2011. The winter of 2013–2014 was especially cold in Urbana, with a minimum soil temperature at 10 cm of −6.2°C and a minimum air temperature of −25.3°C, giving us an opportunity to evaluate hardiness on established year‐3 plants. The parent in common to all three populations, M. sinensis ssp. condensatus ‘Cosmopolitan’, is native to maritime southern Japan, and in Urbana, it is winter‐damaged most years. In contrast, the three other parents, M. sacchariflorus ‘Robustus’ (MapA), M. sinensis ‘Silberturm’ (MapB), and M. sinensis ‘November Sunset’ (MapC), are typically winter hardy in Urbana. Nearly all MapA progeny plants survived and grew vigorously in spring 2014, whereas in MapB and MapC, many progeny plants did not survive the winter, and most of the survivors were severely damaged, with poor vigor. Negative correlations between overwintering ability and spring regrowth date and autumn dormancy date suggested that the genotypes most likely to survive winters were those that emerged early in spring and/or went dormant early in autumn. Using joint‐population analysis, we identified 53 quantitative trait loci (QTLs) for nine adaptation traits, including nine QTLs for overwintering ability and 11 for spring hardiness scores. Many biologically intuitive candidate genes were observed within or near the QTLs detected in this study, suggesting their validity and potential for further study.

Rosana – a new variety of alfalfa (Medicago sativa L.)

Aim. Lucerne sowing in Ukraine is one of the most common fodder crops from perennial legumes. Most varieties grown today are not sufficiently adapted to a number of unfavorable abiotic and biotic environmental factors. Rosana variety was created to solve some of the above problems under the conditions of the Polissya and the forest-steppe of Ukraine. Methods. 560 plants, differing in high winter resistance and a set of economic and valuable features, were selected from the grassland of Regent's varieties of alfalfa, created in previous years from genetic plasma of varieties WL 202 (USA) and Veselopodolianska 11 (Ukraine). During the four study cycles, gumboil counts were carried out at the level of green mass and seed yield, leafyness, resistance to pathogens of root rot and other diseases, intensity of regrowth in spring and autumn. Results. The Rosana variety is similar to the Regina variety in the form of a bush, the size of leaves, the height of plants, the duration of individual phases of growth and development, and the class of rest. The variety is characterized by high intensity of regrowth, during the growing season can form 3–4 slopes, with increased feed quality, increased seed yield. Resistant to root rot, drought-proof and winter-resistant. Resistant to sinking. Medieval The period of productive longevity is 4–5 years. The height of the plants of the first slope is 80–90 cm. The yield of the seeds is 0.5 t / ha. Collection of dry matter – 14.5–15.0 t / ha. Protein content – 20.9 %, cellulose – 21.4 %. The first slope is 54–55 days. Clearness – 48 %. Conclusions. The quality of Rosana's fodder and seed yield is significantly higher than the Regina variety and the conditional standard. Characterized by a number of other economic and valuable features. It is recommended for distribution in Polissya and Forest-steppe zones of Ukraine in clean and mixed crops with other perennial herbs for the production of high-quality feed (haylage, hay, herbal pellets).
 Keywords: alfalfa crop, varietal, winter resistance, dry matter, seeds.

Profound seasonal changes in brain size and architecture in the common shrew

The seasonal changes in brain size of some shrews represent the most drastic reversible transformation in the mammalian central nervous system known to date. Brain mass decreases 10–26% from summer to winter and regrows 9–16% in spring, but the underlying structural changes at the cellular level are not yet understood. Here, we describe the volumetric differences in brain structures between seasons and sexes of the common shrew (Sorex araneus) in detail, confirming that changes in different brain regions vary in the magnitude of change. Notably, shrews show a decrease in hypothalamus, thalamus, and hippocampal volume and later regrowth in spring, whereas neocortex and striatum volumes decrease in winter and do not recover in size. For some regions, males and females showed different patterns of seasonal change from each other. We also analyzed the underlying changes in neuron morphology. We observed a general decrease in soma size and total dendrite volume in the caudoputamen and anterior cingulate cortex. This neuronal retraction may partially explain the overall tissue shrinkage in winter. While not sufficient to explain the entire seasonal process, it represents a first step toward understanding the mechanisms beneath this remarkable phenomenon.

Effect of Repeated Application of Manure on Herbage Yield, Quality and Wintering Ability during Cropping of Dwarf Napiergrass with Italian Ryegrass in Hilly Southern Kyushu, Japan

The effects of two levels of manure application (184 and 275 kg N ha−1 year−1) on herbage yield, quality, and wintering ability during the cropping of a dwarf genotype of late-heading (DL) Napiergrass (Pennisetum purpureum Schumach) oversown with Italian ryegrass (IR; Lolium multiflorum Lam.) were examined and compared with chemical fertilizer application (234 kg N ha−1 year−1) for 4 years to determine a sustainable and environmentally harmonized herbage production in a hilly area (340 m above sea level). No significant (p > 0.05) differences in growth attributes of plant height, tiller density, percentage of leaf blade, or dry matter yield appeared in either DL Napiergrass or IR among moderate levels (184–275 kg N ha−1 year−1) of manure and chemical fertilizer treatments. IR exhibited no significant detrimental effect on spring regrowth of DL Napiergrass, which showed a high wintering ability in all treatments. In vitro dry matter digestibility of DL Napiergrass tended to increase with increasing manure application, especially at the first defoliation in the first three years. Manure application improved soil chemical properties and total nitrogen and carbon content. The results suggested that the lower rate of manure application of 184 kg nitrogen ha−1 year−1 would be suitable, which would be a good substitute for chemical fertilizer application with an equilibrium nitrogen budget for sustainable DL Napiergrass and IR cropping in the hilly region of southern Kyushu.

Phenotyping Winter Dormancy in Switchgrass to Extend the Growing Season and Improve Biomass Yield

Switchgrass is a prominent bioenergy crop. Like most perennial warm season species, switchgrass undergoes growth suspension in winter as a surviving strategy in temperate climates to protect their meristems from cold injuries and dehydration, while storage organs below ground drive spring regrowth when conditions become favourable. In this paper, we describe a reliable phenotyping method for winter dormancy in switchgrass using various traits including regrowth height after clipping in early fall (FRH), senescence percentage, date of spring regrowth (SRD), and flowering date (FD). FRH and senescence percentage appear to be reliable indicators of the onset of winter dormancy, whereby accessions that initiated dormancy early have a low FRH and a high senescence percentage. Even though it is difficult to have an exact assessment of the duration of dormancy because it is hard to determine with precision the date of growth suspension, SRD can be used as a surrogate indicator of the duration. Flowering date showed low correlations with all the traits and biomass yield suggesting that it may not be a reliable indicator for winter dormancy in switchgrass. Combining the variables FRH, senescence, and SRD in a selection index may provide a reliable tool to phenotype winter dormancy in switchgrass. The strong correlation of these variables with biomass yield makes them useful candidates for the manipulation of the duration of dormancy to increase the growing season and consequently improving biomass production. In southern regions with mild winters, it might be possible through intense selection to develop germplasm with much reduced dormancy or even non-dormant switchgrass germplasm.

Associations among U.S. Locations for Orchardgrass Production

Core Ideas Orchardgrass exhibits strong genotype × environment interaction across U.S. production area. There is limited association between US orchardgrass production areas. The choice of best orchardgrass cultivar should be based on local production conditions. Thirteen orchardgrass (Dactylis glomerata L.) cultivars were evaluated across 4 years at five US field locations in Kentucky, Pennsylvania, Utah, Virginia, and Wisconsin. The objective was to determine the relationship among the five locations for orchardgrass agronomic performance. Cultivar × environment interaction was identified for dry matter (DM) yield, stand percentage, maturity rating, disease rating, spring regrowth, and fall regrowth. Significant concordance values were moderate to high (τ = 0.46 to 0.84) among the locations, with the exception of Wisconsin, which showed little association with the other locations. These rankings indicated that there was little association among the locations for orchardgrass performance. This was further illustrated by the mean values of the cultivars for each trait. In only a few cases was a cultivar among the highest ranking for a trait at more than one location. Notable exceptions were the generally high DM yield of the cultivars Benchmark Plus and Persist and the high disease resistance of the cultivars Barlegro, Excellate SA, and Harvestar. The results illustrate that orchardgrass cultivar adaptation is region specific within this subset of U.S. production areas.

Optimal Regulation of the Balance between Productivity and Overwintering of Perennial Grasses in a Warmer Climate

Seasonal growth patterns of perennial plants are linked to patterns of acclimation and de-acclimation to seasonal stresses. The timing of cold acclimation (development of freezing resistance) and leaf growth cessation in autumn, and the timing of de-acclimation and leaf regrowth in spring, is regulated by seasonal cues in the environment, mainly temperature and light factors. Warming will lead to new combinations of these cues in autumn and spring. Extended thermal growing seasons offer a possibility for obtaining increased yields of perennial grasses at high latitudes. Increased productivity in the autumn may not be possible in all high latitude regions due to the need for light during cold acclimation and the need for accumulating a carbohydrate storage prior to winter. There is more potential for increased yields in spring due to the availability of light, but higher probability of freezing events in earlier springs would necessitate a delay of de-acclimation, or an ability to rapidly re-acclimate. In order to optimize the balance between productivity and overwintering in the future, the regulation of growth and acclimation processes may have to be modified. Here, the current knowledge on the coordinated regulation of growth and freezing resistance in perennial grasses is reviewed.

Proline accumulation and related gene expression during spring regrowth in three rosaceae species

Proline (Pro), one of amino acids, not only acts as an osmoprotectant but also is involved in plant developmental processes. We previously revealed that Pro levels increased in peach (Prunus persica) shoots during dehardening in response to warmer temperatures during spring or in controlled laboratory conditions. Our subsequent work suggested that such Pro accumulation is associated with the resumption of growth in eco-dormant shoots and mediated via the ornithine pathway in peach. The present study was conducted to explore whether the aforementioned Pro accumulation response also occurs in other species of the Rosaceae family. Our data indicate that the Pro content of peach and plum (P. salicina) shoots increased during the spring regrowth and were highly similar between these two related species. Whereas the ornithine-δ-aminotransferase (OAT) gene expression dynamics in peach were correlated with Pro accumulation pattern and with pyrroline-5-carboxylate reductase (P5CR) gene expression, OAT expression was not correlated with the Pro content in plum. For apple (Malus domestica), while the absolute amounts of Pro content differed from those of the two Prunus species, this species accumulated Pro during the spring warming/regrowth. These results suggest that Pro accumulation in response to higher temperatures during the spring regrowth is a more general phenomenon across Rosaceae fruit trees, and although peach shoots may accumulate Pro via the ornithine pathway during spring regrowth, there was no evidence for this in plum and apple.

Identification of loci controlling forage yield and nutritive value in diploid alfalfa using GBS-GWAS.

We attempted to identify genomic regions controlling forage yield and nutritive value in alfalfa. Several candidate genes and associated genetic markers were identified that could potentially be useful for alfalfa breeding to more efficiently develop improved cultivars. Alfalfa is one of the most widely cultivated forage legumes worldwide and improving alfalfa forage yield and nutritive value is a major global breeding goal. Genotyping-by-sequencing (GBS) provides cost-effective molecular marker genotyping for genome-wide association studies (GWAS). Using more than 15,000 genome-wide single nucleotide polymorphisms (SNP) identified from GBS, we conducted a GWAS to investigate forage yield and nutritive value-related traits. We have detected a number of associations for all the traits evaluated and a number of associations detected were located on the Medicago truncatula genome. The SNP in a coding region of a cell wall biosynthesis gene was associated with several cell wall-related traits, and we suggest that it may be the causative polymorphism. Two other SNPs residing in meristematic development and early growth genes were found to associate with the total biomass yield. None of the SNPs associated with regrowth after harvest or with spring regrowth were mapped to the M. truncatula genome, possibly reflecting the fact that M. truncatula is an annual species related to alfalfa that typically has limited ability to regrow. The alleles we identify with the major impact on forage yield and nutritive value can be rapidly incorporated into our breeding program.

Morphological features of <i>Hylotelephium triphillum</i> (Haw.) Holub (Crassulaceae DC.) under different light conditions when introduced into the steppe zone

In recent decades floral devices in a natural style has been becoming more common in gardening. In this connection there was a need for the introduction and study of the natural flora of plants in order to attract them to simulate the decorative and resistant plants. The article presents the results of studies of the effect of different light conditions on the habitat features and decorative biomorphological Hylotelephium triphyllum (Haw.) Holub (Crassulaceae DC.) when introduced in SE Donetsk Botanical Garden. This species is found naturally in the flora of Donbass, a decorative, but, according to the results of our analysis, is rarely used in green construction. Bioecological certification of this type has been done. It has been determined that the impact of site lighting conditions on the growth and development of H. triphyllum expressed in significantly smaller numbers of vegetative and generative shoots in the shaded areas. However, since the diameter of the plants does not change, more thickened planting in these areas is not recommended. The author found the dependence of the variation of the biometric data on the lighting conditions. In the study of seasonal dynamics of H. triphyllum the author revealed that the development of above-ground organs of his passes with a positive amount of average daily air temperatures. The growing season lasts an average of 225 days. Start of spring regrowth is observed in the second half of March early April, flowering in August September, fruits in September October. Vegetation stops when temperature goes below zero. Illumination of this type of habitat affect the time of vegetation beginning, budding, flowering, fruit set and fruit-bearing. On the shaded areas due to the later start of budding and flowering the most decorative period of H. triphyllum is shorter by an average of 10 days. This type is recommended for creation of group planting, stony hills, dry streams, rock gardens, rockeries, mixborders, curbs, ornamental compositions in the coastal zone of ornamental ponds and fountains in the steppe zone in areas with different light conditions, taking into account the above factors.

Process-based simulation of growth and overwintering of grassland using the BASGRA model

Process-based models (PBM) for simulation of weather dependent grass growth can assist farmers and plant breeders in addressing the challenges of climate change by simulating alternative roads of adaptation. They can also provide management decision support under current conditions. A drawback of existing grass models is that they do not take into account the effect of winter stresses, limiting their use for full-year simulations in areas where winter survival is a key factor for yield security. Here, we present a novel full-year PBM for grassland named BASGRA. It was developed by combining the LINGRA grassland model (Van Oijen et al., 2005a) with models for cold hardening and soil physical winter processes. We present the model and show how it was parameterized for timothy (Phleum pratense L.), the most important forage grass in Scandinavia and parts of North America and Asia. Uniquely, BASGRA simulates the processes taking place in the sward during the transition from summer to winter, including growth cessation and gradual cold hardening, and functions for simulating plant injury due to low temperatures, snow and ice affecting regrowth in spring. For the calibration, we used detailed data from five different locations in Norway, covering a wide range of agroclimatic regions, day lengths (latitudes from 59° to 70°N) and soil conditions. The total dataset included 11 variables, notably above-ground dry matter, leaf area index, tiller density, content of C reserves, and frost tolerance. All data were used in the calibration. When BASGRA was run with the maximum a-posteriori (MAP) parameter vector from the single, Bayesian calibration, nearly all measured variables were simulated to an overall normalized root mean squared error (NRMSE)<0.5. For many site×experiment combinations, NRMSE was <0.3. The temporal dynamics were captured well for most variables, as evaluated by comparing simulated time courses versus data for the individual sites. The results may suggest that BASGRA is a reasonably robust model, allowing for simulation of growth and several important underlying processes with acceptable accuracy for a range of agroclimatic conditions. However, the robustness of the model needs to be tested further using independent data from a wide range of growing conditions. Finally we show an example of application of the model, comparing overwintering risks in two climatically different sites, and discuss future model applications. Further development work should include improved simulation of the dynamics of C reserves, and validation of winter tiller dynamics against independent data.

Defoliation affects carbohydrate reserves, crown bud development, and spring re-growth in gentian ‘Velvet Glove’

Gentians are herbaceous perennials that utilize preformed crown buds as part of their perennating structure. We used leaf removal at different times in the season to assess the importance of accumulating carbohydrate reserves for plant survival during winter and subsequent re-growth in spring. Defoliation of gentian ‘Velvet Glove’ during the growth season significantly influenced the development of crown buds, winter survival, re-growth in spring, and carbohydrate reserves in crowns (mainly because of reduction in gentianose and sucrose concentrations). Carbohydrate reserves stored in the storage roots of crowns were likely to influence the development of crown buds, winter survival and re-growth. Given the absence of starch in gentians, the predominant carbohydrate reserve in crowns, gentianose, may play a similar role to that of starch in other plant species. From the time of emergence, at least 2884 GDD (base 0°C) retention of full leaf canopy on plants of ‘Velvet Glove’ was required for sufficient accumulation of carbohydrate reserves in crowns to result in similar winter survival and re-growth in spring, as with undefoliated control plants.